[Federal Register Volume 80, Number 55 (Monday, March 23, 2015)]
[Proposed Rules]
[Pages 15340-15474]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-06138]
[[Page 15339]]
Vol. 80
Monday,
No. 55
March 23, 2015
Part III
Environmental Protection Agency
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40 CFR Parts 50, 51, and 93
Fine Particulate Matter National Ambient Air Quality Standards: State
Implementation Plan Requirements; Proposed Rule
Federal Register / Vol. 80 , No. 55 / Monday, March 23, 2015 /
Proposed Rules`
[[Page 15340]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 50, 51, and 93
[EPA-HQ-OAR-2013-0691; FRL-9916-08-OAR]
RIN 2060-AQ48
Fine Particulate Matter National Ambient Air Quality Standards:
State Implementation Plan Requirements
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing
requirements that state, local and tribal air agencies would have to
meet as they implement the current and future national ambient air
quality standards (NAAQS) for fine particulate matter
(PM2.5). Specifically, this notice provides details on how
the EPA proposes that air agencies meet the statutory state
implementation plan (SIP) requirements that apply to areas designated
nonattainment for any PM2.5 NAAQS, such as: general
requirements for attainment plan due dates and attainment dates;
emissions inventories; attainment demonstrations; provisions for
demonstrating reasonable further progress; quantitative milestones;
contingency measures; and nonattainment New Source Review (NNSR)
permitting programs, among other things. This proposed rule clarifies
the specific attainment planning requirements that would apply to
PM2.5 NAAQS nonattainment areas based on their
classification (either Moderate or Serious), and the process for
reclassifying Moderate areas to Serious. Additionally in this notice,
the EPA is proposing to revoke the 1997 primary annual standard because
the EPA revised the primary annual standard in 2012. The EPA first
established the PM2.5 NAAQS in 1997, completed a review of
those standards in 2006, and most recently completed a review of the
PM2.5 NAAQS on December 14, 2012.
DATES: Comments. Comments must be received on or before May 22, 2015.
Public Hearing. The EPA plans to hold one public hearing concerning the
proposed rule in Washington, DC. The date, time and location will be
announced separately. Please refer to SUPPLEMENTARY INFORMATION for
additional information on the comment period and the public hearing.
Information Collection Request. Under the Paperwork Reduction Act
(PRA), comments on the information collection provisions are best
assured of having full effect if the Office of Management and Budget
(OMB) receives a copy of your comments on or before April 22, 2015.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2013-0691, by one of the following methods:
http://www.regulations.gov. Follow the on-line
instructions for submitting comments.
Email: a-and-r-docket@epa.gov.
Mail: Air and Radiation Docket and Information Center,
Attention Docket ID No. EPA-HQ-OAR-2013-0691, Environmental Protection
Agency, Mailcode: 28221T, 1200 Pennsylvania Avenue NW., Washington, DC
20460. In addition, please mail a copy of your comments on the
information collection (ICR) provisions to the Office of Information
and Regulatory Affairs, Office of Management and Budget (OMB), Attn:
Desk Officer for EPA, 725 17th Street NW., Washington, DC 20503.
Hand Delivery: Air and Radiation Docket and Information
Center, Attention Docket ID No. EPA-HQ-OAR-2013-0691, Environmental
Protection Agency in the EPA Headquarters Library, Room No. 3334 in the
EPA Docket Center, located at William Jefferson Clinton Building West,
1301 Constitution Avenue NW., Washington, DC 20004. Such deliveries are
only accepted during the Docket's normal hours of operation, and
special arrangements should be made for delivery of boxed information.
Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2013-0691. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at http://www.regulations.gov, including any personal
information provided, unless the comment includes information claimed
to be Confidential Business Information (CBI) or other information
whose disclosure is restricted by statute. Do not submit information
that you consider to be CBI or otherwise protected through http://www.regulations.gov or email. The http://www.regulations.gov Web site
is an ``anonymous access'' system, which means the EPA will not know
your identity or contact information unless you provide it in the body
of your comment. If you send an email comment directly to the EPA
without going through http://www.regulations.gov, your email address
will be automatically captured and included as part of the comment that
is placed in the public docket and made available on the Internet. If
you submit an electronic comment, the EPA recommends that you include
your name and other contact information in the body of your comment and
with any disk or CD-ROM you submit. If the EPA cannot read your comment
due to technical difficulties and cannot contact you for clarification,
the EPA may not be able to consider your comment. Electronic files
should avoid the use of special characters, any form of encryption and
be free of any defects or viruses. For additional information about the
EPA's public docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm. For additional instructions on
submitting comments, go to the SUPPLEMENTARY INFORMATION section of
this document.
Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Air and Radiation
Docket and Information Center in the EPA Headquarters Library, Room No.
3334 in the William Jefferson Clinton Building West, located at 1301
Constitution Avenue NW., Washington, DC 20460. The Public Reading Room
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The phone number for the Public Reading Room is (202)
566-1744.
FOR FURTHER INFORMATION CONTACT: For general information on this
proposed rule, contact Mr. Rich Damberg, Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency, by phone at (919)
541-5592 or by email at damberg.rich@epa.gov; or Ms. Megan Brachtl,
Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, by phone at (919) 541-2648 or by email at
brachtl.megan@epa.gov. For information on the public hearing, contact
Ms. Pamela Long, Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, by phone at (919) 541-0641 or by email
at long.pam@epa.gov. For information on the ICR, contact Mr. Butch
Stackhouse, Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, by phone at (919) 541-5208 or by email
at stackhouse.butch@epa.gov.
SUPPLEMENTARY INFORMATION:
[[Page 15341]]
I. General Information
A. Preamble Glossary of Terms and Acronyms
The following are abbreviations of terms used in the preamble.
AERR Air Emissions Reporting Rule
BACM Best Available Control Measures
BACT Best Available Control Technology
BART Best Available Retrofit Technology
BC Black Carbon
CAA Clean Air Act
CAIR Clean Air Interstate Rule
CAMx Comprehensive Air Quality Model with Extensions
CBI Confidential Business Information
CBSA Core-based Statistical Area
CDD Clean Data Determination
CFR Code of Federal Regulations
CMAQ Community Multi-Scale Air Quality Model
CSAPR Cross-State Air Pollution Rule
CSN Chemical Speciation Network
DOD Department of Defense
DOT Department of Transportation
EC Elemental Carbon
EGU Electric Generating Unit
EPA Environmental Protection Agency
Fe Iron
FEM Federal Equivalent Method
FIP Federal Implementation Plan
FRM Federal Reference Method
HCl Hydrogen Chloride
ICR Information Collection Request
LAER Lowest Achievable Emission Rate
MACT Maximum Achievable Control Technology
MATS Mercury and Air Toxics Standards
MSM Most Stringent Measures
MPO Metropolitan Planning Organization
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NAPAP National Acid Precipitation Assessment Program
NEI National Emissions Inventory
NESHAP National Emissions Standard for Hazardous Air Pollutants
NH3 Ammonia
NH4 Ammonium
NH4NO3 Ammonium Nitrate
NH4HSO4 Ammonium Bi-Sulfate
(NH4)2SO4 Ammonium Sulfate
NNSR Nonattainment New Source Review
NOX Nitrogen Oxides
NO3 Nitrate
NSPS New Source Performance Standards
O3 Ozone
OM Organic Mass
OMB Office of Management and Budget
PM Particulate Matter
PM2.5 Particulate Matter Equal to or Less than 2.5
Microns in Diameter (Fine Particulate Matter)
PM10 Particulate Matter Equal to or Less than 10 Microns
in Diameter
PRA Paperwork Reduction Act
PSD Prevention of Significant Deterioration
RACM Reasonably Available Control Measures
RACT Reasonably Available Control Technology
RFP Reasonable Further Progress
RICE Reciprocating Internal Combustion Engines
SIP State Implementation Plan
SOA Secondary Organic Aerosols
SO2 Sulfur Dioxide
SO4 Sulfate
TAR Tribal Authority Rule
TIP Tribal Implementation Plan
TIP Transportation Improvement Program
TSP Total Suspended Particles
[micro]m Micrometer (Micron)
VMT Vehicle Miles Traveled
VOC Volatile Organic Compounds
B. Does this action apply to me?
Entities potentially affected directly by this proposed rule
include state, local and tribal governments and air pollution control
agencies responsible for attainment and maintenance of the NAAQS.
Entities potentially affected indirectly by this proposed rule as
regulated sources include owners and operators of sources that emit
PM2.5, sulfur dioxide (SO2), oxides of nitrogen
(NOX), volatile organic compounds (VOC) and/or ammonia
(NH3). Others potentially affected indirectly by this
proposed rule include members of the general public who live, work, or
recreate in areas affected by elevated ambient PM2.5 levels
in areas designated nonattainment for a PM2.5 NAAQS.
C. What should I consider as I prepare my comments for the EPA?
1. Submitting CBI. Do not submit this information to the EPA
through http://www.regulations.gov or email. Clearly mark the specific
information that you claim to be CBI. For CBI in a disk or CD-ROM that
you mail to the EPA, mark the outside of the disk or CD-ROM as CBI and
then identify electronically within the disk or CD-ROM the specific
information that is claimed as CBI. In addition to one complete version
of the comment that includes information claimed as CBI, a copy of the
comment that does not contain the information claimed as CBI must be
submitted for inclusion in the public docket. Information so marked
will not be disclosed except in accordance with procedures set forth in
40 CFR part 2.
2. Tips for preparing comments. When submitting comments, remember
to:
Identify the rulemaking by docket number and other
identifying information (subject heading, Federal Register date and
page number).
Follow directions. The proposed rule may ask you to
respond to specific questions or organize comments by referencing a
Code of Federal Regulations (CFR) part or section number.
Explain why you agree or disagree, suggest alternatives
and substitute language for your requested changes.
Describe any assumptions and provide any technical
information and/or data that you used to support your comment.
If you estimate potential costs or burdens, explain how
you arrived at your estimate in sufficient detail to allow for it to be
reproduced.
Provide specific examples to illustrate your concerns
wherever possible, and suggest alternatives.
Explain your views as clearly as possible, avoiding the
use of profanity or personal threats.
Make sure to submit your comments by the comment period
deadline identified.
D. What information should I know about possible public hearings?
For information pertaining to the one public hearing on this
document, contact Ms. Pamela Long, Air Quality Policy Division, Office
of Air Quality Planning and Standards (C504-03), Environmental
Protection Agency, Research Triangle Park, North Carolina 27711;
telephone number (919) 541-0641; fax number (919) 541-5509; email
address: long.pam@epa.gov.
E. Where can I obtain a copy of this document and other related
information?
In addition to being available in the docket, an electronic copy of
this Federal Register document will be posted at http://www.epa.gov/airquality/particlepollution/actions.html.
F. How is this Federal Register document organized?
The information presented in this document is organized as follows:
I. General Information
A. Preamble Glossary of Terms and Acronyms
B. Does this action apply to me?
C. What should I consider as I prepare my comments for the EPA?
D. What information should I know about possible public
hearings?
E. Where can I obtain a copy of this document and other related
information?
F. How is this Federal Register document organized?
II. Background for Proposal
A. Introduction
B. Atmospheric Chemistry of PM2.5 and Its Precursors
C. Historical Overview of PM2.5 NAAQS Setting and
Implementation
D. State Implementation Planning Process for PM2.5
NAAQS
III. What is the EPA proposing with respect to the treatment of
PM2.5 precursors in nonattainment area planning and
permitting?
A. Background
B. Proposed Precursor Policy Options
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C. Technical Approaches for Demonstrating That a Precursor Does
Not Need To Be Subject to Control Requirements
IV. What are the EPA's proposed requirements for Moderate area
attainment plans?
A. Plan Due Dates
B. Emissions Inventory Requirements
C. Pollutants To Be Addressed in the Plan
D. Attainment Plan Control Strategy
E. Modeling for Attainment Demonstrations
F. RFP Requirements
G. Quantitative Milestones
H. Contingency Measures
I. Attainment Dates
J. Attainment Date Extensions
V. How would a PM2.5 Moderate nonattainment area be
reclassified to Serious?
A. Discretionary Authority
B. Mandatory Duty
VI. What are the EPA's proposed requirements for Serious area
attainment plans?
A. Plan Due Dates
B. Emissions Inventory Requirements
C. Pollutants To Be Addressed in the Plan
D. Attainment Plan Control Strategy
E. Modeling for Attainment Demonstrations
F. RFP Requirements
G. Quantitative Milestones
H. Contingency Measures
I. Attainment Dates
J. Attainment Date Extensions
VII. What are the EPA's proposed requirements for attainment plans
under CAA section 189(d) for Serious areas that fail to attain the
NAAQS by the applicable attainment date?
A. Plan Due Dates
B. Emissions Inventory Requirements
C. Pollutants To Be Addressed in the Plan
D. Attainment Plan Control Strategy
E. Modeling for Attainment Demonstrations
F. RFP Requirements
G. Quantitative Milestones
H. Contingency Measures
I. Attainment Dates
VIII. What are the EPA's proposed NNSR permitting requirements?
A. Statutory Requirements for NSR
B. Federal NNSR Regulations
C. What changes is the EPA proposing for NNSR for
PM2.5 nonattainment areas?
D. Plan Due Dates
E. Avoidance of Dual Review for PSD and NNSR for
PM2.5
IX. What other proposed requirements would apply in PM2.5
nonattainment areas?
A. Waivers Under Section 188(f)
B. Conformity Requirements
C. Clean Data Policy
D. Section 179B/International Border Areas
E. Enforcement and Compliance
F. Efforts To Encourage a Multi-Pollutant Approach When
Developing PM2.5 Attainment Plans
G. Measures to Ensure Appropriate Protections for Overburdened
Populations
H. Tribal Issues
I. Voluntary Programs for Reducing Ambient PM2.5
J. Improved Stationary Source Emissions Monitoring
K. Stationary Source Test Methods for Emissions of Condensable
PM2.5
X. What is the EPA proposing with respect to revoking the 1997
primary annual PM2.5 NAAQS?
A. Background
B. History of Revocation of Other NAAQS
C. Proposed Options for Revocation and Related Anti-Backsliding
Requirements for the 1997 Primary Annual PM2.5 NAAQS
D. Discussion of Options
XI. Environmental Justice Considerations
XII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 13563: Improving Regulation and Regulatory Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination with
Indian Tribal Governments
G. Executive Order 13045: Protection of Children from
Environmental Health and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
K. Determination Under Section 307(d)
Statutory Authority
List of Subjects
II. Background for Proposal
A. Introduction
Ambient, or outdoor, air can contain a variety of pollutants,
including particulate matter (PM). Airborne PM can be comprised of
either solid or liquid particles, and can be a complex mixture of
particles in both solid and liquid form. The most common constituents
of airborne PM include: sulfate (SO4); nitrate
(NO3); ammonium (NH4); elemental carbon (EC);
organic mass (OM); and inorganic material, generally referred to as
``crustal'' material, which can include metals, dust, sea salt and
other trace elements. Airborne PM can be of different sizes, commonly
referred to as ``coarse'' and ``fine'' particles. Fine particles, in
general terms, are particulate matter with an aerodynamic diameter less
than or equal to a nominal 2.5 micrometers ([mu]m). For this reason,
particles of this size are referred to as PM2.5.
PM2.5 particles commonly include ``primary'' particles and
``secondary'' particles. Primary particles, or direct PM2.5,
are emitted by sources directly into the air as solid or liquid
particles (e.g., elemental carbon from diesel engines or wildfires, or
condensable organic particles from gasoline engines). Secondary
particles are formed in the atmosphere as a result of chemical
reactions between specific pollutants known as PM2.5
precursors (e.g., reactions between NOX and SO2
emissions from mobile and stationary sources combined with ammonia to
form NO3 and SO4).
The human health effects associated with long- or short-term
exposure to PM2.5 are significant and include premature
mortality, aggravation of respiratory and cardiovascular disease (as
indicated by increased hospital admissions and emergency room visits)
and development of chronic respiratory disease. In addition, welfare
effects associated with elevated PM2.5 levels include
visibility impairment as well as effects on sensitive ecosystems,
materials damage and soiling and climatic and radiative processes.\1\
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\1\ For a complete discussion of the human health and welfare
effects associated with exposure to elevated concentrations of
particulate matter, see generally ``Integrated Science Assessment
for Particulate Matter.'' U.S. Environmental Protection Agency,
Office of Research and Development, National Center for
Environmental Assessment-RTP Division, February 10, 2010. EPA/600/R-
08/139F. Available at: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_2007_isa.html. See Chapter 2.
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On December 14, 2012, the EPA made revisions to the suite of NAAQS
for PM to provide requisite protection of public health and welfare
with an adequate margin of safety. The EPA also made corresponding
revisions to the data handling conventions for PM and the ambient air
monitoring, reporting and network design requirements for PM.
Specifically, the agency revised the primary annual PM2.5
standard by lowering the level from 15.0 to 12.0 [mu]g/m\3\ to provide
increased protection against health effects associated with long- and
short-term PM2.5 exposures. The EPA did not revise the
secondary annual PM2.5 standard which remains at 15.0 [mu]g/
m\3\.\2\ The EPA eliminated spatial averaging as part of the form of
the PM2.5 annual standards to avoid potential
disproportionate impacts on at-risk populations. In addition, the EPA
retained the level and form of the primary and secondary 24-hour
PM2.5 standards to continue to provide supplemental
protection against health effects associated with short-term
PM2.5 exposures. Although not directly relevant to this
rulemaking with respect to the PM2.5 NAAQS, it should be
noted that in December 2012, the EPA also did not revise the level or
form of the
[[Page 15343]]
primary and secondary 24-hour PM10 standards, which remain
at 150 [mu]g/m\3\.\3\
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\2\ 78 FR 3086 (January 15, 2013).
\3\ This proposed rulemaking is to develop implementation
regulations with respect to the PM2.5 NAAQS. For the
PM10 NAAQS, states and the EPA will continue to implement
those NAAQS in accordance with the applicable statutory requirements
of the Clean Air Act (CAA) and the EPA's existing guidance in the
``The General Preamble for Implementation of Title I of the Clean
Air Act (CAA) Amendments,'' 57 FR 13498 (April 16, 1992); and
``State Implementation Plans for Serious PM-10 Nonattainment Areas:
Addendum to the General Preamble for the Implementation of Title I
of the Clean Air Act (CAA) Amendments,'' 59 FR 41998 (August 16,
1994). Throughout this preamble, these documents will be referred to
as the ``General Preamble'' and the ``Addendum,'' respectively.
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Estimates show that attainment of the primary PM2.5
standards will result in hundreds fewer premature deaths each year,
prevent tens of thousands of hospital admissions each year and prevent
hundreds of thousands of doctor visits, absences from work and school
and respiratory illnesses in children annually.\4\ Attainment of the
primary PM2.5 standards will have welfare co-benefits in
addition to direct human health benefits. The term welfare co-benefits
covers both environmental and societal benefits of reducing pollution,
such as reductions in visibility impairment, materials damage and
ecosystem damage.\5\
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\4\ ``Regulatory Impact Analysis for the Final Revisions to the
National Ambient Air Quality Standards for Particulate Matter.''
U.S. Environmental Protection Agency, Office of Air Quality and
Planning Standards, Health and Environmental Impacts Division,
February 28, 2013. EPA-452/R-12-005. See: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_2007_ria.html.
\5\ Ibid.
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B. Atmospheric Chemistry of PM2.5 and Its Precursors
1. Overview
In order to determine how to regulate sources of direct
PM2.5 and PM2.5 precursors to attain the
PM2.5 NAAQS in a given nonattainment area, it is necessary
to understand the basic chemical processes that cause or contribute to
the formation of ambient PM2.5. Accordingly, an
understanding of these processes is necessary to design appropriate
regulations for implementation of the PM2.5 NAAQS. Properly
designed regulatory requirements will help to assure that the
PM2.5 NAAQS are attained effectively and expeditiously in
all areas.
As noted earlier, the term PM2.5 refers to particles of
solid and liquid material less than 2.5 microns in aerodynamic
diameter.\6\ ``Primary'' PM2.5 is emitted directly from
emissions sources or activities, such as from diesel fuel combustion,
wood burning, construction activities or unpaved roads, and it includes
both filterable and condensable particles.\7\ ``Secondary''
PM2.5 is formed as a result of emissions of certain
precursor gases that undergo chemical reactions in the atmosphere. The
principal precursor gases that contribute to secondary PM2.5
formation are SO2, from the combustion of coal or other high
sulfur fuels; NOX, from many types of fossil fuel
combustion; VOC, from certain fuels, solvents and industrial processes;
and ammonia, from sources such as animal feeding operations, wastewater
treatment and fertilizer. Table 1 provides National Emissions Inventory
(NEI) data for 2011 that represent nationwide anthropogenic emissions
estimates for direct PM2.5 and the four main
PM2.5 precursor gases from major source sectors.
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\6\ The regulatory definition of PM2.5 includes
particles with an upper 50 percent cut-point of 2.5[mu]m aerodynamic
diameter (the 50 percent cut-point diameter is the diameter at which
the sample collects 50 percent of the particles and rejects 50
percent of the particles). PM2.5 particles have a
penetration curve as measured by a reference method based on
Appendix L of 40 CFR part 50 and designated in accordance with 40
CFR part 53, by an equivalent method designed in accordance with 40
CFR part 53, or by an approved regional method designated in
accordance with Appendix C of 40 CFR part 58.
\7\ Certain commercial or industrial activities involving high
temperature processes (e.g., fuel combustion, metal processing,
cooking operations) emit gaseous pollutants into the ambient air
which rapidly condense into particle form. These ``condensable'' PM
emissions exist almost entirely in the 2.5 or less micron range and
can consist of organic material, sulfuric acid and metals.
Table 1--Total Emissions of PM2.5 and Precursors for Major Sectors (in tons/year)
[Source: 2011 National Emissions Inventory (Version 1) \a\]
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Category Direct PM2.5 SO2 NOX VOC NH3
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Chemical and allied products.... 16,464 125,768 49,867 79,236 23,044
Fuel combustion--electric 196,685 4,612,641 2,031,855 40,597 24,968
generating utilities (EGUs)....
Fuel combustion --other......... 628,199 987,552 1,856,716 588,346 79,679
Other industrial................ 273,857 185,859 348,561 328,222 53,039
Onroad mobile................... 208,629 28,969 5,785,570 2,413,026 119,654
Metals processing............... 48,451 144,630 70,655 34,277 1,140
Miscellaneous (mainly fire 4,489,694 219,318 434,547 5,810,566 3,934,405
emissions, dust and some
agricultural operations).......
Offroad mobile.................. 207,543 92,036 3,133,798 2,159,368 3,270
Petroleum & related industries.. 31,738 116,317 684,808 2,488,123 1,643
Solvent utilization............. 3,810 107 893 2,814,551 577
Storage and transport........... 20,098 9,109 19,079 1,221,185 5,734
Waste disposal and recycling.... 172,144 16,842 83,469 131,777 68,281
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\a\ For more details on the definitions of the emission categories listed in Table 1, see Sector/Tier crosswalk
table for the 2011 NEI, available at: ftp://ftp.epa.gov/EmisInventory/2011/doc/scc_eis_crosswalk_2011neiv1.xlsx.
2. Composition and Sources of PM2.5 Constituents
PM2.5 is a complex and highly variable mixture of
particles, but the majority of PM2.5 by mass is often
comprised of five constituents: (i) OM; (ii) EC; (iii) crustal
material; (iv) ammonium sulfate
((NH4)2SO4); and (v) ammonium nitrate
(NH4NO3).\8\ The discussion that follows provides
an overview of each of the five major components of PM2.5,
all of which are known to contribute to ambient PM2.5 levels
in areas throughout the U.S.\9\ Section II.B.3 provides more details on
[[Page 15344]]
the atmospheric chemistry involved in the formation of sulfate, nitrate
and OM, to illustrate the importance of controlling emissions of
PM2.5 precursors as part of any comprehensive strategy to
reduce ambient PM2.5 levels in excess of the NAAQS. Section
II.B.4 presents a brief overview of PM2.5 composition by
region of the U.S.
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\8\ Seinfeld J.H. and Pandis S.N., 2006. Atmospheric Chemistry
and Physics: From Air Pollution to Climate Change. 2nd edition, J.
Wiley, New York.
\9\ U.S. Environmental Protection Agency, 2004. ``The Particle
Pollution Report: Current Understanding of Air Quality and Emissions
through 2003.'' Office of Air Quality Planning and Standards,
Emissions, Monitoring, and Analysis Division, December 2004.
Available at: http://www.epa.gov/airtrends/reports.html.
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OM is the fraction of ambient PM2.5 with the most
diverse chemical composition, containing potentially thousands of
different organic compounds (i.e., those compounds containing carbon)
composed primarily of carbon, hydrogen, oxygen and nitrogen. Both
primary particles and secondary particles contribute to ambient OM
concentrations, with combustion sources being the dominant type of
emissions sources. Another portion of primary OM particles results from
direct emissions of organic compounds from sources of incomplete
combustion, such as gas and diesel engines. Secondary OM particle
formation involves oxidation of both anthropogenic and biogenic (plant-
derived) VOC, and can involve other, more complex chemical reactions.
Further details of the chemistry behind the formation of secondary OM,
known more commonly as secondary organic aerosols (SOA), are described
in Section II.B.3 of this preamble.
EC refers to particulate carbon that has a graphitic molecular
structure, and is sometimes referred to as ``black carbon'' (BC). It is
emitted directly from emission sources and does not undergo any
significant reactions with other gases in the atmosphere. EC particles
result from primary emissions involving combustion, especially from
diesel-fueled vehicles, but also from other processes involving the
burning of fossil fuels. The latter includes anthropogenic sources such
as boilers and waste disposal. In addition, some EC particles originate
from biomass combustion such as from prescribed fires, wildfires and
residential wood combustion.
Crustal PM is comprised of particles of soil and oxides of metals
from some industrial processes. Compounds comprised of elements such as
silicon, aluminum, iron, calcium, titanium, magnesium and potassium, as
well as oxygen, are major components.\10\ Sources of crustal
PM2.5 include windblown dust, dust from mechanical
resuspension (e.g. dust from construction activities or vehicles
driving on unpaved roads) and some forms of combustion, especially of
coal. Crustal PM2.5 comprised of elements, like iron (Fe),
and their oxides can also be emitted from industrial sources.
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\10\ Appel, K.W., Pouliot, G.A., Simon, H., Sarwar, G., Pye,
H.O.T., Napelenok, S.L., Akhtar, F., and Roselle, S.J., 2013.
Evaluation of dust and trace metal estimates from the Community
Multiscale Air Quality (CMAQ) model version 5.0, Geoscientific Model
Development Discussions 61859-1899; Sorooshian, A., Shingler, T.,
Harpold, A., Feagles, C.W., Meixner, T., and Brooks, P.D., 2013.
Aerosol and precipitation chemistry in the southwestern United
States: spatiotemporal trends and interrelationships, Atmospheric
Chemistry and Physics 13, 7361-7379.
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The remaining portion of ambient PM2.5 is mostly
composed of SO4, NO3 and NH4, which
react in the ambient air to form ammonium sulfate
((NH4)2SO4) and ammonium nitrate
(NH4NO3). Another common PM2.5
particle is ammonium bi-sulfate (NH4HSO4). In
some areas, less common ions such as chloride are also found in
PM2.5 samples in the form of particles that include sodium
chloride and ammonium chloride. Particle-bound water is often also
associated with this fraction of PM2.5. Sulfate, nitrate and
ammonium particles originate through both primary and secondary
mechanisms, although the vast majority of these PM2.5
particles are formed through secondary formation, as described in the
following section.
3. Secondary Formation of PM2.5 From Gaseous Precursors
a. Overview. The composition of PM2.5 is complex and
highly variable due in part to the large contribution of secondary
PM2.5 to total fine particle mass in most locations, and to
the complexity of secondary particle formation processes. A large
number of possible chemical reactions, often non-linear in nature, can
convert the gases SO2, NOX, VOC and ammonia to
PM2.5. Thus, these gases are precursors to PM2.5.
A brief discussion of SO4, NO3 and SOA formation,
as well as the role of ammonia in their formation, follows.
b. SO4 formation. SO2 is emitted mostly from the
combustion of fossil fuels in boilers operated by electric utilities
and other industries, with less than 10 percent of SO2
emissions nationwide coming from other industrial sources, such as oil
refining and pulp and paper production.\11\ When SO2
oxidizes it forms sulfuric acid, a highly corrosive compound toxic to
humans and to ecosystems that contributes to acid deposition (acid
rain). In the presence of ammonia, however, sulfuric acid will react to
form (NH4)2SO4, a less acidic compound
and one of the five major components of PM2.5. If there is
not enough ammonia present to fully neutralize the sulfuric acid, part
of it may convert to NH4HSO4, which is more
acidic than (NH4)2SO4, but less so
than sulfuric acid. There is a large amount of emerging scientific
evidence that SO2 may also contribute to the formation of
SOA from biogenic VOC emissions (see section later on SOA). Sulfate
levels in the ambient air peak in summer months due to increased
SO2 emissions, generally from electricity generating units,
and from meteorological conditions that are conducive to sulfate
formation.
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\11\ U.S. Environmental Protection Agency, 2013. ``2008 National
Emissions Inventory: Review Analysis and Highlights.'' Office of Air
Quality Planning and Standards, Air Quality Assessment Division, May
2013. EPA-454/R-005. Available at: http://www.epa.gov/ttn/chief/net/2008report.pdf.
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c. NO3 formation. The main sources of NOX emissions are
combustion of fossil fuel in boilers and mobile sources, accounting for
more than 80 percent of national anthropogenic NOX emissions
(based on the 2011 NEI), with boilers and electric generating units
(EGUs) contributing about 27 percent and mobile sources contributing 56
percent. Oxides of nitrogen react in the atmosphere to form nitric
acid, another prime contributor to acid deposition in the environment.
Nitric acid converts to ammonium nitrate, one of the five main
components of PM2.5, in the presence of ammonia. Low
temperatures and high relative humidity create ideal conditions for the
formation of ammonium nitrate, typically leading to higher atmospheric
levels in winter months and lower levels in summer months.\12\
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\12\ Carlton, A.G., Pinder, R.W., Bhave, P.B., Pouliout, G.A.,
2010. To What Extent Can Biogenic SOA Be Controlled, Environmental
Science and Technology 44(9), 3376-80.
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d. SOA formation. As discussed earlier, the OM component of ambient
PM2.5 is a complex mixture of hundreds or even thousands of
anthropogenic and biogenic organic compounds. These compounds are
either emitted directly from sources (i.e., as ``primary''
PM2.5) or can be formed by reactions in the ambient air to
make SOA (i.e., as ``secondary'' PM2.5).
VOC (both anthropogenic and biogenic) are key precursors to the SOA
component of PM2.5. The relative importance of these
compounds in the formation of organic particles varies between
geographic areas, depending upon local emission sources, atmospheric
chemistry and season of the year. It should be further noted that not
all inventoried VOC may be contributing to the formation of organic
particles. For example, chemical reactions involving VOC are generally
accelerated in warmer temperatures, and for this reason studies show
that SOA typically comprises a higher
[[Page 15345]]
percentage of PM2.5 in the summer than in the winter.\13\
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\13\ Pandis S.N., Harley R.A., Cass G.R., and Seinfeld J.H.,
1992. Secondary Organic Aerosol Formation and Transport, Atmospheric
Environment, 26, 2266-82.
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Anthropogenic sources of VOC include mobile sources, petrochemical
manufacturing, oil and gas emissions and solvents.\14\ In addition,
some biogenic VOC, emitted by vegetation such as trees, can also
contribute significantly to SOA formation, especially in heavily
forested areas, such as the southeastern U.S. It should be noted,
however, that anthropogenic contributions to SOA are likely highest in
the wintertime when biogenic SOA levels are lower; conversely, in the
summertime, biogenic contributions to SOA are likely higher. Despite
significant progress that has been made in understanding the origins
and properties of SOA, it remains the least understood component of
PM2.5 and continues to be a significant topic of research
and investigation.
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\14\ Carlton, A.G., Bhave, P.B., Napelenok, S.L., Edney, E.O.,
Sarwar, G., Pinder, R.W., Pouliout, G.A., and Houyoux, M. (2010),
Model Representation of Secondary Organic Aerosol in CMAQ4.7,
Environmental Science and Technology 44(22), 8553-60.
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e. Role of ammonia in sulfate, nitrate and SOA formation. Ammonia
is a gaseous pollutant emitted by natural and anthropogenic sources.
The EPA's 2011 NEI shows that the two main sources of ammonia emissions
are fertilizer application (27 percent) and livestock raising (54
percent). It should be noted that the 2011 NEI indicates that mobile
sources in the aggregate contribute about 3 percent of nationwide
ammonia emissions. Much of those emissions comes from catalytic
converters installed on light-duty gasoline vehicles, which are
designed to convert NOX to nitrogen (N2);
however, some ammonia is formed as a secondary product during this
process.
As indicated earlier, ammonia plays an important role in
neutralizing acids, such as sulfuric acid and nitric acid, in clouds,
precipitation and particles. On the other hand, deposited ammonia can
contribute to problems of eutrophication in water bodies due to its
nutritive properties.\15\ Ammonia would not exist in particles if not
for the presence of acidic species with which it can combine to form a
particle. In the eastern U.S., sulfate, nitrate and the ammonium
associated with them can together account for between roughly 30
percent and 75 percent of the total PM2.5 mass in a given
area. The ammonium portion by itself roughly accounts for between 5
percent and 20 percent of the total PM2.5 mass in the
East.\16\
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\15\ Seinfeld, J.H. and Pandis, S.N. (1998), Atmospheric
Chemistry and Physics: From Air Pollution to Climate Change, 1st
edition, J. Wiley, New York.
\16\ NARSTO, 2003. Particulate Matter Science for Policy Makers.
A NARSTO Assessment. Parts 1 and 2. NARSTO. Management Office
(Envair), Pasco, Washington. Available at: http://narsto.org/pm_science_assessment.
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f. Role of NOX in sulfate, nitrate and SOA formation. In addition
to the contribution of NOX emissions to secondary
particulate nitrate formation, NOX also reacts with
anthropogenic and biogenic VOC that have an impact on secondary
formation of organic compounds that make up SOA. NOX is thus
involved in all secondary PM chemistry, not just in particulate nitrate
formation.\17\
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\17\ Carlton, A.G., Pinder, R.W., Bhave, P.B., and Pouliout,
G.A., 2010. To what extent can Biogenic SOA be Controlled,
Environmental Science and Technology 44(9), 3376-3380.
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4. Fine Particulate Composition By Location
Table 2 shows regional 3-year mean concentrations (2009-2011) of
PM2.5 and its main components at sites in the Chemical
Speciation Network (CSN).\18\ In addition to the mean values for all
sites in each region, the table includes the minimum and maximum
observed PM2.5 and species concentrations for sites within
each region. These data illustrate broad observed spatial patterns
across the U.S. in PM2.5 concentrations and its composition.
For example, PM2.5 concentrations are highest on average in
the Central and West regions. Sulfate mass comprises a larger fraction
of PM2.5 than nitrate mass in the northeastern U.S., whereas
nitrate has a greater contribution than that of sulfate in the West. OM
is the dominant component in all regions, with the highest
concentrations of OM on average found in the West, Northwest and
Southeast. On a percentage basis, the concentrations of EC and crustal
material are relatively low throughout all regions of the U.S. compared
to the other major PM2.5 components.
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\18\ The organic matter (OM) values in Table 2 were calculated
by multiplying the measured organic carbon (OC) concentrations by
1.6 (Turpin and Lim (2001), Aerosol Science and Technology, 35, 602-
610). PM2.5 concentrations come from measurements of the
Federal Reference/Equivalance Methods (FRM/FEM) rather than from the
CSN PM2.5 measurement.
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The composition of PM2.5 also varies between urban and
rural areas. This is reflective of the distribution of urban and
regional emission sources, atmospheric reactions and transport of fine
particles. More details about the spatial distribution and origins of
PM2.5 components can be found in the docket for this
proposal.\19\
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\19\ Reff and Rao, Memo to the docket, 2013.
Table 2--PM2.5 Chemical Composition Data at 2009-2011 Nonattainment Sites
[Source: EPA Speciation Trends Network]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Concentration ([mu]g/m\3\)
Region Statistic -----------------------------------------------------------------------
SOe NO3 OM EC CrM PM2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Central....................................... Min ([mu]g/m\3\)................ 1.46 0.3 2.73 0.31 0.01 8.92
Mean ([mu]g/m\3\)............... 2.69 1.49 3.57 0.68 0.26 11.63
Max ([mu]g/m\3\)................ 4.19 3.34 4.81 1.1 1.0 13.51
N............................... 61 61 50 50 61 42
East North Central............................ Min ([mu]g/m\3\)................ 0.83 0.38 1.97 0.19 0.01 6.03
Mean ([mu]g/m\3\)............... 1.68 1.8 2.84 0.48 0.19 9.86
Max ([mu]g/m\3\)................ 2.51 3.57 3.69 0.79 0.61 11.87
N............................... 29 28 20 20 28 23
North East.................................... Min ([mu]g/m\3\)................ 0.58 0.12 1.74 0.14 0 4.42
Mean ([mu]g/m\3\)............... 2.06 0.97 3.14 0.69 0.17 9.33
Max ([mu]g/m\3\)................ 5.12 2.26 5.05 1.69 0.52 15.05
N............................... 59 59 39 39 59 46
North West.................................... Min ([mu]g/m\3\)................ 0.24 0.05 2.91 0.42 0.01 6.06
Mean ([mu]g/m\3\)............... 0.54 0.4 5.02 0.81 0.15 8.33
[[Page 15346]]
Max ([mu]g/m\3\)................ 1.09 1.79 8.44 1.25 0.53 10.96
N............................... 33 33 13 13 33 14
South......................................... Min ([mu]g/m\3\)................ 0.88 0.18 1.36 0.12 0.02 5.22
Mean ([mu]g/m\3\)............... 2.06 0.8 3.32 0.57 0.5 10.05
Max ([mu]g/m\3\)................ 3.08 1.67 5.1 1.48 2.38 14.27
N............................... 36 27 23 23 36 23
South East.................................... Min ([mu]g/m\3\)................ 1.6 0.2 1.75 0.37 0.01 6.76
Mean ([mu]g/m\3\)............... 2.39 0.53 4.12 0.63 0.26 10.77
Max ([mu]g/m\3\)................ 4.33 1.51 5.71 1.2 0.85 13.38
N............................... 44 43 30 30 43 29
South West.................................... Min ([mu]g/m\3\)................ 0.34 0.07 2.34 0.46 0.02 5.3
Mean ([mu]g/m\3\)............... 0.63 0.49 3.01 0.7 0.5 7.93
Max ([mu]g/m\3\)................ 1.13 2.65 4.39 1.04 1.96 9.73
N............................... 46 46 11 11 46 12
West.......................................... Min ([mu]g/m\3\)................ 0.33 0.08 1.79 0.52 0.01 6.84
Mean ([mu]g/m\3\)............... 0.9 1.4 5.22 0.85 0.32 11.49
Max ([mu]g/m\3\)................ 2.08 5.14 10.27 1.56 1.05 16.57
N............................... 44 44 20 20 44 21
West North Central............................ Min ([mu]g/m\3\)................ 0.29 0.06 1.22 0.09 0 3.23
Mean ([mu]g/m\3\)............... 0.67 0.48 3.16 0.44 0.22 7.25
Max ([mu]g/m\3\)................ 1.79 2.02 8.28 1.21 0.53 13.72
N............................... 30 30 7 7 30 10
--------------------------------------------------------------------------------------------------------------------------------------------------------
C. Historical Overview of PM2.5 NAAQS Setting and
Implementation
Sections 108 and 109 of the CAA govern the establishment, review
and revision, as appropriate, of NAAQS for widespread pollutants
emitted from numerous and diverse sources considered harmful to public
health and the environment. The CAA requires two types of NAAQS: (i)
Primary standards, which set limits to protect public health, including
the health of at-risk populations; and (ii) secondary standards, which
set limits to protect public welfare, including protection against
visibility impairment, damage to animals, crops, vegetation and
buildings.
The EPA first promulgated annual and 24-hour NAAQS for
PM2.5 in July 1997.\20\ Prior to that time, the EPA had
addressed ambient particulate matter through other means, first by
regulating ``total suspended particles'' (TSP) and then later by
regulating PM10. After protracted litigation, the 1997 NAAQS
for PM2.5 were upheld by the U.S. Court of Appeals for the
District of Columbia Circuit in March 2002.\21\ The EPA subsequently
promulgated designations for the 1997 PM2.5 NAAQS
nationwide, and designated a number of areas as nonattainment for the
1997 PM2.5 NAAQS, effective April 2005.\22\ In April 2007,
the EPA issued a detailed implementation rule to assist states with the
development of SIP submissions to meet attainment plan requirements for
the 1997 NAAQS (the ``2007 PM2.5 Implementation Rule'').\23\
In May 2008, the EPA issued another rule to assist states with SIP
submissions to meet the specific requirements for permitting programs
for NNSR purposes in designated nonattainment areas (the ``2008
PM2.5 NSR Rule'').\24\ The EPA premised both the 2007
PM2.5 Implementation Rule and the 2008 PM2.5 NSR
Rule on the EPA's interpretation of the statute that nonattainment
areas for the PM2.5 NAAQS were subject solely to the general
nonattainment plan requirements of subpart 1, part D of title I of the
CAA (``subpart 1'').
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\20\ 62 FR 38652 (July 18, 1997).
\21\ For a complete summary of legal challenges and related
court decisions on the PM NAAQS, see generally 78 FR 3086 (January
15, 2013).
\22\ 70 FR 944 (January 5, 2005).
\23\ 72 FR 20583 (April 25, 2007).
\24\ 73 FR 28231 (May 16, 2008).
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Section 109(d)(1) of the CAA requires the EPA periodically to
review the science upon which the standards are based and the standards
themselves, and to revise the standards as may be appropriate. In
October 2006, the EPA promulgated revisions to the suite of NAAQS for
PM, and in particular the EPA revised the 24-hour PM2.5
standards.\25\ In accordance with section 107(d), the EPA subsequently
designated a number of areas as nonattainment for the revised 2006 24-
hour PM2.5 standards, effective December 2009.\26\ In March
2012, the EPA issued a guidance document specifically to aid states in
preparing their SIP submissions to meet attainment plan requirements
for the 2006 24-hour PM2.5 NAAQS in designated nonattainment
areas.\27\ The EPA's guidance for the 2006 PM2.5 NAAQS was
based, in large part, on the requirements finalized in the 2007
PM2.5 Implementation Rule, which the EPA based solely upon
the statutory requirements of subpart 1.
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\25\ 71 FR 61144 (October 17, 2006).
\26\ 74 FR 58688 (November 13, 2009).
\27\ Memorandum of March 2, 2012 (withdrawn June 6, 2013), from
Stephen D. Page, Director, Office of Air Quality Planning and
Standards, to EPA Regional Air Directors, Regions I-X,
``Implementation Guidance for the 2006 24-Hour Fine Particle
(PM2.5) National Ambient Air Quality Standards (NAAQS).''
Available at: http://epa.gov/ttn/naaqs/pm/pm25_guide.html.
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The EPA initiated a review of the PM2.5 NAAQS in June
2007, proposing revisions to the primary and secondary PM2.5
NAAQS on June 29, 2012.\28\ The EPA issued its final rule on December
14, 2012, in which it lowered the primary annual PM2.5
standard from 15.0 [mu]g/m\3\ to 12.0 [mu]g/m\3\ to provide increased
protection against health effects associated with long- and short-term
fine particle exposures.\29\ The EPA also eliminated spatial averaging
as part of the form of the annual standard to avoid potential
disproportionate impacts on at-risk populations.\30\ The
[[Page 15347]]
EPA retained the level (35 [mu]g/m\3\) and form (98th percentile,
averaged over 3 years) of the primary 24-hour PM2.5
standard, as revised in 2006, to provide supplemental protection
against health effects associated with short-term PM2.5
exposures, especially in areas with high peak PM2.5
concentrations.\31\ This suite of primary PM2.5 standards
provides increased public health protection, including the health of
at-risk populations which include children, older adults, persons with
pre-existing health and lung disease and persons of lower socioeconomic
status, against a broad range of PM2.5-related effects that
include premature mortality, increased hospital admissions and
emergency department visits and development of chronic respiratory
disease.\32\ With regard to the secondary (welfare-based) standards,
the EPA retained the existing annual PM2.5 standard of 15.0
[mu]g/m\3\ and the existing 24-hour PM2.5 standard of 35
[mu]g/m\3\ to protect against PM-related non-visibility welfare effects
including ecological effects, effects on materials and climate impacts.
In addition, the secondary 24-hour PM2.5 standard provides
protection for PM-related visibility impairment.
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\28\ 77 FR 38890 (June 29, 2012).
\29\ 78 FR 3086 (January 15, 2013).
\30\ Spatial averaging of monitored ambient air quality data was
a feature of the prior PM2.5 NAAQS monitoring regulations
which had the potential for masking particularly high
PM2.5 concentrations at certain monitored locations
within nonattainment areas.
\31\ 71 FR 61144 (October 17, 2006).
\32\ General information regarding the health effects associated
with PM2.5 exposures is available at: http://www.epa.gov/airquality/particlepollution/health.html. Additional information,
such as the EPA's technical documents supporting the latest review
of the standards, is available at: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_index.html.
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On January 4, 2013, shortly after the EPA promulgated the 2012
revisions to the suite of PM NAAQS, the DC Circuit issued its decision
in a challenge to the 2007 PM2.5 Implementation Rule and the
2008 PM2.5 NSR Rule. In NRDC v. EPA, the court held that the
EPA erred in implementing the 1997 PM2.5 NAAQS pursuant only
to the general implementation requirements of subpart 1, rather than
also to the implementation requirements specific to particulate matter
(PM10) in subpart 4, part D of title I of the CAA (``subpart
4'').\33\ The court reasoned that the plain meaning of the CAA requires
implementation of the 1997 PM2.5 NAAQS under subpart 4
because PM2.5 particles fall within the statutory definition
of PM10 and are thus subject to the same statutory
requirements. In addition, although the court stated that its decision
that the EPA must implement the PM2.5 NAAQS pursuant to
subpart 4 requirements meant that it did not have to reach decisions on
other issues concerning the regulation of precursors to
PM2.5, the court nonetheless noted that subpart 4 has
specific requirements with respect to regulation of such precursors. As
a result, the court remanded to the EPA both the 2007 PM2.5
Implementation Rule and the 2008 PM2.5 NSR Rule, both of
which were premised on the EPA's interpretation of the statute that
subpart 1 was the only applicable subpart for the implementation of the
1997 PM2.5 NAAQS. The court instructed the EPA ``to
repromulgate these rules pursuant to Subpart 4 consistent with this
opinion.'' Given the D.C. Circuit's opinion in NRDC v. EPA, the EPA
withdrew its 2012 guidance document for the 2006 24-hour
PM2.5 NAAQS in June 2013. Because the court had concluded
that the EPA and states must implement the PM2.5 NAAQS
consistent with the statutory requirements of subpart 4, the EPA 2012
guidance for attainment plans for the 2006 PM2.5 NAAQS
premised solely upon subpart 1 requirements was no longer appropriate.
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\33\ NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 2013).
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The EPA intends to use this current rulemaking to accomplish
multiple objectives. First, the EPA is taking this action to clarify
how air agencies should meet the statutory SIP requirements that apply
to areas designated nonattainment for any PM2.5 NAAQS under
subparts 1 and 4. To this end, the EPA is proposing regulatory
requirements that will be applicable to attainment plans for the 2012
PM2.5 NAAQS and any future revisions of the PM2.5
NAAQS, subject to revisions that may be necessary for implementation
purposes in the future. Second, the EPA is taking this action to
provide guidance, in addition to regulatory requirements, to assist air
agencies in developing attainment plans for the 2012 PM2.5
NAAQS and any future revisions of the PM2.5 NAAQS. Finally,
the EPA is taking this action in response to the DC Circuit's remand of
the 2007 PM2.5 Implementation Rule and the 2008
PM2.5 NSR Rule. Through this rulemaking, the EPA intends to
address requirements associated with states' ongoing implementation
efforts for the 1997 and 2006 PM2.5 NAAQS. In the interim,
the EPA will rely on the statutory attainment planning requirements
\34\ contained in subparts 1 and 4 and on the EPA's General Preamble
and Addendum for guidance on how to apply those requirements to current
PM2.5 NAAQS nonattainment areas.
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\34\ General Preamble, 57 FR 13498 (April 16, 1992).
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D. State Implementation Planning Process for PM2.5 NAAQS
1. Overview
The CAA establishes important roles both for state and tribal
governments and for the EPA in implementing the NAAQS. In accordance
with the principle of cooperative federalism, both state and tribal
governments and the EPA have respective authorities and
responsibilities under the CAA. At the outset, the EPA has the
authority and responsibility to promulgate the NAAQS. In turn, state,
local and tribal air agencies have the authority and primary
responsibility for developing and implementing attainment plans that
contain emission control measures needed to achieve the air quality
standards in each nonattainment area, consistent with the requirements
of the CAA. The EPA often assists air agencies by promulgating
regulations or providing guidance for meeting implementation
requirements and technical tools, including information on control
measures.\35\ For example, the EPA intends this rulemaking to clarify
the specific statutory requirements, and schedule for meeting those
requirements, that state and tribal air pollution control agencies
(``air agencies'') must address as they prepare SIP submissions for the
PM2.5 standards in future.\36\
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\35\ It is important to note that the EPA does not have a
mandatory duty to promulgate an implementation rule for the
PM2.5 NAAQS, and the obligations of state and tribal air
agencies to develop and submit an attainment plan are independent
obligations and not conditioned upon the EPA promulgating an
implementation rule for the PM2.5 NAAQS.
\36\ When the term ``state'' is used hereafter, it will refer
generically to states, local air agencies, and tribal governments
electing to be treated as states for the purposes of implementing
the CAA. Of additional note is that the 1998 Tribal Authority Rule
(TAR), which is found in 40 CFR part 49, which implements section
301(d) of the CAA, provides that tribes be treated in the same
manner as a state when implementing certain sections of the CAA. It
gives tribes the option of developing tribal implementation plans
(TIPs), but unlike states, tribes are not required to develop
implementation plans. Section IX.I of this preamble provides further
discussion of tribal issues.
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The EPA also promulgates nationally applicable control requirements
and emission limits for many sources such as new motor vehicles,
certain categories of new and modified major stationary sources and
existing stationary sources of toxic air pollutants. These federal
actions assist state and tribal air agencies by achieving emission
reductions from certain categories of sources nationwide, which can
help with local attainment needs in a given nonattainment area. In
addition, the EPA has authority to address
[[Page 15348]]
interstate transport of pollutants, in the event that states fail to do
so. Through this authority, the EPA has addressed regional transport of
pollutants from upwind states to downwind states, and has previously
done so for purposes of the PM2.5 NAAQS.\37\ In addition,
the EPA has the authority and responsibility to review and take action
to approve or disapprove submitted attainment plans based upon whether
they meet applicable statutory and regulatory requirements, to provide
funding and technical assistance to states and to initiate the process
for imposition of sanctions and/or issue federal implementation plans
(FIPs) when states fail to fulfill their CAA obligations. More
information on area designations, the role of ambient air monitoring,
the SIP development process and the role of federal measures in
bringing an area into attainment is presented below.
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\37\ See 70 FR 25162 (May 12, 2005) and 76 FR 48208 (August 8,
2011).
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2. Initial Area Designations and Classifications
The NAAQS implementation planning process begins with initial area
designations, through which states and the EPA identify areas of the
country that either meet or do not meet the new or revised NAAQS, along
with identifying the nearby areas contributing to violations of the
NAAQS. Section 107(d)(1) of the CAA requires that: ``By such date as
the Administrator may reasonably require, but not later than 1 year
after promulgation of a new or revised national ambient air quality
standard for any pollutant under section 109, the Governor of each
state shall . . . submit to the Administrator a list of all areas (or
portions thereof) in the State'' that designates those areas as
nonattainment, attainment, or unclassifiable.\38\ Thus, states are
required to make their initial designation recommendations to the EPA
by no later than 1 year after the promulgation of new or revised NAAQS.
Section 107(d)(1)(B)(i) further provides: ``Upon promulgation or
revision of a NAAQS, the Administrator shall promulgate the
designations of all areas (or portions thereof) . . . as expeditiously
as practicable, but in no case later than 2 years from the date of
promulgation. Such period may be extended for up to 1 year in the event
the Administrator has insufficient information to promulgate the
designations.'' Thus, the EPA is required to promulgate the actual
designations for all areas across the U.S. by no later than 2 years
after the promulgation of any new or revised NAAQS, unless the EPA
elects to take up to one additional year in situations where there is
insufficient information. Under section 107(d)(1)(B)(ii), the EPA is
authorized to modify the designations recommendations from the states,
with respect to the designation of an area and the boundaries of an
area, if the EPA deems that necessary. By no later than 120 days prior
to promulgating final designations, the EPA is required to notify
states of any intended modifications to their recommendations. States
then have an opportunity to demonstrate to the EPA why the EPA's
intended modification is inappropriate. Regardless of whether a state
provides an initial designation recommendation for any area, the EPA
must timely promulgate the designations it deems appropriate.\39\
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\38\ While the CAA provides for ``designating'' with respect to
the Governor's list, in the full context of the CAA section 107 it
is clear that the Governor actually makes a recommendation, to which
the EPA must respond using a specified process if the EPA does not
accept the recommendation.
\39\ While section 107 of the CAA specifically addresses states,
the EPA is following the same process for tribes that choose to make
a recommendation to the extent practicable, pursuant to section
301(d) of the CAA regarding tribal authority, and the TAR. 63 FR
7254 (February 12, 1998). To provide for clarity and consistency,
the EPA issued a 2011 guidance memorandum for working with tribes
during the designations process. Memorandum of December 20, 2011
from Stephen D. Page, Director, Office of Air Quality Planning and
Standards, to EPA Regional Administrators, Regions I-X re:
``Guidance to Regions for Working with Tribes during the National
Ambient Air Quality Standards (NAAQS) Designations Process.''
Available at: http://www.epa.gov/ttn/oarpg/t1/memoranda/20120117naaqsguidance.pdf.
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Under subpart 4, the CAA provides for classification of
PM2.5 nonattainment areas as either ``Moderate'' or
``Serious.'' As provided in section 188(a) and reiterated in the
General Preamble, all PM10 nonattainment areas and by
extension all PM2.5 nonattainment areas are initially
classified as Moderate by operation of law at the time of designation.
Initial classifications are not subject to public notice-and-comment
pursuant to section 107(d)(2)(B), although the EPA may elect to take
comment on designations and classifications and its recent practice has
been to do so.
All areas designated as nonattainment for the 2012 PM2.5
NAAQS and any future revised PM2.5 NAAQS will be initially
classified as Moderate nonattainment areas upon designation, regardless
of the severity of the PM2.5 problem in the area. This
statutory approach to classifications for nonattainment areas under
subpart 4 for the PM2.5 NAAQS is notably different from the
approach for ozone NAAQS nonattainment areas under subpart 2 (of part
D, title I of the CAA), wherein the statute includes several area
classifications, and initial classifications are based on monitored
ozone levels. Thus, unlike for ozone nonattainment areas, all
PM2.5 nonattainment areas initially receive the same
classification--Moderate--and the EPA only reclassifies such areas to
Serious upon a showing by the state or a determination by the agency
that the area cannot practicably attain by the statutory attainment
date, or upon a finding that the area in fact failed to attain the
NAAQS by the applicable Moderate area attainment date. The statute
requires that Moderate nonattainment areas attain the NAAQS as
expeditiously as practicable, but not later than the end of the sixth
calendar year following designation. States have an incentive to avoid
having a Moderate area reclassified to Serious because, as discussed
later in this preamble, the specific subpart 4 requirements for areas
classified as Serious include, among other things, a more stringent
level of control for sources of direct PM2.5 and
PM2.5 precursors than for Moderate areas.
As of the date of this proposal, the first round of initial
designations for most areas for the 2012 primary annual
PM2.5 NAAQS has been completed, and those designations will
become effective on April 15, 2015. All areas designated as
nonattainment for the 2012 PM2.5 NAAQS were classified as
Moderate nonattainment areas.\40\
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\40\ See the Federal Register notice for the first round of
designations for the 2012 PM2.5 NAAQS at 80 FR 2206
(January 15, 2015).
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3. Ambient Air Monitoring for PM2.5
Ambient air quality monitoring for PM2.5 plays an
integral role in implementation of a NAAQS, including identifying areas
violating the NAAQS, control strategy development and tracking progress
toward attainment. States are required to monitor PM2.5 mass
concentrations using approved methods to determine compliance with the
NAAQS.\41\ The locations of monitors are identified in states' Annual
Monitoring Network Plans, which are required to be submitted to the EPA
by July 1 of each year.\42\ The EPA in turn reviews these annual plans
for compliance with applicable regulations and consistency with
relevant guidance. Currently there are more than 900
[[Page 15349]]
monitoring locations across the country eligible for comparison to the
PM2.5 NAAQS. States are required to maintain monitors in
designated nonattainment areas in order to track progress toward
attainment and ultimately determine whether the area has attained the
PM2.5 standards. In addition to the approved monitors for
comparison to the NAAQS, the EPA and states also maintain a chemical
speciation network (CSN) of about 200 stations around the country to
support analyses of chemical composition of PM2.5 (e.g.
sulfate, nitrate and organic carbon). The data provided by the CSN help
states identify contributing source categories and develop control
strategies to reach attainment.
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\41\ The ambient air monitoring requirements that apply to the
PM2.5 NAAQS are detailed in 40 CFR part 58. These
monitoring requirements are applicable to state and local air
agencies.
\42\ See 40 CFR 58.10.
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In conjunction with the promulgation of the 2012 PM2.5
NAAQS, the EPA finalized a schedule for deployment of PM2.5
monitors at near-road monitoring locations. Under revised monitoring
requirements, states are required to locate a minimum of one
PM2.5 monitor in each core-based statistical area (CBSA)
with a population of 1 million or more, to be phased-in between January
2015 and January 2017.\43\
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\43\ Near-road monitors for CBSAs larger than 2.5 million in
population are to be operational by 1/1/2015; and monitors for CBSAs
with population larger than 1 million but less than 2.5 million are
to be operational by 1/1/2017. CBSA is defined by OMB as a
statistical geographic entity consisting of the county or counties
associated with at least one urbanized area/urban cluster of at
least 10,000 population, plus adjacent counties having a high degree
of social and economic integration.
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For initial area designations for any PM2.5 NAAQS, the
EPA relies on monitoring data to identify areas to be designated
nonattainment due to violations of the standard(s). The EPA uses other
information to identify areas contributing to the monitored violations
in those areas.\44\ The agency's protocol for designating areas and
determining whether an area has attained the PM2.5 NAAQS is
based on monitored air quality data collected over a period of 3
calendar years. Data from the new PM2.5 near-road monitors
were not available for the EPA to consider within the timeframe for
initial area designations provided by the CAA for the 2012
PM2.5 NAAQS; the agency will not be able to consider data
from a near-road monitor in the implementation process until 3 years of
data are available. The initial set of near-roadway PM2.5
monitors are to be fully deployed by January 2015, with the first 3
years of air quality data (2015-2017) available beginning in 2018; the
second set of near-roadway monitors are to have the first 3 years of
data available beginning in 2020.
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\44\ See Catawba County v. EPA, 571 F.3d 20 (D.C. Cir. 2009).
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4. SIP Development Process
In general terms, a SIP is the compilation of EPA-approved state
statutes, regulations and programs that a state develops and relies
upon to carry out its NAAQS implementation responsibilities under the
CAA, including the attainment, maintenance and enforcement of NAAQS.
States use the SIP development process to identify the emissions
sources that contribute to the nonattainment problem in a particular
area, and to select the required emissions reduction measures most
appropriate for that area, considering factors such as technological
and economic feasibility. As part of developing an attainment plan, the
states must meet specific requirements of the CAA to attain the NAAQS,
e.g., a state with a Moderate PM2.5 nonattainment area must
impose RACM (including RACT) and additional reasonable measures on
sources located in the nonattainment area. Under the CAA, states must
develop attainment plans that ensure that areas reach attainment as
expeditiously as practicable, but no later than the applicable
statutory attainment date. In these attainment plans, states may take
into consideration emission reductions resulting from federally
applicable national programs (such as mobile source regulations, the
national acid rain program, or maximum achievable control technology
(MACT) standards for air toxics), as well as from state or local
programs not directly mandated, but authorized, under the CAA, if such
measures are incorporated into the SIP and thus are made federally
enforceable.
5. Geographic Extent of PM2.5 Problem
The EPA recognizes the significant variability in the nature and
sources of PM2.5 in different nonattainment areas and
believes it is important to keep this variability in mind when
providing guidance to states as they develop control strategies to
bring their PM2.5 nonattainment areas into attainment with
the relevant NAAQS. The variability of PM2.5 concentrations
across the country has a substantial regional component because the
formation and transport of secondarily formed particles, such as
sulfates and nitrates, can extend over hundreds of miles. As a result,
monitored violations of the PM2.5 NAAQS can often reflect
the impact of the combination of ``local'' sources of emissions located
within the designated nonattainment area and ``regional'' sources of
emissions that may be located much farther away.
In addition, data suggest that ambient PM2.5
concentrations tend to rise and fall in a consistent manner across very
large geographic areas. The transport phenomenon associated with
PM2.5 and its precursors has been well documented for many
years. For example, one significant source of information on long-range
transport is the National Acid Precipitation Assessment Program (NAPAP)
research from the 1980s and its associated reports published in
1991.\45\ Additional studies and air quality modeling analyses since
that time have added to the body of information documenting the
regional nature of PM2.5.\46\
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\45\ National Acid Precipitation Assessment Program. Acid
Deposition: State of the Science and Technology. Washington, DC
1991. See also Environmental Protection Agency. (2004) Air Quality
Criteria for Particulate Matter. Research Triangle Park, NC: Office
of Research and Development; report no. EPA/600/P-99/002a,bF.
Available at: http://www.epa.gov/ttn/naaqs/standards/pm/s_pm_cr_cd.html.
\46\ For example, see technical information for the Cross-State
Air Pollution Rule (CSAPR) at: http://www.epa.gov/airmarkt/programs/cair/index.html; and the Clean Air Interstate Rule (CAIR) at: http://www.epa.gov/airmarkt/programs/cair/index.html. See also: NARSTO
(2004) Particulate Matter Assessment for Policy Makers: A NARSTO
Assessment. P. McMurry, M. Shepherd, and J. Vickery, eds. Cambridge
University Press, Cambridge, England. ISBN 0 52 184287 5.
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6. Strategies for Reducing Ambient PM2.5
The control measures identified and adopted by a state through the
SIP development process for bringing nonattainment areas into
attainment constitute an important component of the CAA's overall
strategy for meeting the PM2.5 standards, but they are not
the only component. The CAA also includes requirements for national
rules or programs that will reduce emissions and help achieve cleaner
air. Specifically, the EPA has adopted a number of national rules over
the past few years that require or will require emission reductions
from sources of both direct PM2.5 and PM2.5
precursors, especially of SO2 and NOX. The
national rules that will help states meet their attainment dates
include, but are not limited to: The Tier 2 Light-Duty Vehicle Rule;
the Tier 3 Tailpipe and Evaporative Emission and Vehicle Fuel
Standards; the Heavy-Duty Engine and Vehicle Standards and Highway
Diesel Fuel Sulfur Control Requirements; the Clean Air Nonroad Diesel
Rule; the Regional Haze Regulations and Guidelines for Best Available
Retrofit Technology Determinations; the NOX Emission
Standard for New Commercial Aircraft Engines; the CSAPR; the Emissions
Standards for Locomotives and Marine
[[Page 15350]]
Compression-Ignition Engines; the Control of Emissions for Nonroad
Spark Ignition Engines and Equipment; the C3 Oceangoing Vessels rule;
area and major source Boilers NESHAPs, New Source Performance Standards
and Emission Guidelines for Hospital/Medical/Infectious Waste
Incinerators; the Reciprocating Internal Combustion Engines (RICE)
NESHAPs; and the Mercury and Air Toxics Standards (MATS).\47\
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\47\ Compliance with the MATS emission standard for acid gas
hazardous air pollutants (HAP) is demonstrated by direct measurement
of either hydrogen chloride (HCl) or SO2 as surrogates
for all acid gas HAP. Thus, compliance with MATS is expected to
result in a substantial amount of new pollution controls (scrubbers
and dry sorbent injection) and upgrading of existing acid gas
controls that will significantly reduce acid gas emissions,
including SO2 emissions, from power plants. MATS
implementation is projected to reduce nationwide SO2
emissions from power plants to a level more than 40 percent lower
than the SO2 emissions projected under CSAPR without MATS
in place. For more information, see: http://www.epa.gov/mats.
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Additionally, there are PM2.5 reductions that will be
achieved as a result of previously adopted state and local agency
regulations and voluntary programs to the extent they can be relied on
under the EPA's voluntary measures policies, such as the use of low
sulfur fuel for home heating and industrial purposes, curtailment of
residential wood burning and burn bans. Furthermore, under the
voluntary PM Advance program, the EPA works with states, tribes and
local governments to ensure they are aware of the advantages of early
action and to provide assistance in taking steps to achieve emission
reductions in areas currently attaining the PM2.5 NAAQS but
approaching levels that could lead to nonattainment in the future.
Early reductions may help these areas maintain the annual and 24-hour
PM2.5 NAAQS over the long-term. Furthermore, there may be
emissions controls that can be implemented to meet NAAQS for ozone
(O3) or SO2 that may have co-benefits for meeting
and continuing to meet the current PM2.5 NAAQS and any
future revised PM2.5 NAAQS.
The EPA will continue to work closely with air agencies as they
develop and use an appropriate combination of national, regional and
local pollution reduction measures to meet the standards as
expeditiously as practicable, as required by the CAA.
III. What is the EPA proposing with respect to the treatment of
PM2.5 precursors in nonattainment area planning and
permitting?
A. Background
The EPA recognizes that a threshold question in developing
PM2.5 attainment plans and implementing NNSR programs is the
question of which precursors must be regulated in a given nonattainment
area in order to attain the relevant NAAQS and to meet the statutory
requirements of part D, including subpart 4, of the CAA. Before
discussing the specific CAA attainment plan and NNSR requirements in
detail in Sections IV through IX of this preamble, the EPA discusses in
this section how a state should evaluate PM2.5 precursors in
order to identify the specific precursors to which the PM2.5
attainment plan and NNSR requirements will apply in a given
nonattainment area. This section first provides a brief overview of the
precursor policies that the agency included in the 2007
PM2.5 Implementation Rule and in the 2008 PM2.5
NSR Rule for the 1997 PM2.5 NAAQS that were remanded by the
court. It then describes the EPA's three proposed options for
addressing PM2.5 precursors under the attainment planning
and NNSR programs to meet the statutory requirements of subpart 4.
Lastly, this section discusses possible approaches for states to
develop an adequate technical demonstration showing whether emissions
of a given PM2.5 precursor significantly contribute to
ambient concentrations that exceed the standard. The EPA requests
public comment on the options and information presented below.
The EPA's 2007 PM2.5 Implementation Rule included
regulatory presumptions concerning the need to address certain
PM2.5 precursors in attainment plans and through control
measures related to those plans.\48\ The EPA has long recognized the
scientific basis for concluding that there are multiple scientific
precursors to PM10, and in particular to
PM2.5.\49\ As described in Section II of this preamble (on
technical background issues associated with PM2.5 and
PM2.5 precursors), appropriate control of precursors is
especially important because secondarily formed particles comprise a
large fraction of ambient PM2.5 concentrations in many
nonattainment areas.
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\48\ See 2007 PM2.5 Implementation Rule, 72 FR 20586,
20589, 20590, 20591, 20592, 20593, 20594, 20595, 20596 and 20597
(April 25, 2007).
\49\ Ibid. For example, the EPA's 2007 PM2.5
Implementation Rule discussed the fact that emissions of
SO2, NOX, VOC and ammonia are factual and
scientific precursors to PM2.5.
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Section 302(g) of the CAA indicates that the term ``air pollutant''
includes ``any precursors to the formation of any air pollutant, to the
extent the Administrator has identified such precursor or precursors
for the particular purpose for which the term `air pollutant' is
used.'' In the 2007 PM2.5 Implementation Rule and the 2008
PM2.5 NSR Rule, the EPA recognized that the main scientific
precursors of fine particle formation are SO2,
NOX, VOC, and ammonia. Pursuant to the discretionary
authority provided under section 302(g) to identify PM2.5
precursors for a particular program, the EPA also included requirements
describing which precursor gases states were to evaluate for potential
emission reductions as part of the state's analysis of control measures
to bring the area into attainment as expeditiously as practicable.
To facilitate the evaluation and identification of reasonable
control measures, the 2007 PM2.5 Implementation Rule
included nationally applicable presumptions regarding the need to
evaluate and potentially control emissions of certain precursors.
Specifically, in 40 CFR 51.1002, the EPA provided that a state must
evaluate sources of direct PM2.5 and SO2 for
potential control measures; a state presumptively was required to
evaluate sources of NOX for potential control measures; and,
a state was presumptively not required to evaluate sources of VOC and
ammonia emissions for potential control measures. The EPA established
these presumptions concerning VOC and ammonia in the 2007
PM2.5 Implementation Rule because of factors such as
uncertainties regarding the emissions inventories for ammonia,
uncertainties concerning the role of some VOC in the formation of
particles, and uncertainties regarding the effectiveness of specific
precursor control measures in various regions of the country in
reducing PM2.5 concentrations. For example, in some areas of
the U.S., emission reductions of a particular precursor may lead to
large changes in PM2.5 concentrations because there are
relatively few tons of such precursor emissions in the area in the
first place. In other areas, the opposite may be true, where emission
reductions of a particular precursor may lead to small changes in
PM2.5 concentrations because the area has an abundance of
emissions of that particular precursor.
The rule also included provisions for potentially reversing the
EPA's initial presumptions for certain precursors in a nonattainment
area where the state or
[[Page 15351]]
the EPA had information demonstrating that the presumption was not
valid for that area. The EPA left open the possibility in the 2007
PM2.5 Implementation Rule for regulation of VOC and ammonia
emissions as PM2.5 precursors in any nonattainment area
where regulation was necessary for purposes of attaining the 1997
PM2.5 NAAQS. Similarly, the EPA left open the possibility
for not regulating NOX where NOX sources from
within the state did not have a significant contribution to
PM2.5 concentrations in the nonattainment area. The preamble
to the 2007 PM2.5 Implementation Rule discussed that to
``reverse'' the presumptions in the rule for NOX, VOC or
ammonia, the state would need to provide an appropriate technical
demonstration, and it provided examples of the types of analyses that
could be included in such a demonstration. The EPA intended these to be
rebuttable presumptions that either the state or the EPA might reverse
through notice-and-comment rulemaking. These presumptions were not
limited to precursor emissions only from major stationary sources, but
rather were presumptions applicable to precursor emissions from all
sources of such emissions within the area.\50\
---------------------------------------------------------------------------
\50\ Ibid.
---------------------------------------------------------------------------
The 2008 PM2.5 NSR Rule included similar policies for
precursor presumptions in connection with the NSR requirements for
nonattainment areas (the NNSR program).\51\ That rule provided a
discussion of the possibility for the state or the EPA to provide a
technical demonstration to reverse the presumptions for NOX,
VOC or ammonia.\52\ The one significant difference between the two
rules was the geographic scope of the requirements. The 2008
PM2.5 NSR Rule indicated that a precursor presumption could
be rebutted if the emissions of that precursor from sources within the
nonattainment area (emphasis added) did not significantly contribute to
PM2.5 concentrations in the nonattainment area. This
distinction is logical because the requirements of the NNSR program
apply only to sources located within a designated nonattainment area.
Conversely, the 2007 PM2.5 Implementation Rule indicated
that the evaluation of whether a given precursor should be regulated
should be based on emissions from sources throughout the entire state
(emphasis added), because the state air agency has jurisdiction over
sources throughout the entire state in developing strategies to improve
air quality specifically in nonattainment areas. A more complete
discussion of the 2008 NNSR program requirements for the
PM2.5 NAAQS and the proposed changes concerning the
regulation of PM2.5 precursors from new or modified major
stationary sources of PM2.5 precursors in PM2.5
nonattainment areas is provided in Section VIII of this preamble.
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\51\ See the Federal Register published on May 16, 2008 (73 FR
28321, 28326 and 28327).
\52\ Ibid.
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The EPA's approach to the evaluation and regulation of
PM2.5 precursors in both the 2007 and 2008 rules for
implementing the 1997 PM2.5 NAAQS was called into question
in the court's 2013 decision in NRDC v. EPA. As an example of the
distinction between the divergent substantive requirements of subpart 1
and subpart 4, the court noted that subpart 4 has specific provisions
related to regulation of precursors not present in subpart 1. Although
the court stated that it was not reaching a decision on the issue of
regulation of precursors, the court's decision specifically discussed
both the approach to precursors in the 2007 PM2.5
Implementation Rule and the 2008 PM2.5 NSR Rule and compared
those to section 189(e) of the CAA, which contains the sole explicit
reference to the regulation of precursors in subpart 4. The court
decision included the following statements with regard to precursors:
Ammonia is a precursor to fine particulate matter, making it a
precursor to both PM2.5 and PM10. For a
PM10 nonattainment area governed by subpart 4, a
precursor is presumptively regulated. See 42 U.S.C. 7513a(e)
[section 189(e)]. But under the PM rules challenged here, the EPA
established a rebuttable presumption against regulating ammonia
unless a state or the EPA ``provides an appropriate technical
demonstration'' that shows emissions from ammonia ``significantly
contribute to PM concentration in the nonattainment area.'' 40 CFR
51.1002(c)(4)(i). When Congress enacted subpart 4, it sought to end
this administrative gamesmanship.\53\
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\53\ NRDC v. EPA, 706 F.3d 428, 437, n.7 (D.C. Cir. 2013).
---------------------------------------------------------------------------
* * * * *
In light of our disposition, we need not address the
petitioners' challenge to the presumptions in [40 CFR 51.1002] that
volatile organic compounds and ammonia are not PM2.5
precursors, as subpart 4 expressly governs precursor
presumptions.\54\
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\54\ NRDC v. EPA, 706 F.3d 428, 437, n.10 (D.C. Cir. 2013).
Section 189(e) for PM10 precursors (which the court
concluded expressly includes PM2.5) provides that: ``The
control requirements applicable under plans in effect under this part
for major stationary sources of PM10 shall also apply to
major stationary sources of PM10 precursors, except where
the Administrator determines that such sources do not contribute
significantly to PM10 levels which exceed the standard in
the area.'' The court reasoned that the EPA's approach to precursors in
the 2007 PM2.5 Implementation Rule and 2008 PM2.5
NSR Rule had the effect of reversing the presumption embodied within
subpart 4 that a state should address all PM10 precursors
unless the state has made a specific showing why regulation of a
particular precursor is not necessary.\55\
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\55\ Ibid.
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The provisions of subpart 4 do not define the term ``precursor''
for purposes of PM10, nor do they explicitly require the
control of any specifically identified particulate matter precursor.
However, as stated above, the statutory definition of ``air pollutant''
provides that the term ``includes any precursors to the formation of
any air pollutant, to the extent the Administrator has identified such
precursor or precursors for the particular purpose for which the term
`air pollutant' is used.'' CAA section 302(g). The EPA has determined
that SO2, NOX, VOC and ammonia are factual and
scientific precursors to PM, and thus the attainment plan requirements
of subpart 4 initially apply equally to emissions of direct
PM2.5 and all of its identified precursors, except as
otherwise provided in the statute (e.g. CAA section 189(e)). Section
189(e) explicitly requires the control of precursors from all major
stationary sources, unless there is a demonstration to the satisfaction
of the Administrator that such major stationary sources do not
contribute significantly to PM levels that exceed the standards in the
area.\56\ Section 189(e) contains the only express exception to control
requirements under subpart 4. The control requirements for major
sources referred to in this exception include requirements for RACM and
RACT, additional reasonable measures, BACM and BACT, most stringent
measures (as applicable) and NNSR on all major sources of precursors in
the nonattainment areas. The General Preamble indicates that
consideration of precursors is necessary for attainment plans, and it
recognizes the specific applicability of section 189(e) to both
existing and new major stationary sources, including new and modified
sources subject to NNSR permitting requirements. Even though section
[[Page 15352]]
189(e) only explicitly contemplates exceptions to control requirements
for PM2.5 precursors from major stationary sources, the EPA
believes that by analogy it has authority to promulgate regulations
that allow states to determine that it is not necessary to regulate
PM2.5 precursors from other source categories as well, under
appropriate circumstances.
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\56\ The EPA notes that it has already addressed the
requirements of subpart 4 for precursors, specifically within the
context of the requirements of section 189(e), in the General
Preamble. See the Federal Register published on April 16, 1992 (57
FR 13498, 13539, 13541 and 13542).
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When Congress adopted the 1990 CAA Amendments, a NAAQS for
PM10 was in effect, but no standard for PM2.5 had
yet been established. At that time, it was understood that the
interaction of PM precursors in the atmosphere led to the formation of
particulate matter in many areas. However, in some of the
PM10 nonattainment areas, air quality problems were caused
primarily by area sources emitting direct PM emissions (e.g., a
nonattainment area with numerous wood burning devices or with
substantial sources of windblown coarse particles from construction
sites), and precursor emissions from major stationary sources were not
considered to make a significant contribution to the local
nonattainment problem. For cases such as these, section 189(e) provided
a possible exception to the requirement to control all PM2.5
precursors from major sources in all nonattainment areas.
While section 189(e) expressly requires control of precursors from
major stationary sources where direct PM from major sources is to be
controlled unless certain conditions are met, as stated above, it is
clear that subpart 4 and other CAA provisions collectively require the
control of direct PM and all PM2.5 precursors from all types
of sources (i.e., stationary sources, area sources, and mobile sources)
as may be needed for the purposes of demonstrating attainment as
expeditiously as practicable in a given area.\57\ Long-standing EPA
guidance for RACM has stated that the state should inventory all
emissions of the relevant pollutants and precursors in the
nonattainment area and evaluate all economically and technologically
feasible control measures for the relevant pollutant and precursors,
and that the state should adopt those measures that are deemed
reasonably available and necessary in order to attain the NAAQS as
expeditiously as practicable.\58\ The state also must ensure that there
is no other collection of available control measures that if adopted
would advance the attainment date by at least one year.\59\ Section
IV.D of this preamble provides additional discussion on the development
of emissions inventories and the identification, adoption and
implementation of reasonable control measures for Moderate
PM2.5 nonattainment areas. \60\
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\57\ See CAA requirements for states to demonstrate attainment
``as expeditiously as practicable'' (section 188(c)(1); section
172(a)(2)).
\58\ 57 FR 13498 (April 16, 1992).
\59\ In the context of the PM10 NAAQS, the EPA has
concluded that ``advancement of the attainment date'' should mean an
advancement of at least 1 calendar year. See State Implementation
Plans; General Preamble for the Implementation of Title I of the CAA
Amendments of 1990, 57 FR 13498 (April 16, 1992). See also Sierra
Club v. EPA, 294 F.3d 155 (D.C. Cir. 2002).
\60\ See Section IV of this preamble for a thorough discussion
of past reasonably available control measures (RACM) and reasonably
available control technology (RACT) policy and guidance. Section IV
discusses the EPA's proposed policy that under subpart 4, for
Moderate areas that demonstrate that attainment by the statutory
attainment date is impracticable, RACM and RACT would constitute all
those technologically and economically feasible measures available
for sources in the area that can be implemented within 4 years of
designation, but they would not constitute the complete set of
measures required to demonstrate attainment as expeditiously as
practicable.
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B. Proposed Precursor Policy Options
The EPA is proposing this rule to address the attainment plan and
certain NNSR requirements for PM2.5 under subpart 4. In
light of the court's decision in NRDC v. EPA, the EPA considers it
necessary to address in this implementation rule how states must
address regulation of PM2.5 precursor gases in attainment
plans and NNSR programs for the PM2.5 NAAQS. As noted
earlier, the court's decision made clear that appropriate regulation of
all precursors is initially presumptively required under the CAA, and
the regulation of precursors is a critical issue for attainment of the
PM2.5 NAAQS because secondarily formed particles are a
substantial component of the PM2.5 nonattainment problem in
most areas of the U.S.
For the purposes of this implementation rule, the EPA considers
that for all nonattainment areas, the PM2.5 precursors for
regulatory purposes are SO2, NOX, VOC and
ammonia. This rule does not propose any national presumption that would
simply allow a state to exclude sources of emissions of a particular
precursor from further analysis for control requirements. However, the
EPA's existing interpretation of subpart 4 requirements--with respect
to precursors in attainment plans for PM10, as set out in
the General Preamble--contemplates that the state may develop an
attainment plan that regulates only those precursors that are necessary
to control for purposes of timely attainment in the area, i.e., states
may determine that only certain precursors need to be regulated for
attainment purposes.\61\ Courts have upheld this approach to the
requirements of subpart 4 for PM10.\62\
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\61\ See the Federal Register published on April 16, 1992 (57 FR
13498, 13540 and 13541).
\62\ See, e.g., Assoc. of Irritated Residents v. EPA, et al.,
423 F.3d 989 (9th Cir. 2005).
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The EPA believes that application of a similar approach to
PM2.5 precursors under subpart 4 is appropriate and
reasonable. Thus, this proposal describes three proposed precursor
options that provide for the possibility that, with appropriate
justification provided by the state, further evaluation and
implementation of control strategies for one or more PM2.5
precursors in a given nonattainment area may not be needed or required.
Under each option, a state may provide a technical demonstration and
reasoned justification for the exclusion of a PM2.5
precursor or precursors from control requirements for a particular
nonattainment area.
As explained above, the EPA interprets the CAA to require states to
inventory and regulate all sources of PM2.5 precursors from
all sources in the area, including area sources, mobile sources and
stationary sources. This interpretation is based on CAA provisions
requiring adoption of all RACM needed to attain the standard as
expeditiously as practicable; section 302(g), which defines an air
pollutant as including all precursors contributing to the formation of
that pollutant; and, the EPA's identification of the four main
PM2.5 precursors. For major stationary sources, section
189(e) requires that the control requirements applicable for major
stationary sources of PM2.5 must also apply to major
stationary sources of PM2.5 precursors, unless the state
provides a showing that emissions of a particular precursor from major
stationary sources do not contribute significantly to levels which
exceed the standard in the area. Thus, the statute generally requires
control of all PM2.5 precursors, but it provides an express
exception applicable to major stationary sources. Because the statutory
provisions of subparts 1 and 4 are not explicit with respect to how
states should address PM2.5 precursors from non-major
sources, the EPA is proposing regulations to assure proper evaluation
and regulation of PM2.5 precursor emissions in
PM2.5 nonattainment areas. Moreover, even with respect to
regulation of precursor emissions from major stationary sources,
section 189(e) contains ambiguities that require interpretation. For
example, section
[[Page 15353]]
189(e) does not specify the method by which the EPA should determine
whether precursor emissions from major stationary sources contribute
significantly to levels which exceed the standard in a given
nonattainment area. Given that the provisions of subpart 4 are
ambiguous with respect to these issues, the EPA believes that it is
necessary to interpret those requirements in this rulemaking.
The EPA is thus seeking comment on three potential approaches to
address PM2.5 precursors pursuant to the specific statutory
requirements of subpart 4 and the overarching requirements of the CAA.
In these proposed options, particular emphasis is given to the
situations and circumstances under which the state would or would not
be required to evaluate emission controls for a particular precursor
and to adopt those controls that are necessary to demonstrate
attainment of the NAAQS as expeditiously as practicable. Note that
these options describe analyses that the state may choose to pursue to
demonstrate that control requirements should not apply to a particular
precursor. However, the state also may choose to require controls for
all PM2.5 precursors in attainment plans and in its NNSR
permitting program, and choose not to conduct any analyses to eliminate
one or more precursors from consideration for controls.
The descriptions of the three precursor policy options being
proposed in this section discuss how PM2.5 precursors would
need to be addressed by the state with regard to three specific
implementation situations: (1) A Moderate area for which attainment of
the relevant NAAQS by the end of the sixth calendar year after
designation can be demonstrated; (2) a Moderate area for which it can
be demonstrated that the relevant NAAQS cannot practicably be attained
by the end of the sixth calendar year after designation; and (3) an
area that is reclassified to Serious and is obligated to develop a
Serious area attainment plan to attain the relevant NAAQS.
Additionally, the EPA describes how each of the proposed precursor
policy options would apply to the implementation of NNSR in a Moderate
or Serious PM2.5 nonattainment area. Later in this section,
the EPA discusses specific issues related to the technical ``precursor
demonstrations'' that states could choose to develop. The technical
demonstration section includes a discussion of several types of
analyses that a state could provide to the EPA to show that control
measures for a specific PM2.5 precursor would not be needed
for attainment or to expedite attainment, or to show that major
stationary sources of a given precursor collectively do not
significantly contribute to PM2.5 levels that exceed the
relevant NAAQS in a given area.
Before discussing the three precursor options, it is important to
introduce a new term that is used throughout this section and other
sections of the notice. Under subpart 4, RACM (including RACT) are
those measures that can and must be implemented within 4 years of the
area's designation as nonattainment (pursuant to section 189(a)(1)(C)).
The EPA recognizes, however, that other, similarly reasonable emissions
reduction measures could be implemented after this 4 year period, and
as late as the end of the sixth calendar year following designation, to
help an area attain as expeditiously as practicable. Therefore, in this
proposal the EPA is proposing to define the term ``additional
reasonable measures'' to describe those technologically and
economically feasible control measures that could not be implemented
within the 4 year period after designation, but could be implemented
starting any time after that 4 year period through the end of the sixth
calendar year after designation (note that this period could extend
almost 3 additional years, depending on when during the year area
designations are finalized). See proposed 40 CFR 51.1000. The EPA
proposes to require implementation of these ``other'' control measures
to the extent necessary to demonstrate attainment by the applicable
attainment date pursuant to section 172(c)(6) of the CAA. That
provision provides that nonattainment ``plan provisions shall include
enforceable emissions limitations, and such other control measures . .
. as may be necessary or appropriate to provide for attainment of such
standard in such area by the applicable attainment date . . .''
Together, RACM and RACT and ``additional reasonable measures'' make up
the set of control strategies referred to in this proposed rule as
``reasonable control measures.'' \63\ (Section IV.D of this preamble
provides a detailed discussion of how a state must determine reasonable
control measures for a Moderate PM2.5 nonattainment area.)
The EPA requests comment on each of the three proposed options
discussed below which describe how a state may demonstrate that
additional emissions reductions of a particular precursor would not be
needed or appropriate for an area's attainment plan, and how it could
demonstrate that emissions control requirements for a particular
precursor would not be needed in NNSR permits for new or modified
sources in the area. In particular, the EPA requests comment on whether
only one of these approaches should be included in the final rule, or
whether it would be appropriate to include multiple approaches (e.g.,
both Options 1 and 2), or only specific elements from the different
options. The three proposed options are summarized as follows:
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\63\ In Section VI.D, the EPA describes a parallel approach for
distinguishing control measures required under sections 172(c)(6)
and 189(b)(1)(B) for Serious nonattainment areas.
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Option 1: Two independent analyses: (a) An attainment
planning analysis demonstrating that control measures for a particular
precursor are not needed for expeditious attainment, meaning that the
precursor can be excluded from measures needed to attain as
expeditiously as practicable for all types of sources; and (b) a
section 189(e) technical demonstration showing that major stationary
sources of a particular precursor do not contribute significantly to
levels that exceed the PM2.5 standard, meaning that the
precursor can be excluded from control requirements for major sources
including NNSR permitting;
Option 2: Single analysis demonstrating that all emissions
of a particular precursor from within the area do not significantly
contribute to PM2.5 levels that exceed the standard, meaning
that control requirements for emissions of the precursor from major
stationary and area sources, as well as mobile sources, would not be
required for expeditious attainment, control requirements for major
sources, or for NNSR permitting;
Option 3: An attainment planning analysis demonstrating
that control measures for all types of sources of a particular
precursor are not needed for expeditious attainment also would be
deemed to meet the section 189(e) technical demonstration requirement,
meaning that the state would not need to regulate emissions of the
particular precursor from major stationary sources under the NNSR
permitting program or other control requirements for major stationary
sources.
Each of these proposed options is presented in greater detail below.
1. Option 1: Two independent analyses: (a) An attainment planning
analysis demonstrating that control measures for a particular precursor
are not needed for expeditious attainment, meaning that the precursor
can be excluded from measures needed to attain as expeditiously as
practicable for
[[Page 15354]]
all types of sources; and (b) a section 189(e) technical demonstration
showing that major stationary sources of a particular precursor do not
contribute significantly to levels that exceed the PM2.5
standard, meaning that the precursor can be excluded from control
requirements for major sources and from NNSR permitting.
As with the other options discussed below, the critical first step
in any precursor analysis is the development of a comprehensive
inventory of all precursor emissions in the nonattainment area. A state
will be unable to reasonably determine whether emissions of a given
PM2.5 precursor contribute significantly to the
nonattainment problem in an area if the state has failed to account
adequately for all such emissions in the area in its emissions
inventory.
In general terms, Option 1 would require separate analyses for
purposes of attainment planning and for NNSR. Section 189(a) of the CAA
describes the requirements for Moderate nonattainment areas. Within 18
months of designation as nonattainment, the state is required to submit
a Moderate area plan that either demonstrates attainment as
expeditiously as practicable but by no later than the end of the sixth
year following designation, or demonstrates that attainment by such
date would be impracticable.
Under Option 1, the state would determine the precursors for which
new control measures need to be adopted for a given nonattainment area
through its determination of reasonable control measures needed for
attainment. The state's analysis of reasonable measures for a given
PM2.5 NAAQS nonattainment area should begin by identifying
potential control measures (and factors related to technological
feasibility, economic feasibility, and time needed for implementation)
for all precursors from all types of sources in the area (i.e.,
stationary, area, mobile) included in the emissions inventory. The
analysis of reasonable measures and selection by the state of those
emissions reduction measures that would provide for attainment as
expeditiously as practicable (but no later than the end of the sixth
calendar year after designation) would determine which precursors must
be regulated in the nonattainment area for purposes of attainment.
Except for the requirement to determine whether implementation of all
remaining reasonable measures could collectively advance attainment by
a year, there would be no additional demonstration needed by the state
to justify that attainment planning control requirements should not
apply to a particular precursor. Therefore, the analysis of reasonable
measures may result in the state controlling only a subset of the four
main PM2.5 precursors as part of the attainment
demonstration.
a. Moderate area for which the state can demonstrate attainment by
the statutory attainment date. For certain nonattainment areas, the
state may be able to demonstrate that attainment of the standard ``as
expeditiously as practicable'' is possible by the end of the sixth year
after designation (the statutory Moderate area attainment date) or
sooner, and could be achieved by adopting regulations to reduce
emissions of only a subset of the four PM2.5 precursors.
Under this scenario, the state would be expected to provide analytical
information showing that, even though new economically and technically
feasible control measures may be available for one or more precursors,
the reductions in emissions of the precursor(s) that could be achieved
are not necessary for expeditious attainment and would not advance the
attainment date by at least a year. Under Option 1, if the state
determined that new emissions reductions of a particular precursor are
not necessary for attainment and would not accelerate the attainment
date by at least 1 year, then for the purposes of this particular
PM2.5 Moderate area attainment plan, the state would not
need to adopt additional control measures for that PM2.5
precursor. Given that additional regulation of that PM2.5
precursor would not be necessary for attaining the standard as
expeditiously as practicable, the EPA would be able to approve the
attainment plan for the area as meeting the requirements of subpart 4.
b. Moderate area for which the state can demonstrate that
attainment by the statutory attainment date is impracticable. Section
189(a)(1)(B) provides that for certain nonattainment areas, the state
may demonstrate that, even with implementation of all reasonable
control measures available for reducing emissions of all direct PM and
PM2.5 precursors, it would be impracticable to attain the
standard by the end of the sixth calendar year after designation. In
other words, the analysis would need to demonstrate that implementing
all economically and technically feasible control measures that are
available in the area, and the expected air quality change from such
measures, would not be able to provide for attainment by the end of the
sixth year after designation.
For states that can make the showing that they cannot attain the
NAAQS by the end of the sixth calendar year after designation, the
question arises as to whether the state should be required to adopt all
reasonable measures (i.e. measures that represent RACM and RACT because
they are technologically and economically feasible and can be
implemented in 4 years and all additional reasonable measures that can
be implemented within 6 years) through regulation as part of the
Moderate area plan, even if a subset of these measures collectively
would have a minimal effect on reducing ambient PM2.5
concentrations. The EPA proposes two sub-options for areas that cannot
demonstrate attainment during the Moderate area timeframe even with the
implementation of all reasonable measures in the area. Under the first
sub-option, the state would be required to adopt all available control
measures for precursors through regulation as part of the Moderate area
plan. The rationale supporting this approach would be that adopting all
technologically and economically feasible measures would bring the area
as close to attainment as possible during the timeframe prescribed for
Moderate areas. Under this approach, if a measure can be implemented by
the end of the sixth calendar year after the nonattainment designation
and it meets the criteria for being considered ``reasonable,'' then the
state must adopt and implement the measure.
Under the second sub-option, the state would be able to elect not
to impose those technologically and economically feasible measures that
collectively have minimal effect on ambient PM2.5 levels in
the area, based on the premise that such measures would be unreasonable
to implement. To support this conclusion, the state would need to
submit a technical demonstration showing that implementing available
emissions controls for a particular precursor and/or a specific set of
sources would provide only minimal changes in PM2.5
concentrations in the area, and therefore such control measures should
not be required during the timeframe prescribed for Moderate areas. The
EPA requests comment on these two sub-options, including any technical
information that would help support the commenter's position. Regarding
the second sub-option, the EPA requests comment on what degree of air
quality change should be considered minimal for purposes of this
analysis.\64\
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\64\ Note that under either sub-option, the state would be able
to show that control of precursor emissions from major stationary
sources would not be required if it could be demonstrated that such
emissions do not contribute significantly to PM2.5 levels
that exceed the standard, consistent with section 189(e).
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[[Page 15355]]
c. Area reclassified to Serious. A Moderate area can be
reclassified to a Serious area under two scenarios. Under the first
scenario, if a Moderate area fails to attain the standard by the
applicable attainment date, it would then be reclassified by the EPA as
a Serious area and the state would be required to develop and submit a
Serious area attainment plan within 18 months of reclassification.
Under the second scenario, the EPA could reclassify an area to Serious
prior to the Moderate area attainment date if the EPA determines that
it would be impracticable for the area to attain by the Moderate area
attainment date. (Section V of this preamble provides additional detail
on reclassifying a Moderate area to Serious under subpart 4.)
After an area has been reclassified to Serious, subpart 4 requires
a state's Serious area attainment plan to include the imposition of
more stringent control measures (best available control measures (BACM)
and best available control technology (BACT)) intended to bring the
area into attainment as expeditiously as practicable but no later than
the end of the tenth calendar year after designation. Given that the
CAA requires a more stringent new attainment plan for Serious areas,
under Option 1 the state would be required to identify the best
available measures for all sources of direct PM2.5 emissions
and emissions of PM2.5 precursors and adopt those measures
to attain the standard as expeditiously as practicable.\65\
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\65\ The EPA's two proposed options for determining BACM and
BACT are discussed in detail in Section VI.D of this preamble.
---------------------------------------------------------------------------
The BACM and BACT determination requires a more rigorous analysis
than the RACM and RACT analysis, and such measures collectively should
lead to a greater degree of emission reduction in the area than the
analysis of reasonable control measures for the Moderate area plan. For
this reason, under Option 1, if the state's previous Moderate area
attainment plan had indicated that new emissions reduction measures
from sources of one or more precursors were not needed to attain by the
end of the sixth calendar year after designation, then for the Serious
area plan the state would need to reevaluate the best control measures
addressing all PM2.5 precursors (i.e. SO2,
NOX, VOC, and ammonia) and require implementation of those
``best'' available control measures for all precursors in order to
bring the area into attainment as expeditiously as practicable, but no
later than the end of the tenth year after designation. Under Option 1,
any precursor demonstration that excluded one or more precursors from
regulation in the Moderate area plan would not by itself also be
sufficient to exclude the precursors from regulation in the Serious
area plan. Further analysis would be needed to determine if control
measures for those precursors qualify as ``best'' control measures. The
EPA has interpreted the starting point for considering ``best'' control
measures as including those control measures to reduce emissions of
direct PM2.5 or PM2.5 precursors that have been
adopted by any state, particularly those states with the most severe
PM2.5 air quality problems. (Note that in Section VI.D of
this preamble, more details are provided on BACM and BACT determination
criteria. The EPA is taking comment on two options for BACM and BACT
determinations--one that expresses it as a requirement independent of
the attainment demonstration, and one that expresses it as only those
``best'' measures that are needed for expeditious attainment no later
than the end of the tenth calendar year after designation. The BACM and
BACT determination approach adopted in the final rule accordingly will
determine whether all best available emission controls for a particular
precursor must be adopted or not in a Serious area).
d. NNSR. Under Option 1, the initial expectation is that the state
will need to address all four PM2.5 precursors under the
NNSR program pursuant to the CAA and as reinforced by the January 2013
NRDC v. EPA court decision. Pursuant to section 189(e), however, the
state may provide a demonstration showing that emissions of a
particular precursor from existing major stationary sources located in
the nonattainment area do not contribute significantly to
PM2.5 levels that exceed the standard in the area. Under
Option 1, this analysis under section 189(e) for major sources would be
completed independently from the analysis of reasonable control
measures conducted for attainment planning purposes. Such an analysis
would involve assessing the potential addition of precursor emissions
in the area due to potential new major stationary sources, and would
likely involve air quality modeling and other technical analyses by the
state, developed in consultation with the EPA (see Section III.C. of
this preamble for further discussion on such technical demonstrations).
Note that under this provision of the CAA, it might be possible that a
precursor would be considered important for attainment planning
purposes, but would not be regulated as a PM2.5 precursor in
NNSR permitting actions which, by definition, only apply to major
sources of the nonattainment pollutant. For example, it might be
possible that in a particular area the principal source of emissions of
a certain precursor could be from mobile and area sources but not from
major stationary sources of that precursor. The EPA requests comment on
all aspects of proposed Option 1 as discussed above.
2. Option 2: Single analysis demonstrating that all emissions of a
particular precursor from within the area do not significantly
contribute to PM2.5 levels that exceed the standard, meaning
that control requirements for emissions of the precursor from
stationary major and area sources, as well as mobile sources, would not
be required for expeditious attainment, control requirements for major
sources, or for NNSR permitting.
Option 2 would provide the state the opportunity to provide the EPA
with a scientifically credible technical analysis that would
demonstrate that one or more precursors do not contribute significantly
to the PM2.5 levels that exceed the standard, therefore
controls on those emissions would not be effective in reducing
PM2.5 levels in the area. As noted earlier in this section
of the preamble, section 302(g) of the CAA includes ``precursors'' in
the definition of ``air pollutant,'' but provides the EPA with some
discretion in defining how these terms should be interpreted. In
subpart 4, the CAA does not explicitly address control of precursors,
except with regard to major stationary sources in section 189(e). The
EPA interprets subpart 4 to require states to address PM2.5
precursors from all source categories in the evaluation of controls
needed for attainment in a given area, e.g., in the evaluation of RACM
and RACT level controls. By analogy to section 189(e), the EPA also
believes that there may be circumstances in which states may validly
demonstrate that control of one or more PM2.5 precursors is
not needed to attain the relevant NAAQS expeditiously.
Section 189(e) provides that precursor control requirements apply
to major stationary sources of precursors of PM2.5 if major
sources of PM are regulated under the attainment plan, unless it can be
shown that such precursor emissions do not contribute significantly to
exceedances of the relevant NAAQS in the area. Under Option 2, the EPA
relies on the discretion provided in section 302(g) and the section
189(e) concept of precursor emissions in an area having a significant
or insignificant effect on
[[Page 15356]]
PM2.5 concentrations that exceed the standard to propose two
precursor technical demonstration suboptions. Option 2A would allow the
state to provide a technical demonstration showing that all emissions
(i.e., from area, mobile and stationary sources in the area) of a
particular precursor collectively do not provide a significant
contribution to PM2.5 levels that exceed the standard in the
area. The kinds of analytical approaches that could be appropriate for
this type of ``contribution demonstration'' are described later in this
section.
For Option 2B, the EPA proposes to allow states to provide a
technical demonstration showing that PM2.5 concentrations in
the area are not sensitive to potential reductions or increases in
emissions of a particular precursor in the nonattainment area (e.g.
because the particular precursor is not the limiting factor in
secondary PM2.5 formation). More information is provided
later in this section about possible analytical approaches to assess
precursor ``sensitivities'' in an area (the optional technical
demonstration described for Options 2A and 2B hereafter will be
referred to as a ``precursor demonstration''). The EPA requests comment
on which of the two options (Option 2A or Option 2B) would be more
preferable, and why. The EPA encourages commenters to provide examples
of specific situations and areas in support of their recommendations.
These proposed options are consistent with the EPA's past practice
for determining which technologically and economically feasible
controls are necessary for expeditious attainment of the NAAQS.
Specifically, the EPA has interpreted the RACM requirement in the CAA
as requiring imposition of all reasonable controls as needed for
expeditious attainment or to advance the attainment date by at least 1
year. The statute does not require imposition of additional controls if
collectively such measures would not advance the attainment date. The
EPA maintains it is reasonable to treat regulation of PM2.5
precursors in a manner similar to the agency's treatment of direct
pollutants and therefore concludes that states should not be required
to implement control measures for a particular precursor or precursors
if such measures will have little or no impact on PM2.5
concentrations in the area or if the state demonstrates that all
emissions of a given precursor or precursors do not contribute
significantly to the PM2.5 NAAQS exceedances in the area.
a. Moderate area for which the state can demonstrate attainment by
the statutory attainment date or for which the state can demonstrate
that attainment by the statutory attainment date is impracticable. An
approved precursor demonstration under Option 2A would show that
emissions of the particular precursor from all types of sources do not
contribute significantly to PM2.5 levels that exceed the
standard. As proposed, this type of demonstration therefore by
definition would also satisfy the section 189(e) provision (which
allows the state to demonstrate that emissions from just major
stationary sources are not significant and therefore should not be
subject to control requirements, such as NNSR, that apply to major
stationary sources of direct PM2.5). Thus, the state could
possibly develop one precursor demonstration analysis that would serve
the purposes of both attainment planning and the section 189(e)
insignificant major source contribution demonstration.
The sensitivity analyses required under Option 2B would need to
assess a series of precursor emissions reductions and increases to
determine the sensitivity to air quality in the area. For example, the
analysis should evaluate the effect on PM2.5 concentrations
of various precursor emissions reduction scenarios appropriate to
determine the sensitivity of precursors for the area (as would be
relevant for an attainment plan); the analysis should also evaluate the
effect on PM2.5 concentrations of various precursor
emissions increase scenarios appropriate to determine the sensitivity
of precursors for the area, simulating the potential effect of the
addition of potential new major stationary sources (or major
modifications) to the nonattainment area under the NNSR program.
The EPA would evaluate the relevant analyses and other supporting
information provided by the state. By submitting a ``precursor
demonstration'' of this type, the state would not need to compile
additional information on precursor control measures, or to proceed
with actions to adopt and implement local or state regulations for the
precursor. Precursor demonstrations as described in Options 2A or 2B
could be conducted for Moderate areas for which the state can show that
it can attain the standard by the end of the sixth calendar year after
designation and for Moderate areas where the state's plan demonstrates
that attainment by such date would be impracticable.
The EPA believes that general legal authorities under the CAA
support the proposal of the overall precursor demonstration concept
described above, and that requesting comment on these proposed options
is appropriate from both a technical and a legal standpoint. This case
specific approach is technically appropriate because the mix of
PM2.5 precursor emissions and other relevant technical
factors varies from area to area. For example, in some areas, one
precursor may be abundant while the main precursor with which it reacts
may be less abundant. In such cases, reducing emissions of the less
abundant precursor (the ``limiting'' precursor) is generally more
effective for reducing PM2.5 concentrations. In another type
of area, the PM2.5 concentrations that exceed the standard
may be commonly dominated by primary PM2.5 emissions rather
than by secondarily formed PM2.5. The emissions of the
particular precursor from sources in the nonattainment area could be
found to have an insignificant contribution to PM2.5 levels
that exceed the standard, and the potential air quality improvement
from reducing emissions of the precursor in the area may be limited.
The EPA believes that proposing Options 2A and 2B is appropriate
from a legal standpoint based on authority provided the Administrator
in sections 302(g) and 301(a)(1) of the CAA. Section 302(g) includes in
the definition of ``air pollutant'' all the precursors to that
pollutant, and it allows the EPA Administrator to regulate precursors
for ``the particular purpose for which the term `air pollutant' is
used.'' Under section 301(a)(1), ``[t]he Administrator is authorized to
prescribe such regulations as are necessary to carry out his functions
under this Act.'' Thus, with Option 2, the EPA proposes a framework by
which the regulation of PM2.5 precursors for a specific
nonattainment area can be modified if the state provides the EPA with a
credible technical demonstration for exempting a particular precursor
which meets certain criteria and can be approved by the EPA. In
addition, as noted earlier the set of analyses described under Option
2A could also satisfy the section 189(e) provision allowing the state
to demonstrate that major stationary source emissions of a particular
precursor do not significantly contribute to levels that exceed the
standard. While this approach is not explicitly described in the
statute, the EPA believes that the proposed Option 2 approach to
precursor regulation is reasonable and allowed under the statutory
authority provided in sections 302(g) and 301(a)(1) noted above.
The EPA anticipates that development of an approvable
PM2.5 precursor demonstration by the state at the
[[Page 15357]]
beginning of the attainment plan development process will require a
substantial level of effort and consultation with the EPA. Such a
demonstration by the state would likely involve a combination of
technically rigorous and complex analyses, such as air quality modeling
and ambient data analyses. The extensive nature of this type of a
technical demonstration early in the attainment plan development
process is necessary because the demonstration serves as the basis for
limiting the applicability and associated control strategy decisions
only to specific precursors for both the attainment plan and for the
NNSR permitting program.
b. Area reclassified to serious. As noted earlier in this section,
a Moderate area can be reclassified to Serious under two scenarios.
Under the first scenario, if a Moderate area fails to attain the
standard by the end of the sixth calendar year after designation, it
would then be reclassified by the EPA as a Serious area, and the state
would be required to develop and submit a Serious area attainment plan
within 18 months of reclassification. Under the second scenario, EPA
could reclassify an area to Serious prior to the Moderate area
attainment date if it can be shown that it would be impracticable for
the area to attain by the Moderate area attainment date.
Proposed Option 2 would allow a ``precursor demonstration''
approach for Serious area plans in the same manner as for Moderate area
plans. However, if the state had previously submitted a precursor
demonstration that the EPA approved for the Moderate area attainment
plan, under either proposed Option 2A or 2B the state would be required
to review and update the precursor demonstration, taking into account
any changes in the emissions inventory and any other relevant
information or advances in technical tools developed since the initial
demonstration was approved. Examples of such information would be
improved emission estimation methods or emission factors for key source
categories; changes in precursor emissions inventories due to emissions
control programs or new source growth; the development of more advanced
technical tools to assess the effectiveness of precursor reductions;
and, updated information about new or more effective control
technologies or emission reduction techniques. Any precursor
demonstration that is approved as part of the Serious area attainment
plan would need to be revised and updated if the area cannot attain the
standard by the end of the tenth calendar year after designation and
seeks an extension under section 188(e) or does not attain the standard
by the applicable Serious area attainment date and is subsequently
subject to 5 percent annual emission reductions under section 189(d).
One other important factor to consider is the substantial amount of
time that can elapse between the submission of a Moderate area
attainment plan for a particular nonattainment area, and submission of
a Serious area attainment plan. The plan for a Moderate area is due
within 18 months of designation. Under the EPA's overall proposed
approach to attainment plan development, the state would be required to
evaluate control measures for all types of sources and for all
PM2.5 precursors in order to ensure attainment of the
standard as expeditiously as practicable. The full assessment to
identify reasonable control measures would involve a thorough
compilation and analysis of information on control technologies and the
technological feasibility of implementation of such measures for
sources in the area; the assessment of associated control costs and
economic feasibility of implementation; information on the time needed
for deployment and implementation of such control measures; and, the
resulting timeline for achieving emissions reductions.
If the Moderate area does not attain the standard by the end of the
sixth calendar year after designation, then as required by to the CAA,
the EPA would have 6 months to make a determination to that effect, and
the area would be reclassified to Serious. The state would then have 18
months to submit, at a minimum, a new attainment demonstration and
control strategy comprising BACM and BACT. Thus, under these
circumstances, these key Serious area plan elements would be due at
least 8 years after the EPA designated the area nonattainment, and more
than 6 years after the state submitted the original Moderate area plan.
Because of the potentially protracted timeline for developing,
implementing and revising as necessary the SIP for a given
PM2.5 nonattainment area under subpart 4, the EPA believes
it is reasonable for the state to be required to update any precursor
demonstration it had previously developed for the area if the area is
reclassified as Serious.
The EPA requests comment on the requirement for the state to review
and update any previously approved ``precursor demonstration'' if the
area fails to attain the standard by the applicable Moderate area
attainment date. The EPA also requests comment on the requirement for
the state to review and update any previously approved ``precursor
demonstration'' if the area fails to attain the standard by the
applicable Serious area attainment date.
c. NNSR. An approvable precursor demonstration under either Option
2A or Option 2B would evaluate emissions of a particular precursor from
all types of sources. Accordingly, if the state provides an approvable
precursor demonstration for all types of sources of a particular
precursor as described above, then under Option 2A, the state would
also be able to rely on the same technical demonstration to conclude
that emissions of that precursor just from major stationary sources in
the area do not provide a ``significant contribution'' to
PM2.5 concentrations in the area pursuant to section 189(e).
Thus, under Option 2A, the state would not need to apply the NNSR
control requirements for PM2.5 to that precursor in the
particular PM2.5 nonattainment area(s) for which the EPA
approves the demonstration.
Under Option 2B, the state would conduct analyses to determine the
sensitivity of PM2.5 levels in the area (that exceed the
standard) to potential increases in emissions (relevant for NNSR) and
decreases (relevant for attainment demonstrations). If the state
provided an approvable precursor demonstration showing that
PM2.5 concentrations are insensitive to potential increases
in emissions of a particular precursor in the area, then under Option
2B the state would be able to rely on this technical demonstration as
the basis for not regulating that precursor for major stationary
sources under NNSR.
Additionally, there could be a situation where the state finds that
emissions of another precursor (i.e., a precursor that was not the
subject of the initial precursor demonstration) from only major
stationary sources located in the nonattainment area could be
considered to have an insignificant contribution to PM2.5
levels that exceed the standard in the area (under Option 2A). For
example, mobile and area source emissions of a PM2.5
precursor could be determined to provide a larger contribution to
PM2.5 levels than major stationary sources in a given
nonattainment area and would be the focus of the attainment strategy,
and the major stationary source emissions of that same precursor might
have only a minimal contribution to PM2.5 levels. In this
situation, the state could develop a separate demonstration under
section 189(e) to support the exclusion of the
[[Page 15358]]
additional precursor from implementation requirements applicable to all
major stationary sources, including NNSR program requirements (assuming
the state analysis includes appropriate consideration of potential new
sources of the relevant precursor). With an approved demonstration
under section 189(e), major stationary sources of that precursor could
also be excluded from the NNSR control requirements for
PM2.5. The EPA seeks comment on all aspects of proposed
Option 2.
3. Option 3: An attainment planning analysis demonstrating that
control measures for all types of sources of a particular precursor are
not needed for expeditious attainment also would be deemed to meet the
section 189(e) technical demonstration requirement, meaning that the
state would not need to regulate emissions of the particular precursor
from major stationary sources under the NNSR permitting program or
other control requirements for major stationary sources.
Under proposed Option 3, the consideration of precursors in the
attainment planning process for Moderate and Serious areas would
closely follow the approach described for Option 1 (see Sections
III.B.1.a-c of this preamble). As described for Option 1, after
developing a comprehensive emissions inventory, the state would conduct
an analysis to identify the new reasonable control measures that need
to be adopted and implemented in order for the Moderate area to attain
the standard as expeditiously as practicable, but no later than by the
end of the sixth calendar year after designation (this analysis is
described in greater detail in Section III.B.1.a in this preamble). If
the state determines that adoption of additional economically and
technically feasible emission reduction measures for a particular
precursor are not necessary for expeditious attainment by the end of
the sixth calendar year after designation, and that such measures
collectively would not accelerate the attainment date by at least a
year, then for the purposes of this Moderate area attainment plan, the
state would not need to adopt such additional measures because they
would not be considered reasonable. (Note that the need for additional
emissions reductions of the particular precursor would have to be re-
evaluated if the area is reclassified to Serious, or if the area
submitted a SIP revision requesting an extension of the Serious area
attainment date under section 188(e)).
To clarify the intent of Option 3, unlike under Option 1, a
separate analysis to show that major stationary sources of a particular
precursor do not contribute significantly to PM2.5 levels in
a given PM2.5 nonattainment area for purposes of section
189(e) would not be needed. If the state's single analysis shows that
emission reduction measures are not needed from sources of a particular
precursor in order to demonstrate expeditious attainment, then under
proposed Option 3 the same analysis would also be considered adequate
to meet the requirements of section 189(e). In effect, the attainment
planning analysis would define the set of precursors that would be
subject to control under both the attainment plan and the NNSR
permitting program for the area.\66\
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\66\ Note that while the NNSR program needs to be implemented
from the effective date of an area's nonattainment designation, in
some situations the state would implement either its existing NNSR
program for PM2.5 or, in the absence of such program, 40
CFR part 51 Appendix S, the default NNSR program, until the EPA
approves the state's PM2.5 attainment plan and revised
NNSR regulations for PM2.5.
---------------------------------------------------------------------------
The rationale supporting the Option 3 approach focuses on the
section 189(e) emphasis on precursor control requirements. If control
measures are not needed in a Moderate nonattainment area to reduce
emissions of a particular precursor from all types of sources in order
to demonstrate attainment or to advance the attainment date, then under
the rationale of proposed Option 3, it would follow that the state
would not need to include any other control requirements that apply to
major stationary sources of that precursor, including control
requirements for PM2.5 under the NNSR program. The theory
for this option would be that if the state determines that new control
requirements for emissions of the particular precursor are not needed
for purposes of attainment planning because they would not contribute
to reducing PM2.5 levels that exceed the standard, then
other control requirements to address emissions of that precursor also
would not be needed. Note that under this option, the state also would
not be required to analyze the potential effect of increases in
emissions of the particular precursor (e.g., from the possible
permitting of new sources) on PM2.5 concentrations in the
area. The EPA requests comment on the rationale supporting Option 3.
Additionally, under Option 3, as was the case with Option 2, there
could be a situation where the state determines that control measures
for a particular precursor are generally needed in order to demonstrate
attainment as expeditiously as practicable, but that the major
stationary sources of that precursor that are located in the
nonattainment area have an insignificant contribution to
PM2.5 levels that exceed the standard in the area. Under
this Option 3, the EPA believes that section 189(e) provides the state
with the authority to develop a separate demonstration to show that,
even though control measures for a specific precursor emitted by
sources other than major stationary sources are necessary to
demonstrate expeditious attainment in an area, major stationary sources
of that precursor have an insignificant contribution to
PM2.5 concentrations that exceed the standard in the area.
Thus, controls from major stationary sources of that precursor would
not be required for either the attainment plan or the NNSR program.
More discussion on the potential options for precursor technical
demonstrations is included in Section III.C of this preamble. The EPA
seeks comment on all aspects of proposed Option 3.
The EPA also seeks comment on whether only one of these approaches
should be included in the final rule, or whether it would be
appropriate to include multiple approaches (e.g., both Options 1 and 2)
or a hybrid of two approaches by which a state could demonstrate that a
particular precursor would not need to be addressed in the attainment
plan or NNSR permitting program for a specific area.
C. Technical Approaches for Demonstrating That a Precursor Does Not
Need To Be Subject to Control Requirements
As noted earlier, in the preamble to the 2007 PM2.5
Implementation Rule, the EPA included a discussion allowing for the
state to submit a technical demonstration to show to the satisfaction
of the EPA that emissions of a particular precursor do not
significantly contribute to PM2.5 concentrations in the
area. In that preamble discussion, the EPA indicated that such a
demonstration should be based on the weight of evidence of available
information, and that any such demonstration by the state must be
approved by the EPA. The 2007 PM2.5 Implementation Rule also
discussed a number of types of analyses that could inform this
precursor demonstration, such as speciation data analyses, air quality
modeling studies, chemical tracer studies, emissions inventories, or
special intensive measurement studies to evaluate specific atmospheric
chemistry in an area. In the 2007 PM2.5 Implementation Rule,
the EPA intended to provide states with the flexibility to provide a
range of different supporting analyses that would be appropriate for
[[Page 15359]]
the area, recognizing that nonattainment areas differed in terms of
such factors as: (i) The mix of emissions sources located in the
nonattainment area and outside the area that are contributing to
PM2.5 concentrations in the area; (ii) the levels of
PM2.5 species measured in the area; (iii) the times of year
when highest PM2.5 concentrations are observed; (iv) the
topography of the area; (v) the severity of the nonattainment problem;
and, (vi) the patterns of emissions and population growth in and around
the nonattainment area. Under the 2007 PM2.5 Implementation
Rule, an important criterion for any technical precursor demonstration
provided by a state, however, was that it had to fairly represent the
information available to the state and the information made available
to it by the public.
For this proposed implementation rule, the EPA similarly proposes
that the state should have the flexibility to present multiple types of
analyses to support any demonstration for exempting a precursor from
control requirements as long as they fairly represent the available
information, and accordingly proposes that the EPA should review any
such demonstration based on the weight of evidence. Unlike in the prior
implementation rule, however, later in this section the EPA raises the
question of whether certain specific types of analyses should be
included as minimum required components of any precursor demonstration
that a state chooses to submit to the EPA for approval.
The preamble to the 2007 PM2.5 Implementation Rule
indicated that if a state developed a precursor demonstration as part
of its draft SIP, then in accordance with the state rulemaking process,
the demonstration would be subject to public review at the state level.
It also stated that, as required under any rulemaking process, the
state had to consider and provide a response in the rulemaking record
to any information or evidence brought forward by commenters during the
state's SIP planning, development and review process. By insuring that
this important issue was explicitly addressed and supported in the
attainment plan submitted to the EPA, the EPA could better evaluate the
precursor demonstration in accordance with its obligations under the
CAA. The EPA believes these are sound procedural steps for a state
rulemaking process, and the regulations being proposed as part of this
rule include similar language providing for public review of any
proposed precursor demonstration.
The 2007 PM2.5 Implementation Rule did not provide a
specific due date for submittal of any precursor demonstration,
although it was assumed that if a state were to pursue such a
demonstration, it would need to be done early in the attainment plan
development process and submitted to the EPA no later than the date of
the attainment plan submission itself. It was recommended that the
state develop any such demonstration in consultation with the
appropriate EPA Regional Office. In this proposal, the EPA is proposing
that if a state is interested in developing a PM2.5
precursor demonstration to support not regulating one or more
PM2.5 precursors in the attainment plan for an area, it
should consult with the EPA Regional Office as early as possible to
discuss appropriate analyses to be included. In its review of any
precursor demonstration provided by a state, the EPA will consider all
currently available information.
Under all three proposed precursor policy options described above,
the state would have the opportunity to provide a precursor
demonstration to meet the requirements of section 189(e) of the CAA.
Precursor demonstrations pursuant to section 189(e) should evaluate the
significance of the contribution of emissions of a particular precursor
from existing major stationary sources to fine particle concentrations
that exceed the standard. However, Options 2A and 2B differ from the
others in that they would provide the state with the ability to conduct
a precursor demonstration that comprehensively assesses the
contribution of a particular precursor from all types of sources in the
nonattainment area (not just from major stationary sources as
specifically addressed by section 189(e)) for the purposes of informing
which precursors must be addressed in both the attainment plan and in
the NNSR program for a particular PM2.5 nonattainment area.
(Note that Option 2 would not prevent the state from also conducting an
additional analysis under section 189(e), if warranted, to further
demonstrate that while all emissions of a particular precursor make a
significant contribution to PM2.5 levels that exceed the
standard, the emissions from just the major stationary sources of that
precursor collectively do not contribute significantly to
PM2.5 levels that exceed the NAAQS in the area.) The EPA has
considered three important questions regarding the scope and the
potential requirements associated with precursor demonstrations, and
requests comment on the questions and technical analysis options
presented below.
1. What is the geographic area from which precursor emissions should be
assessed?
In the 2007 PM2.5 Implementation Rule, the preamble
indicated that a precursor demonstration analysis addressing all source
types covered by the attainment plan should evaluate the impact of
emissions from sources located throughout the entire state. In
contrast, the 2008 PM2.5 NSR Rule suggested that a precursor
demonstration for NNSR purposes should evaluate emissions from major
stationary sources of a particular precursor located within the
nonattainment area only.
In determining which approach to include in the present proposal,
the EPA believes that it continues to be reasonable that any precursor
demonstration conducted to assess precursor significance for NNSR
purposes should evaluate emissions from major stationary sources of the
precursor from within the nonattainment area only. Section 189(e) is
included in a part of the CAA that specifically sets forth
nonattainment area requirements. For attainment planning purposes it is
less clear that the evaluation of emissions should be limited only to
sources from within the nonattainment area, because the state has
jurisdiction over emissions sources located throughout the state, and
can impose emission reduction requirements on contributing sources
outside of nonattainment areas if necessary to help bring areas with
violating monitors into attainment. At the same time, that argument
would suggest that section 189(e) should be interpreted as requiring
two different analyses of the impacts of precursors emitted from two
different geographic scales (from within the nonattainment area, as
well as from a broader area that influences air quality within the
nonattainment area, which could include the entire state). The EPA does
not believe such an interpretation is required, nor does it believe
that such multiple analyses are warranted. The statute simply refers in
general terms to precursor emissions from major stationary sources and
does not differentiate between control requirements for attainment
planning and control requirements for other purposes, such as NNSR
permitting. The statute also does not indicate that multiple analyses
must be done to assess major stationary source impacts from multiple
geographic scales. For these reasons, the EPA is proposing that
[[Page 15360]]
any precursor demonstration must include an evaluation of emissions
from sources located in the nonattainment area only. The EPA requests
comment on this proposed approach.
2. Should the EPA's guidance provide a specific list of analyses as
``minimum requirements'' that must be included in any proposed
precursor demonstration?
As noted above, the EPA encourages states to provide a range of
analyses to thoroughly understand the effect of precursor emissions on
PM2.5 concentrations in an area. In past discussions with
state representatives regarding potential approaches to regulating
PM2.5 precursors, some representatives have suggested that
this PM2.5 implementation rulemaking should include more
specificity about the minimum requirements for technical demonstrations
to support exclusion of PM2.5 precursors from regulatory
requirements in attainment plans, while others have recommended a less
prescriptive approach. One overarching issue is how detailed the EPA's
guidance should be with regard to the analytical requirements for any
proposed precursor demonstration. As noted earlier, technical
demonstrations can include data such as ambient speciation data
analyses, air quality modeling studies, chemical tracer studies,
emissions inventories, and/or special intensive measurement studies.
Air quality modeling analyses are discussed in more detail below.
a. Contribution analysis. Based on the statutory language of
section 189(e), it appears that, at a minimum, any precursor
demonstration conducted specifically pursuant to section 189(e) must
evaluate the contribution of current emissions of the relevant
precursor from existing major stationary sources to current (or most
recent) PM2.5 concentrations observed in the nonattainment
area (note that this type of analysis is possible under Option 1 and
Option 3). In addition, as described above, any precursor demonstration
under Option 2A must evaluate the contribution of emissions of the
relevant precursor from all sources (not just major stationary sources)
to current (or recent) PM2.5 concentrations observed in the
nonattainment area.
In light of the statutory language and the capabilities of existing
technical tools, the EPA proposes to require that the state conduct
such a contribution analysis at a minimum as part of any proposed
precursor demonstration, and that the state conduct an analysis using
an air quality modeling system that adequately accounts for the
PM2.5 pollution problem within the nonattainment area.
Several photochemical air quality models (e.g., Community Multi-Scale
Air Quality Model (CMAQ) and the Comprehensive Air Quality Model with
Extensions (CAMx)) can be used to quantify the contributions of
precursor emissions to PM2.5 concentrations in the area.\67\
For example, states could compare base case conditions (at current
precursor emissions levels) with a separate model simulation in which
the relevant precursor emissions are reduced by a large percentage. The
difference in the estimated PM2.5 concentrations provides
one indication of the relative significance of the precursor emissions
to PM2.5 concentrations in the area. This type of
contribution analysis can also be accomplished by using existing
advanced tools within photochemical air quality models, such as
``source apportionment'' capabilities which allow one to track
precursor emissions as they ``form'' PM2.5 (in the model)
and then report their contributions separately. The EPA requests
comment on including a contribution analysis as a minimum requirement
in any proposed precursor demonstration under Option 2A.
---------------------------------------------------------------------------
\67\ For more information on CMAQ, see http://www.epa.gov/AMD/Research/RIA/cmaq.html. For more information on CAMx, seehttp://
www.camx.com/.
---------------------------------------------------------------------------
b. Sensitivity analysis. The EPA notes that changes in
PM2.5 concentrations from current conditions in any area
will not necessarily be linear with respect to changes in
PM2.5 precursor emissions. Therefore, another important
question is whether any precursor demonstration should be required to
include an assessment of how ``sensitive'' the area will be to
potential reductions or increases in emissions of the relevant
precursor. Sensitivity analyses of potential reductions in emissions
would be most appropriate for attainment planning (and relevant to
Option 2B), whereas sensitivity analyses of potential increases in
emissions (e.g., relevant to NNSR permitting) would be appropriate for
all section 189(e) technical evaluations (possible under Options 1, 2B
and 3). Sensitivity analyses are important because of the complexity
and variability of the atmospheric chemistry affecting PM2.5
concentrations in different areas across the country.
The principal PM2.5 components that are secondarily
formed in the atmosphere are the result of chemical reactions between
various PM2.5 precursors (see Section II of this preamble
for more information on specific precursor reactions). Thus, the most
effective precursor strategies for reducing PM2.5
concentrations as part of attainment planning will vary from area to
area, depending upon which specific precursors play a role in forming
or limiting PM2.5 formation in the particular area.
Likewise, in evaluating which precursors would be appropriate to
exclude from regulation for NNSR in an area, it is important to
understand the current sensitivity of the atmosphere to potential
increases in precursor emissions that could result from the addition of
new sources to the nonattainment area.
One approach to assessing precursor sensitivities would be to
conduct a model simulation that evaluates the effect on
PM2.5 concentrations in the area resulting from a given set
of precursor emission reductions and emission increases. Simulations
could be conducted to assess a set of emission reduction and emission
increase scenarios deemed appropriate to determine the sensitivity of a
particular precursor in a specific area. Another approach that could be
used is a scientific technique called the ``decoupled direct method''
(DDM), which efficiently estimates the impacts on PM2.5
concentrations as a result of reducing or increasing precursor
emissions in the model.\68\
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\68\ See Simon et al., Memorandum to ozone NAAQS docket EPA-HQ-
OAR-2008-0699, ``Model-based Rollback Using the Higher Order Direct
Decoupled Method (HDDM),'' August 14, 2012.
---------------------------------------------------------------------------
For the reasons discussed above, the EPA also proposes that any
precursor demonstration conducted under proposed Option 2B must provide
a set of sensitivity analyses that evaluate the effect of a range of
emissions changes associated with measures considered economically and
technically feasible in a particular nonattainment area. Analyses that
reduce emissions of a particular precursor will help the state and the
EPA to understand how ``responsive'' the atmosphere would be to control
measures and how effective such reductions would be relative to other
precursor reductions. Although not specifically required for other
options under this proposed rule, precursor sensitivity analyses
evaluating the effect of varying degrees of potential precursor
reductions would provide meaningful information for any precursor
demonstration intended to show that a particular precursor does not
need to be addressed for attainment planning. Conversely, sensitivity
analyses that consider the effect of a range of potential emissions
increases in the nonattainment area will help the state and the EPA to
understand the potential response of PM2.5
[[Page 15361]]
concentrations to projected growth in the area, including potential
increases in emissions associated with potential newly permitted
sources that emit the precursor in question. Any precursor
demonstration intended to show that a particular precursor does not
need to be addressed for NNSR should include sensitivity analyses
evaluating the effect of varying degrees of precursor emission
increases in the area. The EPA recommends that the state conduct these
analyses using air quality modeling tools, but the state could provide
additional relevant analyses as well. The EPA requests comment on the
proposed requirement for inclusion of sensitivity analyses in any
precursor demonstration.
3. Should there be a ``bright line'' value to indicate that any
estimated contribution to annual average or 98th percentile
PM2.5 concentrations in the nonattainment area that exceeds
this value would be considered ``significant''?
In considering this question, it is helpful to first look to how
the concept of a significant, or insignificant, contribution has been
interpreted with regard to particulate matter in past PM10
guidance (Addendum to the General Preamble) and in other
PM2.5-related regulations, such as the CAIR. In the
Addendum, the EPA introduced the concept of a ``de minimis'' impact
from a source category for the purposes of the identification and
evaluation of BACM.\69\ While a later discussion in this proposal
addresses whether or not to maintain a similar de minimis source
category-based policy approach for future BACM and BACT source category
analyses, what is relevant for this precursor discussion is the EPA's
guidance in the Addendum on what could be considered a ``de minimis,''
or ``insignificant,'' ambient impact for purposes of PM10.
In the Addendum, the EPA indicated that a 1 [mu]g/m\3\ contribution to
the annual PM10 standard of 50 [mu]g/m\3\ (equal to 2
percent of the applicable NAAQS at the time), or a 5 [mu]g/m\3\
contribution to the 24-hour PM10 standard of 150 [mu]g/m\3\
(equal to 3.3 percent of the applicable NAAQS at the time)
presumptively would be considered ``de minimis.'' The EPA set forth
these levels in a Federal Register document, citing the discretionary
authority of an administrative agency to exempt from regulation
emissions (from source categories) ``which contribute only negligibly
to ambient concentrations which exceed the NAAQS.''
---------------------------------------------------------------------------
\69\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42011.
---------------------------------------------------------------------------
Developed pursuant to subpart 4, this past guidance on what could
be considered to be a de minimis or insignificant level of
PM10 contribution from a source category can potentially
inform this proposed rule for implementing the PM2.5 NAAQS.
Accordingly, this proposal includes two options: (i) A ``no-threshold''
option, and (ii) a proposed threshold option derived from the ambient
levels relied on for the PM10 source category de minimis
thresholds, but adjusted to account for the 2012 PM2.5
NAAQS.
The concept of ``significant contribution'' also has been a central
one with regard to interstate transport and the interpretation of
section 110(a)(2)(D) of the CAA. In past programs to address interstate
transport, such as the CAIR, an ``upwind'' state was identified as
potentially subject to additional emission control requirements if the
impact of SO2 and NOX emissions from the upwind
state to any nonattainment area in a downwind state exceeded 1 percent
of the relevant PM2.5 standard at a violating monitor in
another state. This was merely the first step of the analysis, but it
provided an initial threshold for determining whether further analysis
was warranted. In this proposal, the concept of a significant
contribution refers to the effect of emissions of a particular
precursor from sources within the state or nonattainment area to local
PM2.5 concentrations in the nonattainment area. The specific
purpose and context for which the phrase ``contribute significantly''
is used in section 189(e) is very different from the purpose and
context for which it is used in section 110(a)(2)(D). Thus, while a
previous interstate transport rule under section 110(a)(2)(D)
considered the combined impact of SO2 and NOX
emissions from an upwind state on ambient PM2.5 at a
violating monitor to be insignificant if it was less than 1 percent
(i.e., 0.15 [mu]g/m\3\ on an annual average basis), it would not
necessarily be appropriate to also consider the contribution from
emissions of a specific precursor within a nonattainment area to be
``insignificant'' if it does not exceed a similar 1 percent ambient
concentration level.\70\
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\70\ See Rule To Reduce Interstate Transport of Fine Particulate
Matter and Ozone (Clean Air Interstate Rule); Revisions to Acid Rain
Program; Revisions to the NOX SIP Call, 70 FR 25162 (May
12, 2005).
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There are a number of important distinctions between the section
110(a)(2)(D) interstate transport provision and the section 189(e)
provision addressing contributions of major stationary sources in a
nonattainment area which would indicate that the 1 percent of the NAAQS
significant contribution thresholds that have been included in section
110(a)(2)(D) rulemakings may not be relevant for purposes of section
189(e) precursor demonstrations. Section 110(a)(2)(D) was designed to
address the collective contribution of interstate transport of
pollution from multiple upwind states, while section 189(e) addresses
contributions from major stationary sources in a single nonattainment
area. In addition, section 110(a)(2)(D) requires that SIPs contain
provisions to eliminate the contributions that are deemed significant,
whereas section 189(e) merely requires that the emissions be
controlled. Given the differences in purpose, scale, and scope, the EPA
does not believe it is necessary for a threshold for ``significant
contribution'' to be the same for the two programs.
Based on the considerations discussed above regarding inclusion of
a potential significance ``threshold'' for purposes of this
PM2.5 implementation rulemaking, the EPA proposes and seeks
comment on two options. The first option would not specify a threshold
for what is a significant contribution to levels that exceed the
relevant NAAQS in a given area. Rather, the state would be required to
conduct a contribution analysis and sensitivity analyses as described
above to determine the estimated level of ambient impact from the
relevant precursor, and to provide the analyses to the EPA as part of
its precursor demonstration. The EPA would then consider these analyses
in addition to the other analyses provided by the state in determining
whether to approve the precursor demonstration. This option would
provide greatest flexibility for the state and the EPA to consider the
contribution analysis in combination with other information relevant to
the unique PM2.5 composition, source mix, and attainment
needs of each individual nonattainment area. See proposed 40 CFR
51.1006.
The second option would specify a ``significance'' threshold of 3
percent, such that if contribution modeling indicated that base year
emissions of the precursor from the relevant sources in the
nonattainment area (i.e. from major stationary sources for all analyses
pursuant to section 189(e); from all types of sources for the upfront
analysis in Option 2) leads to an ambient impact that exceeds 3 percent
of the PM2.5 NAAQS (e.g.,, 0.36 [mu]g/m\3\ on an annual
average basis for the 2012 primary annual PM2.5 NAAQS) at
monitors in
[[Page 15362]]
the nonattainment area, then the precursor demonstration would not be
approvable. The threshold equivalent to 3 percent of the relevant
PM2.5 NAAQS is proposed as reasonable because it is between
the two de minimis ambient contribution levels included in previous
PM10 guidance issued under subpart 4 to identify a de
minimis level of ambient contribution from a group of emissions
sources. The EPA acknowledges that the context in which the proposed
threshold is used here is different from the context in which it was
used in previous guidance. Absent any explicit language provided in the
statute to define significant contribution in the context of section
189(e), however, the only other existing guidance that in some way
addresses the concept of significant contribution for PM10
is the de minimis source category threshold values from the Addendum.
One benefit of having a specific threshold in the rule is that states
will have more concrete guidance on what could potentially be
approvable in a precursor demonstration.
The EPA therefore seeks comment on: (1) Whether a specific
significant contribution threshold should be included in the final rule
or not; (2) if the commenter considers inclusion of a specific
threshold to be appropriate, whether the proposed 3 percent of the
relevant NAAQS threshold and its basis would be appropriate, and why;
and (3) whether a threshold with an alternative level and supporting
rationale would be more appropriate.
IV. What are the EPA's proposed requirements for Moderate area
attainment plans?
Sections 189(a), (c), and (e) of the CAA require that Moderate area
attainment plans contain the following: (i) An approved permit program
for construction of new and modified major stationary sources (section
189(a)(1)(A)); (ii) a demonstration that the plan provides for
attainment by no later than the applicable Moderate area deadline or a
demonstration that attainment by that deadline is impracticable
(section 189(a)(1)(B)); (iii) provisions for the implementation of RACM
and RACT no later than 4 years after designation (section
189(a)(1)(C)); (iv) quantitative milestones that will be used to
evaluate compliance with the requirement to demonstrate reasonable
further progress (RFP) (section 189(c)); and, (v) evaluation and
regulation of PM2.5 precursors (in general to meet RACM and
RACT and other attainment planning requirements, and as specifically
required for major stationary sources by section 189(e)). Other subpart
1 requirements for attainment plans continue to apply to
PM2.5 nonattainment areas subject to subpart 4 and include
the following: (i) a description of the expected annual incremental
reductions in emissions that will demonstrate RFP (section 172(c)(2));
(ii) emissions inventories (section 172(c)(3)); (iii) other control
measures (besides RACM and RACT) needed for attainment (section
172(c)(6); and, (iv) contingency measures (section 172(c)(9)).
Each of these statutory requirements is described more fully below.
In certain cases, the EPA is proposing options for implementing a
statutory requirement for purposes of the PM2.5 NAAQS. Based
on comments the agency receives, the EPA will then promulgate
regulations to implement the statutory requirements in the final action
on this proposal, as appropriate. The EPA notes that its longstanding
guidance on these statutory requirements is embodied in the General
Preamble and the Addendum.\71\ Where appropriate, this proposal notes
options that may vary from past EPA guidance and explains the EPA's
reasons for considering an amended approach.
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\71\ See the Federal Register published on April 16, 1992 (57 FR
13498, 13536, 13537, 13538, 13539, 13540, 13541, 13542, 13543, 13544
and 13545); and see the Federal Register published on August 16,
1994 (59 FR 41988).
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A. Plan Due Dates
Section 189 of the CAA specifies the schedule by which states must
submit attainment plans for the PM2.5 NAAQS. Specifically,
CAA section 189(a)(2)(B) requires states to submit an attainment plan
that meets Moderate area attainment plan requirements no later than 18
months from the date of a nonattainment designation.\72\ To be
consistent with this subpart 4 deadline for the attainment plan
submission, the EPA is proposing that states must also submit those
elements of the attainment plan required under subpart 1 (i.e.,
emissions inventories and contingency measures) no later than 18 months
from the date of designation of the area. The provisions of subpart 4
do not explicitly specify when states must submit these attainment plan
elements that carry over from subpart 1, so the EPA needs to interpret
the requirements of the CAA to meet the objectives of the attainment
plan requirements. The EPA believes that requiring states to submit the
necessary emissions inventory (or inventories) either before or at the
same time as the other attainment plan elements due under subpart 4 is
necessary, given that a state will need information contained in the
emissions inventory for other elements of its Moderate area attainment
plan, such as its precursor analysis, analysis of RACM and RACT and
additional reasonable measures, and attainment demonstration modeling.
The EPA also believes it is reasonable to require the state to submit
contingency measures, which need to be adopted and ready for immediate
implementation in the event a nonattainment area fails to meet RFP
requirements or fails to attain the PM2.5 NAAQS by the
applicable attainment date, simultaneous with the other elements of the
attainment plan. The state's evaluation of what emissions controls are
appropriate to meet the contingency measure requirement is closely
related to other aspects of the attainment plan, such as addressing the
proper pollutants for control in a given area, the appropriate sources
for controls beyond those already required for RACM and RACT for the
area, and the amount of emission reductions that the contingency
measures should achieve, based upon the facts and circumstances of the
attainment plan for the area.
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\72\ The EPA notes that Congress provided different statutory
deadlines for submission of attainment plans under subpart 1 and
subpart 4. Under section 172(b), the EPA is directed to establish
the date for the attainment plan submission, but it can extend no
later than 3 years from the date of a nonattainment designation. By
contrast, under section 189(a)(2)(B), the statute provides that
states must make the attainment plan submissions within 18 months
after designation. Due to the December 2013 court decision in NRDC
v. EPA, however, the EPA promulgated an alternative submission date
of December 31, 2014 for attainment plans for the 1997
PM2.5 and 2006 PM2.5 NAAQS in order to provide
a reasonable, prospective due date for attainment plans that must
comply with subpart 4 requirements and to clarify the requirements
that a state must meet prior to redesignation of a PM2.5
nonattainment area. See 79 FR 31566 (June 2, 2014).
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The EPA believes that the statutory deadline for submission of a
Moderate area attainment plan for the PM2.5 NAAQS is
straightforward and, absent unusual circumstances, the statute requires
states to make such attainment plan submissions within 18 months after
the effective date of a nonattainment designation for an area. See
proposed 40 CFR 51.1003(a). Although nothing in the CAA prohibits
states from making separate attainment plan submissions to meet the
individual statutory requirements for attainment plans in advance of
the required date, the EPA presumes that development and submission of
all of the attainment plan elements simultaneously will be most
effective, both for the state in the first instance and for the EPA in
reviewing the state's submission. For example, the EPA designated areas
as nonattainment for the 2012 PM2.5
[[Page 15363]]
NAAQS with an effective date of April 15, 2015; states will thus be
required by statute to submit Moderate area attainment plans for any
nonattainment areas to the EPA no later than October 15, 2016.
B. Emissions Inventory Requirements
Pursuant to its authority under section 110 of title I of the CAA,
the EPA has long required states to submit inventories of the emissions
of criteria pollutants and their precursors. The EPA codified these
requirements in 40 CFR part 51, subpart Q in 1979 and amended them in
1987. Additionally, the 1990 CAA Amendments revised many of the
provisions of the CAA related to attainment of the NAAQS and the
protection of visibility in mandatory Class I federal areas (certain
national parks and wilderness areas). These revisions established new
emissions inventory requirements applicable to areas that were
designated nonattainment for certain pollutants. In the case of
particulate matter, Congress did not create a specific emissions
inventory requirement in subpart 4 that would supersede the emissions
inventory requirement under subpart 1. Thus, the section 172(c)(3)
emissions inventory requirements continue to apply, and that provision
explicitly requires ``a comprehensive, accurate, and current inventory
of actual emissions of the relevant pollutants'' in the nonattainment
area. In addition, the specific attainment plan requirements for the
PM2.5 NAAQS set forth in section 189(a) and associated
modeling requirements make an accurate and up-to-date emissions
inventory a critical element of any viable attainment plan. Because of
the nature of PM2.5, the EPA concludes that the statutory
requirements for emissions inventories need further elaboration through
additional regulatory requirements as described below.
Emissions inventory data serve as the foundation for various types
of analyses that enable states to evaluate the degree to which
different emissions sources contribute to the nonattainment problem in
a given nonattainment area and enable states to estimate the air
quality improvement that can be achieved through different control
measures. States should use the best available, current emissions
inventory information for attainment plan development, because high
quality emissions inventory data are essential for the development of
an effective control strategy. To assist states in preparing complete,
high quality inventories, the EPA provides guidance for developing
emissions inventories called ``Emissions Inventory Guidance for
Implementation of Ozone and Particulate Matter National Ambient Air
Quality Standards (NAAQS) and Regional Haze,'' which is available from
http://www.epa.gov/ttn/chief/eidocs/eiguid/index.html. This guidance is
commonly called the ``SIP Emissions Inventory Guidance.'' The EPA
recommends that states consult this guidance while developing the
emissions inventories to meet statutory and regulatory requirements.
1. How do states meet the inventory requirements for the
PM2.5 NAAQS?
Neither section 172(c)(3), nor the provisions specifically
applicable to attainment plans for the PM2.5 NAAQS in
subpart 4, specify how states should meet statutory emissions inventory
requirements. Although section 172(c)(3) explicitly requires that
states submit only ``an'' emissions inventory in conjunction with other
elements of an attainment plan, that term is ambiguous in the context
of the PM2.5 NAAQS, and the EPA is authorized to interpret
that term and to impose additional requirements as necessary and
appropriate. In addition, pursuant to section 301, the EPA has
additional authority to promulgate regulations as necessary for the
implementation of the PM2.5 NAAQS, including requirements
pertaining to emissions inventories. Accordingly, the EPA is proposing
specific emissions inventory requirements it considers necessary to
effectuate the attainment plan requirements of the CAA for the
PM2.5 NAAQS.
There are three key facets of the EPA's proposed emissions
inventory requirements, as laid out below: (i) The type of inventories
required; (ii) the timing of submittal of these inventories; and, (iii)
the content of these inventories. These inventory requirements are
being proposed to provide all of the requirements in a concise and
direct way. In some cases, the EPA's rationale for the content
requirements needs additional supporting description, which is provided
in the subsequent text related to the use of seasonal inventories,
required pollutants, etc.
First, the EPA believes that in order to implement the
PM2.5 NAAQS effectively, states will be required to submit
at least two separate and distinct nonattainment area emissions
inventories as elements of an attainment plan. The first emissions
inventory is relevant for assessing the current or base year emissions
in the nonattainment area; the second emissions inventory is a
projected inventory relevant for assessing emissions in the target
attainment year in the nonattainment area. The first type of inventory
is expressly required by section 172(c)(3), and is called the ``base
year inventory for the nonattainment area.'' The second type of
inventory the EPA is proposing to require under section 301(a)(1) as
necessary to implement the attainment demonstration requirement of
section 189(a)(1)(B), and is called the ``attainment projected
inventory for the nonattainment area.'' See proposed 40 CFR 51.1000.
The need for this latter inventory stems from the need for both the EPA
and the public to be able to compare, during their reviews of the plan,
the base year inventory against the attainment projected inventory for
the nonattainment area. For these reasons, the EPA is proposing to
establish the regulatory requirement that attainment plans must include
a base year inventory for the nonattainment area and an attainment
projected inventory for the nonattainment area.
Second, as noted above, to meet the statutory requirements for
submission of attainment plans under subpart 4, the EPA believes that
states must meet the same submission schedule for these emissions
inventories as for the other elements of an attainment plan, i.e.,
within 18 months after the effective dates of the designation of the
nonattainment area. This schedule must apply to both of these emissions
inventories because they are necessary for effective evaluation of the
attainment plan as a whole. Consequently, under the authority of
section 172(b), the EPA is proposing to establish the regulatory
requirement that emissions inventories be submitted by 18 months after
designation.
Third, the EPA proposes to establish specific requirements for both
the base year inventory for the nonattainment area and for the
attainment projected inventory for the nonattainment area in order to
implement the PM2.5 NAAQS most effectively. Accordingly, the
EPA proposes that the base year inventory for the nonattainment area
must meet the following minimum criteria (a) through (g):
(a) The inventory year must be one of the 3 years used for
designations or another technically appropriate inventory year. Another
inventory year may be chosen under specific circumstances (e.g., to
account for a change in sources in the nonattainment area, changes in
nonattainment area boundaries, or significant time lag between
designations and preparation of the inventory) with consultation from
the appropriate EPA Regional Office. This requirement is intended to
ensure
[[Page 15364]]
that the inventory will represent the emissions sources whose
contributions resulted in a nonattainment designation for the area.
(b) The inventory must include actual emissions of all sources
within the nonattainment area. This requirement stems directly from the
wording of section 172(c)(3). Sources outside of the nonattainment area
are explicitly not included in the section 172(c)(3) requirement with
the words ``in such area.'' Furthermore, the EPA interprets the Act
requirement for ``actual emissions from all sources'' in section
172(c)(3) as intending to include all emissions that may contribute to
the formation of PM2.5 within the nonattainment area.
(c) The emissions values must either be annual total emissions or
average-season-day emissions, as appropriate for the nonattainment
problem. The rationale for providing annual or seasonal emissions must
be included as part of the plan. A discussion of the EPA's rationale
for proposing the option of seasonal or annual inventories is provided
in Section IV.B.4 of this preamble.
(d) As discussed above and consistent with past implementation rule
requirements, the inventory must include emissions of direct
PM2.5 (both filterable PM2.5 and condensable
PM2.5), as well as all scientific PM2.5
precursors (SO2, NOX, VOC and ammonia). A
discussion of the EPA's rationale for proposing this requirement is
provided in Section IV.B.5 of this preamble.
(e) The emissions thresholds for which emissions sources must be
reported as point sources must be followed from the Air Emissions
Reporting Rule (AERR), 40 CFR part 51, subpart A. This requirement is
consistent with past implementation rules and is needed to define the
data structure (as opposed to the emissions values themselves) of the
emissions submitted to the EPA. A discussion of the use of 40 CFR part
51, subpart A, for the emissions thresholds and data reporting elements
is provided in Section IV.B.6 of this preamble.
(f) The detail of the emissions included in the inventory must be
consistent with the detail required by 40 CFR part 51, subpart A. For
example, all emissions must be subdivided to individual emissions
processes within a facility or county. While these details should
underlie the inventory, the emissions included in the attainment plan
can be summarized. This requirement is consistent with the 2007
PM2.5 Implementation Rule and is needed to define the data
structure (as opposed to the emissions values themselves) of the
emissions submitted to the EPA.
(g) If the base year inventory for the nonattainment area is
submitted to the EPA as a separate plan submission (i.e., severed from
the overall attainment plan and provided separately), the inventory
must still meet all public review requirements associated with that
plan. See proposed 40 CFR 51.1008(a)(1).
For the attainment projected inventory for the nonattainment area,
the EPA also proposes to promulgate more specific requirements in order
to implement the PM2.5 NAAQS most effectively. Accordingly,
the EPA proposes that the attainment projected inventory must meet the
following minimum criteria (a) through (g):
(a) The year of the projected inventory must be the first year for
which attainment is demonstrated by the modeled attainment plan.
(b) The emissions values must be projected emissions of the same
sources included in the base year inventory for the nonattainment area
(i.e., only those located within the nonattainment area) and any new
sources. The projected emissions values should be the best available
representation of expected emissions, and thus should take into account
emissions growth and contraction, facility closures, new facilities,
new controls and other factors forecast to occur between the base year
and the attainment year. In deciding what factors are relevant, states
should consider factors affecting projected emissions that could
significantly alter the conclusions of the attainment demonstration.
(c) The temporal period of emissions must be the same temporal
period (annual or average-season-day) as the base year inventory for
the nonattainment area.
(d) Consistent with the base year inventory for the nonattainment
area, the inventory must include all emissions of direct
PM2.5 (both filterable and condensable PM2.5), as
well as all emissions of all scientific precursors (SO2,
NOX, VOC and ammonia).
(e) The same sources reported as point sources in the base year
inventory for the nonattainment area must also be provided as point
sources in the attainment projected inventory for the nonattainment
area. Likewise, nonpoint and mobile source projected emissions must
also be provided using the same detail (e.g., state, county and process
codes) as the base year inventory.
(f) The detail of the emissions included must be consistent with
the level of detail in the base year inventory (i.e., as required by 40
CFR part 41, subpart A).
(g) If the attainment projected inventory for the nonattainment
area is submitted to the EPA as a separate plan submission (e.g.,
severed from the overall attainment plan and provided separately), the
inventory must still meet all public review requirements associated
with that SIP submission. See proposed 40 CFR 51.1008(a)(2).
2. Are there new inventory requirements in this proposed rule that have
not been included in previous rules?
This proposed rule includes more specific requirements for
emissions inventories than past implementation rules. First, the EPA
proposes to require the attainment projected inventory for the
nonattainment area. In practice, some states were providing this
information at the request of their respective EPA Regional Offices,
but it was not a specific requirement. The EPA believes that a specific
requirement is necessary to ensure that the EPA and the public can
reasonably assess the changes in emissions in the nonattainment area
that the state maintains demonstrate that the area will attain the
standard or that it is impracticable to attain the standard by the
attainment date. Without such information, there is no way for the EPA
to assess the projected emissions changes in the nonattainment area
that the state asserts contribute to attainment. In addition, this
proposed requirement would support the EPA's first proposed approach
for conducting an RFP analysis as described in Section IV.F of this
preamble.
This proposed rule also is more specific about the requirements for
the emissions inventories submitted. While the various criteria (a)
through (g) listed above have been implicit in prior rules and
associated guidance, the EPA believes that not having these specific
requirements has caused confusion and inconsistencies across attainment
plan inventories in the past. Thus, the EPA is proposing to require
these minimum criteria in this proposed rule. Furthermore, the option
for using only seasonal inventories in some attainment plans is a new
facet of this rule, further described in Section IV.B.5 of this
preamble.
3. Are there other inventory requirements from earlier PM2.5
implementation rules that the EPA is proposing to retain or change?
The 2007 PM2.5 Implementation Rule required states to
submit specific emissions inventories in connection with the RFP
requirements of section 172(c)(2) under subpart 1. The EPA believes
that a separate emissions
[[Page 15365]]
inventory will be important to illustrate how a nonattainment area may
achieve incremental emissions reductions toward attainment, and would
be appropriate in light of the agency's proposed approaches for states
to meet the statutory RFP requirements. Past EPA guidance with respect
to RFP requirements under subpart 4 has not required any explicit,
separate emissions inventory for this purpose for PM10
NAAQS. For this reason, the EPA describes this issue and proposed
approaches more fully in Section IV.F of this preamble.
The 2007 PM2.5 Implementation Rule also required states
to submit a statewide base year emissions inventory as part of the
attainment plan. The EPA proposes not to include this statewide
emissions inventory requirement in this rule. Subpart 4 does not
expressly require such an inventory, and the EPA does not believe that
it is needed for successful attainment of the PM2.5 NAAQS.
Furthermore, statewide inventories are already required as part of the
AERR (40 CFR part 51, subpart A) on a triennial basis. While these
inventories do not receive the same level of scrutiny as inventories
associated with attainment plans, the EPA believes that this existing
statewide requirement is sufficient for understanding the
PM2.5 nonattainment problems nationally and assessing the
quality of inventories proposed to be required by this rule.
4. Why is the EPA proposing to permit seasonal inventories to meet the
inventory reporting requirements?
The statute does not explicitly address whether the emissions
inventory required under section 172(c)(3) should include emissions
throughout an entire calendar year or emissions during some shorter
portion of the year that may be appropriate for implementation of a
particular NAAQS. In the case of the PM2.5 NAAQS, the
standards currently include both annual NAAQS and 24-hour NAAQS. With
respect to the annual NAAQS, the form of the NAAQS includes monitored
ambient PM2.5 values at all times throughout the course of
the year and thus an annual emissions inventory is necessarily required
for development of an appropriate attainment plan for a given area. In
the case of the 24-hour NAAQS, however, the form of the NAAQS is based
upon monitored ambient PM2.5 values on particular days with
high levels of PM2.5, and in some nonattainment areas those
days may occur only during a distinct and definable season of the year.
The EPA considers it appropriate to interpret the emissions inventory
requirements of the CAA in light of the specific inventory needs that
are relevant for the NAAQS in question, and in the case of the
PM2.5 NAAQS, the inventory requirement may thus include both
an annual emissions inventory for the attainment area, and a seasonal
emissions inventory for the area as appropriate for the attainment plan
at issue.
In contrast with the annual PM2.5 NAAQS, the 24-hour
PM2.5 NAAQS are designed to protect against peak exposures.
Thus, for the 24-hour PM2.5 NAAQS, there are circumstances
in which the EPA believes that only seasonal emissions inventories may
be required for attainment planning purposes. The EPA proposes to allow
states to use only seasonal inventories for attainment plan development
for attaining the 24-hour PM2.5 standard in areas that are
nonattainment for only the 24-hour standard. In the event that it is
appropriate to rely on a seasonal emissions inventory, the state should
confer with the EPA concerning the exact length of the season and the
start and stop dates of the season. The duration and start and stop
dates of the season will be an important component of the attainment
plan and must be approved by the EPA along with other elements of the
attainment plan for a given nonattainment area. The EPA further
proposes to require that seasonal inventories must use average-season-
day emissions values for this purpose. The average-season-day is
defined as the sum of all emissions during the applicable season
divided by the number of days in that season. The nature of some
seasonal PM2.5 emissions sources (e.g., residential wood
combustion) does not allow for only weekday emissions to be included in
the inventory, therefore all days must be included. The state would
need to explain the rationale for the duration of the season used for
the inventory as part of the attainment plan submission. To justify the
use of a seasonal inventory, the state must demonstrate why a seasonal
attainment plan is appropriate for the particular PM2.5
nonattainment area in question.
5. Why is the EPA requiring certain pollutants be included in the
inventories?
The EPA is proposing that states must submit emissions inventories
that include all emissions of direct PM2.5 and all emissions
of all PM2.5 precursors: SO2, NOX, VOC
and ammonia. Furthermore, the inventory must differentiate between the
condensable and filterable portions of direct PM2.5
emissions. Section II.B of this preamble describes the background
needed to understand the importance of including these precursors in
emissions inventories for attainment plan purposes for the
PM2.5 NAAQS. Emissions information about PM2.5
and its precursors is a necessary precondition to meeting other core
attainment plan requirements, such as effective evaluation of control
measures and adequate demonstration of projected future attainment of
the NAAQS through modeling. The EPA notes that with respect to
requiring states to include emissions of direct PM2.5 and
PM2.5 precursors in emissions inventories, the agency is
following the requirements it established for the PM2.5
NAAQS in the past. Section 172(c)(3) explicitly requires states to
submit a ``comprehensive, accurate, and current inventory of actual
emissions of the relevant pollutants'' and the EPA concludes that in
order to meet these basic statutory requirements for the
PM2.5 NAAQS, states must address PM2.5 and all
PM2.5 precursors in their emissions inventories.
The EPA requires air agencies to use the best available
methodologies for estimating emissions of PM2.5 and its
precursors. It should be noted that for ammonia, in particular, updated
emissions estimating methodologies for animal feeding operations are
under development using data collected during the period 2007-2009 from
representative operations pursuant to the National Air Emissions
Monitoring Study.\73\ The EPA is hopeful that such updated
methodologies will help to reduce uncertainties in current ammonia
inventories and will improve the quality of future emissions
inventories needed for implementing the PM2.5 NAAQS.
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\73\ For more information on the NAEMS study, see: http://www.epa.gov/agriculture/airmonitoringstudy.html.
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6. Why is the AERR used to define data elements and data methods that
are required for the emissions inventories required by this rule?
Because the provisions of the CAA do not specifically state the
form of the emissions information to be reported to the EPA for meeting
their attainment plan inventory requirement, it is necessary for the
EPA to prescribe specifically the data elements of those emissions
inventories. Distinct from the emissions values (i.e., how much
emissions derive from each source or source category), the emissions
elements (i.e., how they are reported) refer to the reporting
definitions, data codes and required data fields. The EPA proposes
[[Page 15366]]
that states must use the emissions elements from 40 CFR part 51,
subpart A, in preparing their inventories submitted to the EPA for
implementing the PM2.5 NAAQS. This is consistent with past
requirements for the form of emissions inventories.
In addition to defining the data elements, 40 CFR part 51, subpart
A also requires states to submit emissions information to the EPA. The
EPA is not referring to those emissions submission requirements here,
but rather the emissions elements--the definitions, data codes and
required data fields. Below, the EPA addresses the issue of whether the
emissions values submitted through the AERR are relevant to the
inventory requirements of this proposed rule (see Section IV.B.8 of
this preamble).
As noted earlier, the EPA recommends that states consult the SIP
Emissions Inventory Guidance in preparing the inventories needed for
this rule. In addition to the AERR, this guidance includes definitions
for data fields that are not required by the AERR, such as seasonal
emissions values and other fields that are optional in the data system
that collects data submitted for the AERR. The EPA is updating the SIP
Emissions Inventory Guidance in coordination with this proposal. It
provides specific guidance to air agencies on how to develop base year
inventories for the nonattainment area and attainment projected
inventories for 8-hour ozone, PM2.5, and regional haze SIPs.
While the AERR sets forth requirements for data elements and
definitions, the guidance complements these requirements, defines all
data elements (even those that are voluntary AERR elements), and
indicates how the data should be prepared, documented and publicly
reviewed for attainment plan submissions.
7. How do emissions inventories support modeling for attainment
demonstrations?
This section attempts to clarify the difference between the
inventories required to be a part of a state's Moderate area attainment
plan submission (as described earlier) and other modeling inventories
that are also relevant for attainment planning. While the EPA is not
proposing additional modeling inventory requirements in this rule
(i.e., for which a state must submit an emissions inventory to the
EPA), to meet the attainment demonstration requirements of CAA sections
189(a)(1) and 189(b)(1), states will need to submit an attainment
demonstration (which includes air quality modeling) to show how the
area will either attain the NAAQS by the applicable attainment date or
that the area cannot attain by the attainment date. The modeled
attainment demonstration requirements for Moderate areas are described
fully in Section IV.E of this preamble.
As part of this demonstration, the EPA presumes that states will
need to prepare attainment demonstration modeling inventories for both
a modeled base year and projected attainment year. Respectively, these
are called the ``base year (baseline) inventory for modeling'' and the
``attainment projected inventory for modeling.'' These inventories
contain emissions for all regions (i.e., not just the nonattainment
area) within the modeling domain being used for the attainment plan
modeling demonstration, which typically includes counties and even
states outside of the nonattainment area. They include detailed spatial
and temporal elements needed to support air quality modeling. States
should follow the requirements laid out in Section IV.E of this
preamble and the procedures described in the SIP Emissions Inventory
Guidance and the Air Quality Modeling Guidance to meet the minimum
requirements for documentation and emissions summaries supporting
modeling demonstrations.\74\
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\74\ The EPA encourages states to consider in any baseline,
modeling, and SIP attainment inventory used and/or submitted to
include emissions expected from projects subject to general
conformity and emissions from wildland fire that reasonably may be
expected in the area.
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The base year inventory and projected attainment year inventory
include emissions from only within the nonattainment area. The EPA
expects that modeling inventories will be consistent with those
nonattainment area inventories; however, some exceptions may exist.
Where possible, the nonattainment area base year and projected
attainment year inventories can be a sum (for annual data) or average
(for PM2.5 season-day data) of day-specific or hour-specific
data used for modeling. In some cases, however, this approach may not
be sufficient for modeling purposes. For example, greater spatial and
temporal detail are needed for on-road mobile modeling inventories as
compared to the base year inventory for the nonattainment area. For the
nonattainment area base year inventory, one goal is to allow for the
repeatability of the approach in order to create average, seasonal or
annual inventories for use in rule requirements, such as reasonable
further progress or conformity demonstrations. That goal is not
necessarily compatible with the modeling need for greater spatial and
temporal detail. In cases where some differences are unavoidable, air
agencies should attempt to promote consistency where feasible.
The AERR includes both triennial and annual statewide reporting
requirements, with more extensive reporting requirements for triennial
inventory years. For the interim annual inventories, reporting is
limited to emissions data from only the larger point sources (Type
``A'' sources), as defined by Appendix A of 40 CFR part 51, subpart A.
For the triennial inventories, lower point source thresholds are given
in Appendix A, consistent with the definition of major sources in 40
CFR part 70, and all other sources of emissions must be reported as
nonpoint or mobile sources on a county basis.
In the past, some states have incorrectly asserted that their AERR
submission meets the requirements for base year inventories required by
past implementation rules. To avoid confusion, the EPA provides here
the limited circumstances in which the AERR emissions inventories can
meet the base year inventory for the nonattainment area requirement for
Moderate areas. The following conditions must be met to use AERR
inventories for attainment planning:
(a) The AERR emissions inventory must have gone through the public
review process required for attainment plans.
(b) The AERR emissions inventory needs to include all sources of
emissions and all pollutants required for the base year inventory for
the nonattainment area. This is only possible if the inventory year for
the base year inventory for the nonattainment area aligns with a
triennial AERR year, because the data system implementing the AERR only
accepts emissions from point sources and not other source categories in
non-triennial years.
(c) The EPA must be accepting data for the inventory year.
Inventories are allowed to be submitted to the AERR for a given year
for only a limited time during the development cycle of the National
Emissions Inventory.
(d) The AERR submission must include emissions from all relevant
sources as described for the base year inventory for the nonattainment
area requirements. In some cases, the AERR requirement can be met
without electronically ``submitting'' emissions, which would not meet
the requirements for the base year inventory for the nonattainment
area. For example, states may elect to accept the EPA estimates for
some nonpoint emissions sectors,
[[Page 15367]]
but this would not meet the requirements of section 172(c)(3). In
addition, the AERR revision finalized in February 2015 replaces the
prior requirement of reporting onroad mobile and nonroad mobile source
emissions with a requirement for reporting the input parameters that
can be used to run the EPA models to generate the emissions. If
choosing to use an AERR submission to meet the base year inventory for
the nonattainment area requirement, the state should submit the
nonattainment area emissions, irrespective of the options provided to
meet the AERR requirements. Since the ``statewide'' emissions are
actually provided for individual point sources and counties, the EPA
believes that these resolutions can be sufficient for most
PM2.5 nonattainment areas.
8. What models should be used for mobile source emissions?
A key part of emissions inventory development includes estimating
mobile source emissions. For all of the mobile source inventories used
for PM2.5 NAAQS implementation, states should use the latest
emissions models available at the time the attainment plan inventory is
developed.\75\ In general, the latest approved version of the MOVES
model should be used by states other than California to estimate
emissions from onroad transportation sources. States should use the
latest available planning emission inputs including, but not limited
to, vehicle miles traveled (VMT), speeds, fleet mix, SIP control
measures and fuels. The current version of MOVES is available at http://www.epa.gov/otaq/models/moves/index.htm. The appropriate EPA-approved
model(s) should similarly be used for California onroad source
emissions.\76\ When using MOVES, states should follow the most current
version of the MOVES Technical Guidance, available at http://www.epa.gov/otaq/models/moves/index.htm#sip. MOVES includes multiple
options for estimating and processing emissions that could result in
different emissions inventories. The EPA recommends that states use the
same approach in any analysis that compares two or more emissions cases
(e.g., different control scenarios, different years). If different
approaches are taken for inventories that serve different purposes (for
example between inventories developed for air quality modeling, which
may require greater temporal and spatial detail, and inventories used
as the motor vehicle emissions budget), states should seek to
understand and minimize any differences in results. For example, an
approach may be used for the modeled attainment demonstration that uses
gridded temperatures and other meteorological data, but this approach
could be too burdensome for use in the base year inventory for the
nonattainment area. This is because emissions inventories created for
purposes of RFP and transportation conformity analysis must use the
same MOVES approach used in the base year inventory for the
nonattainment area, and using a straightforward MOVES approach without
gridded meteorology is more reasonable for that purpose.
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\75\ Section 172(c)(3) requires that SIP inventories and control
measures be based on the most current information and applicable
models that are available when a SIP is developed.
\76\ At this time, the California onroad mobile model is called
EMFAC.
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The most current version of the NONROAD model should be used for
estimates of nonroad mobile source emissions, preferably with state-
supplied model input data. States can alternatively develop
technologically equivalent or superior state-specific nonroad emissions
estimates, but should explain why their approach gives a better
estimate than the EPA model. For nonroad sources not estimated by the
NONROAD model, the best available methods should be used, and the EPA
recommends that states refer to the SIP Emissions Inventory Guidance
for more information on emissions from these sources. Links to Federal
Register documents and policy guidance memos on the latest approved
versions of MOVES and NONROAD can be found at http://www.epa.gov/otaq/models.htm.
9. What special considerations exist for tribal areas?
In the past, there have been instances where portions of tribal
areas have been included in designated nonattainment areas, but when
the base year inventory for the nonattainment area was prepared,
emissions from the tribal lands were not included. This has had the
effect of preventing tribes from generating emissions reductions from
existing sources to develop emissions offsets, as well as impairing the
ability of the state to prepare as accurate a modeling demonstration as
possible. It could also cause sources in tribal areas to remain
uncontrolled even though they are contributing to violations in a given
nonattainment area. The EPA encourages states and tribes to work
together to ensure that the information used in developing the baseline
emissions inventory is inclusive of all emissions from a designated
nonattainment area, including emissions from sources in tribal areas
located therein.
C. Pollutants To Be Addressed in the Plan
Under subpart 4 of the CAA, air agencies are initially required to
analyze and evaluate emissions reduction measures for all sources of
direct PM2.5 and PM2.5 precursors (i.e.,
SO2, NOX, VOC and ammonia) in developing
PM2.5 attainment plans. As described in Section II of this
preamble, and reiterated in the proposed emissions inventory
requirements for Moderate area attainment plans under Section IV.B of
this preamble, direct PM2.5 includes both filterable and
condensable PM2.5 emissions. Thus, a state must evaluate
control measures for sources of filterable and condensable
PM2.5 emissions as part of an approvable control strategy
for a Moderate PM2.5 nonattainment area.
In addition, while evaluating sources of direct PM2.5
for reasonably available controls is an implicit requirement in the
context of implementing the PM2.5 NAAQS under any scenario,
the EPA is proposing and seeking comment on several options for
evaluating PM2.5 precursors under the PM2.5 NAAQS
implementation program. The EPA interprets the requirements of the CAA
to allow the air agency to provide a ``precursor demonstration'' to the
EPA that supports a state's finding that one or more PM2.5
precursors need not be subject to control requirements in a given
nonattainment area. Section III of this preamble presents a complete
discussion of the EPA's proposed options for states to address
PM2.5 precursors in attainment plans and in the NNSR
permitting program. Specifically, the EPA is proposing and seeking
comment on three options describing different approaches to such
precursor demonstrations, and requests comment on each. In general
terms, the three options can be summarized as follows:
Option 1: Two independent analyses: (a) an attainment
planning analysis demonstrating that control measures for a particular
precursor are not needed for expeditious attainment, meaning that the
precursor can be excluded from measures needed to attain as
expeditiously as practicable for all types of sources; and, (b) a
section 189(e) technical demonstration showing that major stationary
sources of a particular precursor do not contribute significantly to
levels that exceed the PM2.5 standard, meaning that the
precursor can be excluded from control requirements for major sources
and from NNSR permitting;
[[Page 15368]]
Option 2: Single analysis demonstrating that all emissions
of a particular precursor from within the area do not significantly
contribute to PM2.5 levels that exceed the standard, meaning
that control requirements for emissions of the precursor from major
stationary and area sources, as well as mobile sources, would not be
required for expeditious attainment, control requirements for major
sources, or for NNSR permitting;
Option 3: An attainment planning analysis demonstrating
that control measures for all types of sources of a particular
precursor are not needed for expeditious attainment also would be
deemed to meet the section 189(e) technical demonstration requirement,
meaning that the state would not need to regulate emissions of the
particular precursor from major stationary sources under the NNSR
permitting program or other control requirements for major stationary
sources.
The EPA will finalize its approach to PM2.5 precursors
and clarify the implications for states conducting analyses to identify
required control measures after considering public comment received on
this proposal.
D. Attainment Plan Control Strategy
1. General Approach to Designing a Control Strategy for a Moderate
Nonattainment Area
The statutory attainment planning requirements of subparts 1 and 4
were established to ensure that the following goals of the CAA are met:
(i) That states implement measures that provide for attainment of the
PM2.5 NAAQS as expeditiously as practicable; and, (ii) that
states adopt emissions reduction strategies that will be the most
effective, and the most cost effective, at reducing PM2.5
levels in nonattainment areas. In addition to having an obligation to
meet the statutory requirements for specific control measures on
sources located within a nonattainment area (e.g., RACM and RACT), a
state has discretion to require reductions from any source inside or
outside of a PM2.5 nonattainment area (but within the
state's boundaries) in order to fulfill its obligation to demonstrate
attainment in a PM2.5 nonattainment area as expeditiously as
practicable. A state may need to require emissions reductions on
sources located outside of a PM2.5 nonattainment area if
such reductions are needed in order to provide for expeditious
attainment of the PM2.5 NAAQS.
With this in mind, the following sections describe the EPA's
proposed approach for a state to follow in order to identify and select
the complete suite of measures needed for an attainment plan submission
for a Moderate PM2.5 nonattainment area. The proposed
process consists of identifying all technologically and economically
feasible control measures, including control technologies, for all
sources of direct PM2.5 and PM2.5 precursors in
the emissions inventory for the nonattainment area which are not
otherwise exempted from consideration for controls.\77\ From that list
of measures, the state must identify those that it can implement within
4 years of designation of the area (and which would thus meet the
statutory requirements for RACM and RACT) and any ``additional
reasonable measures,'' which the EPA proposes to define as those
technologically and economically feasible measures that the state can
only implement on sources in the nonattainment area after the 4 year
deadline for RACM and RACT has passed. See proposed 40 CFR 51.1000. The
state must also assess whether there are other measures that it can
implement to control sources within the state but outside the
nonattainment area that contribute to the PM2.5
nonattainment status of the area in order to bring the area into
attainment as expeditiously as practicable.
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\77\ Such exemptions could be due to a demonstrated lack of
significant contribution of a certain PM2.5 precursor to
the area's elevated PM2.5 concentrations or due to a
presumptive determination that a certain source category contributes
only a de minimis amount toward PM2.5 levels in a
nonattainment area.
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As discussed in Section II.D.6 of this preamble, one important
component of a state's control strategy for a PM2.5
nonattainment area is the suite of control measures that a state is
already implementing or will be implementing to comply with national,
regional, or state and local regulations already adopted or
promulgated, as long as such measures will lead to permanent and
enforceable reductions in emissions after the area is designated
nonattainment. Such ``existing'' measures could apply to sources inside
the nonattainment area, in which case the state must include them in
the RACM and RACT and additional reasonable measures analysis for the
area. The measures may also apply to sources located outside the
nonattainment area but would achieve reductions in direct
PM2.5 emissions or emissions of PM2.5 precursors
to help bring the area into attainment. A state must evaluate the
potential effects of all of these measures as part of its modeled
attainment demonstration for the area, and must clearly indicate which
of these measures will contribute toward timely attainment for the area
in the attainment plan submission.
2. Identification and Selection of RACM and RACT and Additional
Reasonable Measures
a. Statutory requirements and existing guidance. CAA section 172(c)
under subpart 1 describes the general attainment plan requirement for
RACM and RACT, requiring that attainment plan submissions ``provide for
the implementation of all reasonably available control measures as
expeditiously as practicable (including such reductions in emissions
from existing sources in the area as may be obtained through the
adoption, at a minimum, of reasonably available control technology) and
shall provide for attainment'' of the NAAQS. The attainment planning
requirements specific to PM10, including PM2.5,
under subpart 4 likewise impose upon states an obligation to develop
attainment plans that impose RACM on sources of direct PM2.5
and PM2.5 precursors within a Moderate nonattainment area.
CAA section 189(a)(1)(C) requires that states with areas classified as
Moderate have attainment plan provisions to assure that RACM are
implemented by no later than 4 years after designation of the area.\78\
The EPA reads CAA sections 172(c)(1) and 189(a)(1)(C) together to
require that attainment plans for Moderate nonattainment areas must
provide for the implementation of RACM and RACT for existing sources of
PM2.5 and PM2.5 precursors in the nonattainment
area as expeditiously as practicable but no later than 4 years after
designation.\79\
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\78\ States with areas later reclassified as ``Serious''
nonattainment areas under subpart 4 must also develop and submit
later plans to meet additional requirements for Serious areas.
\79\ This interpretation is consistent with guidance described
in the General Preamble. See 57 FR 13498 (April 16, 1992), at page
13540.
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The terms RACM and RACT are not defined within subpart 4, nor do
the provisions of subpart 4 specify how states are to meet the RACM and
RACT requirements. However, the EPA's longstanding guidance in the
General Preamble described in detail considerations for determining
what control measures constitute RACM and RACT for purposes of subpart
4. The EPA's guidance for RACM for sources of PM10 and
PM10 precursors under subpart 4 in the General Preamble
included: (i) A list of some potential measures for states to consider;
(ii) a statement of the EPA's expectation that the state will provide a
reasoned explanation for a decision not to adopt
[[Page 15369]]
a particular control measure; (iii) recognition that some control
measures might be unreasonable because the emissions from the sources
that would be affected by the measure in the area are de minimis (i.e.,
aggregate emissions from all sources in a particular source category do
not contribute significantly to PM2.5 concentrations in the
area); (iv) an emphasis on state evaluation of potential control
measures for reasonableness, considering factors such as technological
and economic feasibility; and, (v) encouragement to states evaluating
potential control measures imposed upon municipal or other governmental
entities to include consideration of the impacts on such entities, and
the possibility of partial implementation when full implementation
would be infeasible (e.g., phased implementation of measures such as
road paving).\80\ Thus, the RACM requirement under subpart 4 applies to
all types of sources and is not necessarily focused upon forms of
control that are strictly technology-based.
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\80\ See 57 FR 13498 (April 16, 1992), at pages 13540-41.
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With respect to RACT requirements, the EPA's guidance in the
General Preamble: (i) noted that RACT has historically been defined as
``the lowest emission limit that a source is capable of meeting by the
application of control technology that is reasonably available
considering technological and economic feasibility''; (ii) Noted that
RACT generally applies to stationary sources, both stack and fugitive
emissions; (iii) suggested that major stationary sources be the minimum
starting point for a state's RACT analysis; and, (iv) recommended that
states evaluate RACT not only for major stationary sources, but for
other source categories as needed for attainment and considering the
feasibility of controls.\81\ Thus, the RACT requirement under subpart 4
is primarily focused on stationary sources and forms of emissions
control that are technology-based.
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\81\ Ibid.
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In addition to the statutory requirements under sections 172(c)(1)
and 189(a)(1)(C) for RACM and RACT, section 172(c)(6) requires that a
state's attainment plan for a nonattainment area ``include enforceable
emission limitations, and such other control measures, means or
techniques (including economic incentives such as fees, marketable
permits, and auctions of emission rights), as well as schedules and
timetables for compliance, as may be necessary or appropriate to
provide for attainment of such standard in such area by the applicable
attainment date specified in this part.'' The EPA interprets this
statutory provision to require a state to identify, select and
implement additional measures to those identified as RACM and RACT for
the area if needed to provide for timely attainment of the area. In the
EPA's proposed approach detailed in this section, the EPA describes
criteria for identifying and selecting ``additional reasonable
measures'' for sources of direct PM2.5 and PM2.5
precursors in a Moderate nonattainment area which may be necessary in
order to bring the area into expeditious attainment.
b. Proposed approach. This section describes the EPA's proposed
approach for determining what measures qualify as RACM and RACT or as
additional reasonable measures for controlling sources contributing to
nonattainment in a Moderate PM2.5 nonattainment area. Under
the proposed approach, the specific determination of RACM and RACT
would be made within the broader context of assessing control measures
for all stationary, area and mobile sources of direct PM2.5
and PM2.5 precursors that would collectively contribute to
meeting the statutory Moderate area attainment date as expeditiously as
practicable.\82\ The proposed approach is designed to ensure that
states consider and adopt control measures for sources in a way that is
consistent with the statute's overarching requirement to attain the
standards as expeditiously as practicable, yet to provide flexibility
for states to focus regulatory resources on those sources of emissions
whose control will most effectively and expeditiously contribute to
attainment in a given area.
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\82\ In Sierra Club v. EPA, 294 F.3d 155 (D.C. Cir. 2002), the
court stated, in upholding the EPA's statutory interpretation of
RACM, that the CAA does not compel a state to consider a measure
without regard to whether it would expedite attainment.
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Specifically, the EPA proposes that a state must follow a process
by which it would: (i) Identify all sources of emissions of direct
PM2.5 and all PM2.5 precursors in the
nonattainment area and all potential control measures to reduce
emissions from those source categories not otherwise deemed de minimis;
(ii) determine if any of the identified potential control measures are
technologically infeasible; (iii) determine if any of the identified
technologically feasible control measures are economically infeasible;
(iv) determine which technologically and economically feasible measures
can be implemented, in whole or in part, within 4 years from the date
of designation of the area and which can be implemented, in whole or in
part, by the end of the sixth calendar year following designation; and,
(v) perform an analysis to determine the earliest practicable
attainment date for the area and identify the control measures and
control technologies that will be needed to achieve attainment by the
demonstrated attainment date and to meet statutory control
requirements.
The statutory attainment date for Moderate nonattainment areas is
as expeditiously as practicable, but not later than the end of the
sixth calendar year after designation of the area as nonattainment. In
the case of Moderate areas that can reach attainment by the statutory
attainment date, and consistent with existing policies, states would be
required to evaluate the combined effect of reasonably available
control measures that are not necessary to demonstrate attainment
within the maximum statutory timeframe to determine whether
implementation of the remaining measures could advance the attainment
date by at least 1 year. The EPA has long applied this particular
test--whether reasonably available control measures that were not
necessary to demonstrate attainment within the maximum statutory
timeframe, collectively can advance an area's applicable attainment
date by at least 1 year--to satisfy the statutory provision related to
an area demonstrating attainment ``as expeditiously as practicable.''
\83\ The EPA continues to believe that this approach provides an
appropriate degree of flexibility to a state to tailor its attainment
plan control strategy to the needs of a particular PM2.5
nonattainment area. In the case of Moderate areas that cannot
practicably attain by the statutory attainment date, states would be
required to implement all RACM and RACT, together with any additional
reasonable measures on sources in the nonattainment area. In either
case, the statute requires that a state's attainment plan provide for
implementation of RACM and RACT within 4 years of designation.
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\83\ The term ``expeditious attainment'' is used throughout this
proposal to describe the ability of a nonattainment area to attain
``as expeditiously as practicable'' based on the test described
here.
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The following discussion provides further detail on the specific
steps and criteria that the EPA proposes states must apply when making
their determinations for RACM and RACT and additional reasonable
measures. The EPA seeks comment on the proposed steps, criteria and
[[Page 15370]]
considerations described below. See proposed 40 CFR 51.1009(a).
Step 1: Identify sources to be controlled and existing and
potential control measures
i. Identify sources to be controlled. As described more fully in
Section IV.B of this preamble, section 172(c)(3) of the CAA requires
that attainment plans for PM2.5 nonattainment areas include
a ``comprehensive, accurate, current inventory of actual emissions from
all sources of the relevant pollutant or pollutants.'' As proposed, the
inventory must include emissions information for all major stationary
sources, nonpoint or area sources, and mobile sources of direct
PM2.5 and PM2.5 precursors in the nonattainment
area.
The EPA proposes to require that a state must look at all of the
sources reflected in the nonattainment area's base year inventory as
part of the first step in identifying reasonable control measures for
the area, as each of these sources may play a role in the area's
PM2.5 problem and thus may be controlled currently or may
need to be controlled to bring the area into attainment as
expeditiously as practicable. Under this proposed approach, a state
would need to consider all inventoried sources of direct
PM2.5 emissions and sources of all four scientific
PM2.5 precursors as it conducts its determination of
reasonable control measures for an area. A possible exception to this
comprehensive review requirement for all inventoried sources could
arise if the EPA finalizes a precursor approach that would allow a
state to demonstrate that one or more precursors in a nonattainment
area do not significantly contribute to the PM2.5 problem in
the area and/or that reducing emissions of one or more precursors in an
area would not be effective in reducing PM2.5 concentrations
in the area.\84\ In such a case, a state could exempt sources of any
precursor for which the state has made such a demonstration from
further consideration for measures to control emissions of that
precursor. Independent of whether or not the EPA finalizes such an
approach to precursors, however, a state could still determine that it
is not necessary to control emissions of direct PM2.5 or any
of the PM2.5 precursors in order to attain the
PM2.5 NAAQS in a given area, or to advance the attainment
date for that area, at a later point in this proposed process for
determining RACM and RACT and additional reasonable measures.
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\84\ See Section III of this preamble for further details on the
agency's proposed options for how to handle precursors in attainment
planning.
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ii. De minimis source category exemptions. The concept of exempting
certain source categories from consideration for control measures due
to their minimal (i.e., de minimis) contribution is discussed at length
in the Addendum for sources located in Serious PM10
nonattainment areas that would otherwise be subject to BACM and BACT
requirements. The EPA's guidance in the General Preamble on Moderate
PM10 nonattainment area requirements also provided support
for exempting de minimis source categories from RACM and RACT
requirements: ``If it can be shown that one or more measures are
unreasonable because emissions from the sources affected are
insignificant (i.e., de minimis), those measures may be excluded from
further consideration as they would not represent RACM for that area.''
85 86
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\85\ 57 FR 13498 (April 16, 1992), at page 13540.
\86\ Where the sources at issue contribute only negligibly to
ambient concentrations that exceed the NAAQS, the EPA's policy is
that it would be unreasonable to regulate those sources, and,
therefore, the sources would not be subject to RACM or other control
requirements, unless it is determined that even sources identified
as de minimis must be controlled in order for the area to attain the
NAAQS. In this regard, it is worth noting that the inherent
authority of administrative agencies to exempt de minimis situations
from regulation has been recognized by courts as ``a tool to be used
in implementing the legislative design'' (see Alabama Power Co. v.
Costle, 636 F.2d 323, 360 (D.C. Cir. 1979)).
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As with RACM for PM10, the EPA proposes to allow states
to exempt de minimis source categories from further consideration as
they determine reasonable control measures for bringing a Moderate
PM2.5 nonattainment area into attainment with the relevant
NAAQS. The EPA proposes that if a state can demonstrate that a
particular source category does not contribute significantly to
nonattainment of the PM2.5 NAAQS in a Moderate nonattainment
area, then the state may eliminate the source category from further
consideration for control measures.\87\ A state would be required to
evaluate all other sources in the nonattainment area in source
categories that do not qualify as de minimis for reasonable control
measures.
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\87\ Ibid. See Alabama Power v. Costle, 636 F.2d 323, 360-61
(D.C. Cir. 1979).
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The EPA notes that there are some challenges in establishing de
minimis source categories for PM2.5 sources in the same
manner as was performed for PM10 sources and seeks comment
on the following proposed options.
(1) Defining source categories. Source categories, in particular
for stationary sources, can be defined very broadly or narrowly, and
the definition could determine which sources are able to meet the
thresholds for de minimis exemptions. The North American Industry
Classification System (NAICS) is the standard industrial classification
system used by federal agencies. NAICS codes are between 2 and 6
digits, with greater industrial source specificity with increased
digits.\88\ Each digit in the code is part of a series of progressively
narrower categories, and the more digits in the code signify greater
classification detail. The first two digits designate the economic
sector, the third digit designates the subsector, the fourth digit
designates the industry group, the fifth digit designates the NAICS
industry, and the sixth digit designates the national industry. The 5-
digit NAICS code is the level at which there is comparability in code
and definitions for most of the NAICS sectors across the three
countries participating in NAICS (the United States, Canada and
Mexico). The 6-digit level allows for the United States, Canada, and
Mexico each to have country-specific detail. A complete and valid NAICS
code contains six digits.
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\88\ More information on the NAICS is available at: http://www.census.gov/eos/www/naics (last accessed August 12, 2013).
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Defining source categories by NAICS codes would still require a
determination of how broadly to set the source category boundaries as
NAICS codes with fewer digits represent larger source categories (e.g.,
sector `21' is for mining processes, while a further specification of
`2122' is for metal mining processes, and `212210' is for iron ore
mining). If source categories are defined in a very narrow or specific
way, it is possible that many source categories will be below a set de
minimis threshold, and therefore potentially inappropriately exempted
from consideration for reasonable control measures. For this reason,
the EPA proposes and seeks comment on a requirement that a state would
need to define any source category for which a NAICS code exists at the
four-digit industry group level. The EPA believes that relying on the
four-digit industry group level to define ``source category'' for this
purpose would provide an appropriate degree of distinction between
industrial processes, while not making the source category definition
overly broad. The EPA also seeks comment on two other alternative
approaches for defining source category for this purpose, at the six-
digit level, and the two-digit level. The EPA notes that not all source
categories have NAICS codes, and for these other categories, states
would need to use the
[[Page 15371]]
appropriate recognized categories, e.g., on-road mobile sources. The
EPA also seeks comment on alternative source categorization approaches
that would ensure that sources that could be controlled with reasonable
control measures to achieve meaningful reductions are not
inappropriately excluded from consideration for such control measures
as de minimis.
(2) Determining the appropriate threshold for de minimis emissions.
For the PM10 NAAQS, the EPA's guidance in the Addendum
recommended that a source category is presumed not to be de minimis if
the aggregate emissions from such source category have an impact that
exceeds 5 [mu]g/m\3\ with respect to the then-applicable 24-hour
PM10 NAAQS or an impact that exceeds 1 [mu]g/m\3\ with
respect to the then-applicable annual PM10 NAAQS. The EPA
designed these presumptive thresholds for de minimis source categories
to apply to PM10 NAAQS nonattainment areas and to the level
and form of the PM10 NAAQS at the time the Addendum was
written. However, because of the differences in level and form of the
PM10 and PM2.5 NAAQS, the agency finds that those
levels are not appropriate for current or future PM2.5 NAAQS
implementation.
The EPA therefore proposes two options regarding the threshold for
de minimis emissions. Under the first proposed option, the EPA would
not establish a nationally applicable ``bright line'' threshold for
defining a de minimis source category for purposes of implementing the
PM2.5 NAAQS in a Moderate nonattainment area. Rather, under
this option, the EPA proposes to allow a state to determine whether a
particular source category should be considered de minimis given the
particular facts and circumstances of a specific PM2.5
nonattainment area and subject to approval by the EPA. See proposed 40
CFR 51.1007.
Under the second option, the EPA proposes to establish a nationally
applicable de minimis source category threshold that would be a
specific percentage of the level of the relevant PM2.5
NAAQS. The EPA seeks comment on what value within the range of 1 and 3
percent of the relevant NAAQS would represent an appropriate threshold
level. The 3 percent upper end of the proposed range is generally
derived from the de minimis source category contribution levels for
PM10 as described in the General Preamble. The EPA defined
these PM10 de minimis levels as follows: (i) For the annual
standard of 50 [mu]g/m\3\, a source category contribution of 1 [mu]g/
m\3\ or less to the annual average design value (e.g., a contribution
of about 2 percent or less); and, (ii) for the 24-hour standard of 150
[mu]g/m\3\, a source category contribution of 5 [mu]g/m\3\ or less to
the 24-hour design value (e.g., a contribution of about 3 percent or
less). The 1 percent lower end of the proposed range is consistent with
the value that the EPA established in the CAIR as a preliminary
threshold for further evaluation of a state's contribution to
interstate transport. That is, under the CAIR, a state was identified
as potentially subject to additional emission control requirements if
the impact of SO2 and NOX emissions from sources
in that state to any nonattainment or maintenance area in another state
exceeded 1 percent of the relevant PM2.5 standard at a
receptor monitor in the other state. This value was merely the first
step of the analysis, but it provided an initial threshold for
determining whether further analysis was warranted.
The EPA is requesting comment on the appropriateness of including
de minimis threshold options for exempting certain source categories
from consideration for reasonable control measure determinations, and
seeks input on several key questions: First, if a de minimis threshold
is included, what is the appropriate definition for source categories?
In addition, what are the appropriate thresholds for impacts on ambient
PM2.5 concentrations that would adequately reflect
presumptive de minimis concentrations from a given source category
comparable to those recommended for purpose of the PM10
NAAQS? Also, should the de minimis source category thresholds be a
percentage of the relevant NAAQS (i.e., similar to what was recommended
for PM10, but set at a level that is more appropriate for
the level and form of the relevant NAAQS)? The EPA requests that
commenters submit any relevant data or analyses to support their
comments with respect to these issues. Furthermore, the EPA notes that
even in the event the agency finalizes this rulemaking with a de
minimis source category policy of any kind, states are obligated under
the CAA to demonstrate how their PM2.5 nonattainment area(s)
will attain the standard as expeditiously as practicable. Accordingly,
a state could not elect to treat source categories as de minimis if
doing so would prevent the state from being able to demonstrate
attainment for an area by the statutory attainment date.
iii. Identify existing and potential control measures and
technologies. The state's compilation of existing and potential control
measures must be sufficiently broad to provide a basis for identifying
all technologically and economically feasible controls that may be RACM
or RACT for sources of direct PM2.5 and PM2.5
precursor emissions in the nonattainment area at issue. Because RACM
applies to area and mobile sources as well as stationary sources, the
EPA proposes to require that states consider a variety of types of
measures in conducting their control strategy analysis. As stated
earlier, inherent to the concept of RACM and RACT is the basic premise
that the measure be ``reasonable,'' thus the EPA believes that a state
may decline to evaluate control measures that are plainly ``absurd,
unenforceable, or impractical,'' for example, measures that would cause
``severely disruptive socioeconomic impacts, (e.g. gas rationing and
mandatory source shutdowns).'' It is the agency's interpretation that
evaluation of such measures is not required by the CAA.\89\
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\89\ 55 FR 38327 and 57 FR 13560.
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Furthermore, the EPA believes that reducing air emissions may not
justify adversely affecting other resources, for example, by increasing
pollution in bodies of water, creating additional solid waste disposal
problems or creating excessive energy demands. An otherwise available
control technology may not be reasonable if these other environmental
impacts are sufficiently adverse and cannot reasonably be mitigated.
The EPA proposes that a state may consider a control measure for direct
PM2.5 or a PM2.5 precursor not reasonable if,
considering the availability of mitigating adverse impacts of that
control on pollution of other media, the control would not, in the
state's reasoned judgment, provide a net benefit to public health and
the environment. It should be noted that, in many past situations,
states and owners of existing sources have adopted control technologies
for direct PM2.5 and/or PM2.5 precursors with
known energy penalties and some adverse effects on other media, based
on the reasoned judgment that installation of such technology would
result in a net benefit to public health and the environment. States
should consider this before determining that a control technology is
not reasonable because it may have other, negative environmental
impacts that are, on balance, marginal.
Generally, this proposed approach allows states to apply reasoned
judgment as they identify potential control measures for sources of
direct PM2.5 and PM2.5 precursors in their
respective nonattainment areas, and the EPA expects that a state will
provide a complete and reasoned explanation to support its selection of
potential control
[[Page 15372]]
measures and control technologies as part of the attainment plan
submission for any Moderate nonattainment area. The proposed
regulations include language to require the inclusion of this
explanation in a state's attainment plan submission.
(1) Existing control measures. The EPA proposes that, as a starting
point, a state must include in its initial list of control measures
those measures and technologies that are being implemented or will be
implemented due to promulgated and/or adopted (i.e., ``on the books'')
regulations for sources of direct PM2.5 and PM2.5
precursors in its Moderate PM2.5 nonattainment area. The EPA
expects that the state will incorporate current or anticipated
emissions reductions from these ``existing'' control measures (such as
expected SO2 reductions from the MATS; reductions of
NOX and direct PM2.5 from engine and fuel
standards to reduce emissions from on-road and nonroad mobile sources)
into its attainment demonstration modeling for the nonattainment area,
and therefore the EPA believes it is appropriate for the state to
clearly indicate such measures in the attainment plan for the area.
The EPA recognizes that for some sources located in a Moderate
PM2.5 nonattainment area, a state may have previously
conducted RACM and RACT analyses to address emissions for other
statutory purposes. Some of the RACM and RACT determinations could be
relatively recent, while other determinations may be 15 years old or
older. The EPA proposes that a state may not simply rely on a previous
RACM or RACT determination for a particular source or source category
when developing the attainment plan for a PM2.5 NAAQS, but
rather that the state must consider all existing and potential new
measures together as part of a comprehensive RACM and RACT analysis. In
this way, the state's new RACM and RACT analysis will represent the
most thorough, up-to-date review of control measures for its
PM2.5 nonattainment area. For example, the state would still
need to provide a RACT analysis for a stationary source that has
installed new emissions controls recently (e.g., within the last 3
years), but the state's determination may consider that recent
installation when determining whether additional control is
technologically and economically feasible.
(2) Potential control measures. In addition to identifying existing
control measures for sources in a Moderate PM2.5
nonattainment area, a state must develop a comprehensive list of
potential control measures for sources in the area. There are a number
of resources available to assist states in identifying additional,
potential control measures and control technologies for their RACM and
RACT and additional reasonable measures determinations for their
Moderate PM2.5 nonattainment areas. First, the EPA's Office
of Air Quality Planning and Standards maintains a Menu of Control
Measures document, available online at http://www.epa.gov/air/criteria.html. This document was developed to provide information
useful in the development of local emissions reduction and NAAQS SIP
scenarios, and identifying and evaluating potential control measures.
It provides a broad, though not comprehensive, listing of potential
emissions reduction measures for direct PM2.5 and precursors
of ozone and PM2.5 from stationary, area and mobile sources.
More complete information on mobile source control measures can be
found on the EPA's Office of Transportation and Air Quality Web site at
http://www.epa.gov/otaq.
The RACT/BACT/LAER Clearinghouse (RBLC) provides a central database
of air pollution technology information (including past RACT, BACT and
LAER decisions contained in NSR permits) to promote the sharing of
information among permitting agencies and to aid in future case-by-case
control measure determinations. The RBLC permit database contains over
5,000 determinations that can help a state identify appropriate
technologies to mitigate most air pollutant emission streams. The RBLC
includes data submitted by several U.S. territories and all 50 states
on over 200 different air pollutants and 1,000 industrial processes.
The RBLC can be found at: http://cfpub.epa.gov/rblc/.
Additionally, the EPA maintains a Web site with links to other
online sources of information on control measures for states to
consider.\90\ Again, the EPA recognizes that some control technology
guidance for certain source categories has not been updated for many
years, and, for this reason, the agency expects states to identify and
consider new and updated information in their RACM and RACT
determinations as it becomes available.
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\90\ Links are provided to a number of national, state and local
air quality agency sites from the EPA's PM2.5 Web site:
http://www.epa.gov/pm/measures.html.
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(3) RACM for managing emissions from wildfire and prescribed fire.
Wildfire emissions account for a large portion of direct
PM2.5 emissions nationally and can significantly contribute
to periodic high PM2.5 levels.\91\ Besides their effect on
air quality, wildfires pose a direct threat to public safety--a threat
that can be mitigated through management of wildland vegetation.
Attempts to suppress wildfires have resulted in unintended
consequences, including increased risks to both humans and
ecosystems.\92\ The use of wildland prescribed fire can influence the
occurrence, behavior, and effects of catastrophic wildfires which may
help manage the contribution of wildfires to background
PM2.5 levels and periodic peak PM2.5 events.
Additionally prescribed fires can have benefits to those plant and
animal species that depend upon natural fires for propagation, habitat
restoration, and reproduction, as well as myriad ecosystem functions
(e.g., carbon sequestration). The EPA understands the importance of
prescribed fire which mimics a natural process necessary to manage and
maintain fire-adapted ecosystems and climate change adaptation, while
reducing risk of uncontrolled emissions from catastrophic wildfires,
and is committed to working with federal land managers, tribes, and
states to effectively manage prescribed fire use to reduce the impact
of wildfire related emissions on PM2.5.
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\91\ For example, see ``miscellaneous'' category of direct
PM2.5 emissions in Table 1.
\92\ Indeed, ``fire policy that focuses on [wildfire]
suppression only, delays the inevitable, promising more dangerous
and destructive future . . . fires.'' Stephens, SL; Agee, JK; Fule,
PZ; North, MP; Romme, WH; Swetnam, TW. (2013). Managing Forests and
Fire in Changing Climates. Science 342: 41-42.
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If wildfire impacts are significant, contributing to exceedances of
the standard, the EPA proposes that air agencies should consider RACM
for this source. Fires play an important ecological role across the
globe, benefiting those plant and animal species that depend upon
natural fires for propagation, habitat restoration, and reproduction.
Fires are one tool that can be used to reduce fuel load, unnatural
understory, and tree density, helping to reduce the risk of
catastrophic wildfires. Some wildfires and the use of prescribed fire
can influence the occurrence of catastrophic wildfires which may reduce
the probability of fire-induced smoke impacts and subsequent health
effects. RACM must be determined for each area on a case-by-case basis.
Possible RACM for wildfire may include measures that reduce wildland
fuels through fuels management, including the use of prescribed fire
and possibly allowing some wildfire to occur naturally in systems that
are ecologically fire
[[Page 15373]]
dependent. Where appropriate, states, land managers, and landowners may
consider developing plans to ensure that fuel accumulations are
addressed and fuels management efforts, including prescribed fire, are
not delayed. The EPA also proposes that air agencies should consider
RACM for managing emissions from prescribed fires (including those
prescribed fires conducted to reduce future wildfire emissions).
Information is available from the DOI and the USDA Forest Service on
smoke management programs and basic smoke management practices. The EPA
requests comment on the concept of, and practical considerations
associated with, RACM for wildfire and prescribed fire, including such
issues as how such measures can be characterized in the emissions
inventory and attainment demonstration and made federally enforceable
for adoption in a SIP.
(4) RACT for EGUs. Through guidance in the preamble to the 2007
PM2.5 Implementation Rule, the EPA established a rebuttable
presumption that compliance with the CAIR would satisfy RACM and RACT
requirements for SO2 and NOX emissions from EGUs
in states participating in the CAIR cap-and-trade program for such
emissions.\93\ The EPA indicated that states could presume that EGUs
located within a given nonattainment area were meeting the RACM and
RACT requirements, based solely upon a regional program that imposed
controls for SO2 and NOX emissions from sources
both within and outside designated nonattainment areas.
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\93\ See the Federal Register published on April 25, 2007 (72 FR
20586, 20623, 20624 and 20625).
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In June 2007, the EPA received a petition for reconsideration
questioning the legality of this presumption, which the D.C. Circuit
later found to be unlawful in the context of a similar presumption in
the Phase 2 Ozone (NAAQS) Implementation Rule.\94\ The agency granted
the petition for reconsideration in 2011 and proposed to withdraw from
the 2007 PM2.5 Implementation Rule any presumption that
compliance with the CAIR automatically satisfies RACM and RACT
requirements for SO2 and NOX emissions from EGUs
located in nonattainment areas for the 1997 PM2.5
NAAQS.95 96 In that proposal, the EPA explained that given
the explicit wording of section 172(c)(1) that sources ``in the area''
(i.e., in the nonattainment area) must at a minimum adopt RACT controls
for that area, the agency believes that it is no longer appropriate to
presume that this requirement is satisfied merely based upon the
participation of a source in a regional cap-and-trade program. Indeed,
implicit in a regional cap-and-trade program is that some sources,
including those located within nonattainment areas, may elect to buy
allowances in lieu of controlling emissions in order to meet the
regional emissions reductions requirements.
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\94\ See ``Petition for Reconsideration,'' filed by Paul Cort,
Earthjustice, on behalf of the American Lung Association, Medical
Advocates for Healthy Air, Natural Resources Defense Council, and
the Sierra Club (June 25, 2007). A copy of the petition is in the
docket for this action. The EPA's decision to grant the petition for
reconsideration on the issue of the CAIR being presumptively equal
to RACT for EGUs was in part based on a D,C. Circuit decision
related to a similar issue. Specifically, the Court decided that the
provisions in the Phase 2 Ozone Implementation Rule indicating that
a state need not perform (or submit) a NOX RACM/RACT
analysis for EGU sources subject to a cap-and-trade program that
meets the requirements of the NOX SIP Call are
inconsistent with the statutory requirements of section 172(c)(1).
The Court concluded that the phrase ``in the area'' means that
reductions must occur from sources within the area and ``reductions
from outside the nonattainment area do not satisfy the
requirement.'' See NRDC v. EPA, 571 F.3d 1245 (D.C. Cir. 2009).
\95\ Letter dated April 25, 2011, from former Administrator Lisa
Jackson to Paul Cort, Earthjustice. A copy of this letter is located
in the docket for this action.
\96\ 79 FR 32892 (June 9, 2013).
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Accordingly, the EPA is not proposing any rebuttable presumption
that the CAIR or any other regional control strategy constitutes RACM
or RACT for EGUs or any other source category. Instead, the EPA is
clarifying that in order to meet the RACM and RACT requirements for the
PM2.5 NAAQS, states should evaluate EGU sources for RACM and
RACT level controls just like any other source category, and not merely
presume for EGUs located in a nonattainment area that compliance with a
cap-and-trade program, including the CAIR or any other program, would
satisfy their obligation to implement RACM and RACT. As required by the
CAA, states are required to analyze what constitutes RACM and RACT for
EGUs in each nonattainment area.
Step 2: Determine whether an available control measure or
technology is technologically feasible. Once a state has identified
existing and potential control measures and technologies for sources of
direct PM2.5 and PM2.5 precursors in the
nonattainment area(s), it must evaluate these controls to determine if
any of those controls would be technologically infeasible in the
particular nonattainment area.
i. Stationary sources. With respect to the technological
feasibility of control technologies for stationary sources, the EPA has
a longstanding approach to evaluating facts relevant to this criterion
under subpart 4.\97\ The EPA interprets the term technological
feasibility to include consideration of factors such as a source's
processes and operating procedures, raw materials, physical plant
layout, and potential environmental impacts such as increased water
pollution, waste disposal and energy requirements. For example, the EPA
recognizes that the process, operating procedures and raw materials
used by a source can affect the feasibility of implementing process
changes that reduce emissions and can also affect the selection of add-
on emissions control equipment. The feasibility of modifying processes
or applying control equipment also can be influenced by the physical
layout of the particular plant, if the physical space available in
which to implement such changes limits the choices. The EPA proposes to
retain its longstanding practice that a state should be allowed to
consider such factors in order to eliminate from consideration control
measures that are not technologically feasible to implement.\98\
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\97\ See the Federal Register published on April 16, 1992 (57 FR
13498, 13540 and 13541).
\98\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42013. Guidance is provided in the context of Serious
area BACM determination, but the EPA is proposing to apply it here
for Moderate area RACM determinations.
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ii. Area and mobile sources. With respect to determining whether a
given control measure might not be technologically feasible for an area
or mobile source, the EPA also proposes to retain its longstanding
practice that a state may consider relevant factors in conducting its
analysis, such as the social acceptability of the measure (e.g.,
residential woodstove change-out programs rely in large part on the
willingness of individual citizens to participate in such a program)
and local circumstances, such as the condition and extent of needed
infrastructure, population size, or workforce type and habits, which
may prohibit certain potential control measures from being
implementable.
The EPA seeks comment on the factors described above for states to
consider when determining whether a control technology or measure is
technologically feasible.
Step 3: Determine whether an available control measure or
technology is economically feasible. The EPA has a longstanding
interpretation of the term ``economic feasibility'' in the context of
evaluating potential RACM and RACT which involves considering the cost
of reducing emissions and the difference between the cost of an
emissions reduction measure at a particular source
[[Page 15374]]
and the cost of emissions reduction measures that have been implemented
at other similar sources in the same or other areas.\99\ Absent other
indications, the EPA presumes that it is reasonable for similar sources
to bear similar costs of emissions reductions. Economic feasibility of
RACM and RACT is thus largely informed by evidence that other sources
in a source category have in fact applied the control technology,
process change or measure in question in similar circumstances.
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\99\ See the Federal Register published on April 16, 1992 (57 FR
13498, 13540 and 13541).
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In the preamble to the 2007 PM2.5 Implementation Rule,
the EPA provided guidance on how to interpret the term ``economic
feasibility'' which deviated from the agency's longstanding
interpretation of the term. After promulgating the final rule, the EPA
received and granted a petition for reconsideration on issues related
to the agency's revised approach to interpreting the term
``economically feasible.'' 100 101 Consistent with the EPA's
granting of that petition for reconsideration, the EPA is proposing in
this action an interpretation of economic feasibility that is
consistent with the EPA's longstanding interpretation of what factors
are appropriate for consideration of economic feasibility in a RACM and
RACT analysis, instead of that adopted in the 2007 PM2.5
Implementation Rule.
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\100\ ``Petition for Reconsideration,'' filed by Paul Cort,
Earthjustice, on behalf of the American Lung Association, Medical
Advocates for Healthy Air, Natural Resources Defense Council, and
the Sierra Club (June 25, 2007). A copy of the petition is in the
docket for this action.
\101\ Letter dated April 25, 2011, from former Administrator
Lisa Jackson to Paul Cort, Earthjustice. A copy of this letter is
located in the docket for this action.
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Specifically, the EPA proposes that for each technologically
feasible control measure or technology, a state must evaluate the
economic feasibility of the measure or control, through consideration
of the capital costs, operating and maintenance costs, and cost
effectiveness (i.e., cost per ton of pollutant reduced by that measure
or technology) associated with such measure or control. Furthermore,
the EPA proposes that a state may not reject a technologically feasible
control measure or technology as being economically infeasible if such
a measure or technology has been implemented at other similar sources
(i.e., at sources that would be included in the same source category in
the emissions inventory data collection process), unless the state
provides an adequate justification that clearly explains the specific
circumstances of the source or sources in the nonattainment area that
make such a measure or technology economically infeasible in that
particular area.
The EPA believes that it is appropriate for states to give
substantial weight to cost effectiveness in evaluating the economic
feasibility of an emission reduction measure or technology. The cost
effectiveness of a measure is its annualized cost ($/year) divided by
the emissions reduced (tons/year) which yields a cost per amount of
emission reduction ($/ton). Cost effectiveness provides a relative
value for each emissions reduction option that is comparable with other
options and, in the case of control technologies, other facilities.
The EPA also seeks comment on an alternative cost effectiveness
metric that would allow a state to take into account the effect of
controlling a particular precursor on reducing PM2.5
concentrations in the area. Such a cost effectiveness metric would be
the annualized cost ($/year) of a control measure divided by the
emissions reduced (tons/year) multiplied by the amount of reductions
needed in the precursor emissions to yield 1 [mu]g/m\3\ reduction in
PM2.5 ($/([mu]g/m\3\)). Such a metric would allow a state to
compare the relative cost effectiveness associated with each measure
toward the attainment goal for the nonattainment area. The EPA notes
the difficulty in determining the appropriate value to relate precursor
reductions to reductions in ambient PM2.5 concentrations,
and therefore seeks comment on the appropriateness of this approach and
how a state might demonstrate the validity of the input values it
chooses to use.
In considering what level of control is reasonable, the EPA is not
proposing a fixed dollar per ton cost threshold for economic
feasibility of controls identified as potential RACM and RACT. In
addition, if a state contends that a source-specific control-level
should not be established because the source(s) cannot afford the
control measure or technology that is demonstrated to be economically
feasible for other sources in its source category, the EPA proposes
that the state must support the claim with information regarding the
impact of imposing the identified control measure or technology on the
following financial indicators, to the extent applicable:
1. Fixed and variable production costs ($/unit)
2. Product supply and demand elasticity
3. Product prices (cost absorption vs. cost pass-through)
4. Expected costs incurred by competitors
5. Company profits
6. Employment costs
7. Other costs (e.g., for RACM implemented by public sector
entities).\102\
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\102\ These long-standing factors were established in EPA
guidance in 1992 and are applicable to implementation programs for
all NAAQS pollutants. See the appendices to the General Preamble, 57
FR 18070 (April 28, 1992).
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The EPA seeks comment on the factors described above for states to
consider when determining whether a control technology or measure is
economically feasible.
Step 4: Determine the earliest date by which a control measure or
technology can be implemented in whole or in part. CAA section
189(a)(1)(C) requires that the attainment plan for a Moderate
PM2.5 nonattainment area provide for the implementation of
RACM and RACT no later than 4 years after designation. The agency has
long interpreted the term ``implement'' to mean that a control measure
or technology has not only been submitted to the EPA for approval as
part of a SIP but has also been built, installed and/or otherwise
physically manifested, and is achieving the intended emissions
reductions, and the EPA proposes to retain such a definition in this
rule. See proposed 40 CFR 51.1000. However, the EPA recognizes that a
state may be able to implement a given control measure only partially
within 4 years after designation. The EPA addressed this situation in
the General Preamble, stating: ``It is important to note that a State
should consider the feasibility of implementing measures in part when
full implementation would be infeasible.'' \103\ This guidance endorses
the notion that a state should not reject an otherwise technologically
and economically feasible control measure or technology as RACM or RACT
even if it can be only partially implemented within the statutory 4-
year timeframe following designation of the area. Instead, the EPA
interprets the statute to require states to adopt as RACM and RACT that
portion of a control measure or technology that can feasibly be
implemented within 4 years of the effective date of designation. For
instance, if paving unpaved roads is a control measure that is
technologically and economically feasible in a nonattainment area but a
state cannot pave all roads within 4 years of designation, the state
must adopt as RACM a measure that requires paving of that portion of
roads that the state could feasibly accomplish within 4 years if
[[Page 15375]]
such a measure is needed for timely attainment of the PM2.5
NAAQS in the area.
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\103\ 57 FR 13498 (April 16, 1992), at page 13541.
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The EPA thus proposes that a state must identify those
technologically and economically feasible control measures and
technologies that it can implement fully or partially within 4 years of
designation of its Moderate PM2.5 nonattainment area.
Depending on the severity of the PM2.5 nonattainment problem
in the area, some or all of these measures identified as implementable
within 4 years may be needed in order to bring the area into attainment
as expeditiously as practicable. These measures will satisfy the EPA's
criteria for RACM and RACT if the state determines, through its
attainment demonstration that it needs to implement them to achieve
timely attainment for the area.
In addition, the EPA proposes that a state must separately identify
those technologically and economically feasible control measures that
can only be implemented after the statutory window for implementing
RACM and RACT. The statutory 4-year timing requirement for implementing
RACM and RACT under section 189(a)(1)(C) limits the control measures
and technologies that can qualify as RACM and RACT for a Moderate
PM2.5 nonattainment area. However, the statutory requirement
of CAA 172(c)(6) also requires states to implement ``other measures''
necessary to provide for timely attainment in an area. The EPA proposes
that among such other measures should be ``additional reasonable
measures,'' which would be those measures and technologies that are
otherwise technologically and economically feasible but can only be
implemented in whole or in part later than 4 years after designation
and initiated no later than the beginning of the sixth calendar year
following designation of the area.\104\ Such additional reasonable
measures would necessarily be implemented on sources in the
nonattainment area. However, the EPA interprets the ``other measures''
required under section 172(c)(6) to apply to stationary, area and
mobile sources located outside of the nonattainment area but within the
state if the application of reasonable control measures on such sources
would facilitate attainment of the PM2.5 NAAQS in the
nonattainment area. See proposed 40 CFR 51.1009(b).
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\104\ With respect to ``partial measures'' under this proposed
approach, the EPA would require that a state implement as RACM that
portion of any control measure determined to be technologically and
economically feasible and implementable within 4 years after
designation of a nonattainment area. The state would then be
required to implement as an additional reasonable measure that
portion of the same control measure that can be implemented starting
4 years from designation through the sixth calendar year following
designation.
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Step 5: Model to determine the attainment date that is as
expeditious as practicable and select the control measures necessary to
achieve attainment and meet statutory requirements for control
measures. Section 189(a)(1) of the CAA establishes a requirement that
the attainment plan for a Moderate PM2.5 nonattainment area
must demonstrate either that an area can attain the relevant NAAQS by
the applicable attainment date or that it is impracticable for the area
to do so. As noted previously, for Moderate PM2.5
nonattainment areas, the ``applicable attainment date'' is as
expeditious as practicable, but no later than the end of the sixth
calendar year after designation as nonattainment. A complete discussion
of the EPA's proposed requirements for attainment demonstration
modeling is presented in Section IV.E of this preamble. However, one of
the key features of attainment demonstration modeling is that it
provides a means of synthesizing the effects of emissions reductions
from all existing and potential new control measures identified for
sources in a given nonattainment area on overall air quality in that
area. States will be required to use the results of their attainment
demonstration modeling to identify the appropriate combination of
reasonable control measures for sources in their Moderate
PM2.5 nonattainment area and any other control measures
needed on sources outside the nonattainment area to ensure expeditious
attainment of the relevant NAAQS in the area and to meet the statutory
requirements of sections 189(a)(1)(B) and 172(c)(6) as explained
below.\105\
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\105\ Note that under section 110(l) of the CAA, after a state
has adopted a control measure into the SIP for an attainment
demonstration, it may remove or modify a measure if the state
demonstrates to the satisfaction of the EPA that such removal or
modification will not interfere with any applicable requirement of
the CAA, such as attainment of the PM2.5 NAAQS or meeting
RFP requirements.
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Step 5a: If the state can demonstrate attainment in the area by the
statutory attainment date for a Moderate area, then the state must
implement those control measures needed for expeditious attainment of
the NAAQS in the area. If a state determines that a Moderate
nonattainment area can attain the PM2.5 NAAQS by the
statutory attainment date, the state must adopt and implement any
technologically and economically feasible control measures that are
necessary to ensure that the area will attain the NAAQS as
expeditiously as practicable. The EPA will consider any such measures
that can be implemented within 4 years of designation of the area to
fulfill the RACM and RACT requirements for the area. In addition, the
EPA will consider any such measures that can only be implemented
between 4 years and the sixth calendar year after designation to meet
the requirements of section 172(c)(6) as ``additional reasonable
measures'' for the area and necessary to demonstrate timely attainment
under section 189(a)(1)(B).
Under this approach, the state may reject any otherwise
technologically or economically feasible measures that are not needed
to demonstrate attainment or that will not advance the attainment date
by at least 1 year. That is, for a Moderate area that can demonstrate
attainment by the statutory Moderate area attainment date, the EPA
proposes to define as ``reasonable'' only those technologically and
economically feasible measures that are necessary for expeditious
attainment of the NAAQS, as the CAA does not require a state to adopt
measures that are not needed for expeditious attainment in a Moderate
PM2.5 nonattainment area. Thus, a state may exclude those
otherwise reasonably available measures that, if adopted and considered
collectively, would not advance the attainment date for the area by at
least 1 year, so long as the state can demonstrate attainment as
expeditiously as practicable and no later than the statutory Moderate
area attainment date. See proposed 40 CFR 51.1009(a)(4)(i).
The EPA recognizes that identifying which measures could not
collectively advance the attainment date for a Moderate area by at
least 1 year may be an iterative process that requires additional
analysis and/or modeling. The agency believes that such effort is
reasonable for a state seeking to demonstrate the lack of need for
certain controls that are determined to be technologically and
economically feasible in light of the requirement for expeditious
attainment in a given Moderate nonattainment area. The basis for
deciding that it would be reasonable not to require imposition of
otherwise available and appropriate controls because they would not be
needed for attainment, or would not advance attainment, requires a
suitably robust analysis and explanation.
Step 5b: If the state cannot demonstrate attainment by the
statutory attainment date for a Moderate area, then the state must
adopt all reasonable control measures. As noted elsewhere in
[[Page 15376]]
this section, section 189(a)(1)(B) of the CAA requires a state to
submit as part of the attainment plan either a demonstration that the
plan will provide for attainment of the relevant NAAQS by the
applicable attainment date, or a demonstration that attainment by such
date is ``impracticable.'' This subpart 4 requirement anticipates that
not all nonattainment areas initially classified as Moderate will
necessarily be able to attain by the latest statutory attainment date
for Moderate areas, and it incorporates the concept of an
``impracticability demonstration'' for such areas.\106\ The CAA is thus
structured to provide that Moderate areas that cannot timely attain the
NAAQS through the required elements of a Moderate area attainment plan
will be reclassified to Serious and will have to meet additional
control requirements beyond those that are ``reasonable'' to assure
attainment of the NAAQS by a later date that is as expeditious as
practicable.
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\106\ The concept of an ``impracticability demonstration'' is
established in section 188(b), which addresses reclassifying
Moderate PM2.5 areas to Serious. Section 188(b)(1)
describes the EPA's discretionary authority to reclassify an area
upon a determination that an area cannot practicably attain by the
Moderate area attainment date. More relevant to this determination,
however, section 189(a)(1)(B) specifically provides for submission
of a demonstration addressing this concept in the case of Moderate
areas that cannot attain the NAAQS by the applicable attainment
date.
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Existing guidance in the General Preamble on implementing this
section of the CAA states that ``the EPA believes it is reasonable for
all available control measures that are technologically and
economically feasible to be adopted for areas that do not demonstrate
attainment [by the applicable attainment date].'' \107\ The EPA
maintains that it is reasonable to require a state to model the effects
of emissions reductions from all technologically and economically
feasible controls identified by the state for sources in a
nonattainment area before asserting a claim that the area cannot
practicably attain the relevant NAAQS by the Moderate area attainment
date. However, the magnitude of certain PM2.5 precursor
emissions and/or local atmospheric conditions of some PM2.5
nonattainment areas may render certain technologically and economically
feasible control measures ineffective in reducing ambient
PM2.5 levels. Therefore, even in a Moderate PM2.5
nonattainment area that cannot practicably attain the relevant NAAQS by
the statutory attainment date, the EPA believes that it may not be
reasonable in all cases to require that a state implement all
technologically and economically feasible control measures identified
for sources in the area.
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\107\ 57 FR 13498 (April 16, 1992), at page 13544.
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Consistent with the EPA's long-standing interpretation that subpart
4 Moderate area control requirements must be reasonable, the EPA
proposes that, for a Moderate PM2.5 nonattainment area that
cannot practicably attain the NAAQS by the statutory attainment date, a
state must adopt and implement all technologically and economically
feasible measures identified for sources in the area, except for any
such measures that collectively will not effectively reduce ambient
PM2.5 concentrations. See proposed 40 CFR 51.1009(a)(4)(ii).
The EPA views this approach as similar to the agency's approach of
allowing states to reject any otherwise technologically or economically
feasible measures that are not needed to demonstrate attainment and
that will not advance the attainment date by at least 1 year for
nonattainment areas for which states can demonstrate attainment by the
statutory attainment date. Once again, the EPA recognizes that
identifying which measures collectively will not effectively reduce
ambient PM2.5 concentrations will likely be an iterative
process that requires specific analysis, potentially including
modeling. However, the agency believes that such effort is appropriate
for a state seeking to demonstrate the lack of need for certain
controls that are determined to be technologically and economically
feasible in a Moderate nonattainment area that cannot practicably
attain the relevant PM2.5 NAAQS by the latest statutory
Moderate area attainment date. The basis for establishing that it would
not be reasonable to require imposition of otherwise available and
appropriate controls because they would not be effective in reducing
ambient PM2.5 concentrations requires an adequately robust
analysis and explanation.
The EPA also proposes an alternative approach to identifying all
reasonable control measures for a Moderate nonattainment area that
cannot practicably attain the PM2.5 NAAQS by the end of the
sixth calendar year following designation. Under this alternative,
states would be required to implement all technologically and
economically feasible control measures that they have identified for
sources of direct PM2.5 emissions and sources of emissions
of significant PM2.5 precursors in the area. The EPA
believes that this interpretation would be consistent with the agency's
previous guidance in the General Preamble and is compelled by the
language of section 189(a)(1)(C), which separately requires a state to
submit a Moderate area attainment plan and meet the RACM and RACT
requirement, even if the state submits a demonstration that it cannot
attain the NAAQS through those measures by the applicable attainment
date. In addition, as with a Moderate PM2.5 nonattainment
area which a state demonstrates can attain the NAAQS by the end of the
sixth calendar year following designation, the EPA interprets the
provisions of section 172(c)(6) to require that such an area must
implement all additional reasonable measures that it can implement
through the sixth calendar year following designation of the area, in
addition to those measures meeting the definition of RACM and RACT, in
order to make progress toward attainment after the end of the fourth
year following designation.
As described in Section III of this preamble, the EPA is proposing
three options for implementing CAA requirements applicable to
PM2.5 precursors in the context of attainment planning and
NNSR permitting. Proposed precursor Options 2A and 2B would provide an
opportunity for a state to demonstrate that emissions of a particular
precursor from all sources located in a Moderate PM2.5
nonattainment area do not contribute significantly to ambient
PM2.5 levels that exceed the standard in the area, or
reductions of which will not be effective in reducing ambient
PM2.5 concentrations, in which case the state would not be
required to identify or otherwise evaluate control measures for the
particular precursor. Under proposed precursor Options 1 and 3, on the
other hand, states would rely on their control strategy analyses (e.g.,
for Moderate nonattainment areas, analyses to determine RACM and RACT
and additional reasonable measures) to identify whether and/or which
controls on sources of PM2.5 precursors are ``reasonable.''
The EPA believes that if proposed precursor Option 1 or 3 is finalized,
it would be most appropriate to finalize the first approach to
identifying reasonable control measures for Moderate areas that cannot
practicably attain the NAAQS by the statutory attainment date, since
states would not have an opportunity prior to evaluating the specific
control measures for sources of PM2.5 precursors in the
nonattainment area to demonstrate that controlling all sources of a
particular precursor would not be effective in reducing ambient
PM2.5 levels in the area. Likewise, if the agency finalizes
proposed precursor Options 2A or 2B, the EPA believes that it would be
most appropriate to finalize the alternative
[[Page 15377]]
proposed approach of requiring a state to implement all technologically
and economically feasible measures identified by the state for sources
in the area that can be implemented by the end of the sixth calendar
year following designation if the state demonstrates that the area
cannot practicably attain the NAAQS by the statutory attainment date,
since the ``measures identified by the state'' would already implicitly
exclude control measures on sources of any ``insignificant'' precursor.
The EPA seeks comment on the two proposed approaches to selecting RACM
and RACT and additional reasonable measures for Moderate nonattainment
areas that cannot practicably attain the NAAQS by the statutory
attainment date, and on the EPA's evaluation of the compatibility of
these proposed approaches with the agency's proposed precursor options.
The EPA's proposed analytical process for determining RACM and RACT
is intended to result in a comprehensive list of such technologically
and economically feasible controls that would include local and state
measures that could achieve emissions reductions from sources within
the area, beyond those that could or would be achieved through regional
or national measures. Furthermore, the EPA is proposing to require that
the Moderate area attainment plan must include modeling of all RACM and
RACT and additional reasonable measures, and other state, regional and
federal measures, to demonstrate that a state will not be able to
attain the NAAQS by the end of the sixth calendar year after
designation due to the severity of nonattainment in the area and/or due
to the lack of availability or feasibility of implementing controls in
the area by such date.
Subpart 4 requires that Moderate areas that cannot or do not meet
the Moderate area attainment date be reclassified as Serious
nonattainment areas, in which case sources in the areas are then
subject to BACM and BACT requirements. In the General Preamble, the EPA
indicated that ``it may be reasonable, in some limited circumstances,
for States to consider the compatibility of RACM and RACT with the BACM
and BACT that will ultimately be implemented under the Serious area
plans for those areas.'' \108\ Furthermore, for such areas that do not
meet the Moderate area attainment date, the EPA indicated that ``in the
case of RACM for area sources, EPA anticipates that any future
implementation of BACM for these sources will be additive to, and hence
compatible with, RACM. This is because BACM will generally consist of a
more extensive implementation of the RACM measures . . . Since EPA
anticipates that RACM and BACM for these sources will be compatible,
the SIP's (sic) for these areas should reflect the application of
available control measures to existing sources in moderate
nonattainment areas as determined by the analysis described . . . for
RACM.'' \109\ The EPA believes that a state should consider selecting
and implementing controls that may qualify as BACM or BACT in a
Moderate nonattainment area as part of their RACM and RACT analysis if
they have reason to suspect that the area may not be able to attain the
NAAQS by the applicable Moderate area attainment date as long as the
control can be implemented by the statutory Moderate area attainment
date. Early adoption of controls that would constitute BACM or BACT
could be more efficient and could further the objectives of attaining
the NAAQS expeditiously to protect public health and the environment.
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\108\ Ibid. at 13544.
\109\ Ibid.
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3. RACM and RACT and Additional Reasonable Measures Submission
Requirements
To ensure that attainment plan submissions contain the necessary
supporting information to enable the EPA to review and approve a
state's evaluation and selection of measures that constitute RACM and
RACT in a given nonattainment area, the EPA proposes to require under
the authority of section 301(a) that a state must submit the following
information as part of its submission:
A list of all source categories, sources and activities in
the nonattainment area that emit direct PM2.5 or any
PM2.5 precursor (for multi-state nonattainment areas, this
would include source categories, sources and activities from all states
which make up the area);
For each source category, source or activity in the
nonattainment area, an inventory of direct PM2.5 emissions
and emissions of all PM2.5 precursors;
For each non-de minimis source category, source or
activity in the nonattainment area, a comprehensive list of potential
control measures considered by the state for the nonattainment area;
110 111
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\110\ If the EPA finalizes proposed precursor Option 2A or 2B,
which would effectively allow a state to demonstrate that a given
precursor does not contribute significantly to PM2.5
concentrations in a nonattainment area, then this step would require
potential control measures only for sources of direct
PM2.5 and precursors not exempted from further analysis.
\111\ Menu of Control Measures document available at http://www.epa.gov/air/criteria.html.
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For each potential control measure considered by the state
but eliminated from further consideration due to a determination by the
state that the control measure or technology was not technologically
feasible, a narrative explanation and quantitative or qualitative
supporting documentation to justify the state's conclusion;
For each technologically feasible emission control measure
or technology, the state must provide the following information
relevant to economic feasibility: (1) The control efficiency by
pollutant; (2) the possible emissions reductions by pollutant; (3) the
estimated cost per ton of pollutant reduced; and, (4) a determination
of whether the measure is economically feasible, with narrative
explanation and quantitative supporting documentation to justify the
state's conclusion.
For each technologically and economically feasible
emission control measure or technology, the date by which the
technology or measure could reasonably be implemented.
Each of these elements will provide information needed by the EPA
to evaluate correctly and efficiently whether the state is meeting the
statutory requirements for an attainment plan, and in particular
meeting the statutory requirement for states to implement RACM and RACT
on sources within the nonattainment area. The EPA recognizes that the
base year emissions inventory for the area that the state submits in
conjunction with its attainment plan will likely contain some of the
information proposed to be required under the first two items in this
list. However, the EPA believes that it is incumbent on the state to
ensure that the information needed for the EPA to evaluate the state's
RACM and RACT analysis is presented more specifically as part of the
RACM and RACT analysis and in a format that provides transparency,
consistency and the ability for another party to evaluate the state's
analysis effectively. For this reason, the EPA is including emissions
inventory information specifically relevant to the RACM and RACT
element of the state's attainment plan.
4. Criteria for Effective Regulations To Implement RACM and RACT and
Additional Reasonable Measures
After a state has identified a particular control measure as RACM
or RACT or additional reasonable measure for a particular nonattainment
area, it must
[[Page 15378]]
then implement that measure through a legally enforceable mechanism
that will be included in the SIP (e.g., a state rule that the EPA will
approve as a part of the federally enforceable SIP for the state). The
EPA is proposing that in order for the EPA to be able to approve any
such measure as part of the SIP, the state would have to provide
information to meet the following four criteria. These criteria are
similar to the criteria finalized as part of the remanded 2007
PM2.5 Implementation Rule.
First, the base year emissions from the source or group of sources
to which the control measure applies and the future year projected
emissions from those sources once controlled must be quantifiable so
that the projected emissions reductions from the sources can be
attributed to the specific measures being implemented. It is important
that the emissions from the source category in question are accurately
represented in the base year inventory so that emissions reductions are
properly calculated. In particular, it is especially important to
ensure that both the filterable and condensable components of direct
PM2.5 emissions are accurately represented in the base year.
Second, the control measures must be enforceable. This means that
they must specify clear, unambiguous and measurable requirements. The
measurable requirements for larger emitting facilities must include
periodic source testing, monitoring or other viable means to establish
whether the affected source meets the applicable emission limit.
Additionally, to verify the continued performance of the control
measure, specific emissions monitoring programs appropriate for the
type of control measure employed and the level of emissions must be
included to verify the continued performance of the control measure.
The control measures and monitoring program must also have been adopted
according to proper legal procedures.
Third, the results of application of the control measures must be
replicable. This means that where a rule contains procedures for
interpreting, changing or determining compliance with the rule, the
procedures are sufficiently specific and objective so that two
independent entities applying the procedures would obtain the same
result.
Fourth, the control measures must be accountable. This means, for
example, that source-specific emission limits must be permanent and
must reflect the assumptions used in the attainment plan for the area,
including the modeling conducted in conjunction with the attainment
demonstration. It also means that the attainment plan must establish
requirements to track emissions changes at sources and provide for
corrective action if emissions reductions are not achieved according to
the plan.
The EPA seeks comment on these criteria for approval of any control
measures adopted by a state for a Moderate area to assure that such
measures are legally enforceable.
5. Determination of RACM and RACT and Additional Reasonable Measures in
Multi-State Nonattainment Areas
States in multi-state nonattainment areas will need to consult with
each other on appropriate control measures for the shared nonattainment
area. The agency anticipates that states could decide upon RACM and
RACT and additional reasonable measures that differ from state to state
in a shared nonattainment area, based upon each state's determination
of the most effective strategies given the relevant mixture of sources
and potential controls in the respective states' portions of a shared
nonattainment area. As long as each state can adequately demonstrate
that its chosen attainment strategy, including its selection and
adoption of RACM and RACT and additional reasonable measures, will
provide for meeting RFP requirements and for attainment of the NAAQS as
expeditiously as practicable for the nonattainment area at issue, the
EPA anticipates being able to approve individual state plans that may
elect to control a different mix of sources or to implement different
controls, under the proper circumstances. Nevertheless, in evaluating
RACM and RACT and additional reasonable measures for a particular
nonattainment area, states must consider potential reasonable control
measures developed for other areas or other states, and particularly
for other portions of an interstate nonattainment area. In addition,
states in multi-state nonattainment areas must evaluate whether the
reasonable measures each state may have identified as not being
necessary for attainment could collectively advance the attainment date
for the area by at least 1 year. The EPA may consider such measures in
assessing the approvability of each state's individual attainment plan
for a multistate nonattainment area.
6. Environmental Justice Considerations in Developing the Attainment
Plan Control Strategy for a Moderate PM2.5 Nonattainment
Area
The EPA strongly urges states to consider environmental justice
concerns with respect to any control measures they have identified as
potential RACM or RACT or additional reasonable measures in an area,
particularly to the extent that control measures that a state may be
considering are otherwise approximately equal (in terms of
technological and economic feasibility) but unequal with respect to
their direct or indirect impacts on overburdened populations.\112\ In
such cases, the EPA encourages the state to prioritize imposition of
the control measures that will result in the least possible burden and
greatest degree of health protection for overburdened populations in
the nonattainment area. Section IX of this preamble discusses this and
other possible approaches for states to incorporate ways to address
environmental justice concerns associated with implementation of the
PM2.5 NAAQS in their attainment plans and SIP development
process, and the EPA seeks comment on ways to more fully address such
concerns.
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\112\ The term ``overburdened populations'' is defined in the
EPA's ``Plan EJ 2014'' to describe the minority, low-income, tribal,
and indigenous populations or communities in the U.S. that
potentially experience disproportionate environmental harms and
risks as a result of greater vulnerability to environmental hazards.
This increased vulnerability may be attributable to an accumulation
of both negative and lack of positive environmental, health,
economic or social conditions within these populations or
communities. For more information on Plan EJ 2014, see: http://www.epa.gov/environmentaljustice/plan-ej/.
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E. Modeling for Attainment Demonstrations
1. Statutory Requirements
Section 189(a) generally requires a state with a designated
Moderate nonattainment area to submit an attainment plan for such area.
As discussed earlier, section 189(a)(1)(B) more specifically requires
the state to submit an attainment demonstration including air quality
modeling to establish either: (i) That the area will attain the
relevant NAAQS by the applicable attainment date; or, (ii) that it is
impracticable for the area to attain the relevant NAAQS by the
applicable attainment date. For Moderate nonattainment areas, the
attainment date is as expeditiously as practicable, but no later than
the end of the sixth calendar year after designation as nonattainment.
Section 189(a)(2)(B) of the CAA requires states with designated
nonattainment areas to submit attainment plans no later than 18 months
after designation.
[[Page 15379]]
2. What is an attainment demonstration?
Section 189(a)(2)(B) does not define the term ``demonstration'' and
does not specify precisely how a state should make the required
demonstration. Thus, the EPA believes it is necessary to provide more
specific parameters for such demonstrations in order to assure that
they contain the requisite information to allow for meaningful
evaluation of the issues that the demonstrations are intended to
address. An attainment demonstration is a set of analyses that provide
an explanation of how a state will attain the PM2.5 NAAQS by
the applicable attainment date in a particular nonattainment area.\113\
The EPA is proposing that the demonstration must contain: (i) Technical
analyses such as base year and future year modeling of emissions which
identify sources and quantify emissions that are contributing to
violations of the PM2.5 NAAQS; and, (ii) analyses of future
year emissions reductions and air quality improvement resulting from
existing (i.e., already-adopted or ``on the books'') national, regional
and local programs, and potential new local measures needed for
attainment, including RACM and RACT controls for the area. Each state
with a Moderate nonattainment area must submit an attainment plan with
an attainment demonstration that includes analyses supporting the
state's determination of its proposed attainment date. In all cases,
the state must show that the Moderate area will attain the NAAQS as
expeditiously as practicable, but not later than the end of the sixth
calendar year after designation. In order to establish that the
attainment date is as expeditious as practicable, the state must
explain why any control measures adopted in the attainment plan provide
for the most expeditious attainment and, specifically, must demonstrate
that collectively the reasonable measures that were not adopted as RACM
or RACT or additional reasonable measures will not advance the
attainment date by at least 1 year if implemented. See proposed 40 CFR
51.1011(a).
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\113\ An area is designated nonattainment for either the annual
PM2.5 NAAQS or the 24-hr PM2.5 NAAQS or both.
The attainment demonstration should show that the area is attaining
the form of the NAAQS for which they have been designated
nonattainment.
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A state may alternatively submit a demonstration that shows that
attainment by the statutory attainment date for a Moderate area is
impracticable.\114\ The statute does not define the term
``impracticable'' in this context, so it is necessary for the EPA to
interpret this term in the context of a submission from the state for
this purpose. In order to support this type of demonstration, the EPA
proposes to require that the state must show that, even if all
technologically and economically feasible controls that can be
implemented within 6 years were implemented, the state could not attain
the NAAQS within the statutory timeframe for a Moderate area. A state
could do this by performing a modeling analysis which projects
emissions to the sixth year after designations in order to predict
future year PM2.5 design values in the area. The projected
emissions would account for all existing federal and state SIP-adopted
regulations on sources outside the nonattainment area that were in
place at the time, plus all measures that were identified as
technologically and economically feasible controls that can be
implemented in the nonattainment area within 6 years of designation
(i.e. all measures that would qualify as RACM or RACT or as additional
reasonable measures), as well as any other reasonable measures
available in the state that could aid in achieving timely attainment.
If the modeling shows that attainment cannot be reached by the end of
the sixth calendar year following designation, then the analysis could
be used to demonstrate that it is impracticable for the area to attain
the relevant NAAQS by the statutory attainment date. Other information
can also be used to support the demonstration, including ambient data
and emissions trends data. States are encouraged to work with their
respective EPA Regional Office to identify appropriate information that
could be used to support an impracticability demonstration. The EPA
emphasizes that states that can make the required showing that a
Moderate nonattainment area cannot attain the NAAQS by the statutory
attainment date are nonetheless required to meet the substantive
requirements for a Moderate area attainment plan, including the
implementation of control measures that are RACM and RACT and
additional reasonable measures in that area.
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\114\ Pursuant to section 188(b)(1)(B), upon an EPA
determination that attainment by the Moderate date is impracticable,
the EPA shall reclassify the area as Serious within 18 months after
the Moderate area attainment plan due date.
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3. What modeling is required?
States are required to submit air quality modeling in support of an
attainment demonstration for a Moderate PM2.5 nonattainment
area. Although air quality modeling is not expressly required for a
Moderate area demonstration showing that attainment by the attainment
date is impracticable (per section 189(a)(1)(B)(ii)), the EPA proposes
to interpret the CAA to require air quality modeling similar to that
required for an attainment demonstration in order to demonstrate that
attainment of the relevant PM2.5 NAAQS by the statutory
attainment date is impracticable. Because air quality modeling is a
required element of the attainment demonstration in section
189(a)(1)(B), the EPA believes that it logically follows that similar
modeling should also be required to show that an area will not be able
to attain by the attainment date contemplated by the statute.
There may be limited cases in which a state may be able to
demonstrate through a rigorous technical analysis with supporting
documentation that attainment by the statutory Moderate area attainment
date is impracticable. Given that the statute may be interpreted as not
requiring air quality modeling for an impracticability demonstration,
the EPA proposes and seeks comment on an alternative option under which
air quality modeling would not be a requirement for a Moderate area
impracticability demonstration. The EPA would recommend that a state
submit modeling as part of any Moderate area impracticability
demonstration, but under this alternative option such modeling would
not be a regulatory requirement.
Given that secondarily formed PM2.5 (e.g. ammonium
sulfate, ammonium nitrate and SOA) is a large fraction of the total
measured PM2.5 in most PM2.5 nonattainment areas,
the EPA assumes that photochemical grid modeling (which considers
secondary PM2.5 formation) will be needed for a state to
demonstrate attainment with the NAAQS. Most previous PM2.5
attainment demonstrations for both the 1997 and 2006 PM2.5
NAAQS have utilized photochemical grid models. However, in some
nonattainment areas that are dominated by primary PM2.5
emissions (e.g. residential wood smoke), more simplistic dispersion
models, such as a combination of dispersion, receptor and box airshed
models, may suffice to demonstrate that the area will attain the NAAQS.
Regardless of the modeling approach selected to support the attainment
demonstration, the analyses must be based on technically credible
methods and provide for the timely submittal of the attainment
demonstration and implementation of control measures. States should
consult with their respective EPA Regional
[[Page 15380]]
Office to determine the appropriate type of modeling demonstration for
the particular nonattainment area.
4. Do states need to develop new modeling for their attainment
demonstrations?
The EPA believes that the statutory provision requiring attainment
demonstrations for Moderate PM2.5 nonattainment areas to
include air quality modeling can be fulfilled in a variety of ways.
Thus the EPA proposes to allow states to fulfill the statutory modeling
requirement through either locally generated photochemical and/or
dispersion modeling or, with proper justification, through appropriate
regional or national modeling. The EPA seeks comment on what types of
modeling demonstrations should be required to fulfill the CAA
requirement to ``include air quality modeling'' as part of the
attainment demonstrations for Moderate nonattainment areas.
New modeling analyses that follow the EPA modeling guidance,
conducted by the state for implementing the PM2.5 NAAQS,
will presumably satisfy the attainment demonstration modeling
requirement. However, many areas that were designated as nonattainment
for the 1997 and/or 2006 PM2.5 NAAQS have already invested
considerable resources in local and/or regional PM2.5
modeling analyses. Most states with potential PM2.5
nonattainment areas are already participating in regional modeling
analyses through multi-jurisdictional organizations (MJOs). These MJOs
(e.g. SESARM, LADCO and WRAP) represent most states with
PM2.5 nonattainment areas in the country. There is ongoing
PM2.5 modeling that may provide useful information for state
PM2.5 NAAQS attainment demonstrations.
In addition to local and regional modeling, the EPA conducts
nationwide modeling (generally limited to the contiguous 48 states) in
support of various national rulemakings. The base and future modeling
year for national rule modeling varies depending on compliance dates
for the rule being analyzed and on when the modeling was conducted. For
example, there are several analyses of recent and ongoing rules which
may provide useful PM2.5 modeling information for state
attainment demonstrations. Among them are modeling to support the 2012
PM2.5 NAAQS review, the final Tier 3 mobile source emissions
standards, and the current ozone NAAQS review.\115\ While the analyses
in these rulemaking actions may not be precisely relevant for the
purposes of a PM2.5 attainment plan, they may nevertheless
provide useful information or input relevant to states developing
attainment plans for the PM2.5 NAAQS. Similar nationwide
modeling efforts may be helpful for purposes of future PM2.5
NAAQS.
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\115\ Even though the ozone NAAQS modeling will be focused on
ozone, PM2.5 modeling results will likely be generated
from the analysis in order to inform health benefits calculations.
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States may be able to use regional and/or EPA modeling to
demonstrate that specific nonattainment areas will attain the relevant
PM2.5 NAAQS by the applicable attainment date, but states
must evaluate the relevant modeling information to show that it is
suitable for that purpose. For example, the modeling should be
evaluated to show that it is performing adequately for the area; that
the future modeling year is appropriate for the particular attainment
demonstration; and that the base year emissions and projected emissions
and controls adequately represent the base year conditions and
emissions expected to occur in the area in the future. States should
work closely with the appropriate EPA Regional Office to determine what
(if any) existing modeling may be suitable for use in an attainment
demonstration (or an impracticability demonstration) for a Moderate
PM2.5 nonattainment area.
The EPA requests comment on how states can use existing regional
and/or national modeling to meet their attainment demonstration
requirements. The agency also notes that even when regional or EPA
modeling is available to show that an area is expected to attain the
PM2.5 NAAQS by the applicable attainment date, other CAA
requirements may be difficult to satisfy through the use of regional or
EPA modeling. For example, states may or may not be able to satisfy
their CAA requirements for emissions inventory submittals or RFP
demonstrations by using data derived from MJO or EPA modeling. The
available regional/national modeling may not include an appropriate
base year or future year, and the level of detail or how the emissions
were derived may not be appropriate or compatible with inventories
needed to satisfy specific CAA requirements. States may have to derive
more local specific inventory data, for the appropriate years, to
adequately satisfy these CAA requirements.
Because it will be challenging for states to prepare new modeling
analyses to meet the submission deadline for the Moderate area
attainment plans, the EPA encourages states to start work on modeling
analyses as soon as possible, in order to ensure that adequate time is
devoted to developing a technically credible attainment demonstration.
States that have the most challenging PM2.5 problems will
likely need to develop new and/or updated photochemical modeling
analyses for their nonattainment areas, with emissions (including
potential new controls) projected to the appropriate future attainment
year.
5. What guidance is available for using models to demonstrate
attainment?
The procedures for modeling PM2.5 as part of an
attainment demonstration are described in the EPA's ``Guidance on the
Use of Models and Other Analyses for Demonstrating Attainment of Air
Quality Goals for Ozone, PM2.5, and Regional Haze.'' \116\
All modeling in support of an attainment demonstration should be
consistent with the EPA's PM2.5 photochemical modeling
guidance (referenced above) as well as the Guideline on Air Quality
Models (40 CFR part 51, Appendix W).
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\116\ The 2007 modeling guidance can be found at the following
Web site: http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf. As noted, the EPA recently released revised draft
modeling guidance.
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The PM2.5 attainment demonstration modeling guidance
describes how states can apply air quality models to generate results
needed to demonstrate attainment. These recommendations include
developing a conceptual description of the problem to be addressed;
developing a modeling/analysis protocol; selecting an appropriate model
to support the demonstration; selecting appropriate meteorological
episodes or time periods to model; choosing an appropriate area to
model with appropriate horizontal/vertical resolution; generating
meteorological and air quality inputs to the air quality model;
generating emissions inputs to the air quality model; and, evaluating
performance of the air quality model. After these steps are completed,
the state can apply a model to simulate effects of future year
emissions and candidate control strategies.
The EPA is not requiring a specific model for use in the attainment
demonstration for the PM2.5 NAAQS. At present, there is no
single model which has been extensively tested and shown to be clearly
superior to other available models. The current modeling guideline, 40
CFR part 51, Appendix W, does not identify a preferred model for use in
attainment demonstrations of the PM2.5 NAAQS. Thus, states
may choose from several alternatives so long as the
[[Page 15381]]
alternative is appropriate for the nonattainment area under evaluation.
In some cases, a state may need to apply multiple models in the
attainment demonstration. In most cases, a photochemical grid model is
needed to predict base and future year concentrations of secondary
PM2.5. Photochemical grid models can also be used to predict
concentrations of primary particulate and are useful in assessing steep
concentration gradients arising from area sources. However, in areas
with high concentrations of primary PM2.5, or strongly
stratified air at the surface, a Gaussian plume model or puff model may
also be needed to more accurately represent steep concentration
gradients (or lack of mixing to the surface) in locations with a large
contribution from a single or multiple primary PM2.5 point
sources or locations in near-road areas. The EPA's attainment
demonstration modeling guidance provides details and recommendations on
using multiple models.
Models are used to test whether control measures in an attainment
plan are likely to result in attainment of the relevant standard(s).
The attainment demonstration modeling guidance recommends a modeled
attainment test for the annual and 24-hour PM2.5 NAAQS that
uses a combination of ambient PM2.5 and PM2.5
species data and modeled PM2.5 concentrations to estimate
future year air quality. In the recommended attainment test, the state
applies the test at each PM2.5 ambient monitor location
within or near a designated nonattainment area. Models are used in a
relative sense to estimate the response of measured air quality to
future changes in emissions. Future air quality is estimated by
multiplying recent monitored PM2.5 values by the modeled
relative response (percent change) to projected future changes in
emissions. If the future design value at all monitoring locations in
the nonattainment area does not exceed the concentration of
PM2.5 specified in the NAAQS, the area is projected to
attain the NAAQS.
Because PM2.5 is a mixture of chemical components,
states should use recent observations and modeled responses of major
components of PM2.5 (i.e. sulfate, nitrate, organic carbon,
etc.) to estimate future concentrations of each component.\117\ The
predicted future concentration of PM2.5 is the sum of the
future year predicted component concentrations.
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\117\ The exact years of the ``recent'' ambient data are defined
by the base year selected for the modeling. The guidance recommends
using 5 years of ambient data, centered about the base modeling
year.
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The attainment demonstration modeling guidance contains additional
details regarding the treatment of PM2.5 and speciation
monitoring data. Because PM species data are not available at each
PM2.5 FRM site, the EPA recommends a methodology which
interpolates species data to each FRM site in order to estimate the
species concentrations in the area. This information, combined with
modeling results, may be used to calculate future air quality at each
FRM monitoring site. The EPA has developed software to perform both the
annual and 24-hour PM2.5 attainment test (including
interpolating PM species data). The software is called the Modeled
Attainment Test Software (MATS) and is available for no cost at: http://www.epa.gov/scram001/modelingapps_mats.htm. The software is provided
to make it relatively easy for states to apply the recommended modeled
attainment test. However, states are not required to use MATS and can
develop their own post-processing software.
The modeling guidance also describes the opportunity for states to
supplement their modeling with a ``weight of evidence'' demonstration.
States may use other information and analyses, in addition to the
modeled attainment test, to estimate whether future attainment of the
NAAQS in an area is likely. Other analyses may include, but are not
limited to, emissions trends, ambient data trends and analyses, other
modeling analyses, and documentation of other non-modeled emissions
control strategies, including voluntary programs.
The reliability of tests for estimating future attainment depends
upon having reliable databases for inputs to those tests. The modeling
guidance identifies and prioritizes key data-gathering activities and
analytical capabilities that will increase credibility of analyses used
to estimate if the NAAQS will be attained in the area by the statutory
attainment date.
The EPA is considering updates to the modeling guidance to address
PM2.5 modeling for the 2012 PM2.5 NAAQS. The
agency released a revised draft modeling guidance for developing
demonstrations to meet PM2.5, ozone, and regional haze air
quality goals in December 2014, and intends to revise the guidance
after considering public comments received.\118\
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\118\ See ``Draft Modeling Guidance for Demonstrating Attainment
of Air Quality Goals for Ozone, PM2s, and Regional Haze,'' issued by
Richard Wayland, Director of Air Quality Assessment Division, EPA
Office of Air Quality Planning and Standards, to EPA Regional Air
Division Directors, Regions I-X, December 3, 2014. Available at:
http://www.epa.gov/ttn/scram/guidance/guide/Draft_O3-PM-RH_Modeling_Guidance-2014.pdf.
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The application of air quality models requires a substantial effort
by state and local agencies. Therefore, states should work closely with
their respective EPA Regional Office in executing each step of the
modeling process. Doing so will ensure that states know what EPA
analyses they can rely on, if they wish, to simplify this task, and it
will increase the likelihood of the EPA's approval of a state's
demonstration submitted at the end of the modeling and overall
attainment plan development process.
6. Demonstrating Attainment at Near-Road Monitors
The 2012 PM2.5 NAAQS final rule contains new
requirements for operating near-road monitors in the largest
metropolitan areas.\119\ The first monitors were required to be in
place as of January 1, 2015 (see Section II of this preamble for more
details). These monitors will not have the requisite 3 years of
monitoring data necessary to calculate a PM2.5 design value
until 2018 at the earliest. Therefore, these data were not available to
inform the first round of initial designations for the 2012
PM2.5 NAAQS and there will be less than 3 years of data
available when the initial attainment demonstrations for Moderate areas
are due in October 2016. As a result of this timing, the agency is
proposing that the initial set of Moderate area attainment
demonstrations will not need to include projected design values for
near-road monitor locations. However, subsequent attainment
demonstrations for the PM2.5 NAAQS (after 2018, when 3 or
more years of complete ambient data are available at near-road
monitors) will need to address those monitor locations in attainment
plans and will need to include a demonstration that those monitor
locations will show attainment of the NAAQS by the applicable statutory
attainment date. The revised modeling guidance document for the
PM2.5 NAAQS includes procedures for applying a dispersion
model or a combination of photochemical grid models and dispersion
modeling to demonstrate attainment at near-road monitor locations.
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\119\ 78 FR 3085 (January 15, 2013), at page 3283.
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7. Demonstrating Attainment in Unmonitored Areas
As explained in the 2012 PM2.5 NAAQS final rule and
summarized in Section II of this preamble, the EPA's
[[Page 15382]]
monitoring requirements for PM2.5 are designed to ensure a
robust nationwide monitoring network in both nonattainment and
attainment areas. Air agencies have achieved this by maintaining their
PM2.5 networks in accordance with EPA's network design
criteria. Historically, these criteria provided that CBSAs have at
least one PM2.5 monitoring site located in an ``area-wide''
location of expected maximum concentration (within the CBSA).\120\
Thus, by assuring compliance with the NAAQS at the location of the
expected highest area-wide concentration in the CBSA, air quality is
protected throughout each CBSA. However, due to limited resources,
there are limits to the number of air quality monitors that can be
deployed and it therefore may be useful to consider what, if any,
additional analysis needs there may be as agencies prepare their
attainment plans.\121\
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\120\ As explained in the final 2012 PM NAAQS rule, the EPA
expects that each CBSA will maintain its existing highest
concentration area-wide monitoring site (referred to as the design
value site), See 78 FR 3085 (January 15, 2013), at page 3240. These
sites were set up during the period of time when the network design
criteria required having at least one site in an area-wide location
of expected maximum concentration. The EPA intends to maintain the
highest priority sites in the existing network, which are often at
the neighborhood scale, as the largest part of the PM2.5
monitoring network to continue to support a number of monitoring
objectives, while also allowing lower value sites to move to near-
road locations as that part of the network is phased in.
\121\ Annual monitoring network plans and 5 year assessments are
required by regulation in 40 CFR 58.10. The 5 year monitoring
network assessment is a comprehensive evaluation of a monitoring
agency's ambient air monitoring network, while the annual plan
describes the existing network and changes being proposed to support
implementing recommendations from the most recent 5 year assessment
as well as any applicable changes finalized in association with
NAAQS revisions.
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Under the 2007 PM2.5 Implementation Rule, the EPA
required states to follow existing modeling guidance, which suggested
that a state's PM2.5 attainment plan could be approved if it
demonstrated attainment, through the modeled attainment test, at
monitored locations only. But the guidance also recommended that states
conduct further analyses based on the modeling results to determine
whether there were unmonitored areas that merited additional analysis
or investigation. The guidance further recommended that states either
reduce emissions that, based on these recommended additional analyses,
could cause violations in unmonitored areas, or that they place a new
monitor in such an area. The EPA found that the minimum requirements
for the unmonitored area analysis in the 2007 modeling guidance (and
the 2007 PM2.5 Implementation Rule) were not sufficiently
clear. The EPA is therefore proposing several alternative options in
order to clarify the appropriate treatment of model results in
unmonitored areas for purposes of implementing current and future
PM2.5 NAAQS.
The EPA is proposing four possible approaches to demonstrating
attainment in unmonitored areas. Option 1 would only require states to
perform the attainment test at locations that have current or recent
FRM and/or FEM monitoring data. The EPA would not require states to
analyze areas that have no monitoring data with which to anchor the
attainment demonstration modeling results. The EPA is proposing this
approach to evaluating monitored and unmonitored areas in order to be
consistent with how attainment of the PM2.5 NAAQS is
determined for purposes of designations and redesignations, and due to
uncertainty in modeled projections in locations where there are no
monitoring data to anchor the future year model results. As discussed
in Section II of this preamble, the EPA promulgates designations for
PM2.5 NAAQS nonattainment areas based primarily on ambient
data measured at FRM and FEM monitors.\122\ Although the EPA considers
other forms of information for purposes of evaluating areas with
sources that contribute to those monitored violations for inclusion
within the nonattainment area boundaries, the fundamental basis for
designating an area as nonattainment for a PM2.5 NAAQS is
the presence of one or more FRM or FEM monitors with data showing
violations of the NAAQS in question. Similarly, determinations of
attainment of the PM2.5 NAAQS for purposes of redesignation
actions are based primarily on monitored data. When all FRM and FEM
monitors in a nonattainment area measure attainment of the
PM2.5 NAAQS, the state is eligible to submit a redesignation
request for the area, assuming that it has complied with all other
applicable requirements for purposes of redesignation. Specifically,
the EPA's approval of a redesignation request is subject to meeting the
requirements of CAA section 107(d)(3)(E). Among those requirements is
that the area has attained the NAAQS. For the PM2.5 NAAQS,
this determination is based on ambient data measured at the FRM and FEM
monitors in the area in question. Thus, neither PM2.5
designations nor redesignations currently take into account information
regarding potential violations of the NAAQS at unmonitored locations
throughout a given area. Therefore, consistent with how
PM2.5 areas are designated and redesignated, the EPA is
first proposing to require that states only show attainment at
PM2.5 FRM and FEM monitoring locations as an element of
their attainment demonstrations for the PM2.5 NAAQS.
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\122\ A monitor must have 3 years of quality-assured ambient
data available to be used to calculate a PM2.5 design
value and determine compliance with the NAAQS.
---------------------------------------------------------------------------
In addition, the ``relative'' attainment test for PM2.5
uses FRM or FEM ambient monitoring data, combined with future year
modeled percentage changes in PM2.5 concentrations, to
project future year design values. Since the attainment test relies on
ambient monitoring data, an analysis of future year concentrations in
unmonitored areas can only be accomplished by interpolating ambient
data to a particular location where there is no existing monitor or
recent monitoring data. Therefore, in the context of an attainment
demonstration, the projection of future year PM2.5
concentrations in unmonitored locations is inherently more uncertain
than projections in monitored locations due to the fact that the
ambient concentrations from which these projections are developed are
unknown in the unmonitored locations.
Proposed Option 2 for unmonitored area analyses would require the
state to conduct an unmonitored area analysis as part of all attainment
demonstrations (for Moderate and Serious areas) and require the state
to eliminate potential violations in unmonitored areas through
enforceable emissions reductions in the SIP. The requirement would be
based on a premise that states must demonstrate attainment of the NAAQS
in all locations of a nonattainment area, and models can and should be
used for that purpose. Modeled attainment demonstrations using
photochemical grid models provide modeling results for all grid cells
in the nonattainment area. Therefore, notwithstanding the uncertainty
that is inherent to this approach as discussed above, model outputs
(optionally combined with interpolated ambient data) could be used to
derive estimates of PM2.5 concentrations in unmonitored
areas.
Proposed Option 3 would require states to show attainment at all
current and recent monitoring locations. In addition, states would be
required to provide an unmonitored area analysis as part of all
attainment demonstrations (for Moderate and Serious areas). However,
rather than requiring states to impose additional enforceable emissions
reductions in the SIP to address potential violations in these
locations, states would be required to use the unmonitored area
analysis
[[Page 15383]]
results to develop an assessment of the likelihood of violations in
unmonitored areas. This assessment may be especially important in areas
with a relatively sparse PM2.5 monitoring network or in
locations where information such as modeling data, emissions
inventories or non-FEM monitoring data (such as from special purpose
monitors or saturation monitoring studies) may indicate potential high
PM2.5 concentrations in areas that are currently
unmonitored.
The nature of the assessment of likelihood of violation that is
required under proposed Option 3 would depend on local area modeling,
but could include, as appropriate, elements such as an evaluation of
the emissions inventory (particularly for local direct PM2.5
sources), the existing ambient data for the area, and meteorological
model inputs to determine if the modeled violations in unmonitored
areas appear to be credible. If potential violations are found to be
credible, additional steps may include imposition of enforceable
emissions reductions at nearby emission sources or a commitment to
deploy special purpose monitors and/or saturation monitors in the area
(in order to further evaluate the problem). The state would be required
to document the assessment, including analyses of emissions,
meteorological inputs and ambient data and/or make a commitment to
establish special purpose monitors as part of the attainment
demonstration. Special purpose ambient air monitoring data that is
collected after the attainment demonstration is submitted should be
summarized for use in the area's 5-year monitoring assessment and,
where appropriate, annual monitoring network plans.\123\ Additionally,
monitoring data that is collected as a result of the unmonitored area
analysis assessment (after the attainment demonstration is submitted)
must be reported as a quantitative milestone required under section
189(c)(1) (see Section IV.G of this preamble).
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\123\ All states are required to have an annual monitoring plan
(see Section II of this preamble) which meets the siting criteria
for PM2.5 monitors (40 CFR 58.10).
---------------------------------------------------------------------------
In summary, Option 3 would clarify that an unmonitored area
analysis would be required in all attainment demonstrations, and an
assessment of the unmonitored area analysis results would be required
as part of the attainment demonstration documentation. In contrast to
Option 2, however, the unmonitored area analysis results would not be
used as part of the specific analytical approach for determining
whether a particular control strategy will result in the area attaining
the NAAQS.
Finally, proposed Option 4 would require states to show attainment
at all current and recent monitoring locations. States would not be
required to provide an unmonitored area analysis as part of the
attainment demonstration. However, the EPA would encourage states to
use information available to them to consider what, if any, impacts may
be occurring in unmonitored areas. States could consider information
such as modeling data, emissions inventories or non-FEM monitoring data
(such as from special purpose monitors or saturation monitoring
studies) which may indicate potential high PM2.5
concentrations in areas that are currently unmonitored. Under this
approach, states could consider model results to develop an assessment
of the likelihood of violations in unmonitored areas. This proposed
option differs from Option 3 in that it would not require an
unmonitored area analysis. Rather, under proposed Option 4, an
unmonitored area analysis would be recommended where the state and/or
the EPA has reason to believe that potential violations may be
occurring in unmonitored areas, or other available information
indicates that further analysis is warranted. States would be expected
to consult with the appropriate EPA Regional Office to evaluate
available information to determine if an unmonitored area analysis is
needed for a particular area.
The four options presented above would lead to a range of potential
analysis costs by requiring attainment demonstrations at more locations
and with varying degrees of specificity. To the extent that these
analyses reveal additional locations with potential violations, the
effort needed to address these violations could also be higher, and may
ultimately lead to additional reductions, with their associated costs
and benefits. In terms of analysis costs, Option 1 would be expected to
be the least costly option, whereas Option 2 would be expected to be
the most resource intensive. Option 3 is similar to Option 2, except
that if a potential violation is indicated in an unmonitored area,
there would not be a regulatory requirement for the air agency to
identify enforceable controls to eliminate the potential violation. For
example, the air agency could instead elect to site a new monitor to
further characterize air quality in the area. The analysis costs
associated with Option 3 would thus be similar to Option 2.
Option 4 most closely describes the current policy for the
PM2.5 NAAQS implementation program. Currently, the EPA
recommends that air agencies conduct an unmonitored area analysis, but
there is no regulatory requirement for the air agency to either perform
an unmonitored area analysis or to impose control requirements if the
analysis indicates potential violations. Thus, under Option 4, if an
unmonitored area analysis is performed, the analysis costs associated
with this option would be the same as for Options 2 and 3. Under Option
4, if it is determined by the EPA and the air agency to be unnecessary
to perform an unmonitored area analysis, there would be no additional
analysis costs beyond the monitor-only approach of Option 1. Regarding
the costs and benefits of reductions resulting from additional efforts
to address unmonitored locations (i.e., to the extent that efforts
necessary to address monitored locations do not also address
unmonitored locations), the EPA does not have enough information to
determine the extent of such areas or the measures that would be needed
to address them, nor can the agency predict the extent to which such
measures would be adopted under one option but not another.
The EPA's four proposed options reflect various combinations with
respect to whether such an analysis is required and the purposes for
which the state and the EPA might use the results of the analysis. The
EPA requests comment on whether an unmonitored area analysis should be
a required component of an attainment demonstration for a
PM2.5 nonattainment area and, if required, how the results
of an unmonitored area analysis should be used. The EPA also requests
comment on the potential costs and benefits of each of the four
specific options, and on which of the options the commenter believes
should be included in the final rule and why.
8. What future year(s) should states model in attainment
demonstrations?
A state performing a modeling analysis for an attainment
demonstration or impracticability analysis must select a future year
for the analysis. For an attainment demonstration, a state should
select the future modeling year such that all control measures relied
on for attainment will have been fully implemented by the beginning of
that year. To demonstrate attainment, the modeling results for the
nonattainment area must predict that emissions controls implemented no
later than the beginning of the last calendar year preceding the
attainment date will
[[Page 15384]]
result in PM2.5 concentrations that meet the level of the
standard.\124\
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\124\ Note that for purposes of the PM2.5 NAAQS, a
determination of attainment (or failure to attain), which the EPA is
required to make after the attainment date has passed, is based on
an average of the most recent 3 years of ambient data prior to the
area's attainment date.
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While states should choose the future modeling year based on a
number of factors, the EPA recommends the last possible year permitted
under the statute as a starting point for modeling. There are several
reasons for this. First, states with Moderate areas that submit an
impracticability demonstration must show that the area cannot attain
the NAAQS by the end of the sixth calendar year following designation
of the area. Therefore, the appropriate future modeling year for such a
demonstration is the sixth calendar year after designation. Even if a
state does not submit (or does not intend to submit) an
impracticability demonstration, modeling the sixth calendar year is a
logical starting point to determine if attainment by that year is
likely. Second, even though attainment is determined based on 3 years
of ambient data, states do not have to model 2 years before the
attainment date to show modeled attainment. Since the design value is
an average of the annual or 98th percentile value for 3 consecutive
years of data, attainment can still be shown even if concentrations
exceed the NAAQS in one or more of the 3 years used to determine
attainment (as long as the average of the three annual values is below
the level of the NAAQS). Therefore, it can be appropriate to model any
of the 3 years used to determine attainment. Third, if ambient data
show attainment level concentrations in the final statutory attainment
year, a state may be eligible for up to two 1-year extensions of the
attainment date, if the area meets the criteria for such extensions
under CAA section 188(d). Therefore, modeling attainment level
concentrations for the last year permitted by statute is acceptable.
For all of the reasons stated above, it is both acceptable, and
will in fact be most efficient, for a state to begin the attainment
demonstration process by modeling the last year permitted under the
statute to determine future year modeled PM2.5
concentrations in the sixth year after designations. Thus, in the
attainment demonstrations for areas designated nonattainment in the
first round of designations for the 2012 PM2.5 NAAQS, it
would be appropriate for states to model air quality for 2021.
Because an area must attain ``as expeditiously as practicable''
according to the CAA, additional considerations are necessary before an
attainment date can be established for a Moderate PM2.5
nonattainment area. For purposes of determining the attainment date
that is as expeditious as practicable, the state must conduct future
year modeling which takes into account expected growth and known
controls. For example, for a Moderate nonattainment area for the 2012
PM2.5 NAAQS, a future base case scenario for the year 2021
(6 years after designations) would project future air quality given
implementation of existing federal, state and local measures. If this
base case scenario demonstrates attainment, then the state must
demonstrate whether attainment could be achieved in an earlier year.
Therefore, the state needs to conduct an analysis to determine if,
collectively, all technologically and economically feasible measures
identified by the state for which the state can initiate implementation
by the beginning of the sixth calendar year following designations, can
advance the attainment date by at least 1 year. Results of this
analysis may indicate attainment can be achieved earlier, through
implementation of all reasonable control measures (i.e., RACM and RACT
and additional reasonable measures).
If the future base case scenario does not demonstrate attainment,
then a control case scenario is needed to examine whether the
implementation of all technnologically and economically feasible
measures identified by the state would result in attainment in 2021
(for purposes of this example based on the 2012 PM2.5
NAAQS). The control case scenario would add to the model potential
control measures (i.e., RACM and RACT and additional reasonable
measures, plus any additional intrastate transport measures or other
measures on sources outside of the nonattainment area that the state
has identified as feasible to implement by the attainment date). This
modeling, along with other relevant information, would inform a
judgment as to whether attainment of the relevant NAAQS is practicable
by the end of the sixth year after designation or earlier. In the case
of areas designated nonattainment for the 2012 PM2.5 NAAQS
in the first round of designations, if the analysis does not
demonstrate attainment by December 31, 2021, then the analysis could
serve as the technical basis for the state to submit a demonstration
that attainment by the latest statutory attainment date for Moderate
areas is impracticable. This demonstration in turn could serve as the
technical basis for the Administrator to reclassify the area to
Serious.\125\
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\125\ A demonstration that the area cannot practicably attain by
the Moderate area attainment date would not be the only trigger for
a discretionary reclassification to Serious. The Administrator
maintains wide discretion in making such a determination, with an
impracticability demonstration serving as one potential source of
analysis to inform such a determination.
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The EPA believes that it is not reasonable to require states to
model each and every calendar year to determine the appropriate
attainment date for a nonattainment area. Developing and modeling
future year inventories is a time-consuming and resource intensive
process. Multiple emissions models are needed in order to generate
year-specific emissions for the various emissions sectors (e.g. mobile,
non-road, non-EGU point and EGU point). In some cases it may be
reasonable to model one additional interim year before the maximum
statutory attainment date.\126\ However, in most cases, the air quality
benefits of an identified set of RACM and RACT and additional
reasonable measures can be estimated through model sensitivity analyses
and the development of transfer factors (factors to relate tons of
emissions reductions in the area to PM2.5 concentration
changes in the area). For example, states can model across-the-board
percentage reductions in direct PM2.5 and/or precursor
emissions (in separate model runs) to determine the impact of emissions
reductions on PM2.5 concentrations in the area. This
modeling can be performed with a single attainment year modeling
platform, which is much less resource intensive than modeling
additional future years. The identified potential emissions reductions
available from RACM and RACT and additional reasonable measures can be
compared to the magnitude of the modeled PM2.5 reductions
from the sensitivity analyses to determine if all such controls will
advance attainment by a year. The EPA strongly recommends that states
discuss the selection of the future year(s) to model with their
respective EPA Regional Office as part of the modeling protocol
development process and before embarking on running the model(s).
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\126\ If several future modeling years are available, in some
cases it may be appropriate for states to interpolate
PM2.5 concentrations between years.
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9. Modeling Analysis of Controls That Have a De Minimis Impact on
Ambient PM2.5 Concentrations
In Section IV.D of this preamble, the EPA is proposing that if a
state determines that a Moderate nonattainment area can attain the
PM2.5
[[Page 15385]]
NAAQS by the statutory attainment date, the state must adopt and
implement as reasonable control measures (i.e., as RACM and RACT and
additional reasonable measures) only those technologically and
economically feasible control measures that are necessary to ensure
that the area will attain the NAAQS as expeditiously as practicable. In
a Moderate PM2.5 nonattainment area that cannot practicably
attain the relevant NAAQS by the statutory attainment date, the EPA
similarly believes that it may not be reasonable in all cases to
require that a state implement all technologically and economically
feasible control measures. The EPA is thus proposing an option under
which the state may evaluate the air quality impact of technologically
and economically feasible control measures to determine if there is a
subset of such measures that collectively will only achieve negligible
reductions in ambient PM2.5 concentrations in the area.
Similar to the EPA's proposed approach, described earlier in this
section, to determine if a set of technologically and economically
feasible control measures can collectively advance the attainment date
by a year for a Moderate nonattainment area for which a state can
demonstrate attainment by the statutory attainment date, the state
would be required under this proposed option (for a Moderate area that
cannot practicably attain the NAAQS by the statutory attainment date)
to use an air quality model to determine the impact on ambient
PM2.5 levels of the set of otherwise ``reasonable'' controls
that it believes will not collectively reduce ambient PM2.5
concentrations in the area. For this analysis, the state would have to
show that the collective set of controls will have little to no effect
on reducing PM2.5 concentrations in the area.
10. Attainment Year Motor Vehicle Emissions Budgets
The transportation conformity rule requires that attainment plans
establish motor vehicle emissions budgets for the area's attainment
year. Therefore, once an area's attainment date has been established,
the state would establish motor vehicle emissions budgets for direct
PM2.5 and any relevant PM2.5 precursor for the
attainment year.\127\ A motor vehicle emissions budget for the purposes
of a PM2.5 attainment plan is that portion of the total
allowable emissions within the nonattainment area allocated to on-road
sources as defined in the submitted attainment plan.\128\ Such motor
vehicle emissions budgets would be calculated using the latest planning
assumptions and the latest approved motor vehicle emissions model
available at the time that the attainment plan is developed.\129\
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\127\ For more information on PM2.5 precursor
requirements, see section 93.102(b)(2)(iv) and (v) of the
transportation conformity rule. See also the May 6, 2005, final
transportation conformity rule that addressed requirements for
PM2.5 precursors. (70 FR 24280).
\128\ A state would also establish motor vehicle emissions
budgets for an area's attainment year. Those budgets would be the
motor vehicle emissions that the SIP establishes as being necessary
to attain the NAAQS.
\129\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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F. RFP Requirements
1. Statutory Requirements and Existing Guidance
``Reasonable further progress'' (RFP) is a concept included in the
CAA under part D, title I to assure that states make steady,
incremental progress toward attaining air quality standards in the
years prior to the attainment date for a nonattainment area, rather
than merely deferring implementation of control measures and therefore
emissions reductions until the date by which the standards are to be
attained. As discussed elsewhere in this preamble, section 172 of the
CAA addresses nonattainment plan provisions in general. Section
172(c)(2) requires attainment plans to provide for RFP, which is
defined in section 171(l) as ``such annual incremental reductions in
emissions of the relevant air pollutant as are required by [part D of
title I] or may reasonably be required by the Administrator for the
purpose of ensuring attainment of the applicable national ambient air
quality standard by the applicable date.'' Section 172(c)(3) requires
the state plan to include ``a comprehensive, accurate, current
inventory of actual emissions from all sources of the relevant
pollutant or pollutants in such area . . .'' Section 172(c)(1) requires
the state plan to include ``all reasonably available control measures
as expeditiously as practicable (including such reductions in emissions
from existing sources in the area as may be obtained through the
adoption, at a minimum, of reasonably available control technology) . .
.''
In general terms, the EPA interprets that the purpose of requiring
RFP is to ensure that states with nonattainment areas develop
attainment plans that achieve generally linear progress toward
attainment, rather than deferring emissions reductions until the
applicable attainment date for the area. In the context of implementing
the PM2.5 NAAQS, ``generally linear progress'' means that
emissions of direct PM2.5 and PM2.5 precursors
from controlled sources generally decrease year by year such that the
area ultimately attains the relevant NAAQS by the applicable attainment
date. In the Addendum, the EPA provided guidance and identified four
specific situations in which ``linear progress'' in emissions
reductions to meet RFP may be appropriate:
1. When pollutants are emitted by numerous and diverse sources.
2. Where the relationship between any individual source and the
overall air quality is not explicitly quantified.
3. Where a chemical transformation is involved.
4. Where the emission reductions necessary to attain the standard
are inventory-wide.\130\
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\130\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42015.
---------------------------------------------------------------------------
For example, a state with an area whose nonattainment problem is
caused primarily by area sources, such as residential wood combustion,
should be able to demonstrate generally linear progress toward
attainment in that area. In such an area, the state might be able to
require the replacement of a specified percentage of the residential
woodstoves on an annual basis for each year to assure RFP on an annual
basis.
The EPA's guidance in the Addendum also provided examples of
situations in nonattainment areas in which it might be less appropriate
to expect RFP to be linear, including:
1. Where there are a limited number of sources.
2. Where the relationships between individual sources and air
quality are relatively well defined.
3. Where the emission control systems utilized (e.g., at major
point sources) will result in swift and dramatic emission
reductions.\131\
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\131\ Ibid.
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In nonattainment areas characterized by any of these circumstances,
the EPA understands that RFP may be better represented as step-wise
progress as controls are implemented and achieve significant reductions
soon thereafter. For example, if an area's nonattainment problem can be
attributed to a few major stationary sources, the EPA's guidance
indicates that ``RFP should be met by `adherence to an ambitious
compliance schedule' which is likely to periodically yield significant
emission reductions.'' 132 133 While the EPA noted
[[Page 15386]]
in the Addendum that adherence to such a schedule does not necessarily
mean it would be unreasonable to achieve generally linear progress, the
agency has long interpreted the language of section 171(1) not to
require some specific level of emissions reductions in any given year.
Unlike certain provisions under subpart 2 governing ozone NAAQS
implementation, subpart 4 does not specify a set percentage of
emissions reductions to be achieved over a certain period of time.
Accordingly, the EPA believes that the facts and circumstances of each
specific area will be relevant to whether the emissions reductions meet
the agency's expectations for ``generally linear progress.''
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\132\ USEPA, Office of Air Quality Planning and Standards,
``Guidance Document for Correction of Part D SIP's for Nonattainment
Areas,'' Research Triangle Park, NC, January 24, 1984, page 25.
\133\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42015.
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With respect to implementation schedules, the EPA recommended in
the Addendum that to meet the statutory RFP requirements, attainment
plans must include ``detailed schedules for compliance with emission
regulations in the [nonattainment] areas and accurately indicate the
corresponding annual emission reductions to be realized from each
milestone in the schedule. In reviewing the SIP, the EPA will determine
whether the annual incremental emission reductions to be achieved are
reasonable in light of the statutory objective to ensure timely
attainment of the PM10 NAAQS. Additionally, the EPA believes
that it is appropriate to require early implementation of the most
cost-effective control measures . . . while phasing in the more
expensive control measures.'' \134\
---------------------------------------------------------------------------
\134\ Ibid. at 42016.
---------------------------------------------------------------------------
The EPA believes that these prior interpretations of the Act's
provisions for RFP continue to be appropriate for the PM2.5
NAAQS. Accordingly, the following section describes the EPA's proposal
for requirements to ensure that states meet the statutory provisions
for RFP for Moderate PM2.5 nonattainment areas.
2. General Proposed Approach to RFP
To satisfy the statutory requirements for RFP at section 172(c)(2),
the EPA proposes that a state must submit an RFP plan as part of its
Moderate area attainment plan submission. The RFP plan must contain
appropriate information to demonstrate that adequate emissions
reductions will be achieved through control measures in the attainment
plan in order to meet the statutory definition of RFP. The plan must
include an implementation schedule for control measures on sources in
the nonattainment area and an analysis that demonstrates when--and
through what control measures--emissions will decline from the
applicable baseline year to the attainment year. As part of the
analysis, the RFP plan must include a projected inventory for sources
in the area for one (or more) interim year(s). The EPA is proposing and
seeking comment on two options for developing an RFP plan, as well as
on related requirements, as described below. See proposed 40 CFR
51.1012. The EPA also notes that quantitative milestones required under
section 189(c) are directly linked to the RFP plan, as interim
quantifiable indicators intended to demonstrate that an area is making
progress toward attaining the PM2.5 NAAQS, and are therefore
related to the implementation schedule of control measures for a
PM2.5 nonattainment area. Quantitative milestones are more
fully discussed in Section IV.G of this preamble.
a. Proposed Option 1. Under the first option, the EPA proposes that
the RFP analysis for any Moderate PM2.5 nonattainment area
that can demonstrate attainment by the statutory attainment date must
demonstrate either: (i) Generally linear progress toward attainment by
the applicable attainment date through emissions reductions to be
achieved annually between a baseline year and the projected attainment
date for the area; or, (ii) step-wise progress toward attainment by the
applicable attainment date that will be achieved through adherence to
an ambitious compliance schedule that would not necessarily achieve
reductions on an annual basis. In the second case, the state would be
required to submit a clear rationale and supporting information to
explain why generally linear progress during the attainment period is
not reasonable on an annual basis (e.g., due to the nature of the
nonattainment problem and the types of sources contributing to
PM2.5 levels in the area as discussed in Section IV.F.1 of
this preamble). The EPA also proposes to require that RFP analyses need
to show progress in achieving emissions reductions only for direct
PM2.5 and any precursors that are controlled in the
attainment plan for the nonattainment area.
Note that the two approaches presented in Option 1 for
demonstrating RFP within the nonattainment area are consistent with the
pattern of emissions reductions of many nationally-applicable federal
emissions reduction measures. For example, new emission standards for
mobile sources may achieve reductions in a generally linear manner over
time, as a portion of the existing vehicle fleet is replaced each year
with new vehicles meeting the more stringent standards. On the other
hand, regulations to reduce emissions from certain stationary source
sectors often have a single compliance date by which controls must be
in place, which typically result in a significant drop in emissions
over a relatively short period (i.e., yield step-wise reductions).
Because the statute does not clearly establish the applicable
baseline year from which to begin calculating annual emissions
reductions for purposes of demonstrating RFP, the EPA is proposing to
require and seeks comment on a requirement that states use the same
year as the base year inventory chosen for the area, as this inventory
will serve as the basis for developing the control strategy necessary
to bring the area into expeditious attainment. Furthermore, in
developing their RFP analyses for specific nonattainment areas, the EPA
expects that states will use the emissions inventories developed for
those areas and air quality modeling they have completed for attainment
planning purposes. This approach is consistent with the EPA's proposed
approach, described later in this section, not to interpret the CAA as
allowing states to take credit for emissions reductions from sources
outside a nonattainment area when developing their plan to meet the
statutory RFP requirements for PM2.5 nonattainment areas.
For states with Moderate areas that cannot demonstrate attainment
by the statutory Moderate area attainment date, the statutory RFP
requirements still apply. However, the EPA proposes to require that,
for such areas, the state must provide an analysis of the anticipated
emissions reductions associated with implementing the control measures
identified as RACM and RACT and additional reasonable measures for the
area. The EPA notes that even if a state adequately demonstrates that
it cannot attain the NAAQS in a given area by the statutory attainment
date, the CAA still requires the state to submit a Moderate area
attainment plan meeting the requirements for such attainment plans,
including for RFP. An additional RFP analysis will be required as part
of the Serious attainment plan for the area once the EPA reclassifies
it to Serious.
Similar to the approach taken for RFP in the remanded 2007
PM2.5 Implementation Rule, the EPA is proposing under this
option that all states must follow one primary
[[Page 15387]]
approach for conducting the RFP analysis, but that they also have an
option to conduct a secondary analysis that will provide greater
flexibility in setting RFP goals with alternative emissions reductions
and air quality improvement scenarios. The primary approach would be to
benchmark emissions reductions on a pollutant-by-pollutant basis
starting from the pollutant's baseline emissions level. The state would
then be required to calculate reductions in emissions of each pollutant
on an annual basis that would be needed to bring the area into
attainment by the projected attainment date.
The EPA recognizes that different control measures address
different pollutants, and that states may be able to implement some
measures more quickly than others. Thus, in the optional secondary
analysis, the state could present a different combination of emissions
reductions at similar time intervals that would provide an equivalent
or better result in terms of net air quality improvement. This
``equivalency determination'' would allow states flexibility to address
different pollutants (i.e., direct PM2.5 and
PM2.5 precursors regulated under the control strategy for
the area) according to different schedules so long as the EPA finds the
projected net air quality improvements to be achieved through this
alternative combination of emissions reductions to be equivalent to or
better than those that would be achieved through generally linear
emissions reductions across all pollutants in the area. This proposed
approach recognizes that an important element of establishing
appropriate emissions reductions targets for meeting RFP requirements
for PM2.5 is quantifying the relative degrees of control of
various pollutants.
As discussed above, the primary approach for ensuring that RFP is
met in a PM2.5 nonattainment area is to require that the
state reduce each pollutant--that is, direct PM2.5 and all
precursors not otherwise eliminated from control requirements--by some
amount on an annual basis. The EPA's primary proposed RFP analysis, an
emissions benchmark analysis, would reflect generally linear progress
(or step-wise progress if more appropriate and adequately justified) to
reduce those pollutants that the state intends to control to attain the
PM2.5 NAAQS by the applicable attainment date. See proposed
40 CFR 51.1012(b). For example, a state that can demonstrate that their
Moderate nonattainment area can attain the 2012 PM2.5 NAAQS
by an attainment date of December 31, 2021 would also need to achieve
emissions levels that represent attainment in 2021. If the attainment
plan requires a 10 percent reduction in NOX emissions and a
14 percent reduction in PM2.5 direct emissions from 2011
levels in order for the area to demonstrate attainment in 2021, then
the RFP benchmark for NOX would reflect roughly a 1 percent
reduction in NOX emissions per year, and the benchmark level
for PM2.5 would be roughly a 1.4 percent reduction per year.
The EPA proposes that states must provide an implementation
schedule for control measures that would achieve emissions reductions
consistent with those calculated as part of the RFP benchmark analysis.
However, a state could choose to submit an ``equivalency'' analysis in
addition to the RFP benchmark analysis and associated implementation
schedule that presents an alternative combination of pollutant emission
reductions (i.e., alternative implementation schedule for control
measures) that achieves air quality improvements that are equivalent to
or better than the RFP benchmark analysis. In such a case, the state
would need to make an adequate showing that the alternative schedule
for implementing control measures will provide estimated air quality
improvements that are roughly the same as, if not better than, those
that the emissions reductions determined through the RFP benchmark
analysis would provide. If a state elects to follow this approach, it
must provide in its RFP plan the information necessary to assess
whether an alternative schedule of emissions reductions is generally
equivalent, in air quality terms, to the RFP benchmark analysis
reduction levels, such as attainment demonstration modeling results
that link emissions reductions of various precursor emissions with air
quality improvements. Under this proposed approach, the EPA would
require states to use this information to evaluate the equivalence of
alternative combinations of pollutant emissions reductions. The EPA
would recommend that states estimate air quality improvements
associated with intermediate emissions control levels (i.e., air
quality improvement targets) by assuming that the same relationship
between emissions and air quality applies at intermediate levels as
would apply at attainment levels.
The EPA continues to recognize that because atmospheric processes
are quite complex, a specific percent change in emissions of
PM2.5 precursors does not lead to an equivalent percent
change in air quality, potentially creating uncertainty as to whether
alternate emissions control scenarios will achieve equivalent benefits.
Nevertheless, the EPA believes that it is important to provide the
flexibility to address different pollutants on different timetables so
long as the plan can reasonably be expected to achieve the intended air
quality benefits represented by the RFP benchmark analysis. In general,
the EPA would not expect a state to conduct dispersion modeling
specifically to assess whether an alternative approach to meeting RFP
will provide equivalent air quality benefits as the benchmark approach.
Instead, the attainment plan modeling addresses the nonlinearities at
attainment levels, and the EPA believes for RFP analysis purposes that
the relationship between emissions and air quality at attainment levels
provides an adequate approximation of the relationship at interim RFP
levels.
b. Proposed Option 2. Under the second option, the EPA proposes a
simplified approach to developing an RFP plan that focuses on the
emissions reductions anticipated from each of the particular control
measures identified by the state as part of the analysis to identify
RACM and RACT and additional reasonable measures for sources in the
nonattainment area. Under this option, the first step in developing the
RFP plan would be for the state to establish the implementation
schedule on a year-by-year basis for all control measures contained in
the control strategy for sources in the area beginning with the date of
designation of the area and ending with the projected attainment date
of the area. The schedule would need to comply with the statutory
requirement that all RACM and RACT must be implemented within the first
4 years following designation, but the state would have discretion
beyond that requirement to schedule the implementation of any other
measures necessary for expeditious attainment. Overall, the
implementation schedule would need to demonstrate that control measures
to bring the area into attainment will be implemented as expeditiously
as practicable.
The second step in developing an RFP plan under this second
proposed option would be for the state to calculate the emissions
reductions that would be achieved by all measures implemented on
sources in the area corresponding with quantitative milestone dates
(i.e., by 4.5 years and 7.5 years after designation of the area). These
are the dates by which milestones for the area must be met, after which
a report is due to the EPA from the state to verify that
[[Page 15388]]
the area has met the milestones identified for the area and thereby has
also met the RFP requirements for the area. The EPA proposes that the
state must calculate the emissions reductions to be achieved at each
milestone year on a pollutant-by-pollutant basis.
The third step under this proposed option would be for the state to
conduct modeling or employ another quantitative method to predict the
overall PM2.5 concentrations in the nonattainment area in
each milestone year. This air quality target could simply be
interpolated between the design value at the time of the area's
designation and the design value in the projected attainment year.
These air quality target values would serve as a points of comparison
for the monitored ambient air data that the EPA is proposing that the
state must submit as part of the milestone report due after the area
reaches each milestone date.
This simplified approach to determining RFP for a Moderate
nonattainment area could apply equally well to areas that can
demonstrate attainment with the relevant NAAQS by the statutory
attainment date and those that cannot. See proposed 40 CFR 51.1012(c).
In addition, the EPA believes it offers a reasonable approach to ensure
that RFP is generally being met in the area without requiring extensive
quantitative analysis so long as it is generally linear for purposes of
achieving annual emissions reductions. The EPA seeks comment on these
two options proposed for states to meet the statutory RFP requirements.
3. RFP Inventories for RFP Analyses
The EPA proposes that a state with a Moderate PM2.5
nonattainment area must submit one or more emissions projections as
part of the RFP plan (the ``RFP inventory'') for the area that, at a
minimum, includes projected emissions by different source types
corresponding to the quantitative milestone date(s) for the area,
described in greater detail in Section IV.H of this preamble.
Specifically, the EPA proposes that the RFP plan for any Moderate area
must contain a projected RFP inventory for each calendar year in which
quantitative milestones for a Moderate nonattainment area must be met.
For example, as explained in Section IV.H of this preamble, a state
must identify as part of the attainment plan submission for a Moderate
nonattainment area quantitative milestones to be achieved every 3 years
from the Moderate area attainment plan due date, or 4.5 years from the
effective date of designation of the area.\135\ For example, the first
round of designations for the 2012 PM2.5 NAAQS become
effective in April 2015; Moderate area attainment plans for these areas
will thus be due 18 months later, or in October 2016. The first
quantitative milestones for each of these areas would then have to be
met in October 2019; the second quantitative milestones, in October
2022; and so on, until the area attains the NAAQS. Under the EPA's
proposed approach for projected emissions inventories for RFP analyses,
the state would be required to submit such inventories as part of the
Moderate area attainment plan due in October 2016 that project
emissions from sources in the nonattainment area for the same calendar
years as those for which quantitative milestones would be due.
---------------------------------------------------------------------------
\135\ According to section 189(a)(2)(B), Moderate area
attainment plans are due to the EPA 18 months after designation.
---------------------------------------------------------------------------
The transportation conformity rule requires that attainment plans
establish motor vehicle emissions budgets. RFP plans submitted as part
of an attainment plan submission would therefore be required to
establish motor vehicle emissions budgets for direct PM2.5
and any relevant PM2.5 precursor.\136\ A motor vehicle
emissions budget for the purposes of a PM2.5 RFP plan is
that portion of the total allowable emissions allocated to on-road
sources as defined in the submitted RFP plan for the relevant years as
described above.\137\ Such motor vehicle emissions budgets would be
calculated using the latest planning assumptions and the latest
approved motor vehicle emissions model available at the time that the
attainment plan is developed.\138\
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\136\ For more information on PM2.5 precursor
requirements, see section 93.102(b)(2)(iv) and (v) of the
transportation conformity rule. See also the May 6, 2005, final
transportation conformity rule that addressed requirements for
PM2.5 precursors. (70 FR 24280).
\137\ A state would also establish motor vehicle emissions
budgets for an area's attainment year. Those budgets would be the
motor vehicle emissions that the SIP establishes as being necessary
to attain the NAAQS.
\138\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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4. Geographic Coverage of Emission Sources for RFP
The EPA is proposing that the RFP demonstration to be included with
a state's PM2.5 nonattainment area plan must include
emissions only for sources located in the nonattainment area, and not
from an area larger than the nonattainment area. This policy approach
differs from the remanded 2007 PM2.5 implementation rule.
This section describes the evolution of policy on a similar RFP issue
in the ozone NAAQS implementation program, and it discusses the
reasoning behind this revised approach for PM2.5.
In the preamble to the remanded 2007 PM2.5
Implementation Rule, the EPA allowed states to incorporate reductions
of NOX and SO2 emissions up to 200 km from
outside the nonattainment area (and potentially for reductions of VOC
or ammonia) into their RFP plan when certain conditions were met. This
policy was included in the 2007 PM2.5 Implementation Rule in
part to be consistent with a similar RFP policy for NOX and
VOC that was included in the November 2005 Phase 2 ozone NAAQS
implementation rule which provided guidance for states on implementing
the 1997 ozone NAAQS.\139\
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\139\ See Phase 2 Ozone Implementation rule, 70 FR 71612
(November 29, 2005).
---------------------------------------------------------------------------
Under the policy in the 2007 PM2.5 NAAQS implementation
rule, if a state intended to include emissions reductions from outside
the nonattainment area in the RFP plan, the state would need to take on
the additional work associated with developing: (i) An expanded
baseline emissions inventory for the entire geographic area (i.e., the
nonattainment area plus the additional area outside the nonattainment
area) that characterizes emissions for all stationary, area and mobile
sources (rather than for just a select few stationary sources) in the
overall area; and, (ii) a projected attainment year inventory for this
expanded area outside the boundaries of the designated nonattainment
area. By requiring inclusion of all types of sources in these
``expanded area'' emissions inventories, the EPA intended for this
approach to reflect the projected net emissions reductions in this area
(the difference between the ``expanded area'' base year inventory and
the projected attainment year inventory). However, it should be noted
that development of these more extensive inventories would likely have
involved a substantial amount of additional time and resources. In
addition, the state would have needed to have provided information
supporting its decision regarding how far outside the nonattainment
area the RFP inventory should extend. While this ``outside the
nonattainment area'' RFP approach was theoretically available to states
in developing their PM2.5 attainment plans due in 2008,
there were no states to the agency's knowledge that elected to follow
this approach.
[[Page 15389]]
Both the 2005 Phase 2 ozone implementation rule and the 2007
PM2.5 Implementation Rule were challenged on several issues.
With regard to the Phase 2 ozone implementation rule, the EPA granted a
petition for reconsideration and ultimately issued a final notice of
reconsideration in June 2007. In November 2008, the U.S. Court of
Appeals for the DC Circuit heard oral argument concerning multiple
petitions for judicial review of the Phase 2 ozone rule and the notice
of reconsideration. One of the issues in this case involved whether
compliance by EGUs with a regional emissions trading program could be
considered to meet the RACT requirement for those sources located in a
nonattainment area. In its July 2009 decision, the court emphasized
that: ``the RACT requirement calls for reductions in emissions from
sources in the area; reductions from sources outside the nonattainment
area do not satisfy the requirement . . . Accordingly, participation in
the NOX SIP call would constitute RACT only if participation
entailed at least RACT-level reductions in emissions from sources
within the nonattainment area.''
In light of this court decision, the EPA has determined that the
best reading of the statute would be to interpret the term ``sources in
the area'' in the same manner where it appears in different
nonattainment provisions for ozone. The term appears in CAA section 182
(requirements for ozone nonattainment areas) with regard to RFP as well
as RACT. The decision on the Phase 2 ozone rule found that section
182(b)(2) requires that a SIP must provide for implementation of RACT
(under section 172(c)) for emissions sources ``in the area,'' meaning
in the nonattainment area. Similarly, the EPA believes that when
section 182(b)(1)(A)-(B) defines baseline emissions for RFP as ``the
total amount of actual VOC or NOX emissions from all
anthropogenic sources in the area,'' this also means sources in the
nonattainment area.
With regard to the 2007 PM2.5 Implementation Rule, the
EPA received a petition for reconsideration in June 2007 that raised
objections on several issues. One such issue dealt with the EPA's
interpretation of the statutory RFP requirements to allow a state to
take ``credit'' for emissions reductions from outside the nonattainment
area when addressing RFP in its attainment plan.\140\ The EPA granted
the petition for reconsideration on this issue in 2010, after the D.C.
Circuit issued its decision on the Phase 2 Ozone Implementation
Rule.141 142
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\140\ This same petition raised concerns regarding the criteria
used to determine the economic feasibility of controls being
considered for RACT for the 1997 PM2.5 NAAQS. See
``Petition for Reconsideration,'' filed by Paul Cort, Earthjustice,
on behalf of the American Lung Association, Medical Advocates for
Healthy Air, Natural Resources Defense Council, and the Sierra Club
(June 25, 2007). A copy of the petition is in the docket for this
action.
\141\ Letter dated May 13, 2010, from Gina McCarthy to David S.
Baron and Paul Cort, Earthjustice. A copy of the letter is located
in the docket for this action.
\142\ See NRDC v. EPA, 571 F.3d 1245 (D.C. Cir. 2009).
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Specifically, the EPA believes that the DC Circuit's interpretation
of the phrase ``sources in the area'' applies to RACT and RFP
requirements for both the ozone NAAQS and the PM2.5 NAAQS.
In particular, for PM2.5, the statutory language at section
171(1) defines RFP in terms of ``reductions in emissions'' required in
an attainment plan, which the EPA interprets as being directly linked
to the baseline emissions inventory for sources located in a
PM2.5 nonattainment area. The baseline emissions inventory
is the foundation for the attainment plan. The emissions inventory
requirement of section 172(c)(3) explicitly requires that the
attainment plan inventory include all sources of the relevant
pollutants ``in such area,'' which is a clear reference to the
designated nonattainment area. Given that the baseline inventory must
reflect the emissions ``in such area,'' and that this inventory
provides the starting point for a state's RFP analysis, in which the
state must calculate generally linear progress in emissions reductions
that will lead to attainment of the NAAQS in the area, the EPA believes
it is appropriate that a state should focus on sources located within
the nonattainment area when conducting its analysis to determine the
annual emissions reductions necessary for demonstrating RFP.
The EPA believes that the most appropriate approach with regard to
the geographic area required to be covered for demonstrating RFP in a
PM2.5 attainment plan also should be limited to the
nonattainment area for two other reasons. First, EPA believes that it
makes policy sense for the PM2.5 implementation rule
approach to be consistent with the approach in the ozone implementation
rule. In the past, a number of areas have been designated as
nonattainment for both standards, and the nonattainment area boundaries
often are the same. For such areas, a common policy approach for the
geographic area covered by the RFP plan will be more efficient to
implement and would be expected to be less burdensome for the air
agency than if the geographic areas covered by RFP plans for the two
pollutants differed.
Second, a policy allowing the geographic area of the RFP plan to be
larger than the nonattainment area would conflict with a key provision
of subpart 4 which requires annual incremental reductions in emissions
from sources within the nonattainment area. Under subpart 4, an area
that fails to attain the standard by the Serious area attainment date
is then subject to the provisions of section 189(d). Section 189(d)
specifies that the state must submit a plan revision within 12 months
which provides for ``an annual reduction in PM10 or
PM10 precursor emissions within the area of not less than 5
percent of the amount of such emissions as reported in the most recent
inventory prepared for such area'' (emphasis added). The EPA does not
believe the rule should include an RFP policy approach which would not
be consistent with section 189(d).
After reconsideration of the approach to RFP that was opposed in
the petition for reconsideration of the 2007 PM2.5
Implementation Rule, and in light of the DC Circuit decision on the
Ozone Phase 2 Implementation Rule, the EPA believes the best reading of
the statute is that the CAA does not allow for a state to include
emissions reductions from sources outside a nonattainment area when
developing the plan to meet the CAA section 172(c)(2) RFP requirements
for a PM2.5 nonattainment area. The EPA seeks comment on
this proposed approach.
5. Other RFP Considerations
In general, the EPA seeks to ensure that PM2.5
nonattainment areas that are shared by more than one state or tribe
meet RFP requirements as a whole. States and tribes that share a
nonattainment area should therefore consult with one another to develop
the RFP analysis and control strategy implementation schedule for the
area as a whole. Such states and tribes should work with the EPA region
or regions that oversee them to confirm that their collective approach
is appropriate for RFP.
The EPA's proposed approach for states to meet the RFP requirement
is designed to ensure emissions reductions will yield incremental
improvements in air quality on the path to attainment, while being
sufficiently flexible to accommodate the range of control strategies
necessary to address the complex mixtures of pollutants comprising
PM2.5 in different areas. The EPA seeks comment on all of
its proposed requirements and options for
[[Page 15390]]
RFP plans and analyses for Moderate PM2.5 attainment plans.
G. Quantitative Milestones
1. Statutory Requirements and Existing Guidance
Section 189(c)(1) requires that a PM10 NAAQS attainment
plan submission has ``quantitative milestones which are to be achieved
every 3 years until the area is redesignated to attainment and which
demonstrate reasonable further progress . . . toward attainment by the
applicable date.'' Section 189(c)(2) further requires that, within 90
days of each milestone, each affected state must submit a demonstration
that all measures to assure RFP have been implemented and that the
quantitative milestone has been met. Thus, the CAA imposes requirements
upon states not only to make ``reasonable further progress'' toward
attainment, but also to identify objective means (i.e., quantitative
milestones) by which to measure this reasonable further progress every
3 years, and to submit them as part of the attainment plan for the
nonattainment area. In addition, according to section 189(c)(2), states
must, within 90 days of the passage of each such milestone, submit to
the EPA a demonstration that control measures have been implemented
according to the approved RFP plan schedule and the milestone has been
met.
The EPA has previously described its interpretation of the
requirements under section 189(c) for the PM10 NAAQS in the
General Preamble and the Addendum and believes that these
interpretations should also apply both in developing plans that
demonstrate RFP and include appropriate quantitative milestones, and in
demonstrating that those milestones have been met for the
PM2.5 NAAQS.143 144 The EPA's guidance in the
Addendum also noted that: ``Section 189(c) provides that the
quantitative milestones submitted by a State for an area also must be
consistent with RFP for the area. Thus, EPA will determine an area's
compliance with RFP in conjunction with determining its compliance with
the quantitative milestone requirement. Because RFP is an annual
emission reduction requirement and the quantitative milestones are to
be achieved every 3 years, when a state demonstrates an area's
compliance with the quantitative milestone requirement, it should also
demonstrate that RFP has been achieved during each of the relevant 3
years.'' \145\
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\143\ See the Federal Register published on April 16, 1992,
General Preamble (57 FR 13498 and 13539).
\144\ See the Federal Register published on August 16, 1994,
Addendum to General Preamble (59 FR 41998, 42015, 42016 and 42017).
\145\ Ibid.
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The EPA's existing guidance in the Addendum with respect to the
quantitative milestone requirements of CAA section 189(c) thus includes
several important features: (i) That the control measures comprising
the RFP plan should be implemented and in place to meet the statutory
quantitative emissions reductions milestone requirement; (ii) that it
is reasonable for the 3-year periods for quantitative milestones to run
from the statutory due date for the Moderate area attainment plan
submission; and, (iii) that the precise form that the quantitative
milestones should take is not specified, but the state must choose
milestones that will allow it to quantify or measure, track and report
progress adequately and objectively.
The EPA's proposed approach to identifying quantitative milestones
for any Moderate PM2.5 nonattainment area and demonstrating
compliance with the milestones is generally consistent with the
existing guidance, as described in the following sections.
2. Proposed Approach
The statute at section 189(c) is clear that quantitative milestones
must be achieved every 3 years, however it does not make clear the
starting date for counting the 3 year periods. In the General Preamble,
the agency proposed that quantitative milestones must be achieved every
3 years starting from the attainment plan submission due date (i.e.,
because the Moderate area attainment plan is due no later than 18
months after designation of the area, the first set of milestones would
need to be achieved 4.5 years after the area's designation) until the
attainment date.\146\ The EPA proposes to maintain this approach for
the PM2.5 NAAQS. Specifically, the EPA proposes that the
attainment plan for a Moderate area that can demonstrate attainment by
the statutory Moderate area attainment date must identify appropriate
quantitative milestones to be achieved by 4.5 years following
designation of the area. For a Moderate area that cannot practicably
attain the relevant PM2.5 NAAQS within the statutory
timeframe for a Moderate area, the EPA proposes that a state must
submit two sets of quantitative milestones--one set to be achieved at
year 4.5 from designation and the second set to be achieved at year 7.5
from designation. The EPA believes that this proposed requirement will
help to ensure that the state maintains progress toward bringing the
area into attainment during the period in which such area is
reclassified to Serious, the state works to develop a Serious area
attainment plan for the area, and the EPA approves it. Pursuant to the
statute, the EPA must reclassify a Moderate area for which a state
submits an attainment impracticability demonstration within 18 months
after the Moderate area attainment plan due date, or no later than 3
years after the date of designation of the area. Even under a scenario
in which the state develops and submits a Serious area attainment plan
18 months after being reclassified to Serious, the milestone date of
4.5 years after designation would likely come and go before the area
had a new set of approved quantitative milestones with which to
demonstrate compliance. Similarly, the milestone date of 7.5 years
after designation could also come and go before the EPA is able to
fully approve the Serious area plan and any quantitative milestones
contained therein. Because of the timing of the various steps involved
in reclassifying a Moderate area to Serious and a state developing a
new Serious area plan, the EPA believes that requiring a state to
identify quantitative milestones that the area must achieve 4.5 years
and 7.5 years after designation as elements of its Moderate area
attainment plan is reasonable and seeks comment on this proposed
requirement.
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\146\ General Preamble, 57 FR 13498 (April 16, 1992), at page
13539.
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The EPA is also proposing that the quantitative milestones
contained in the attainment plan for a Moderate nonattainment area must
be constructed such that they can be tracked, quantified and/or
measured adequately in order for the state to meet its milestone
reporting obligations, which come due 90 days after a given milestone
date. In the Addendum, the EPA suggested some possible metrics that
``support and demonstrate how the overall quantitative milestones
identified for an area may be met,'' such as percent implementation of
control strategies, percent compliance with implemented control
measures, and adherence to a compliance schedule. This list was not
exclusive or exhaustive but reflected the EPA's view that the purpose
of the quantitative milestone requirement is to provide an objective
way to assess that the state is making the necessary progress towards
attainment in the area by the applicable attainment date.\147\ The EPA
continues to believe that the quantitative milestone requirement
[[Page 15391]]
should be interpreted to allow states to devise milestones that are
suitable for the specific facts and circumstances of the attainment
plan for a particular area, so long as they provide an objective means
to measure RFP.
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\147\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42016.
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The EPA therefore proposes to require that states select the
quantitative milestones that are appropriate and quantifiable and that
will provide for objective evaluation of progress toward attainment in
their Moderate PM2.5 nonattainment area, whether the area
can practicably attain the PM2.5 NAAQS by the statutory
attainment date or not. For this approach, the EPA is not proposing to
require that such quantitative milestones must take any particular
form, merely that they provide a means to evaluate progress (i.e.,
demonstrate RFP) meaningfully. The EPA, in its attainment plan approval
process, will determine if the specific quantitative milestones
developed by the state for a specific nonattainment area satisfy the
statutory requirements. The EPA recommends that states confer with
their respective EPA regional office to develop appropriate
quantitative milestones. See proposed 40 CFR 51.1013(a)(1).
In addition to this general proposed approach for selecting
quantitative milestones for a Moderate nonattainment area, the EPA is
proposing and seeks comment on a requirement that, at a minimum, states
must include in all attainment plans for Moderate PM2.5
nonattainment areas a metric to confirm that all control measures
identified and adopted as RACM and RACT for the area have been fully
implemented within 4 years of designation. This metric specifically
derives from the statutory provision that applies to all Moderate areas
and thus represents a milestone that all Moderate areas must meet
regardless of whether it is listed explicitly as an individual
milestone. The EPA believes it would be appropriate to include it as a
metric that any state with a Moderate nonattainment area would need to
demonstrate compliance with when they submit their milestone report as
described below, and thus seeks comment on this proposal.
3. Milestone Report Submittal
Under the quantitative milestone requirement of section 189(c)(2),
a state must demonstrate to the EPA that the RFP plan for the area and
its approved milestones are being met within 90 days after the
milestone due date. The EPA then has 90 days to determine whether or
not a state's demonstration is adequate. Specifically, section
189(c)(2) requires that: ``Not later than 90 days after the date on
which a milestone applicable to the area occurs, each State in which
all or part of such [nonattainment] area is located shall submit to the
Administrator a demonstration that all measures in the plan approved
under this section have been implemented and that the milestone has
been met. A demonstration under this subsection shall be submitted in
such form and manner, and shall contain such information and analysis,
as the Administrator shall require.''
In the event a state fails to submit a milestone demonstration
report by the due date or the EPA determines that a milestone was not
met, the state must submit a SIP revision within 9 months of either the
missed reporting deadline or the EPA's determination of the state's
failure to meet a milestone. According to the statutory requirements of
section 189(c)(3), the new SIP revision must assure ``that the State
will achieve the next milestone (or attain the national ambient air
quality standard . . ., if there is no next milestone) by the
applicable date.'' If a state fails to make a SIP submission to correct
a failure to meet RFP expeditiously, sanctions under sections 110(m)
and 179(b) may apply. If a state is unable to correct a failure to meet
RFP, this may be evidence that the state cannot practicably attain the
NAAQS by the applicable attainment date and may serve as a basis for
reclassification of the area to Serious under the agency's
discretionary authority. See proposed 40 CFR 51.1013(c).
Because the statute does not define the parameters of these
demonstrations, the statute grants the EPA discretion to determine the
components of the required demonstration and the form and manner for
submission. In the Addendum, the EPA offered guidance about what the
milestone report should contain: ``This report must contain technical
support sufficient to document completion statistics for appropriate
milestones. For example, the demonstration should graphically display
RFP over the course of the relevant 3 years and indicate how the
emission reductions achieved to date compare to those required or
scheduled to meet RFP and the required [quantitative] milestones. The
calculations (and any assumptions made) necessary to determine the
emission reductions to date should also be submitted. The demonstration
should also contain an evaluation of whether the PM10 NAAQS
will be attained by the projected attainment date.'' \148\ The EPA
believes this guidance is still appropriate for states demonstrating
compliance with RFP and quantitative milestones for PM2.5
NAAQS and hereby proposes under the authority of section 301(a) to
require that the milestone report submission must include the following
four components:
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\148\ Ibid. at 42017.
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First, the report must include a certification by the Governor or
Governor's designee that the state's attainment plan control strategy,
including the RFP plan, is being implemented as described in the
applicable attainment plan. Second, as described in the Addendum, the
report must contain technical support, including calculations,
sufficient to document completion statistics for appropriate milestones
and to demonstrate that the quantitative milestones have been satisfied
and how the emissions reductions achieved to date compare to those
required or scheduled to meet RFP. Third, the state must submit an air
quality screening analysis to determine if measured air quality
progress is consistent with the expected air quality improvement target
correlated with the RFP emissions reductions for the previous 3-year
period. Fourth, the report must contain an evaluation of whether the
PM2.5 NAAQS will be attained by the projected attainment
date for the area. In addition, the EPA proposes that the milestone
report must include a description and schedule for any remedial actions
the state has taken or will take to address any failure to meet a
quantitative milestone, including the implementation status of
contingency measures for failing to meet RFP in the area. See proposed
40 CFR 51.1013(b). The EPA seeks comment on these proposed components
to a milestone report.
The EPA stated in the Addendum that the milestone report must be
submitted from the Governor or Governor's designee to the Regional
Administrator of the respective EPA Regional Office serving the
submitting state, and that the EPA will notify the state of its
determination (regarding whether or not the state's report is adequate)
by sending a letter to the appropriate Governor or Governor's designee.
The EPA believes that it would be appropriate for states to submit
milestone reports, including supporting documents, through the agency's
electronic SIP (eSIP) submission system in order to simplify the
process and reduce resource burden on all sides. The EPA seeks comment
on how electronic reporting could facilitate a state's submittal of the
required milestone report, how it could accommodate the various
narrative and
[[Page 15392]]
data-dependent components that the EPA is proposing be part of such a
submittal, and what particular system features might be desirable to
accommodate milestone report submissions through the eSIP system.
H. Contingency Measures
States with PM2.5 nonattainment areas must include
contingency measures in their attainment plans consistent with section
172(c)(9). Contingency measures are additional control measures to be
implemented in the event that an area fails to meet RFP requirements or
fails to attain the PM2.5 standard by the applicable
attainment date. These measures must be fully adopted rules or control
measures that are ready to be implemented quickly upon failure to meet
RFP or failure of the area to meet the standard by its attainment date,
and such measures are required to take effect without further action by
the state or the EPA. The EPA provided extensive guidance on
contingency measures in the General Preamble and Addendum, including
the following: ``States must show that their contingency measures can
be implemented with minimal further action on their part and with no
additional rulemaking actions such as public hearings or legislative
review. After the EPA determines that a moderate PM10
nonattainment area has failed to attain the PM10 NAAQS, the
EPA generally expects all actions needed to effect full implementation
of the measures to occur within 60 days after the EPA notifies the
state of the area's failure. The state should ensure that the measures
are fully implemented as expeditiously as practicable after they take
effect.'' \149\
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\149\ Ibid. at 42015.
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The EPA does not believe that the D.C. Circuit's decision in NRDC
v. EPA affects the overall contingency measure requirements that were
finalized in the remanded 2007 PM2.5 Implementation Rule,
because section 172(c)(9) imposes the contingency measure requirement
for attainment plans for the PM2.5 NAAQS and it is not
superseded or subsumed by any specific contingency measure requirements
under subpart 4. Although section 172(c)(9) requires contingency
measures, the provision does not specify exactly what parameters such
measures must meet. The EPA has longstanding interpretations of the
statute with respect to the contingency measure requirement, both for
PM and for other pollutants, in the General Preamble and Addendum. The
EPA proposes to adopt an approach to contingency measures for the
PM2.5 NAAQS similar to that recommended in earlier EPA
guidance, but seeks comment on particular proposed approaches that
differ in important ways from earlier guidance on contingency measures
for the PM2.5 NAAQS. The EPA believes that it may be
necessary to adopt a different approach to contingency measures for
PM2.5 attainment plans due to proposed changes in
determining RFP for a PM2.5 nonattainment area and in order
to accommodate Moderate PM2.5 nonattainment areas that
cannot practicably attain the standard by the statutory Moderate area
attainment date.
The EPA is proposing and seeking comment on the following general
requirements for contingency measures to be approvable as part of a
state's Moderate area attainment plan submission for the
PM2.5 NAAQS:
1. Contingency measures must be fully adopted rules or control
measures that are ready to be implemented quickly upon a determination
by the Administrator of the nonattainment area's failure to meet RFP or
failure to meet the standard by its attainment date.
2. The state's attainment plan submission must contain trigger
mechanisms for the contingency measures, specify a schedule for
implementation, and indicate that the measures will be implemented with
minimal further action by the state or by the EPA.
3. Contingency measures must consist of control measures that are
not otherwise included in the control strategy for the attainment plan.
4. Contingency measures must provide for emissions reductions
approximately equivalent to 1 year's worth of reductions needed for
RFP, based on the overall level of reductions needed to demonstrate
attainment divided by the number of years from the base year to the
attainment year, or approximately equivalent to 1 year's worth of air
quality improvement or emissions reductions proportional to the overall
amount of air quality improvement or emissions reductions to be
achieved by the area's attainment plan. See proposed 40 CFR 51.1014.
The EPA interprets the contingency measure requirement of section
172(c)(9) to require control measures that are not already included in
the attainment plan for other purposes, such as to meet RACM and RACT
requirements. However, suitable contingency measures may be measures
that were technologically and economically feasible for the area, but
did not qualify as RACM or RACT or additional reasonable measures for
one or more reasons. For example, a candidate contingency measure may
have been deemed technologically and economically feasible, but it was
not needed to achieve expeditious attainment in a Moderate area for
which the state could demonstrate attainment by the statutory
attainment date and therefore was not included as part of the
attainment demonstration for the area. The agency believes it is
important that states make decisions concerning contingency measures in
conjunction with their determination of the overall control strategy
for bringing the area into expeditious attainment, and that states
first must identify those control measures needed in order to
demonstrate expeditious attainment of the standards; any remaining
measures should then be considered as candidates for contingency
measures.
For Moderate areas that cannot practicably attain the NAAQS by the
statutory attainment date, the EPA is proposing that states must
implement all control measures that they determine to be reasonable for
sources in the area. In such cases, the EPA expects that contingency
measures for such nonattainment areas would necessarily exceed the
criteria for determining whether a measure is reasonable (i.e.,
technologically and economically feasible) as described in Section IV.D
of this preamble. Such contingency measures would only be triggered in
the event the area fails to meet RFP; the EPA does not interpret the
requirement for contingency measures for failing to attain the NAAQS by
the applicable attainment date to apply to a Moderate area that a state
demonstrates cannot practicably attain the NAAQS by the statutory
attainment date. Rather, the EPA believes it is appropriate for the
state to identify and adopt contingency measures for failing to attain
the NAAQS in a timely way as part of the Serious area attainment plan
that it will develop once the EPA reclassifies such an area.
The EPA proposes that for any Moderate PM2.5
nonattainment area, contingency measures can include measures that
achieve emissions reductions on sources located outside the
nonattainment area as well as from sources within the nonattainment
area, provided that the measures are factually demonstrated to produce
the appropriate air quality impact within the nonattainment area. The
EPA continues to believe it appropriate that a state might choose to
rely on federal measures (e.g. federal mobile source measures based on
the incremental turnover of the motor vehicle fleet each year) and
local measures already scheduled for implementation for
[[Page 15393]]
purposes other than meeting attainment plan requirements, such as RACM
and RACT, as meeting part or all of the contingency measure
requirements, as the purpose of the contingency measures is to provide
a cushion while the attainment plan for the area is being revised to
meet the missed attainment milestone. The EPA has approved numerous
attainment plans under an interpretation that one or more federal or
local measures that are in place and provide reductions in the year
following a failure to attain the relevant NAAQS or meet RFP in excess
of the reductions required by the attainment demonstration or RFP plan
can meet the contingency measure requirements.150 151
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\150\ See, e.g., 62 FR 15844 (April 3, 1997); 62 FR 66279
(December 18, 1997); 66 FR 30811 (June 8, 2001); 66 FR 586 and 66 FR
634 (January 3, 2001).
\151\ A court ruling upheld contingency measures for ozone
attainment plans that were previously required and implemented where
they were in excess of the attainment demonstration and RFP SIP. See
LEAN v. EPA, 382 F.3d 575 (5th Cir., 2004).
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The EPA recognizes that some states have historically relied on
emissions reductions achieved through the implementation of control
measures in excess of what was determined to be necessary to meet RFP
in certain PM2.5 nonattainment areas in order to satisfy the
contingency measure requirement in such areas. The EPA believes that
this approach is reasonable for Moderate PM2.5 nonattainment
areas that can demonstrate attainment by the statutory attainment date,
as the state would calculate the emissions reductions needed for RFP
separately from the control strategy determination for such an area.
However, crediting an area for ``excess'' emissions reductions to
satisfy the contingency measure requirement would not be possible for a
Moderate area that cannot practicably attain by the statutory
attainment date under the EPA's proposed approach for calculating RFP
for such areas, as RFP would be calculated directly from the projected
emissions reductions from all control measures identified for the area
(as RACM and RACT or additional reasonable measures), such that there
would be no difference between emissions reductions estimated from
control measures and those estimated for demonstrating RFP.
As mentioned earlier, contingency measures should represent a
portion of the actual emissions reductions necessary to bring about
attainment in the area. Consistent with the EPA's past approach for
contingency measures for PM2.5 nonattainment areas, the EPA
proposes to require that the emissions reductions anticipated by
imposition of the contingency measures must be equal to approximately 1
year's worth of emissions reductions while the state is revising its
attainment plan for the area. The EPA has historically applied a policy
of equating 1 year's worth of emissions reductions for contingency
measures with those annual reductions determined to be necessary to
achieve RFP for the area, unless the state demonstrates that some
smaller reduction is appropriate. As described in Section IV.F of this
preamble, the EPA is proposing an approach for interpreting the
statutory RFP requirement that would require demonstrating RFP based on
reductions from sources located inside the nonattainment area. Keeping
with the historic linkage between RFP and contingency measures, the EPA
is also proposing and seeking comment on a similar approach for
calculating 1 year's worth of emissions reductions for purposes of
adopting appropriate contingency measures. That is, the EPA's proposed
approach for determining the level of emissions reductions for
contingency measure purposes is to calculate the annual reductions in
emissions of direct PM2.5 and PM2.5 precursors
needed from sources located inside the nonattainment area. The EPA
seeks comment on this proposed approach.
The CAA requires that states must implement contingency measures
after the EPA determines that the area has either failed to meet RFP
requirements, or failed to attain the standards by the applicable
attainment date. The purpose of the contingency measure provision is to
ensure that corrective measures are put in place automatically at the
time that the EPA makes its determination that an area has either
failed to meet RFP or failed to meet the standard by its attainment
date. The EPA is required to determine within 90 days after receiving a
state's milestone demonstration, and within 6 months after the
attainment date for an area, whether these requirements have been met.
The consequences for states with areas that fail to attain the NAAQS or
to meet RFP are described in section 179(d) of the CAA and discussed in
Section V of this preamble.
As noted earlier in this section, the EPA proposes to require that
states must submit contingency measures at the same time as the rest of
the Moderate area attainment plan elements, i.e., within 18 months
after designation. Section 172(b) requires the Administrator to
``establish a schedule according to which the State containing such
[nonattainment] area shall submit a plan or plan revision (including
the plan items) meeting the applicable [subpart 1 nonattainment plan]
requirements. . . Such schedule shall, at a minimum, include a date or
dates, extending no later than 3 years from the date of the
nonattainment designation . . .'' The EPA believes it is reasonable to
require the submittal of contingency measures for Moderate
PM2.5 nonattainment areas on the same schedule as the other
Moderate area attainment plan requirements because of the close
relationship between an area's control strategy, RFP analysis and
selection of quantitative milestones, and contingency measures. The EPA
seeks comment on this proposed due date for submission of contingency
measures.
I. Attainment Dates
1. Statutory Requirements
Section 188 establishes the attainment dates for Moderate and
Serious PM10 nonattainment areas, which also apply to
Moderate and Serious PM2.5 nonattainment areas. Section
188(c)(1) provides that for a Moderate area, ``the attainment date
shall be as expeditiously as practicable but no later than the end of
the sixth calendar year after the area's designation as
nonattainment.'' The EPA has the responsibility for determining whether
a nonattainment area has attained the standard by its applicable
attainment date. Section 179(c)(1) requires the EPA to make
determinations of attainment no later than 6 months following the
attainment date for the area. Under section 179(c)(2), the EPA must
publish a notice in the Federal Register identifying those areas which
failed to attain by the applicable attainment date. The statute further
provides that the EPA may revise or supplement its determination of
attainment for the affected areas based upon more complete information
or analysis concerning the air quality for the area as of the area's
attainment date.
Section 179(c)(1) provides that the EPA is to base the attainment
determination for an area upon an area's ``air quality data as of the
attainment date.'' The EPA will make the determination of whether an
area's air quality is meeting the PM2.5 NAAQS by the
applicable attainment date based upon data gathered from the air
quality monitoring sites which have been entered into the EPA's Air
Quality System (AQS) database. No special or additional attainment plan
submission will be required from the state for this determination.
A Moderate PM2.5 nonattainment area's air quality status
is determined in accordance with Appendix N of 40 CFR
[[Page 15394]]
part 50. To show attainment of the current 24-hour and annual standards
for PM2.5, the most recent 3 consecutive years' data prior
to the area's attainment date must show that PM2.5
concentrations over the prior 3-year period are at or below the levels
of the standards. A complete year of air quality data, as described in
part 50, Appendix N, is comprised of all 4 calendar quarters with each
quarter containing data from at least 75 percent of the scheduled
sampling days.
The EPA will begin processing and analyzing data related to the
attainment of Moderate PM2.5 nonattainment areas after the
applicable attainment date for the affected areas. Current EPA
regulations, under 40 CFR part 58, set the deadline for the state to
submit air quality data into the AQS database as no later than 90 days
after the end of the calendar year.
While the EPA may determine that an area's air quality data
indicates that an area may be meeting the PM2.5 NAAQS for a
specified period of time, this does not eliminate the state's
responsibility under the Act to adopt and implement an approvable
attainment plan. If the area's monitored data indicates that the area
is factually attaining the NAAQS, however, the EPA may issue a ``clean
data determination'' which will suspend the obligation of the state to
submit the elements of the attainment plan for the area that are
related to planning requirements, as discussed in Section IX.C of this
preamble. If the EPA determines that an area has attained the standard
as of its attainment date, the area will remain classified as
nonattainment until the state has requested, and the EPA has approved,
redesignation to attainment for the area.
In order for an area to be redesignated as attainment, the state
must comply with the five requirements listed under section
107(d)(3)(E) of the CAA. Briefly, this section requires that:
The EPA has determined that the area has met the
PM2.5 NAAQS;
The EPA has fully approved the applicable state
implementation plan;
The improvement in air quality is due to permanent and
enforceable reductions in emissions;
The EPA has fully approved a maintenance plan for the
area; and,
The state(s) containing the area or portions of the area
have met all applicable requirements under section 110 and part D.
2. Proposed Approach
As noted earlier, section 188(c)(1) states that for a Moderate
area, ``the attainment date shall be as expeditiously as practicable
but no later than the end of the sixth calendar year after the area's
designation as nonattainment.'' For purposes of clarity, the EPA
proposes to interpret the reference to ``the area's designation'' in
this provision as meaning ``the area's effective date of designation,''
consistent with the agency's approach for implementing the 1997 and
2006 PM2.5 NAAQS and with its approach for implementing
NAAQS for other criteria pollutants under part D, title I of the CAA.
See proposed 40 CFR 51.1000. As discussed elsewhere in this preamble,
the effective date of designation is April 15, 2015, for areas
designated nonattainment in the first round of designations for the
2012 PM2.5 NAAQS. For these areas, the Moderate area
attainment date would be as expeditious as practicable, but no later
than December 31, 2021 (i.e., the end of the sixth calendar year after
designation). The EPA seeks comment on this proposed interpretation of
the date of designation of a PM2.5 NAAQS nonattainment area
and the resulting attainment date for such areas.
As described in Sections IV.D and IV.E of this preamble, in the
case of a Moderate PM2.5 nonattainment area for which a
state can demonstrate attainment by the end of the sixth calendar year
following designation, the state must follow a two-step process for
determining the appropriate attainment date for the area. First, the
state must demonstrate through air quality modeling that the area can
attain the relevant NAAQS by the latest statutory attainment date and
determine which control measures and technologies are needed for the
area to attain by that date. Second, the state must determine whether
implementing other reasonable controls (i.e., those not needed for
attainment by the latest possible date but that are technologically and
economically feasible) can cumulatively advance the attainment date for
the area by at least 1 year. In the event that a state determines that
the area can attain the relevant NAAQS earlier through the application
of other measures, the state must propose the earlier date as part of
the attainment plan submission for the area. When the EPA takes action
to approve the different elements of the attainment plan for the area,
one of the elements that the agency will take action on will be the
state's proposed attainment date for the area. If the EPA approves an
attainment date for the area that is earlier than the latest date
allowed by statute, then the applicable attainment date for the area
will be the approved date. See proposed 40 CFR 51.1004(a)(1)(i). If the
area ultimately needs additional time to attain the relevant NAAQS, the
state may request an attainment date extension for the Moderate
nonattainment area under section 188 as long as certain conditions are
met, as described in Section IV.J.
The EPA's approach to approving an attainment date for a
PM2.5 nonattainment area will be different for a Moderate
area that cannot practicably attain the relevant PM2.5 NAAQS
by the end of the sixth calendar year after designation. Given that the
agency will reclassify any such area to Serious and thereby trigger
additional Serious area requirements for the area, the EPA will approve
an attainment date for the area when it takes action on the Serious
area attainment plan submitted for the area. In the interim, before the
EPA takes action to reclassify the area, the statutory Moderate area
attainment date will continue to apply to such an area. See proposed 40
CFR 51.1000 and 51.1004(a)(1)(ii). When the EPA reclassifies the area,
then the presumptive attainment date for the area will be as
expeditious as practicable, but no later than the end of the tenth
calendar year following designation. A complete discussion of Serious
area attainment dates is provided in Section VI.H of this preamble.
J. Attainment Date Extensions
1. Statutory Requirements
The CAA under subpart 4 provides the EPA with authority to grant
extensions of the attainment date for a Moderate area that otherwise
could be found to have failed to attain the relevant PM2.5
NAAQS, if the area can meet specific statutory criteria related to the
implementation of measures contained in the attainment plan for the
area, and to monitored air quality in the area. Specifically, under
section 188(d), a state may apply to the EPA for an extension of a
Moderate area's attainment date of one additional year (the ``Extension
Year'') if ``(1) the state has complied with all requirements and
commitments pertaining to the area in the applicable implementation
plan; and (2) no more than one exceedance of the 24-hour [NAAQS] level
for PM10 has occurred in the area in the year preceding the
Extension Year, and the annual mean concentration of PM10 in
the area for such year is less than or equal to the standard level.''
Section 188(d) limits the number of 1-year extensions that the EPA may
grant for a Moderate nonattainment area to two.
The provisions of section 188(d) thus allow a state an opportunity
to demonstrate that a Moderate area should continue to be classified as
[[Page 15395]]
Moderate and not be reclassified to Serious even if the area exceeded
the level of the applicable PM2.5 NAAQS in one or both of
the 2 calendar years preceding the year in which the area is otherwise
required to attain the NAAQS. Although section 188(d) provides the
criteria for such an extension, the EPA believes that there are some
ambiguities in the statutory language that warrant interpretation and
clarification through regulations for the PM2.5 NAAQS. The
EPA is thus proposing a preferred interpretation of section 188(d) to
provide clarity to states about how and when they may qualify for a
Moderate area attainment date extension for purposes of the
PM2.5 NAAQS.
2. Proposed Interpretations of Attainment Date Extension Criteria
With respect to the criterion in section 188(d)(1) that requires
that ``the state has complied with all requirements and commitments
pertaining to the area in the applicable implementation plan,'' the EPA
proposes to interpret this provision to mean that the state has
implemented the control measures in the SIP submission it made to
address the attainment plan requirements for the applicable
PM2.5 NAAQS, and not to require the area to have a fully
approved attainment plan that meets all of the CAA's requirements for
Moderate areas. This proposed interpretation is based on the plain
language of section 188(d) that does not explicitly require that the
state comply with all requirements pertaining to the area in the CAA,
but merely requires that the state comply with all requirements in the
applicable SIP.\152\ In other words, the EPA believes that section
188(d)(1) should be interpreted to mean that so long as the state has
submitted the necessary attainment plan for the area for the applicable
PM2.5 NAAQs and is implementing the control measures in the
submission, the fact that the EPA has not yet acted on such submission
to make it an approved part of the applicable SIP should not be a
barrier to the state obtaining an extension of the attainment date
under section 188(d)(1). For the same reason, the EPA also proposes to
read this provision not to bar an extension if all or part of an area's
Moderate area plan is disapproved or has been promulgated by the EPA as
a federal implementation plan (FIP). In the case that the ``applicable
implementation plan'' is a FIP (or combination of SIP and FIP), then
the EPA proposes that the state must have implemented the control
measures contained therein in order to meet the statutory criteria at
section 188(d)(1) for a Moderate area attainment date extension. The
EPA seeks comment on this proposed interpretation of section 188(d)(1).
See proposed 40 CFR 51.1005(a)(2).
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\152\ This interpretation as applied to section 188(e) for
Serious area attainment date extensions was upheld by the Ninth
Circuit Court of Appeals in Vigil v. Leavitt, 366 F.3d 1025, amended
at 381 F.3d 826 (9th Cir. 2004).
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The EPA also proposes and seeks comment on an alternative
interpretation of section 188(d)(1) that would require a state to have
a Moderate area attainment plan fully approved by the EPA as meeting
the applicable attainment plan requirements under sections 172 and 189
for a Moderate PM2.5 nonattainment area before the state
obtains an extension. Given that Moderate area attainment plans are due
18 months from the date of designation, and that RACM and RACT must be
implemented within 4 years after designation, states should have
sufficient time under the statutory schedule to satisfy all applicable
requirements in advance of seeking a Moderate area attainment date
extension. Under this alternative approach, the EPA proposes that a
state subject to a FIP (or SIP and FIP) for a Moderate PM2.5
nonattainment area could qualify for an attainment date extension for
the area if it had implemented all requirements and commitments of the
FIP (or SIP and FIP), as the FIP (or SIP and FIP) would be the
``applicable implementation plan'' for the area. Although this
alternative interpretation could also be a reasonable reading of this
criterion of section 188(d)(1), the EPA considers it less appropriate
than the preferred interpretation because this approach could foreclose
states from obtaining an otherwise appropriate extension merely because
of logistical and timing considerations that might have prevented the
EPA from acting on the state's attainment plan by the requisite point
in time. Nevertheless, the EPA seeks comment on this alternative
interpretation of section 188(d)(1).
The second criterion that states must meet to qualify for an
extension relates to the monitored ambient air in a nonattainment area
in the year prior to the attainment date for the area. If a state has
met the requirements of section 188(d)(1), the EPA may grant an
extension of a Moderate area's attainment date if the state also
satisfies the requirements of section 188(d)(2) that ``no more than one
exceedance of the 24-hour national ambient air quality standard level
for PM10 has occurred in the area in the year preceding the
Extension Year, and the annual mean concentration of PM10 in
the area for such year is less than or equal to the standard level.''
Again, the EPA may grant up to two such 1-year extensions and thus this
criterion would apply to the calendar year prior to the applicable
attainment date and to the Extension Year, in the case of a second
extension.
The EPA believes that the references to the ambient air quality
standards in section 188(d)(2) are ambiguous in two significant ways in
the context of the PM2.5 NAAQS implementation. First, the
statutory language explicitly sets ambient air quality conditions for
an attainment date extension in terms that relate factually to the 24-
hour PM10 NAAQS that was in effect at the time of the 1990
Amendments of the CAA, which has a statistical form that is
substantially different from the 24-hour PM2.5 NAAQS.
Specifically, the form of the 24-hour PM10 NAAQS allows for
no more than one ``exceedance'' of the standard per year on average
over 3 years, and if there is more than one such exceedance on average
over 3 years the area is violating the NAAQS. Thus, as a means of
limiting extensions to areas that are close to attaining the NAAQS in
the calendar year prior to the applicable attainment date, section
188(d)(2) imposes the criterion of having ``no more than one exceedance
of the 24-hour . . . standard level'' as a way of demonstrating that a
nonattainment area has ``clean data'' for the year prior to the
attainment date.\153\ This statutory language does not translate
readily to the PM2.5 NAAQS, which postdate the creation of
section 188(d) and are not structured with the same mathematical form.
For example, the 2006 24-hour PM2.5 NAAQS incorporates a 3-
year average of the 98th percentile form, which means that an area with
valid monitored ambient readings every day (or almost every day) could
have seven readings above the numerical level of the standard (i.e.,
``exceedances'') in any given year and still have ``clean data'' for
that year. A literal interpretation of section 188(d)(2) to permit only
one exceedance of the 24-hour PM2.5 NAAQS, rather than the
number of exceedances that is relevant for purposes of determining
attainment of such NAAQS, is illogical. In light of the different form
of the PM2.5 NAAQS, the statutory language of section
188(d)(2) is thus ambiguous in how it should apply to implementation of
the 24-hour PM2.5 NAAQS.
---------------------------------------------------------------------------
\153\ The 24-hour PM10 NAAQS, set at 150 [mu]g/m\3\,
cannot be exceeded more than once per year on average, over 3 years.
---------------------------------------------------------------------------
Additionally, the language of section 188(d)(2) may be considered
ambiguous
[[Page 15396]]
as to how it should apply to the PM2.5 NAAQS to the extent
that it does not specify whether the air quality criteria for an
attainment date extension apply equally for a Moderate area designated
nonattainment for both the 24-hour and annual standards, or for just
one of the standards. In practice, most areas designated nonattainment
for the PM10 NAAQS following passage of the 1990 CAA
Amendments were designated nonattainment only for the 24-hour
PM10 NAAQS, with a few designated for only the annual
PM10 NAAQS or for both the 24-hour and the annual
PM10 NAAQS. The 24-hour NAAQS has served as the
``controlling'' (i.e., functionally more stringent) PM10
standard, such that the agency's experience to date in granting
PM10 Moderate area attainment date extension requests has
been limited to extending the attainment date for the 24-hour
PM10 NAAQS.\154\
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\154\ For examples of the EPA actions to extend attainment dates
for Moderate PM10 areas, see 61 FR 20730 (May 8, 1996),
61 FR 66602 (December 18, 1996), and 66 FR 32752 (June 18, 2001).
---------------------------------------------------------------------------
The situation is distinctly different for PM2.5
nonattainment areas, as the specific facts and circumstances of a
particular area may warrant a nonattainment designation for either the
24-hour standard or the annual standard, but often not both. In most
cases, for instance, the current nonattainment areas for
PM2.5 are designated either for the 1997 annual NAAQS or for
the 2006 24-hour NAAQS, but not both.\155\ For example, the EPA
recently promulgated designations for areas violating only the annual
PM2.5 NAAQS revised in 2012, not the 24-hour NAAQS which was
retained at the level established during the 2006 p.m. NAAQS review. If
a PM2.5 nonattainment area is designated only for the 24-
hour or only for the annual PM2.5 NAAQS, this situation
raises the question of how section 188(d)(2) air quality criteria for
both standards should apply to such a PM2.5 NAAQS
nonattainment area if the state seeks an extension of the applicable
attainment date for such area.
---------------------------------------------------------------------------
\155\ Nonattainment areas designated for both the 24-hour and
annual PM2.5 NAAQS are located in central and southern
CA.
---------------------------------------------------------------------------
Due to the ambiguities associated with applying this subpart 4
requirement to current and future PM2.5 NAAQS, the agency
believes it is important to propose a reasonable interpretation of the
statutory requirement and seek public comment on this preferred
interpretation as well as two alternative interpretations specifying
the PM2.5 standard or standards for which a state would need
to demonstrate a Moderate nonattainment area met the air quality
criteria of section 188(d)(2) in order to qualify for an attainment
date extension. The agency also believes it is important to clarify how
the air quality criteria of section 188(d)(2) apply specifically for
the 24-hour PM2.5 NAAQS. For this reason, the EPA is
proposing a preferred interpretation of section 188(d)(2) for
application to current and future PM2.5 NAAQS, and is
seeking comment on two alternative interpretations that the agency
considers less appropriate.
The preferred proposed approach would only require a state to
demonstrate that in the year prior to the applicable attainment date
for the area, a Moderate area did not exceed the level of (i.e., had
clean data for) the specific PM2.5 NAAQS for which the area
is designated nonattainment (the ``applicable NAAQS'') and for which
the state is seeking the extension of the attainment date. The second
approach, on which the EPA seeks comment, would require that a state
demonstrate that in the year prior to the applicable attainment date
for an area, the Moderate area did not exceed the level of the specific
PM2.5 NAAQS for which the area is designated nonattainment
(the applicable NAAQS), and did not exceed the most stringent level of
any other PM2.5 NAAQS in effect nationally at the time the
area was designated for the applicable NAAQS. The third approach, on
which the EPA also seeks comment, would require that a state
demonstrate that in the year prior to the applicable attainment date
for an area, the Moderate area did not have more than one exceedance of
the level of the 24-hour PM2.5 standard, and that the annual
mean concentration of PM2.5 in the area for the attainment
year was less than or equal to the annual standard, regardless of the
NAAQS for which the state is seeking an attainment date extension.
The EPA prefers the proposed interpretation (described in more
detail later in this section) for implementing the Moderate area
attainment date extension criteria of section 188(d)(2) considering the
fact that, due to the specific atmospheric conditions and source-
dependent nature of PM2.5 problems in different areas around
the country, the EPA has historically designated, and may continue to
designate, PM2.5 nonattainment areas for either the annual
or the 24-hour NAAQS. As discussed earlier, the agency's designations
processes for the 2006 revised 24-hour PM2.5 NAAQS and the
2012 revised annual PM2.5 NAAQS have each been conducted to
address only one standard individually. In addition, the current 24-
hour PM2.5 NAAQS does not have a ``one exceedance'' form of
the standard, as cited in section 188(d)(2). Nevertheless, the EPA
requests comment on the second and third interpretations of section
188(d)(2) described later in this section because they more closely
reflect the specific statutory wording.
a. Proposed approach: the EPA preferred option. The EPA's proposed
interpretation of section 188(d)(2) would simply require that a state
demonstrate that in the year prior to the applicable attainment date
for the area, a Moderate nonattainment area had clean data for the
specific PM2.5 NAAQS for which the state was seeking an
attainment date extension (the applicable NAAQS). Under this proposed
approach, a state seeking an attainment date extension for a Moderate
nonattainment area for a 24-hour PM2.5 NAAQS would be
required to demonstrate that the area had clean data for that
particular standard in the calendar year prior to the applicable
attainment date for the area, rather than demonstrating that the area
necessarily had no more than one exceedance of the 24-hour
PM2.5 NAAQS.
For example, under this proposed interpretation of section
188(d)(2), in the case of a state seeking an extension of the
attainment date for a Moderate area designated nonattainment for the
2006 24-hour PM2.5 NAAQS, the state would need to
demonstrate that the area had no more than the allowable number of
valid monitored readings exceeding 35[mu]g/m\3\ to meet the 98th
percentile statistical form of the standard in the year prior to the
area's attainment date. The state would not have to demonstrate that
the area also had clean data for any other PM2.5 NAAQS,
including any annual PM2.5 NAAQS or later revision of the
24-hour PM2.5 NAAQS.
Likewise under the EPA's preferred approach, a state seeking an
attainment date extension for a Moderate nonattainment area for an
annual PM2.5 NAAQS would be required to demonstrate that the
area had clean data for that particular standard in the calendar year
prior to the applicable attainment date for the area. For example, in
the case of a state seeking an extension of the attainment date for a
Moderate area designated nonattainment for the 2012 annual
PM2.5 NAAQS, the state would need to demonstrate that the
annual mean concentration of PM2.5 at each monitor in the
area as analyzed in accordance with Appendix N to 40 CFR part 50 for
the year prior to the area's attainment date was less than or equal to
12.0 [mu]g/
[[Page 15397]]
m\3\. Again, under this proposed approach, the state would not have to
demonstrate that the area had clean data for any other PM2.5
NAAQS.
Under the EPA's preferred approach, if a state were to have an area
that is designated nonattainment for both the 24-hour and the annual
PM2.5 NAAQS, with the same applicable attainment date, then
a state seeking attainment date extensions for both NAAQS would need to
meet the ambient air quality criterion for both NAAQS. The EPA notes
that this would not be a common occurrence, but under this
interpretation, these would be the only circumstances under which a
state should be required to have clean data for both NAAQS in order to
qualify for an extension of the applicable attainment date under
section 188(d)(2). If a state has a nonattainment area that is only
designated for either the 24-hour or the annual PM2.5 NAAQS,
the EPA believes that the state need only meet the air quality
criterion of section 188(d)(2) for the NAAQS relevant to the attainment
date at issue. See proposed 40 CFR 51.1005(a)(1)(ii) and (iii).
The EPA believes this preferred interpretation of section 188(d)(2)
is appropriate for two reasons. First, as discussed above, while most
PM10 nonattainment areas were designated nonattainment for
either just the 24-hour PM10 NAAQS or for both the 24-hour
and annual PM10 NAAQS, the majority of current
PM2.5 nonattainment areas are designated for either the 24-
hour or the annual PM2.5 NAAQS, and should arguably only
need to demonstrate clean data for the NAAQS for which the area is
designated nonattainment. For those few PM2.5 nonattainment
areas designated for 24-hour and annual PM2.5 NAAQS, the EPA
believes it may also be appropriate that a state must only demonstrate
clean data for the specific NAAQS for which the state is seeking an
attainment date extension because such an approach is consistent with
the statute's overall approach to designating nonattainment areas and
implementing control strategies for each separate PM2.5
NAAQS.
Second, as discussed earlier, the statutory language that requires
that a nonattainment area have ``no more than one exceedance of the 24-
hour'' NAAQS level reflects a statistical form for the 24-hour
PM10 standard that is different from the current form of the
24-hour PM2.5 NAAQS. This difference, and the fact that the
form could be subject to further revision in the future, leads the EPA
to conclude that it is appropriate to describe this particular
criterion more broadly so that it can apply to any 24-hour
PM2.5 NAAQS, now or in the future regardless of the specific
statistical form any such NAAQS may take. The EPA seeks comment on this
preferred proposed approach.
b. Alternative approach 1. The EPA also seeks comment on two
alternative interpretations of section 188(d)(2). The EPA's first
alternative interpretation of section 188(d)(2) would require that a
state seeking an attainment date extension for a Moderate
PM2.5 nonattainment area would have to demonstrate that the
area met the level of the PM2.5 NAAQS for which it is
seeking the attainment date extension, as well as met the numerical
level of the most stringent PM2.5 NAAQS in effect at the
time the area was designated nonattainment. That is, under this
approach, the area would need to have clean data for the year preceding
the attainment date for the PM2.5 NAAQS for which the state
is seeking an attainment date extension and for the other
PM2.5 NAAQS that were part of the same suite of
PM2.5 standards (i.e., both the 24-hour and the annual
PM2.5 NAAQS) in effect at the time the EPA designated the
area nonattainment.
For example, if a state seeks an extension of the attainment date
for an area designated nonattainment only for the 2012 annual
PM2.5 NAAQS, it would have to demonstrate that the annual
mean concentration of PM2.5 at each monitor in the Moderate
area as analyzed in accordance with Appendix N to 40 CFR part 50 in the
attainment year was less than or equal to 12.0 [mu]g/m\3\.
Additionally, the state would have to demonstrate that the 98th
percentile of valid 24-hour monitored readings in the area for the year
preceding the attainment date did not exceed 35 [mu]g/m\3\, the level
of the 24-hour PM2.5 NAAQS set in 2006 and retained with the
2012 p.m. NAAQS review as part of the suite of PM NAAQS, even if the
area was not designated nonattainment for the 2006 24-hour
PM2.5 NAAQS.\156\ As with the agency's preferred approach, a
state seeking an attainment date extension for a Moderate nonattainment
area for a 24-hour PM2.5 NAAQS would be required to
demonstrate that the area had clean data for that particular standard
in the calendar year prior to the applicable attainment date for the
area in accordance with the statistical form of the 24-hour
PM2.5 NAAQS, rather than demonstrating that the area had no
more than one exceedance of the 24-hour PM2.5 NAAQS.
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\156\ Given the rounding provisions specified in 40 CFR part 50,
Appendix N, these criteria would be satisfied if the concentrations
before final rounding are less than an annual average of 12.05
[mu]g/m\3\ and a 24-hour value of 35.5 [mu]g/m\3\.
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The EPA presents this first alternative interpretation of the
statute for two reasons. First, as noted earlier, the statute at
section 188(b)(2) does not specify whether the air quality criteria for
an attainment date extension apply for Moderate areas designated
nonattainment for both the 24-hour and annual PM10
standards, or for just one of the standards. Read literally, however,
the statute seems to require that an area seeking an extension of a
Moderate area attainment date for any PM10 NAAQS must be
meeting the level of both the 24-hour standard and the annual standard,
even if it was only designated for just one of the standards. Under
this interpretation of the statute for purposes of implementing the
PM2.5 NAAQS, even though an area may be designated
nonattainment for only one PM2.5 NAAQS and therefore seeking
an attainment date extension only for that particular NAAQS, it would
also have to meet the level of the other PM2.5 standards. As
explained above, the EPA does not consider this the most appropriate
interpretation of section 188(d). However, under this alternative
interpretation the agency would take the position that the other
PM2.5 standards whose level the state must show the Moderate
nonattainment area met in the year preceding its attainment date would
be the most stringent PM2.5 NAAQS in effect nationally at
the time the area was designated nonattainment. For example, if the EPA
were to strengthen the 24-hour PM2.5 standard below the
current 35 [mu]g/m\3\ prior to December 31, 2021 (the anticipated
statutory Moderate area attainment date for the 2012 PM2.5
NAAQS), then an area seeking an extension of the Moderate area
attainment date for the 2012 PM2.5 NAAQS would have to
demonstrate that the area met the most stringent 24-hour
PM2.5 NAAQS that applied at the time it was designated (35
[mu]g/m\3\), and not the less stringent 24-hour NAAQS set in 1997 (65
[mu]g/m\3\) or any more stringent standard set after designation but
before the attainment date.
Second, as with the proposed approach to interpreting section
188(d)(2), the EPA believes it is appropriate to interpret the
statutory language regarding ``no more than one exceedance of the 24-
hour'' NAAQS level broadly to mean that the area had clean data for the
24-hour PM2.5 NAAQS, consistent with the form of the NAAQS
at issue, so that the requirement can apply to any 24-hour
PM2.5 NAAQS, now or in the future. Even if it were
appropriate to interpret section
[[Page 15398]]
188(d)(2) to require that a state meet the air quality criterion for
both the 24-hour and the annual PM2.5 NAAQS, the EPA
believes that the statutory provision concerning the number of
exceedances must still be read in light of the different form of the
24-hour PM2.5 NAAQS. The EPA seeks comment on this first
alternative interpretation of section 188(d)(2).
c. Alternative approach 2. The EPA's second alternative
interpretation of section 188(d)(2) would require that a state
demonstrate that a Moderate area did not have more than one exceedance
of the applicable 24-hour PM2.5 standard level, and the
annual mean concentration of PM2.5 in the area was less than
or equal to the applicable annual PM2.5 standard level, in
the year preceding the applicable attainment date for the area. In
other words, the EPA would not interpret the air quality criterion with
respect to the 24-hour PM2.5 NAAQS in light of the
significantly different form of the PM2.5 NAAQS.
Furthermore, as with the first alternative interpretation, the
``applicable'' PM2.5 standards would be those that applied
at the time the Moderate area was designated for a given
PM2.5 NAAQS, even if the area was not designated
nonattainment for all of them. This interpretation would mean that
regardless of the form of the applicable 24-hour PM2.5
standard, the Moderate area seeking an attainment date extension could
not have more than one exceedance of the numerical level of the
applicable 24-hour standard in order to qualify for a Moderate area
attainment date extension. This requirement would be more stringent--
and in some cases considerably so--than under the preferred proposed
and first alternative interpretations, given the current statistical
form of the 24-hour PM2.5 NAAQS. Additionally, under this
reading of section 188(d)(2), any future changes to the
PM2.5 NAAQS in terms of form or averaging time would also
not be addressed, potentially creating confusion with respect to how a
PM2.5 Moderate area could qualify for an attainment date
extension in the future.
The EPA believes that, while this interpretation of section
188(d)(2) may appear to be a straightforward reading of the statutory
language, it does not reasonably account for the important differences
between the statistical form of the PM10 and
PM2.5 NAAQS or between the EPA's longstanding convention for
designating PM10 and PM2.5 nonattainment areas
generally. The EPA therefore seeks comment on its preferred proposed
approach and two alternative approaches for interpreting the air
quality criteria of section 188(d)(2) that a state would need to
demonstrate compliance with in order for the EPA to consider granting
an extension of a Moderate PM2.5 area attainment date.
3. Proposed Process for Attainment Date Extension Request Submittals
Regardless of which interpretation of section 188(d)(1) the EPA
finalizes as part of this rulemaking, the EPA proposes to require
states to submit sufficient information to demonstrate that they have
complied with applicable requirements and commitments in the applicable
implementation plan. This information would be needed in order for the
EPA to make a decision on whether to grant a 1-year attainment date
extension. The EPA would not be authorized to grant an attainment date
extension to an area unless the state can demonstrate that it has met
all of the requirements and commitments contained in the state's
applicable implementation plan for the area. Under the EPA's first
proposed approach for interpreting section 188(d)(1), a state would
have to demonstrate that control measures have been submitted in the
form of a SIP revision and that RACM and RACT and additional reasonable
measures for sources in the area have been implemented. Under the
agency's alternative proposal for interpreting section 188(b)(1), the
attainment plan submitted by the state would have to have been fully
approved by the EPA and the state would have to be in compliance with
any elements required under any applicable FIP for the area. In
addition, under the EPA's second proposed approach, the state would
have to demonstrate that: (i) RACM and RACT and additional reasonable
measures for sources in the area have been implemented, and (ii) the
area has made emissions reductions progress that represents RFP toward
attainment of the NAAQS and has met its quantitative milestones, and
the state has submitted a milestone compliance demonstration (milestone
report) to that effect if due. Any decision made by the EPA to extend
the attainment date for an area would be based on facts specific to the
nonattainment area at issue.
Section 188(d) does not specify the process by which the EPA should
evaluate and act upon requests from states for an extension of the
Moderate area attainment date. However, the EPA proposes that an
attainment date extension would only be granted after the agency
provides notice in the Federal Register and an opportunity for the
public to comment. This notice-and-comment process would allow for
appropriate evaluation of the relevant criteria and facts in order to
assure that the extension is granted or denied after full evaluation.
This process also is consistent with past practice by the EPA in
granting attainment date extensions, most recently for ozone
nonattainment areas. In addition, for ease of implementation, the EPA
proposes to interpret section 188(d) to authorize the EPA to stipulate
that any extension would begin on January 1 and end on December 31 of
the extension year and these dates would not depend on when the state
submitted its request for an extension or was granted the extension by
the EPA. The EPA believes this is a reasonable approach as the
applicable attainment date for the area will either be the end of the
sixth calendar year following designation of the area, or the end of an
earlier calendar year if the state could advance attainment of the area
by at least 1 year through the implementation of extra control
measures. In addition, compliance with the relevant NAAQS will be
evaluated based on monitored data collected over a full calendar year
(i.e., over the period beginning January 1 and ending December 31), so
starting the extension year on January 1 is logical.
Because air quality criteria are part of the conditions that must
be met in order for the EPA to grant a Moderate area attainment date
extension, the EPA proposes to require that a state seeking such an
extension must submit its complete attainment date extension request,
including any available preliminary data for the year preceding the
area's applicable Moderate attainment date, on or before the area's
attainment date. The EPA also proposes to require that the state
requesting such an extension must submit to the respective EPA Regional
Office certified ambient PM2.5 monitoring data for the year
preceding the attainment date for the area in question by no later than
February 28 of the year following the area's attainment date.
Submission of the necessary data by this date will allow the EPA to
review the state's request and take appropriate action on the request
prior to the date by which the EPA is required to make a determination
that the area failed to attain by its Moderate area attainment date,
i.e., within 6 months of the applicable attainment date (see the
discussion of reclassification in Section V of this preamble). The EPA
seeks comment on these proposed deadlines for a state to request an
extension of a Moderate area's attainment date and submit certified air
quality data as required under CAA section 188(d)(2).
[[Page 15399]]
As noted earlier in this discussion of Moderate area attainment
date extensions, the statute at section 188(d) provides that a state
may seek up to two 1-year extensions of the Moderate area attainment
date if it meets the applicable criteria of sections 188(d)(1) and
188(d)(2). The statute makes no distinction between the criteria that
must be met for the first 1-year extension and the criteria for the
second 1-year extension, therefore the EPA plans to apply the same
interpretations of the statutory criteria proposed throughout this
section, including the proposed deadlines for the state to submit the
extension request and the certified air quality data, for purposes of a
state seeking a second 1-year attainment date extension for a Moderate
nonattainment area.
The EPA seeks comment on the proposed approaches described above
for interpreting the criteria of section 188(d)(1) and 188(d)(2) and
establishing a process for states to request attainment date extensions
for Moderate areas.
V. How would a PM2.5 Moderate nonattainment area be
reclassified to Serious?
As discussed elsewhere in this preamble, subpart 4, part D of title
I of the CAA establishes a two-tier classification system for areas
designated nonattainment for the PM2.5 NAAQS. While all
areas designated nonattainment are initially classified as Moderate,
section 188(b) describes two pathways by which the EPA has the
authority or the duty to reclassify a Moderate nonattainment area to a
Serious nonattainment area. Pursuant to section 188 (b)(1), the EPA has
general discretionary authority to reclassify from Moderate to Serious
any area that the Administrator determines cannot practicably attain
the NAAQS by the applicable Moderate area attainment date. Pursuant to
section 188(b)(2), the EPA has a mandatory duty to reclassify from
Moderate to Serious any area that fails to attain the NAAQS by the
applicable Moderate area attainment date. Both of these pathways are
more fully described below.
A. Discretionary Authority
The EPA's discretionary authority to reclassify a Moderate area to
Serious derives from language in section 188(b)(1) of the CAA which
provides that: ``The Administrator may reclassify as a Serious
PM10 nonattainment area . . . any area that the
Administrator determines cannot practicably attain the [NAAQS] . . . by
the attainment date . . . for Moderate Areas.'' The use of this
discretionary authority thus would be triggered by the EPA making a
determination that the Moderate area in question could not practicably
attain by its statutory attainment date.
The CAA does not specify the basis on which the EPA may make the
determination that the area cannot practicably attain by the applicable
attainment date. In the General Preamble, the EPA explained that the
agency could base this determination upon whatever factors are
pertinent and do so whether or not the state in question has submitted
a Moderate area attainment plan, and whether or not the state has made
the demonstration contemplated in section 189(a)(1)(B).\157\ The EPA
may make such a determination based on evaluation of the attainment
plan for the Moderate area in question or other facts known to the
agency. As discussed earlier in this preamble, the attainment plan that
a state would submit for a Moderate nonattainment area must include
either a demonstration that the area will attain the NAAQS by the
statutory Moderate area attainment date or a demonstration that
attaining by the statutory Moderate area attainment date is
impracticable. If the state makes and the EPA concurs with an
impracticability demonstration submitted as part of the attainment
plan, then the demonstration could serve as the basis for the EPA
initiating a notice-and-comment rulemaking to reclassify the area to
Serious. However, the CAA does not specify the basis for the EPA's
exercise of its discretionary authority and does not require the EPA to
make its determination based on a submission from the state. Indeed,
such a prerequisite would be illogical in the case of a state that
fails to make any attainment plan submission or fails to address the
issue of the need for reclassification in such submission.
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\157\ See the Federal Register published on April 16, 1994 (57
FR 13498, 13537 and 13538).
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Section 188(b)(1)(B) does establish mandatory timeframes by which
EPA must act if it intends to exercise its discretionary authority to
reclassify areas as appropriate following the Moderate area attainment
plan due date, stating that ``the Administrator shall reclassify
appropriate areas within 18 months after the required date for the
state's submission of a SIP for the Moderate Area.'' In the case of
areas designated nonattainment for the 2012 PM2.5 NAAQS in
the first round of designations, states will be required by statute to
submit a Moderate area attainment plan within 18 months of the date of
designation (April 2015), or no later than October 2016. Pursuant to
section 188(b)(1)(B), the EPA would then have until April 2018 (18
months following the Moderate area attainment plan submission deadline)
to use its discretionary authority to reclassify any area that the EPA
determines at that time cannot practicably attain by the Moderate area
attainment date of December 2021.
As noted above, the EPA believes that while a Moderate area
impracticability demonstration as contemplated in section 189(a)(1)(B)
is desirable in order to help the agency make a determination that the
area cannot practicably attain by its attainment date, such a
demonstration is not necessary to trigger action by the EPA to
reclassify a Moderate area to Serious. The statute does not prohibit
the EPA from using the weight of available evidence, including
information available in the public record of a state, to make such a
determination, even in the absence of a complete attainment plan
submission. Thus, the EPA expressed in the General Preamble that:
. . . under the plain meaning of the terms of section 188(b)(1) EPA
has general discretion to reclassify at any time before the
applicable attainment date any area EPA determines cannot
practically attain the standards by such date. Accordingly, CAA
section 188(b)(1) is a general expression of delegated rulemaking
authority. In addition, subparagraphs (A) and (B) of CAA section
188(b)(1) mandate that the EPA reclassify at specified timeframes
any areas it determines appropriate for reclassification at those
dates. These subparagraphs do not restrict the general authority but
simply specify that, at a minimum, it must be exercised at certain
times.\158\
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\158\ Ibid. at 13537.
The EPA continues to consider this the correct interpretation of the
statutory requirements concerning its authority to reclassify a
Moderate nonattainment area to Serious at any time prior to the area's
Moderate area attainment date, if the agency determines that the area
cannot practicably attain the relevant PM2.5 NAAQS by that
date.
The EPA emphasizes that states with an area designated as
nonattainment for the PM2.5 NAAQS are required to meet all
Moderate area attainment plan requirements, even after the EPA
reclassifies the area to Serious. Section 189(b)(1) states clearly that
``in addition to'' the Moderate area attainment plan requirements,
states with areas reclassified to Serious must also meet Serious area
attainment plan requirements, i.e., the reclassification does not
eliminate the statutory obligation to meet Moderate area
[[Page 15400]]
attainment plan requirements.\159\ Thus, the EPA believes that
reclassifying Moderate areas to Serious at any time under its
discretionary authority does not reward areas who delay development and
implementation of control measures by excusing states from meeting
substantive Moderate area attainment plan requirements or by extending
the applicable attainment date. The EPA articulated this position in
the General Preamble, explaining that this interpretation:
---------------------------------------------------------------------------
\159\ See, Vigil v. Leavitt, 366 F.3d 1025, amended at 381 F.3d
826 (9th Cir. 2004).
. . . creates an incentive for the timely submittal and effective
implementation of moderate area SIP requirements and facilitates the
PM10 attainment objective. For example, if an area that
fails to submit a timely moderate area SIP is reclassified, this does
not obviate the requirement that the area submit and implement RACM
consistent with the moderate area schedule. Accordingly, the area could
be subject to sanctions for its delay in submitting the RACM SIP
requirement . . . Further, reclassification before the applicable
attainment date will ensure that additional control measures (i.e., in
addition to RACM, serious areas must implement best available control
measures (BACM)), are implemented sooner and will expedite the
application of more stringent new source review requirements to the
area . . . Similarly, where an area submits a timely moderate area SIP,
EPA may not discover that the area cannot practicably attain until
sometime after it begins implementing its moderate area control
measures. The EPA then may want to reclassify the area in order to
facilitate the development and implementation of BACM.\160\
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\160\ 57 FR 13498 (April 16, 1992), at page 13537.
The EPA considers this the correct interpretation of the statutory
requirements and proposes to apply this longstanding interpretation of
section 188(b)(1) to nonattainment areas for the PM2.5
NAAQS.
B. Mandatory Duty
In addition to the EPA's discretionary authority to reclassify a
Moderate area to Serious under certain circumstances, the CAA also
directs the EPA to do so under other circumstances. The alternative
circumstances under which the EPA will reclassify an area from Moderate
to Serious are if that area fails to attain the relevant NAAQS by the
applicable Moderate area attainment date, including any extension of
that date under section 188(d) for which the area qualifies. Under such
circumstances, the EPA has a mandatory duty to identify any area that
fails to attain the PM2.5 NAAQS by the applicable Moderate
area attainment date. Reclassification under such circumstances would
happen by operation of law when the EPA determines that the area failed
to attain the NAAQS by the applicable attainment date, in accordance
with section 188(b)(2)(A). Section 188(b)(2) requires that ``within six
months following the applicable attainment date for a PM10
nonattainment area, the Administrator shall determine whether the area
attained the standard by that date'' and publish its determination in
the Federal Register. The EPA proposes that the date of
reclassification for an area reclassified under the EPA's mandatory
duty to reclassify an area would be the effective date of the Federal
Register document announcing that the area had not attained the
relevant PM2.5 NAAQS and is therefore reclassified by
operation of law. Thus, for example in the case of the 2012
PM2.5 NAAQS, assuming a Moderate PM2.5
nonattainment area fails to attain the standard by its approved
attainment date of December 31, 2021, the EPA would be required to
publish in the Federal Register no later than June 30, 2022 its
determination that the area failed to attain the NAAQS and is therefore
reclassified as Serious by operation of law. The date of
reclassification for the area would be the effective date of the
Federal Register document, or sometime after June 30, 2022. To meet the
requirements of section 189(b)(2), the Serious area attainment plan for
the area would be due within 18 months thereafter, or no later than
December 2023.
An alternative approach for setting the date of reclassification
for an area reclassified to Serious under the EPA's mandatory authority
could be to make it the same date as the missed attainment date for the
area. Applying this approach in the example above would yield an
earlier date of reclassification of December 31, 2021, and an earlier
Serious area attainment plan due date of June 30, 2023.
Although section 188(b)(2) does not explicitly address this issue,
the EPA believes that its proposed approach is a reasonable
interpretation of statutory ambiguity in section 188(b)(2) and
preferable over the alternative approach for two reasons. First, the
statute at section 189(b)(2) gives a state 18 months from the date of
reclassification of an area to submit for the EPA's approval an
attainment demonstration with air quality modeling and provisions to
assure timely implementation of BACM and BACT on sources in the
nonattainment area. The EPA believes that it is reasonable for a state
with a Serious PM2.5 nonattainment area to have 18 months
plus the additional time needed by the EPA to issue a Federal Register
document announcing the area's failure to attain by the applicable
Moderate area attainment date and subsequent reclassification (up to 6
additional months) to ensure that the state has time to develop and
submit a thorough, complete and accurate Serious area attainment plan
that will provide for timely attainment of the NAAQS. Second, the
statutory attainment date for a Serious area reclassified under any
circumstances is as expeditious as practicable but no later than the
end of the tenth year following designation of the area, and is thus
independent of the date of reclassification of the area. Allowing a
state some additional amount of time beyond 18 months from the missed
attainment date to develop and submit a complete Serious area
attainment plan, including adopting BACM and BACT, will not change the
statutory obligation on the state for the area to attain the relevant
NAAQS by the applicable attainment date. On the contrary, the EPA
believes that the extra time may in fact help the area timely attain
the relevant NAAQS by allowing the state to develop a more effective
attainment plan for the area.
The EPA seeks comment on its proposed approach of basing the date
of reclassification for an area reclassified under the agency's
mandatory duty in section 188(b)(2) on the effective date for the
Federal Register document in which the EPA announces that the area
failed to attain the PM2.5 NAAQS by the applicable Moderate
area attainment date and is reclassified by operation of law. The EPA
intends to make determinations of whether or not an area attained the
relevant NAAQS pursuant to section 188(b)(2) via notice-and-comment
rulemaking.
VI. What are the EPA's proposed requirements for Serious area
attainment plans?
Sections 189(b) and (c) of the CAA include the following
requirements for Serious area attainment plan submissions: (i) An
attainment demonstration (section 189(b)(1)(A)); (ii) provisions for
the implementation of best available control measures (BACM) no later
than 4 years after reclassification of the area to Serious (section
189(b)(1)(B)); (iii) quantitative milestones that will be used to
evaluate compliance with the requirement to
[[Page 15401]]
demonstrate RFP (section 189(c)); and, (iv) regulation of
PM2.5 precursors (in general to meet attainment and control
strategy requirements and as specifically required for major stationary
sources by section 189(e)). Other subpart 1 requirements for attainment
plans not otherwise superseded under subpart 4 also apply to Serious
areas for the PM2.5 NAAQS, including: (i) A description of
the expected annual incremental reductions in emissions that will
demonstrate RFP (section 172(c)(2)); (ii) emissions inventories
(section 172(c)(3)); (iii) other control measures (besides BACM and
BACT) needed for attainment (section 172(c)(6)); and, (iv) contingency
measures (section 172(c)(9)).
Additionally, section 189(b)(1) requires that ``in addition'' to
the attainment plan requirements specific to Serious areas, states must
also meet all Moderate area attainment plan requirements. The EPA
interprets the statutory language of section 189(b)(1) to require
states with areas that are reclassified to Serious to meet Moderate
area attainment plan requirements, including any areas that the EPA
reclassifies through rulemaking under its discretionary authority, even
if that occurs before the area has met all of its Moderate area
attainment plan requirements.\161\
---------------------------------------------------------------------------
\161\ See Vigil v. Leavitt, 366 F.3d 1025, amended at 381 F.3d
826 (9th Cir. 2004).
---------------------------------------------------------------------------
The remainder of this section presents the EPA's proposed
regulatory approaches to implement the requirements for attainment plan
submissions for Serious areas.
A. Plan Due Dates
The timing of Serious area attainment plan elements is dictated by
two provisions of the CAA: Section 189(b)(2) for certain subpart 4
elements and section 172(b) for subpart 1 elements not superseded by
subpart 4 requirements. Section 189(b)(2) addresses the due dates for
Serious area attainment demonstrations due under section 189(b)(1)(A)
and provisions for BACM and BACT implementation under section
189(b)(1)(B). Specifically, section 189(b)(2) stipulates two
alternative schedules for states to submit Serious area attainment
demonstrations, depending upon the statutory authority invoked by the
EPA to reclassify the area from Moderate to Serious. For an area
reclassified to Serious by operation of law under section 188(b)(2)
upon a determination by the EPA that the area failed to attain the
relevant NAAQS by the applicable Moderate area attainment date, a state
must submit a new attainment demonstration for the area no later than
18 months after reclassification. For an area reclassified to Serious
pursuant to the agency's discretionary authority provided under section
188(b)(1), a state must submit a new attainment demonstration no later
than 4 years after reclassification of the area.\162\ For all Serious
nonattainment areas, section 189(b)(2) requires a state to submit
within 18 months of an area's reclassification ``provisions to assure
that the best available control measures [BACM] for the control of
PM10 shall be implemented no later than 4 years after the
date the area is classified (or reclassified) as a Serious Area.''
---------------------------------------------------------------------------
\162\ Section V of this preamble provides a more detailed
discussion of the process for reclassifying areas with severe
nonattainment problems to Serious.
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In contrast, section 172(b) provides the EPA discretion to set a
due date for subpart 1 attainment plan elements that is no later than 3
years after designation of the area. In the Addendum, the EPA
interpreted the date of reclassification of an area to Serious to be
analogous to the date of designation of the area to nonattainment
generally.\163\ If the EPA selects the proposed option, discussed later
in this section, to adopt this convention, the subpart 1 attainment
plan elements of provisions to demonstrate RFP, emissions inventories,
additional control measures beyond BACM and BACT needed for expeditious
attainment of the PM2.5 NAAQS, and contingency measures
could in theory be due as late as 3 years after reclassification of an
area to Serious. For the reasons discussed below, the EPA believes that
it is necessary to harmonize the submission dates of the various
elements of a Serious are attainment plan for the PM2.5
NAAQS to provide for more effective evaluation of such attainment plan
submissions by states, the EPA and members of the general public.
---------------------------------------------------------------------------
\163\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42015.
---------------------------------------------------------------------------
As with Moderate area attainment plans consisting of both subpart 1
and 4 elements, the EPA presumes that simultaneous development and
submission of most, if not all, of the Serious area attainment plan
elements will be most effective, both for the state in developing the
plan and for the EPA in reviewing the state's submission, given the
interplay between all plan elements in the formation of a successful
control strategy for the area. Just as importantly, a complete
attainment plan submission facilitates the general public's review of
the entire control strategy adopted by the state. Therefore where there
is ambiguity in the statutory provisions, the EPA is proposing one or
more approaches to schedule submission of the various elements of
Serious area attainment plans in a way that will facilitate better
development and evaluation of such attainment plan submissions. The
EPA's proposed options for due dates for specific elements of a Serious
area attainment plan are described below.
1. Area Reclassified to Serious After Failing To Attain the
PM2.5 NAAQS
If the EPA reclassifies a Moderate area to Serious because of a
failure to attain the relevant NAAQS by the applicable attainment date,
section 189(b)(2) requires that the state must submit both the
attainment demonstration for the area and provisions to ensure timely
BACM and BACT implementation to the EPA within 18 months after
reclassification. Because an up-to-date base year emissions inventory,
required under section 172(c)(3), will serve as the foundation of a
state's BACM and BACT determination, and additional control measures
(beyond BACM and BACT) that are necessary for expeditious attainment of
the PM2.5 NAAQS as required under section 172(c)(6) will
need to be identified in order to complete the control strategy for the
area, the EPA proposes that both the base year inventory and additional
control measures (beyond BACM and BACT) needed for expeditious
attainment must also be submitted within 18 months after
reclassification of the area to Serious by operation of law.
The EPA also proposes and seeks comment on two possible due dates
for the remaining Serious area attainment plan elements for areas that
failed to attain the NAAQS by the applicable Moderate area attainment
date. Those plan elements are provisions for RFP, quantitative
milestones and contingency measures. The first proposed due date for
these remaining Serious area attainment plan elements would be no later
than 18 months after reclassification of the area, consistent with the
due date for the plan elements already described above. As noted above,
the EPA maintains that requiring states to submit all elements of an
attainment plan by the same date is reasonable because it allows for a
complete review of the state submission by the EPA, regulated entities,
and the general public, and it also may prove most efficient for
states. See proposed 40 CFR 51.1003(b)(2)(ii).
The alternate proposed due date for the remaining elements would be
3 years following reclassification to
[[Page 15402]]
Serious, which would be consistent with guidance the EPA provided in
the Addendum specific to the due date for contingency measures for
Serious areas.\164\ This guidance references the EPA's discretion under
section 172(b) to establish due dates up to 3 years after designation
for attainment plan elements required under section 172(c), which also
include RFP provisions. Subpart 4 meanwhile requires quantitative
milestones to demonstrate RFP but does not specify a due date for
submitting such milestones as part of the attainment plan for the area
(as separate and distinct from the clear statutory requirements related
to demonstrating compliance with those milestones established in the
attainment plan). When taken together, the EPA believes that these
statutory provisions may be read to permit a state to submit these
three elements of the plan as late as 3 years after reclassification of
the area. While the EPA does not believe that such a reading is as
logical as the agency's first proposed approach, the EPA seeks comment
on this alternative proposed approach to setting due dates for a state
to submit an RFP plan, quantitative milestones and contingency measures
for a Serious area reclassified under the EPA's mandatory authority.
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\164\ Ibid. at 42015.
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2. Area Reclassified to Serious Due to an Inability To Practicably
Attain the NAAQS by the Statutory Moderate Area Attainment Date
If the EPA determines that a Moderate area cannot practicably
attain the relevant NAAQS by the applicable attainment date and
reclassifies the area to Serious pursuant to its discretionary
authority under section 188(b)(1), section 189(b)(2) requires the state
to submit provisions to ensure timely implementation of BACM and BACT
to the EPA within 18 months after reclassification. As stated earlier,
because an up-to-date emissions inventory serves as the foundation for
a state's BACM and BACT determination and pursuant to the authority
granted to the EPA under section 172(b), the EPA proposes that the
state must meet the emissions inventory requirement under section
172(c)(3) also within 18 months after reclassification of the area by
submission of an up-to-date emissions inventory.
With respect to the attainment demonstration requirement for
Serious areas reclassified pursuant to section 188(b)(1), section
189(b)(2) allows the state up to 4 years after reclassification to
submit a new attainment demonstration for an area reclassified to
Serious because it cannot practicably attain the PM2.5 NAAQS
by the applicable Moderate area attainment date. This due date could
generally be appropriate, notwithstanding the related issues discussed
in the following paragraphs, if the EPA finalizes an approach for
determining the overall control strategy for the area in which BACM and
BACT are identified independent of the attainment demonstration for the
area (see proposed Option 1 for BACM and BACT determinations described
in Section VI.D of this preamble).
However, the EPA is also proposing an alternative approach for
determining the control strategy for a Serious area, under which BACM
and BACT and additional feasible measures would be identified in
conjunction with the attainment demonstration for the area (see
proposed Option 2 for BACM and BACT determinations described in Section
VI.D of this preamble). Under such an approach, the EPA proposes that
the due date for the Serious area attainment demonstration would be no
later than 18 months after reclassification if the EPA finalizes its
proposed Option 2 for determining BACM and BACT for the area, as the
attainment demonstration would be necessary in order for the EPA and
the public to determine whether the control strategy identified for the
area is adequate, and the statute requires that a state submit its BACM
provisions within 18 months after reclassification of an area.
With respect to other elements of a Serious area attainment plan,
under the EPA's prior interpretation as described in the Addendum, the
EPA had suggested that states could submit contingency measures no
later than 3 years after reclassification of an area to Serious because
of the language of section 172(b).\165\ The EPA believes it may be
appropriate to extend a similar approach to establishing due dates for
some other attainment plan elements required under subpart 1.
Therefore, the EPA proposes to provide a state with the maximum time
permitted under section 172(b)--3 years from the date of
reclassification of the area--to submit the following plan elements:
Provisions to demonstrate RFP, other control measures (beyond BACM and
BACT) needed to bring the area into expeditious attainment, and
contingency measures. The EPA proposes that quantitative milestones,
required under subpart 4 but linked to RFP which is required under
subpart 1, would also be included with the plan elements due 3 years
following reclassification.
---------------------------------------------------------------------------
\165\ Ibid. at 42015.
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The EPA believes that this proposed due date for certain attainment
plan elements required under subparts 1 and 4 would be most appropriate
if finalized in conjunction with proposed Option 2 for BACM and BACT,
which would require the state to submit the attainment demonstration
for the area within 18 months after reclassification of the area to
Serious. However, in the event the EPA finalizes proposed Option 1 for
determining BACM and BACT for a Serious nonattainment area independent
of the attainment demonstration for the area, the attainment
demonstration for the area would be due no later than 4 years after the
date of reclassification of the area to Serious. Given the integral
role that the attainment demonstration plays in helping to identify
additional feasible measures (beyond BACM and BACT) that an area may
need to attain the relevant standard expeditiously (and which are
required under section 172(c)(6)), to calculate emissions reductions
needed on an annual basis to demonstrate RFP, and to calculate the
emissions reductions that contingency measures need to achieve and
identify what controls could constitute such measures, the EPA is
proposing and seeking comment on an alternative submittal deadline for
provisions for RFP and quantitative milestones, additional control
measures needed for expeditious attainment, and contingency measures
that would align their due date with the statutory Serious area
attainment demonstration due date, no later than 4 years from the date
of reclassification. See proposed 40 CFR 51.1003(b)(2)(i). The EPA
believes that coordinating submission of attainment plan elements so
that they may be developed and reviewed together can prove most
efficient for the submitting state, the EPA, and the general public,
and therefore this proposed alternative is the agency's preferred
approach. However, the EPA seeks comment on all of its proposed due
date options for the various elements of a Serious area attainment
plan.
B. Emissions Inventory Requirements
1. What emissions inventory requirements apply to Serious area
attainment plans?
As with PM2.5 nonattainment areas classified as
Moderate, Congress did not create a specific emissions inventory
requirement in subpart 4 that would supersede the emissions inventory
requirement under subpart 1 for Serious areas. Thus, the statutory
emissions
[[Page 15403]]
inventory requirements that apply for Serious area attainment plans
continue to be those of section 172(c)(3), which explicitly requires
``a comprehensive, accurate, and current inventory of actual emissions
of the relevant pollutants'' in the nonattainment area. In addition,
the specific attainment plan requirements for the PM2.5
NAAQS set forth in section 189(a) and associated modeling requirements
make an accurate and up-to-date emissions inventory a critical element
of any viable attainment plan. Finally, the additional attainment plan
requirements for the PM2.5 NAAQS for Serious areas contained
in subpart 4 at section 189(b) have additional requirements that affect
the emissions inventory requirements for Serious areas.\166\
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\166\ All definitions described in Section IV.B of this preamble
for areas classified as Moderate apply in this section.
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As noted earlier in this preamble, states must use the best
available, current emissions inventory information for attainment plan
development, because complete, high quality emissions inventory data
are essential for the development of an effective control strategy. To
assist states in preparing complete, high quality inventories, the EPA
provides guidance for developing emissions inventories in its SIP
Emissions Inventory Guidance, available at http://www.epa.gov/ttn/chief/eidocs/eiguid/index.html. The EPA recommends that states consult
this guidance while developing emissions inventories to meet
requirements for Serious area attainment plans.
2. How do states meet the inventory requirements for the
PM2.5 NAAQS for areas classified as Serious?
As with Moderate PM2.5 nonattainment areas, neither
section 172(c)(3) nor the provisions specifically applicable to
attainment plans for the PM2.5 NAAQS in subpart 4 specify
how states should meet statutory emissions inventory requirements for
Serious PM2.5 nonattainment areas. Section 172(c)(3)
requires that states submit ``a comprehensive, accurate, current
inventory of actual emissions from all sources of the relevant
pollutant or pollutants in such area, including such periodic revisions
as the Administrator may determine necessary to assure that the
requirements of this part are met'' (emphasis added). The EPA
interprets this provision to authorize the agency to require states to
revise their base year emissions inventories whenever the state is
required to submit a new attainment plan because of a change in the
nonattainment area's status (e.g. failure to attain by the applicable
attainment date resulting in reclassification). In addition, pursuant
to CAA section 301, the EPA has additional authority to promulgate
regulations as necessary for the implementation of the PM2.5
NAAQS, including requirements pertaining to emissions inventories.
Accordingly, the EPA is proposing specific emissions inventory
requirements it considers necessary to effectuate the attainment plan
requirements of the CAA for the PM2.5 NAAQS.
Like Moderate areas, there are three key facets of the EPA's
proposed emissions inventory requirements, as laid out below: (i) The
types of inventories required; (ii) the content of these inventories;
and, (iii) the timing of submittal of these inventories. The three
facets are addressed in the following paragraphs.
First, the EPA proposes that the same two types of inventories
required for Moderate areas are also required for Serious areas. While
these inventories are the same types and names of inventories as for
Moderate areas, they must be created specifically for Serious area
attainment plans in accordance with the applicable Serious area
requirements. The first type of inventory, the ``base year inventory
for the nonattainment area,'' is expressly required by section
172(c)(3). The second type of inventory the EPA is proposing to require
under section 301(a)(1) is necessary to implement the attainment
demonstration requirement of section 189(a)(1)(B). This second
inventory is called the ``attainment projected inventory for the
nonattainment area.'' See proposed 40 CFR 51.1008(b)(1) and (2).
Second, the EPA proposes that the content of the inventories will
follow the content requirements for Moderate area inventories, with one
exception needed to meet the requirements of section 189(b)(3). For
Serious areas, section 189(b)(3) defines a separate emissions threshold
for major sources in Serious nonattainment areas (70 tpy potential to
emit of PM10), and this major source threshold is used in 40
CFR part 51, subpart A (the AERR) to define which sources must be
reported as point sources for PM10. This threshold is lower
than the 100 tpy potential to emit general requirement for major
sources of PM10, PM2.5 or one of its precursors
that is used for Moderate area emissions inventories. Inventories for
Serious area attainment plans must include these smaller sources as
point sources (rather than the nonpoint source category that would
apply for these in Moderate area plans) using the lower threshold
specified in the CAA and codified in 40 CFR part 51, subpart A. Also as
described above and in 40 CFR part 51, subpart A, this means that all
other smaller stationary sources must be included in the inventory as
nonpoint sources.
Third, Section VI.A of this preamble describes the EPA's proposal
to require that a state submit the base year inventory for a Serious
nonattainment area at the same time that it submits provisions to
implement BACM and BACT on sources in the area (due no later than 18
months from reclassification of the area pursuant to section 189(b)(2))
as the base year inventory serves as the starting point for conducting
a BACM and BACT determination. On the other hand, because the
attainment projected inventory is more closely related to the Serious
area attainment demonstration, the EPA believes that a state should be
required to submit its attainment projected inventory with the
attainment demonstration for a given Serious area in order to allow
effective evaluation of the attainment plan as a whole. Consequently,
the EPA is proposing to establish the regulatory requirement that
attainment projected emissions inventories be submitted at the same
time as the Serious area attainment demonstration, which would mean no
later than 18 months after reclassification for areas reclassified
after failing to attain the NAAQS by the applicable Moderate area
attainment date, or no later than 4 years after reclassification for
areas reclassified by the EPA because the area cannot practicably
attain the NAAQS by the statutory attainment date if the EPA finalizes
proposed Option 1 for determining BACM and BACT for area. See proposed
40 CFR 51.1008(b)(3) and (4). If the EPA finalizes an approach for
determining BACM and BACT that links the control strategy analysis to
the attainment demonstration, then the attainment demonstration
including the attainment projected emissions inventory would be due no
later than 18 months after reclassification (i.e., at the same time
BACM provisions are due under the statute).
The EPA seeks comment on these proposed requirements and due dates
for emissions inventories for Serious area attainment plans.
C. Pollutants To Be Addressed in the Plan
Section III of this preamble includes a detailed discussion about
how states should address PM2.5 precursors in attainment
plans and in the NNSR
[[Page 15404]]
program for purposes of implementing current and future
PM2.5 NAAQS. While evaluating sources of direct
PM2.5 for BACM and BACT is an implicit requirement in the
context of implementing the PM2.5 NAAQS under any scenario,
the EPA is proposing and seeking comment on several options for
addressing PM2.5 precursors under the PM2.5 NAAQS
implementation program. The EPA interprets the requirements of the CAA
to allow an air agency to provide a ``precursor demonstration'' that
can seek to make a technical case to the EPA that one or more
PM2.5 precursors need not be subject to control requirements
in a given nonattainment area, whether from sources in general or from
major stationary sources. Section III presented three options
describing different proposed approaches to such precursor
demonstrations, and requested comment on each. The discussion for each
option described how precursors would be addressed for Moderate areas
and for Serious areas.
In general terms, the three options can be summarized as follows:
Option 1: Two independent analyses: (a) An attainment
planning analysis demonstrating that control measures for a particular
precursor are not needed for expeditious attainment, meaning that the
precursor can be excluded from measures needed to attain as
expeditiously as practicable for all types of sources; and, (b) a
section 189(e) technical demonstration showing that major stationary
sources of a particular precursor do not contribute significantly to
levels that exceed the PM2.5 standard, meaning that the
precursor can be excluded from control requirements for major sources
and from NNSR permitting. For an area reclassified to Serious, the
state would once again need to evaluate potential control measures for
all sources of direct PM2.5 and all PM2.5
precursor emissions as part of the control strategy determination
process (described more fully in Section VI.D of this preamble).
Option 2: Single analysis demonstrating that all emissions
of a particular precursor from within the area do not significantly
contribute to PM2.5 levels that exceed the standard, meaning
that control requirements for emissions of the precursor from major
stationary and area sources, as well as mobile sources, would not be
required for expeditious attainment, control requirements for major
sources, or for NNSR permitting. For an area reclassified to Serious
for which a precursor had previously been demonstrated to not
significantly contribute to PM2.5 levels that exceed the
standard, the air agency would be required to update the precursor
demonstration taking into account any relevant information or technical
tools that had been developed since the initial demonstration was
approved, but could still conclude that control requirements are not
required for Serious area attainment planning if the updated
demonstration still shows that all source emissions of a precursor do
not significantly contribute to PM2.5 levels that exceed the
standard.
Option 3: An attainment planning analysis demonstrating
that control measures for all types of sources of a particular
precursor are not needed for expeditious attainment also would be
deemed to meet the section 189(e) technical demonstration requirement,
meaning that the state would not need to regulate emissions of the
particular precursor from major stationary sources under the NNSR
permitting program or other control requirements for major stationary
sources. As under proposed precursor Option 1, for an area reclassified
to Serious, the state would once again need to evaluate potential
control measures for all sources of direct PM2.5 and all
PM2.5 precursor emissions as part of the control strategy
determination process (see Section VI.D of this preamble).
The EPA will finalize its approach to PM2.5 precursors
and clarify the implications for states conducting analyses to
determine the appropriate control strategy for a Serious area after
considering public comment received on this proposal.
D. Attainment Plan Control Strategy
1. General Approach To Designing a Control Strategy for a Serious
Nonattainment Area
As noted in Section IV.D of this preamble, the statutory attainment
planning requirements of subparts 1 and 4 were established to ensure
that states meet the following goals of the CAA: (i) Implement measures
that provide for attainment of the PM2.5 NAAQS as
expeditiously as practicable, and (ii) adopt emission reduction
strategies that will be the most effective, and the most cost
effective, at reducing PM2.5 levels in nonattainment areas.
A state has discretion to require reductions from any source inside or
outside of a PM2.5 nonattainment area (but within the
state's boundaries) in order to fulfill its obligation to demonstrate
attainment in a PM2.5 nonattainment area as expeditiously as
practicable, in addition to having an obligation to meet the statutory
requirements for specific control measures on sources located within a
nonattainment area (e.g., BACM and BACT). A state may need to require
emissions reductions on sources located outside of a PM2.5
nonattainment area if such reductions are needed in order to provide
for expeditious attainment of the PM2.5 NAAQS.
The following sections describe the EPA's proposed approach for a
state to follow in order to identify and select the complete suite of
measures needed for an approvable attainment plan submission for a
Serious PM2.5 nonattainment area.
2. Identification and Selection of BACM and BACT and Additional
Feasible Measures
a. Statutory requirements and existing guidance. As discussed
earlier, a state must prepare a new attainment plan for any Moderate
area reclassified to Serious. Such a plan must include provisions to
implement BACM on sources in a Serious nonattainment area, as provided
by section 189(b)(1)(B), no later than 4 years after reclassification.
Under section 189(b)(2), a state has 18 months following
reclassification to submit these BACM provisions.
Section 189(b)(1)(B) refers only to BACM, but the EPA has long
interpreted this term to include BACT, just as the analogous term for
RACM includes RACT for Moderate areas. The legislative history for the
1990 Amendments to the CAA supports this interpretation, as the EPA has
explained in past guidance.\167\ Additionally, the requirement for BACT
in the context of PM2.5 NAAQS implementation in
nonattainment areas is separate and distinct from the requirement for
BACT under the Prevention of Significant Deterioration (PSD) permitting
program for new stationary sources in areas designated as attainment or
unclassifiable for the PM2.5 NAAQS. As described later in
this section, the process and criteria that states have historically
used to determine BACT for PSD have been applied to determine BACT for
PM10 NAAQS implementation, but these requirements are
otherwise unrelated.
---------------------------------------------------------------------------
\167\ Ibid. at 42008-09.
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Longstanding guidance in the General Preamble and Addendum,
together with past practice associated with implementing the
PM10 NAAQS under subpart 4, have helped to establish a
general approach for states and the EPA to determine BACM and BACT for
Serious PM10 nonattainment areas. This approach has served
as the basis for developing a more stringent control strategy for a
Serious PM10 nonattainment area than that developed
[[Page 15405]]
for such area when it was classified as Moderate. Indeed, as BACM and
BACT are required to be implemented when a Moderate nonattainment area
is reclassified as Serious due to its actual or projected inability to
attain the relevant NAAQS by the Moderate area attainment date through
the implementation of ``reasonable'' measures, it is logical that
``best'' control measures should represent a more stringent and
potentially more costly level of control.\168\ The level of stringency
generally refers to the overall level of emissions reductions of a
control measure or technology, or of such measures and technologies
combined.
---------------------------------------------------------------------------
\168\ Ibid. at 42009.
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Congress first defined BACT in CAA section 169(3) for the PSD
permitting program as: ``an emission limitation based on the maximum
degree of reduction of each pollutant . . . which the permitting
authority, on a case-by-case basis, taking into account energy,
environmental, and economic impacts and other costs, determines is
achievable for such facility through application of production
processes and available methods, systems, and techniques . . .''
In the Addendum, the EPA provided guidance concerning the
requirements for BACM and BACT for Serious area attainment plan
requirements for the PM10 NAAQS.\169\ The EPA discussed in
the Addendum that when Congress amended the CAA, Congress selected the
same ``best'' terminology for PM10 nonattainment areas as
they did for the language selected for the PSD program in 1977. The EPA
interpreted this word choice at the time to mean that PSD BACT and
PM10 nonattainment area BACM should be generally analogous
in definition and implementation, but with some differences due to
different end policy goals between the PSD and nonattainment area
programs.\170\ The EPA thus defined BACM for PM10 Serious
nonattainment area planning to be the maximum degree of emission
reduction achievable from a source or source category which is
determined on a case-by-case basis, considering energy, economic and
environmental impacts and other costs.\171\
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\169\ Ibid. at 42009.
\170\ Ibid. at 42010. ``EPA will interpret PSD BACT and PM-10
BACM as generally similar because, despite the similarity in
terminology, certain key differences exist between control measures
applicable in the PSD and PM-10 serious nonattainment area programs.
The BACT under the PSD program applies only in areas already meeting
the NAAQS, while PM-10 applies in areas which are seriously
violating the NAAQS. The difference in policy goals, arguably,
suggests that the PM-10 BACM control standard should be more
stringent than that for PSD BACT. . . . EPA considers it reasonable
to use the approach adopted in the PSD BACT program as defined in
section 169(3) of the Act as an analogue for determining appropriate
PM-10 nonattainment control measures in serious areas, while at the
same time retaining the discretion to depart from that approach on a
case-by-case basis as particular circumstances warrant.''
\171\ Ibid.
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The EPA has described BACM as a generally independent requirement,
to be determined without regard to the specific attainment analysis
(i.e., attainment demonstration) for the area.\172\ The EPA established
that such an interpretation is in accordance with the structural scheme
of the CAA, which by its definition requires that when an area is
classified as Serious, BACM are implemented in addition to RACM.
Because of the two types of measures employed, the EPA found it
reasonable in the past to interpret the statute as requiring a
different analysis for determining BACM, i.e., that while RACM has been
interpreted as those reasonable measures necessary to bring a
nonattainment area into expeditious attainment, BACM has been
interpreted as those measures that best control sources' emissions
without regard to whether such measures are needed for purposes of
attainment of the relevant NAAQS in the area. The view that BACM and
BACT measures are generally independent of the attainment needs of the
area is also consistent with the statutorily specified submission date
for BACM and BACT control measures, versus the statutorily specified
submission date for the attainment demonstration for Serious areas.
Specifically, states with Serious nonattainment areas must submit BACM
and BACT measures within 18 months of reclassification of areas to
Serious, whereas they are given up to 4 years from reclassification to
submit the attainment demonstration for such areas.
---------------------------------------------------------------------------
\172\ Ibid. at 42011.
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In addition, the EPA has historically provided an exemption from
BACM and BACT for source categories that contribute only de minimis
levels to ambient PM10 concentrations in a Serious
nonattainment area. In the Addendum, the EPA proposed that all sources
in a Serious area are subject to BACM unless ``the state adequately
demonstrates that a particular source category does not contribute
significantly to nonattainment of the NAAQS.''\173\ Because the
language regarding BACM implementation in section 189(b)(1)(B) of the
CAA requires ``provisions to assure that best available control
measures (BACM) for the control of PM10 shall be implemented
. . .'' without stating that ``all'' BACM must be implemented, the EPA
has interpreted this language as providing the EPA discretion to
exclude from BACM requirements source categories that do not contribute
significantly to an area's nonattainment status. Additionally, in the
Addendum, the EPA argued that based on the decision in Alabama Power
Co. v. Costle, the courts have supported the interpretation that
sources that contribute negligibly to an area's nonattainment status
can be excluded from regulation.\174\ The EPA further indicated that
the same criteria used in the NSR permitting program at the time to
determine if a source category contributes significantly to an area's
nonattainment status should apply, such that a source category would be
considered a significant contributor to an area's nonattainment status
if its emission contribution was expected to exceed 5 [micro]g/m\3\ for
the 24-hour PM10 NAAQS (150 [micro]g/m\3\ at the time), or 1
[micro]g/m\3\ for the annual PM10 NAAQS (50 [micro]g/m\3\ at
the time).
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\173\ Ibid. at 42011.
\174\ See Alabama Power Co. v. Costle, 636 F.2d 323, 360-61
(D.C. Cir. 1979).
---------------------------------------------------------------------------
A discussion of the EPA's existing process and criteria for
determining BACM and BACT for Serious PM10 nonattainment
areas and the agency's proposed options for defining the criteria by
which a state must determine BACM and BACT and additional feasible
measures for a Serious PM2.5 nonattainment area are
presented in the sections that follow.
In accordance with the PM10 guidance in the Addendum,
the EPA has applied a four-step process for states to use to identify
measures that constitute BACM or BACT for sources located in
PM10 Serious areas. The four-step BACM selection process was
designed to take into account the local facts and circumstances and the
nature of the air pollution problem in a given nonattainment area. The
BACM determination process for PM10 Serious nonattainment
areas has historically entailed: (i) Developing a comprehensive
inventory of sources and source categories of directly emitted
PM10 and PM10 precursors; (ii) evaluating source
category impact and determining if any source categories are de minimis
and thus do not need further evaluation for emission controls; (iii)
evaluating alternative control measures available for significant
source categories for technological feasibility; and, (iv) evaluating
costs (i.e., economic feasibility) of the technologically
[[Page 15406]]
feasible control measures.175 176 These steps are described
more fully below.
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\175\ For additional information, see ibid. at 42012-13.
\176\ For examples of how states have applied these steps and
criteria for Serious PM10 nonattainment areas and how the
EPA has evaluated them, see generally Approval and Promulgation of
Implementation Plans for California--San Joaquin Valley PM-10
Nonattainment Area; Serious Area Plan for Attainment of the 24-Hour
and Annual PM-10 Standards, 69 FR 5412 (February 4, 2004); Approval
and Promulgation of Implementation Plans for California--San Joaquin
Valley PM-10 Nonattainment Area; Serious Area Plan for Attainment of
the 24-Hour and Annual PM-10 Standards, 69 FR 30006 (May 26, 2004);
Approval and Promulgation of Implementation Plans for Arizona;
Maricopa County PM--10 Nonattainment Area; Serious Area Plan for
Attainment of the 24-Hour and Annual PM-10 Standards, 73 FR 45542
(August 14, 2008); Approval and Promulgation of Implementation
Plans; Arizona--Maricopa County PM-10 Nonattainment Area; Serious
Area Plan for Attainment of the Annual PM-10 Standard, 65 FR 19964
(April 13, 2000), at page 19972.
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Step 1: Inventory sources and precursors. As with any control
strategy analysis for a nonattainment area, the EPA recommended that a
state begin with a current emissions inventory as the first step toward
determining what constitutes BACM or BACT for a particular Serious
PM10 nonattainment area. The EPA expected that a state would
start with the base year emissions inventory submitted with the
Moderate area attainment plan for the area as required under section
172(c)(3), and update it as necessary to reflect new source
construction, facility shutdowns, growth in certain source categories,
and any other relevant changes. The EPA reiterated in the Addendum that
the emissions inventory for the area must identify both
nonanthropogenic and anthropogenic emissions sources.\177\
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\177\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42012.
---------------------------------------------------------------------------
Step 2: Evaluate source category impact. The next step in the BACM
analysis for PM10 Serious areas was for the state to
identify source categories having significant (i.e., non-de minimis)
impacts on air quality in the Serious area. The EPA suggested in the
Addendum that receptor modeling, screening modeling, or refined
dispersion modeling would likely be necessary to identify key source
categories, which the state may have performed during the development
of the Moderate area attainment plan.\178\
---------------------------------------------------------------------------
\178\ Ibid.
---------------------------------------------------------------------------
Step 3: Evaluate alternative control techniques. Once the
significant source categories were identified for a PM10
Serious nonattainment area, the state was expected to evaluate the
technological and economic feasibility of control measures ``discussed
in the BACM guidance documents and other relevant materials for all
source categories impacting the nonattainment area except those with a
de minimis impact considering emission reductions achieved with RACM.''
\179\ Control measures were supposed to be expanded to include options
not previously considered RACM as well as consider additional measures
not previously evaluated in the RACM analysis.
---------------------------------------------------------------------------
\179\ Ibid. at 42012. At the time of publication of the
Addendum, the EPA had already issued BACM guidance documents
pursuant to section 190 for residential wood combustion, prescribed
burning, and fugitive dust. The agency referred to these documents
as establishing the control measures that a state should consider,
at a minimum, as BACM for those PM10 sources in Serious
PM10 nonattainment areas.
---------------------------------------------------------------------------
Under the Addendum, the test for determining technological
feasibility could differ depending on the type of source category
evaluated. For area sources, the EPA's guidance suggested that
technological feasibility depended on the ability to alter the
characteristics that affect emissions from the sources, such as the
size or extent of the area sources and operation procedures. The EPA's
guidance suggested that for specific point sources, technological
feasibility should consider factors such as layout of the plant, space
available to make changes in the plant, energy requirements, operating
procedures, and materials used, among others.\180\
---------------------------------------------------------------------------
\180\ Ibid. at 42013 (discussing in detail factors which affect
the selection of mobile, area, and point source alternative control
techniques for particulate matter).
---------------------------------------------------------------------------
Step 4: Evaluate costs of control. The EPA's previous guidance
recommended that a control should be considered economically feasible
by the state when ``the control technology in question has previously
been implemented at other sources in a similar source category without
unreasonable economic impacts.'' \181\ Feasibility of public funding
for BACM could have been a consideration that states evaluated for all
of the technologically feasible control measures determined in Step 3.
Other costs that could be considered included capital costs, operating
and maintenance costs, and the cost effectiveness of a particular
control measure or technology.\182\
---------------------------------------------------------------------------
\181\ Ibid. at 42013.
\182\ EPA Air Pollution Control Cost Manual, Sixth Edition,
(EPA/452/B-02-001), July 2002 (explaining how to determine costs
under a BACT analysis).
---------------------------------------------------------------------------
The EPA believes that the difference between RACM and BACM
primarily lies in the extent of the actual emissions reductions
achieved through the application of a given suite of candidate
measures. For example, a state may have deemed a candidate RACM or RACT
measure economically infeasible because its cost effectiveness (dollar
per ton of pollutant reduced) was high relative to other measures, but
the same measure could qualify as BACM if, for the increased cost, it
would ultimately provide substantial PM2.5 attainment
benefits. An example of RACM might be to implement a particular control
in a limited way, while BACM could mean a more widespread
implementation of that same measure, even though wider implementation
would incur greater cost. In the PM10 context, states and
the EPA have determined that BACM have sometimes been measures that
were first implemented as RACM, but were then later implemented on a
broader scale as BACM in the nonattainment area after it was
reclassified as Serious.\183\
---------------------------------------------------------------------------
\183\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42014. The Addendum provides one example of RACM to
reduce PM10, to ``[p]ave 4 miles of unpaved city
streets.'' Ibid. BACM for PM10 for the same nonattainment
area could later mean to ``[p]ave 10 miles of the most heavily-
traveled, unpaved county roads.'' Ibid. Therefore, the measure
itself was not necessarily changed, but the extent to which the
measure was implemented was significantly expanded. Such a measure
would also contribute to more expeditious attainment of the NAAQS.
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While the proposed approaches and criteria for identifying
appropriate control measures for a Serious area are necessarily
different than for a Moderate area, it is important to note two
similarities: first, that the EPA interprets the requirement under
section 172(c)(6) for a state to adopt ``other measures'' needed for
attainment to apply to sources located inside and outside of any
PM2.5 nonattainment area (but within the state's
boundaries), whether the area is classified as Moderate or Serious;
and, second, similar to the RACM requirement for Moderate nonattainment
areas under subpart 4, section 189(b)(1)(B) requires that BACM must be
implemented no later than 4 years after a Moderate area is reclassified
to Serious.
Taking these two statutory provisions together, the EPA proposes
that the other measures required under section 172(c)(6) must include
``additional feasible measures,'' which would be those measures and
technologies that otherwise meet the criteria for BACM and BACT but
that can only be implemented in whole or in part beginning 4 years
after reclassification of an area, but no later than the statutory
attainment date for the area. See proposed 40 CFR 51.1000. Such
measures would necessarily be implemented on sources in the
nonattainment area, and a state would only be required to implement
them if they were needed in addition to BACM and BACT to bring the area
into expeditious attainment. The state must
[[Page 15407]]
also assess whether there are other control measures that it can
implement to control sources within the state but outside the
nonattainment area that contribute to the PM2.5
nonattainment status of the area in order to bring the area into
attainment as expeditiously as practicable, and may consider existing
measures that, applied more extensively, could meet the more stringent
criteria for control measures that must be adopted to bring a Serious
nonattainment area into expeditious attainment.
These ``additional feasible measures'' would be analogous to the
``additional reasonable measures'' in the proposed RACM and RACT
analysis process, which are technologically and economically feasible
measures that cannot qualify as RACM or RACT because they cannot be
implemented within 4 years of designation of a Moderate nonattainment
area. Under either of the two proposed approaches for determining BACM
and BACT for sources in a Serious nonattainment area descrfibed later
in this section, a state would identify additional feasible measures as
part of the BACM and BACT determination process, just as additional
reasonable measures would be identified as part of the state's RACM and
RACT determination process.
The EPA recognizes that only a nonattainment area that is
reclassified under the agency's discretionary authority might have
sufficient time between the required date for implementing BACM and
BACT and the statutory Serious area attainment date to implement
additional measures beyond BACM and BACT. BACM and BACT must be
implemented no later than 4 years after reclassification of the area;
areas reclassified to Serious because they cannot practicably attain
the relevant NAAQS by the applicable attainment date could potentially
have significantly more than 4 years between the date of
reclassification and the statutory Serious area attainment date, during
which time the area could continue to implement additional measures to
bring the area into attainment. By way of illustration, for areas
designated in the first round of designations for the 2012
PM2.5 NAAQS, the statutory Moderate area attainment date
will be no later than December 31, 2021. If a state submits a Moderate
area attainment plan by the statutory attainment plan due date (18
months after designation, or in this example, October 2016) and the
plan demonstrates that the area cannot practicably attain the NAAQS by
December 31, 2021, then the EPA has a statutory duty to reclassify such
an area within 18 months of the attainment plan due date (i.e., by
April 2018). The statutory Serious area attainment date would be the
end of the tenth year following designation, or December 31, 2025. In
such a case, the state would need to implement BACM for the area within
4 years of reclassification, or by April 2022, leaving over 3.5 years
between the statutory deadline for implementing BACM and the statutory
attainment date for the area. The EPA's proposal to require the state
to identify and adopt additional feasible measures for the area would
mean that the state would need to identify those control measures and
technologies that are feasible (according to the proposed BACM and BACT
criteria described later in this section) and that can be implemented
between April 2022 and December 2025. The EPA expects that while such a
long span of time may be available only to a very few Serious
nonattainment areas, it would be appropriate to require such areas to
implement measures in addition to BACM and BACT if, taken together,
they can advance the attainment date for the area by at least 1 year.
The EPA seeks comment on its proposal to require additional feasible
measures for Serious nonattainment areas as described here.
b. Proposed approaches for determining BACM and BACT and additional
feasible measures for Serious PM2.5 nonattainment areas. The EPA
proposes and seeks comment on two approaches for a state to meet the
statutory control requirements that apply for Serious nonattainment
areas. The EPA is first proposing an approach consistent with prior
guidance summarized in the preceding section of this preamble which
would center on determining BACM and BACT and additional feasible
measures ``generally independent'' of whether such measures are needed
for expeditious attainment of the relevant NAAQS in a Serious
PM2.5 nonattainment area. Under this first proposed
approach, states would have the option, with the proper evidence and
justification, to eliminate de minimis source categories from
consideration for controls.
The EPA's second proposed approach would require states to identify
BACM and BACT and additional feasible measures simply within the
context of what is necessary to bring an area into attainment as
expeditiously as practicable. In other words, the second proposed
option would take a different approach to determining Serious area
control measures from the approach included in prior EPA guidance, in
that it would allow states not to impose specific measures that would
otherwise be BACM or BACT (or additional feasible measures) in the
area, if those measures would not be necessary to bring the area into
attainment with the relevant NAAQS by the statutory attainment date,
and the collective emissions reductions from such measures would not be
sufficient to advance the attainment date by at least 1 year in the
area. A discussion of the proposed options follows.
i. Proposed Option 1. The EPA seeks comment on a proposed approach
to maintain, with some modifications, the existing approach to
determining BACM and BACT for Serious PM10 nonattainment
areas to BACM and BACT determinations for Serious PM2.5
nonattainment areas. Under this approach, a state would be required to
determine BACM and BACT and additional feasible measures for a Serious
PM2.5 nonattainment area independent of an analysis of the
specific attainment needs of the Serious area; in other words, the BACM
and BACT analysis would need to be conducted without regard to whether
all such controls are needed to bring the area into expeditious
attainment. Keeping in mind that the overall objective of the
implementation of BACM and BACT and additional feasible measures is to
bring a Serious PM2.5 nonattainment area into attainment as
expeditiously as practicable, this option would continue to provide
that the test for BACM puts a ``greater emphasis on the merits of the
measure or technology alone,'' rather than on ``flexibility in
considering other factors,'' in contrast to the approach for
determining RACM and RACT described in both the EPA's past guidance and
in this proposal in Section IV.D.\184\ This Option 1 is consistent with
the statutory provisions governing the timing for submission of BACM
and BACT measures versus the timing for attainment demonstrations for
Serious areas. By interpreting the statutory requirement for BACM and
BACT for Serious PM2.5 nonattainment areas as a requirement
that a state must meet independent of the attainment planning needs of
the area, the EPA would not consider such requirement to be a
``planning'' requirement tied to the actual attainment status of the
area, and thus would not suspend such a requirement in the event the
agency determines that a Serious area is attaining the relevant
PM2.5 NAAQS and
[[Page 15408]]
in turn grants a clean data determination for the area.\185\
---------------------------------------------------------------------------
\184\ Ibid.
\185\ For a complete discussion of the EPA's Clean Data Policy
and the EPA's proposal for applying this policy for purposes of
implementing the PM2.5 NAAQS, see Section IX.C of this
preamble.
---------------------------------------------------------------------------
Under the EPA's first proposed approach, a state would be required
to follow a multi-step process similar to the existing BACM process for
PM10 (outlined earlier in this section) to identify and
select control measures and technologies more stringent than RACM and
RACT and additional reasonable measures for non-de minimis source
categories in the nonattainment area. This process would involve
analyzing the impact of the different source categories identified in
the up-to-date base year emissions inventory for the area to identify
those with a significant contribution to the area's PM2.5
concentrations. Any source categories found not to have such an impact
would be considered de minimis and therefore exempt from further
consideration. The specific steps the EPA is proposing for this
approach are explained below. See proposed 40 CFR 51.1010(a) for
proposed Option 1.
Step 1: Update base year emissions inventory for the area. The
first step under this proposed approach would be for the state to
develop a detailed emissions inventory of the various sources and
source categories that emit direct PM2.5 and
PM2.5 precursors in the Serious area. This inventory should
be the most comprehensive and accurate inventory available. The EPA
expects that the work for this step would be completed in order to meet
the emissions inventory requirements for Serious area plans as
described in Section VI.B, and would start with reviewing and updating
the emissions inventory submitted as part of the Moderate area
attainment plan for the area.
Step 2: Evaluate source category impacts. As with BACM for
PM10, the EPA proposes to allow states to exempt from
further consideration de minimis source categories in Step 2 of the
agency's first proposed approach for determining BACM and BACT for a
Serious PM2.5 nonattainment area. The EPA proposes to apply
the same overarching test for identifying de minimis source categories
as that described in the Addendum.\186\ That is, if a state can
demonstrate that a particular source category does not contribute
significantly to nonattainment of the PM2.5 NAAQS after the
application of any RACM or RACT controls on the sources in the source
category, then the state may eliminate the source category from further
consideration for BACM or BACT.\187\ A state would be required to
evaluate for BACM and BACT controls all other sources in the
nonattainment area in source categories that do not qualify as de
minimis.
---------------------------------------------------------------------------
\186\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42011.
\187\ Ibid. See also Alabama Power v. Costle, 636 F.2d 323, 360-
61 (D.C. Cir. 1979).
---------------------------------------------------------------------------
This option could be beneficial for some states that may already
exclude de minimis PM10 source categories from BACM in
Serious PM10 nonattainment areas or that may exclude de
minimis PM2.5 source categories from RACM and RACT and
additional reasonable measures in Moderate PM2.5
nonattainment areas. As discussed earlier, a state may rely on receptor
or dispersion modeling conducted for the area as part of its Moderate
area attainment plan. Alternative or additional modeling, including
screening modeling, or filter analysis may also be necessary to
identify significant contributors to PM2.5 levels in the
area. More discussion on the EPA's proposal regarding how to evaluate
source category impacts and identify those that are de minimis can be
found in Section IV.D of this preamble. The EPA notes that a state may
face the same challenges in establishing de minimis source categories
for PM2.5 sources in a Serious nonattainment area as it did
in establishing de minimis source categories for PM2.5
sources when the area was classified as Moderate. Therefore, the EPA
seeks comment on its proposed options, described in Section IV.D, for
defining source categories and determining the appropriate threshold
for de minimis emissions. The EPA requests that commenters submit any
relevant data or analyses to support their comments. In the absence of
compelling evidence to support establishing a nationally-applicable
``bright line'' threshold for defining a de minimis source category for
purposes of implementing the PM2.5 NAAQS in a Serious
nonattainment area, the EPA would apply a presumptive approach allowing
a state to apply its own reasoned judgment to determine whether a
particular source category should be considered de minimis in the event
the EPA finalizes proposed Option 1 for BACM and BACT determinations.
Step 3: Identify existing and potential control measures. After
evaluating source category impacts to eliminate de minimis source
categories from further consideration, the state would identify all
existing and potential measures (including those measures that were
rejected in the RACM and RACT determination and additional new
potential measures) for reducing emissions from the remaining (i.e.,
non-de minimis) source categories listed in the latest base year
emissions inventory for the area. For purposes of identifying new
measures to consider in its BACM and BACT analysis, the EPA proposes to
require that the state conduct a survey of other nonattainment areas
for the PM2.5 NAAQS and other NAAQS (i.e., PM10,
ozone, SO2 and NOX) both in the same state and in
other states to identify potential control measures that other air
agencies are implementing, and the state must incorporate such measures
into the list of potential control measures for the source categories
in the Serious nonattainment area. The EPA would expect the state to
identify an array of existing and potential new measures at least as
broad as that identified for the same area as part of the RACM and RACT
analysis, in order to ensure that the state has a sufficiently
expansive and comprehensive set of potential measures to evaluate.
Therefore, at a minimum, the EPA proposes that the list of potential
measures must include all measures identified as potential control
measures for the nonattainment area when it was classified as Moderate
or, for a given source category, one or more alternative control
measures or technologies that would control emissions even more
stringently than the measures and technologies included in the RACM and
RACT analysis. In this way, the state will begin its BACM and BACT
determination with a list of potential control options that is as
complete and up-to-date as possible.
In addition to identifying existing control measures for sources in
a Serious PM2.5 nonattainment area, a state must develop a
comprehensive list of potential control measures for sources in the
area. The EPA's RACT/BACT/LAER Clearinghouse provides a central data
base of air pollution technology information that may be highly
relevant to states seeking information on stationary source control
technology that may qualify as BACT for PM2.5 NAAQS
implementation, and is available online at http://cfpub.epa.gov/RBLC/.
There are also other resources available to assist states in
identifying other potential control measures and control technologies
for their BACM and BACT determinations. The EPA encourages states with
Serious PM2.5 nonattainment areas to visit the agency's Web
site to find links to other online sources of information on potential
[[Page 15409]]
control measures for states to consider.\188\
---------------------------------------------------------------------------
\188\ Links are provided to a number of national, state and
local air quality agency sites from the EPA's PM2.5 Web
site: http://www.epa.gov/pm/measures.html.
---------------------------------------------------------------------------
Specific to potential control measures for mobile source emissions,
the EPA's past guidance has indicated that where mobile sources
contribute significantly to PM2.5 violations, ``the state
must, at a minimum, address the transportation control measures listed
in CAA section 108(f) to determine whether such measures are achievable
in the area considering energy, environmental and economic impacts and
other costs.'' \189\ The EPA proposes to retain this guidance and
require that a state include for evaluation as BACM for mobile sources
those measures listed in section 108(f), and the agency seeks comment
on this specific requirement.
---------------------------------------------------------------------------
\189\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42013.
---------------------------------------------------------------------------
Step 4: Determine whether an available control measure or
technology is technologically feasible. After developing a list of
existing and potential new measures to evaluate for BACM and BACT, the
state would then need to determine the technological feasibility of
each identified control measure in light of a number of considerations,
including each measure's individual energy and environmental
impacts.\190\
---------------------------------------------------------------------------
\190\ Ibid. at 42012.
---------------------------------------------------------------------------
(1) Stationary sources. As described under the technological
feasibility criteria for the control measures analysis for Moderate
area attainment plans in Section IV.D, the EPA's prior guidance on
factors to consider for judging whether a particular control technology
is technologically feasible should include a source's processes and
operating procedures, raw materials, physical plant layout and
potential environmental impacts such as increased water pollution,
waste disposal and energy requirements. For example, the EPA recognizes
that the process, operating procedures and raw materials used by a
source can affect the feasibility of implementing process changes that
reduce emissions and can also affect the selection of add-on emission
control equipment. The feasibility of modifying processes or applying
control equipment also can be influenced by the physical layout of the
particular plant, if the physical space available in which to implement
such changes limits the choices.\191\
---------------------------------------------------------------------------
\191\ Ibid. at 42013.
---------------------------------------------------------------------------
(2) Area and mobile sources. With respect to determining whether a
given control measure might not be technologically feasible as BACM for
an area or mobile source, the EPA proposes that a state may consider
factors in conducting its analysis that are similar to factors the
state may have considered during the RACM and RACT determination
process, such as the social acceptability of the measure, and local
circumstances, such as the condition and extent of needed
infrastructure, population size or workforce type and habits, which may
prohibit certain potential control measures from being implementable.
However, in the instance where a given control measure has been applied
in another NAAQS nonattainment area (for PM2.5 or other
pollutant), the EPA proposes that the state will need to provide a
detailed justification for rejecting any potential BACM measure as
technologically infeasible. Furthermore, if the state identifies a
certain control measure for area or mobile sources that has been
implemented in another nonattainment area and may qualify as BACM or
BACT for the state's Serious nonattainment area, the state must provide
a reasoned justification if it deems it technologically infeasible to
implement the same control measure to the same extent or magnitude as
it was applied in the other nonattainment area.
The EPA seeks comment on the factors described above for states to
consider when evaluating the technological feasibility of a control
measure or technology for BACM and BACT.
Step 5: Determine whether an available control technology or
measure is economically feasible. The fifth step under this proposed
approach is to evaluate the costs of implementing each of the
technologically feasible control measures and technologies in order to
eliminate from further consideration any measures determined to be
economically infeasible. As discussed elsewhere in this proposal, in
assessing ``best'' control measures and technologies, states with
Serious PM2.5 nonattainment areas must identify a control
strategy for the area that overall is more stringent than that
identified for the area when the state considered only the
``reasonableness'' of potential control measures. Thus the EPA is
proposing to require states to consider emission reduction measures
with higher costs per ton when assessing the economic feasibility of
BACM and BACT controls (and, where applicable, additional feasible
measures) as compared to the economic feasibility criteria applied in
their RACM and RACT analysis (and analysis for additional reasonable
measures) for the same nonattainment area.
Indeed, consistent with prior guidance on evaluating costs of a
potential BACM or BACT control, the EPA maintains that while the
economic feasibility of a control measure is as important as its
technological feasibility under the RACM and RACT determination
process, economic feasibility is a less significant factor in the BACM
and BACT determination process. In other words, a state must apply a
higher standard for eliminating a technologically feasible control
measure from further consideration as BACM due to cost alone.
In the Addendum, the EPA stated that ``for PM10 BACM
purposes, it is reasonable for similar sources to bear similar costs of
emission reduction.'' \192\ Additionally, the EPA indicated that
``economic feasibility for PM10 BACM purposes should focus
upon evidence that the control technology in question has previously
been implemented at other sources in a similar source category without
unreasonable economic impacts.'' \193\ Thus, a state may not eliminate
a particular control measure from further consideration as potential
BACM if similar sources have successfully implemented such a measure.
That is, a state must at a minimum continue to consider as potential
BACM any technologically feasible control measures or technologies
implemented by similar sources.
---------------------------------------------------------------------------
\192\ Ibid.
\193\ Ibid.
---------------------------------------------------------------------------
In addition, the EPA seeks to clarify that a state may not
automatically eliminate a particular control measure merely because
other sources have not implemented the measure. In other words, a state
must continue to consider technologically feasible measures that have
not been implemented by similar sources but that can nonetheless
effectively reduce emissions from the source category in question at a
cost that is not wholly cost prohibitive.
As with the EPA's proposed approach for evaluating economic
feasibility of potential reasonable measures for Moderate area
attainment plans, the EPA proposes that for each technologically
feasible control measure or technology, a state must evaluate the
economic feasibility of the measure or control through consideration of
the capital costs, operating and maintenance costs, and cost
effectiveness (i.e., cost per ton of pollutant reduced by that measure
or technology) associated with such measure or control. While the EPA
is
[[Page 15410]]
not proposing a fixed dollar per ton cost threshold for economic
feasibility of controls identified as potential BACM and BACT, the EPA
proposes that the threshold should be higher for the BACM and BACT
analysis than it was for the RACM and RACT analysis for the same
nonattainment area. In addition, if a state contends that a source-
specific control-level should not be established because the source(s)
cannot afford the control measure or technology that is demonstrated to
be economically feasible for purposes of BACM for other sources in its
source category, the state must support the claim with information
regarding the impact of imposing the identified control measure or
technology on the following financial indicators, to the extent
applicable:
1. Fixed and variable production costs ($/unit);
2. Product supply and demand elasticity;
3. Product prices (cost absorption vs. cost pass-through);
4. Expected costs incurred by competitors;
5. Company profits
6. Employment costs;
7. Other costs (e.g., for BACM implemented by public sector
entities).
The EPA seeks comment on the factors described above for states to
consider when determining whether a control measure or technology is
economically feasible as BACM or BACT.\194\
---------------------------------------------------------------------------
\194\ These long-standing factors were established in EPA
guidance in 1992 and are applicable to implementation programs for
all NAAQS pollutants. See the appendices to the General Preamble, 57
FR 18070 (April 28, 1992).
---------------------------------------------------------------------------
Step 6: Determine the earliest date by which a control measure or
technology can be implemented in whole or in part. Section 189(b)(1)(B)
requires that Serious area attainment plans provide for the
implementation of BACM no later than 4 years after reclassification of
the area to Serious. As with the EPA's proposed approach to RACM and
RACT, the EPA proposes the term ``implement'' to mean that the control
measure or technology has not only been adopted into the SIP for the
area but has also been built, installed and/or otherwise physically
manifested and the affected sources are required to comply. See
proposed 40 CFR 51.1000. The EPA thus expects a state with a Serious
nonattainment area to take deliberate and timely action to implement
BACM and BACT in the area. The EPA proposes that if a state evaluates a
potential BACM or BACT measure and determines that it can be
implemented only partially within 4 years after reclassification, the
state must adopt the partial measure as BACM.
The EPA proposes that a state must identify those technologically
and economically feasible control measures and technologies that it can
implement fully or partially within 4 years of reclassification of its
Serious PM2.5 nonattainment area. These measures will be
considered BACM and BACT for the area. ``Additional feasible measures''
would be ``best''-level, feasible measures that a state could implement
in whole or in part on sources in the area sometime after the fourth
year following reclassification and prior to the statutory attainment
date for the area.
ii. Proposed Option 2. The second proposed approach for evaluating
control measures and technologies and determining which qualify as BACM
or BACT or additional feasible measures for a Serious PM2.5
nonattainment area would directly link the control strategy
determination process with the attainment demonstration for the area,
allowing a state to eliminate potential measures that are not necessary
to demonstrate attainment of the relevant NAAQS in the area and would
not collectively advance the attainment date for the area by at least 1
year. For this second proposed approach, the EPA proposes a process
similar to the one proposed for Moderate area control strategy
determinations. However, the specific potential control measures to be
evaluated as BACM and BACT and additional feasible measures would
continue to be distinguished by stricter criteria to yield a set of
control measures that reflects an overall higher level of stringency in
the control strategy for the nonattainment area than that provided by
the implementation of reasonable control measures (i.e., RACM and RACT
and additional reasonable measures).
Under the EPA's second proposed approach for determining which
measures must be part of the control strategy for a Serious
PM2.5 nonattainment area, a state would follow many of the
same steps as described under the EPA's first proposed approach for the
such determinations, with two important differences. First, Step 2 as
described above would be eliminated from the process. That is, after a
state updates the baseline emissions inventory for sources located in
the area, the state would be required to identify existing and
potential new measures for all sources in the inventory for evaluation
as potential BACM and BACT and additional feasible measures without
exempting any source categories as de minimis. Second, Step 6 as
described above would not be the last step in the control strategy
determination process, but rather would serve as another interim step
in the process prior to making a final determination of what
constitutes BACM and BACT and additional feasible measures for the area
through modeling for the attainment demonstration. The EPA's proposed
requirements for what the state would need to evaluate during this step
under this second proposed approach are described in greater detail in
the following section.
The EPA emphasizes that proposed Option 2 for determining BACM and
BACT and additional feasible measures depends on the state submitting
its attainment demonstration earlier than may otherwise be required
under the statute so that it can be contemporaneous with the submission
of BACM and BACT measures, due 18 months after the date of
reclassification of a PM2.5 nonattainment area to Serious.
Given all of the above, the EPA is proposing and seeking comment on
a second approach for determining BACM and BACT and additional feasible
measures for a Serious PM2.5 nonattainment area comprised of
the following steps. See proposed 40 CFR 51.1010(a) for proposed Option
2. Note that Steps 1 through 5 would incorporate the same
considerations and requirements as those in the equivalent steps
described in the EPA's first proposed approach with the two important
exceptions discussed in the preceding section:
Step 1: Update base year emissions inventory for the area.
Step 2: Identify existing and potential control measures for all
emissions sources in the emissions inventory for the area.
Step 3: Determine whether an available control measure or
technology is technologically feasible.
Step 4: Determine whether an available control measure or
technology is economically feasible.
Step 5: Determine the earliest date by which a control measure or
technology can be implemented in whole or in part.
During this step in the process, the state would be required to
identify two groups of measures. The first group of measures would be
potential BACM and BACT; that is, ``best''-level, feasible measures
that the state could implement in whole or in part within 4 years of
reclassification. The second group of measures would be additional
feasible measures, defined as ``best''-level, feasible measures that a
state could implement in whole or in part on sources in the area
sometime after the fourth year following reclassification
[[Page 15411]]
and prior to the statutory attainment date for the area.
Step 6: Model to determine the attainment date that is as
expeditious as practicable. As with the proposed Moderate area
attainment plan control strategy analysis, the EPA proposes that states
would need to model air quality impacts to determine the Serious area
attainment date that is as expeditious as practicable for the area.
After developing an inventory, identifying potential measures,
determining economic and technological feasibility, and determining
whether a measure would be able to be implemented in 4 years or between
4 years from reclassification and the statutory attainment date for the
area, the state would conduct modeling that shows the combined air
quality impact of all BACM and BACT measures and additional feasible
measures as applicable. The purpose of this modeling would be to
determine the attainment date that is as expeditious as practicable and
to identify whether there are certain control measures that a state
could eliminate from the Serious area attainment plan because they
cannot collectively expedite attainment of the area by 1 year or more.
A complete discussion of the EPA's proposed modeling requirements for
Serious area attainment demonstration is presented in Section VI.E
below.
Step 6a: If area can demonstrate attainment by the statutory
attainment date, then select only those control measures needed for
expeditious attainment as BACM or BACT or additional feasible measures.
Under this second proposed approach to BACM and BACT determinations,
the EPA proposes that if a Serious area will be able to demonstrate
attainment by the statutory Serious area attainment date, then the
state must adopt all measures identified as potential BACM and BACT,
and additional feasible measures if applicable, that will ensure that
the attainment date is as expeditious as practicable. The state may,
however, reject those potential BACM and BACT and additional feasible
measures that would not collectively contribute to emissions reductions
that could advance the attainment date for the area by at least 1 year.
The EPA recognizes that identifying the measures that would not
collectively advance the attainment date for a Serious area by at least
1 year will likely be an iterative process that requires additional
modeling. As with modeling for Moderate area attainment demonstrations,
the EPA believes that such extra effort is reasonable for a state
seeking to reject certain potential BACM or BACT or additional feasible
measures from implementation in a given Serious nonattainment area.
One notable point of discussion in the Addendum indicates that
short-term BACM measures are not preferred by the EPA unless such a
measure is the only way to implement BACM within 4 years.\195\ This is
because the ultimate goal of selection of BACM controls is that those
measures will prevent future emissions, rather than a temporary
reduction of emissions. Therefore, consistent with this previous
guidance, the EPA proposes that those measures that a state must reject
first under this proposed approach would be those that offer only
short-term emissions reductions.
---------------------------------------------------------------------------
\195\ Ibid.
---------------------------------------------------------------------------
Step 6b: If an area cannot demonstrate attainment by the statutory
attainment date, then submit request for Serious area attainment date
extension including adopting MSM. Section 189(b)(1)(A) of the CAA
requires a state to submit as part of its Serious area attainment plan
either a demonstration that the plan will provide for attainment by the
statutory Serious area attainment date, or a demonstration that
attainment by such date is ``impracticable.'' If the state cannot
demonstrate attainment based on the implementation of all BACM and BACT
and additional feasible measures by the end of the tenth calendar year
following designation of the area, then under sections 189(b)(1)(A)(ii)
and 188(e), the state must submit as part of its Serious area
attainment plan a complete request to extend the attainment date for
the area that meets the statutory provisions of section 188(e) and
meets all of the regulatory criteria proposed under Section VII in this
preamble, including the evaluation and adoption of MSM.
The EPA acknowledges that this second proposed approach for
determining BACM and BACT and additional feasible measures for a
Serious area, which would authorize states to link the attainment
control strategy to the attainment needs for an area, is different from
the approach the agency has historically applied to BACM determinations
for PM10. The EPA believes that effectively eliminating the
step of exempting de minimis source categories the beginning of the
control strategy determination process and linking the determination of
BACM and BACT and additional feasible measures with the attainment
analysis for a Serious area would not be a relaxation of the statutory
requirement for implementation of ``best'' measures in Serious
PM2.5 nonattainment areas as Congress required in section
189(b)(1)(B), however. Rather, the agency believes that in order to
ensure that a state develops an appropriately stringent control
strategy for a Serious PM2.5 nonattainment area, it is
appropriate to require that state to identify and evaluate potential
control measures for all sources of direct PM2.5 emissions
and emissions of any PM2.5 precursors not otherwise found to
contribute insignificantly to PM2.5 levels in the area.
Eliminating the possibility for de minimis source category exemptions
means that a state's evaluation of potential control measures and
technologies will be more thorough and comprehensive and potentially
lead to the implementation of controls on a wider variety of source
categories. Additionally, the test of whether the potential BACM and
BACT and additional feasible measures not needed for an area to attain
the NAAQS by the outside statutory attainment date could collectively
advance the attainment date for the area by at least 1 year could
result in a state implementing such measures on source categories
which, if they had each been evaluated separately for purposes of a de
minimis source category analysis, might have been exempted from
control. Furthermore, as noted earlier in this section, in order for
the state, the EPA, and the general public to be able to fully evaluate
whether the selected control strategy (i.e., BACM and BACT and
additional feasible measures) will provide for expeditious attainment
of the NAAQS in a Serious PM2.5 nonattainment area, the
state would be required to submit the attainment demonstration for the
area at the same time as it submits provisions to meet the BACM and
BACT requirement under section 189(b)(1)(B), 18 months after
reclassification of the area to Serious. This date would be stricter
than the statutory due date for a Serious area attainment demonstration
for areas reclassified to Serious under the EPA's discretionary
authority of section 188(b)(1), which is no later than 4 years from the
date of reclassification of the area.
By defining a process for determining BACM and BACT and additional
feasible measures in a way that is similar to the process for
determining RACM and RACT and additional reasonable measures for the
same area, the EPA believes that a state with a Serious
PM2.5 nonattainment area may be able to conserve resources
by relying in part on the analytical work performed for the RACM and
RACT analysis for the area when it was classified as Moderate.
Furthermore, the challenges associated
[[Page 15412]]
with properly identifying de minimis source categories as described
earlier in this section may be avoided. Finally, the EPA believes that
tying the final selection of BACM and BACT and additional feasible
measures to the specific attainment needs of a nonattainment area could
help to focus limited air agency resources on control measures that are
most needed to bring a Serious area into expeditious attainment for the
PM2.5 NAAQS.
The EPA seeks comment on all aspects of both proposed approaches
and criteria for determining BACM and BACT and additional feasible
measures for a Serious nonattainment area. The agency may finalize
either of the proposed approaches or various elements of each after
analyzing submitted comments.
3. BACM and BACT Submittal Requirements
To ensure that attainment plan submissions contain the necessary
supporting information for EPA review and approval of the state's
selected BACM and BACT and additional feasible measures as applicable,
the EPA proposes to require under the authority of section 301(a) that
a state must submit the following information as part of its Serious
area attainment plan submission:
A list of all emissions source categories, sources and
activities in the nonattainment area that emit direct PM2.5
or any PM2.5 precursor (for multi-state nonattainment areas,
this would include source categories, sources and activities from all
states which make up the area);
For each source category, source or activity in the
nonattainment area, an inventory of direct PM2.5 and all
PM2.5 precursor emissions;
For each source category, source or activity in the
nonattainment area, a comprehensive list of potential control measures
considered by the state for the nonattainment area; \196\ \197\
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\196\ The EPA believes that it is not necessary to identify
every possible variation of every type of control measure, or all
possible combinations of technologies and measures that would apply
to a given source or activity, as long as the state has properly
characterized the potentially available emissions reductions and
their costs. For example, the EPA believes that the state can
conduct a thorough analysis of VMT reduction measures without
including every possible level or stringency of implementation of
certain possible measures or combinations of measures for reducing
VMT, so long as those measures would not affect the overall
assessment of VMT reduction capabilities and the associated costs.
\197\ The Menu of Control Measures document is available at:
http://www.epa.gov/air/criteria.html.
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For each potential control measure considered by the state
but eliminated from further consideration due to a determination by the
state that the control measure or technology was not technologically
feasible, a narrative explanation and quantitative or qualitative
supporting documentation to justify the state's conclusion;
For each technologically feasible emission control measure
or technology, the state must provide the following information
relevant to economic feasibility: (i) The control efficiency by
pollutant; (ii) the possible emission reductions by pollutant; (iii)
the estimated cost per ton of pollutant reduced; and, (iv) a
determination of whether the measure is economically feasible, with
narrative explanation and quantitative supporting documentation to
justify the state's conclusion;
For each technologically and economically feasible
emission control measure or technology, the date by which the
technology or measure could be implemented.
As with a Moderate area attainment plan submission, the EPA
recognizes that the base year emissions inventory for the area that the
state submits in conjunction with its Serious area attainment plan will
likely contain the information proposed to be required under the first
two items in this list. However, the EPA believes that it is incumbent
on the state to ensure that the information needed for the EPA to
evaluate the state's BACM and BACT and additional feasible measures
analysis is presented as part of that analysis and in a format that
provides transparency, consistency and the ability for another party to
evaluate the state's analysis effectively and to duplicate the state's
results. For this reason, the EPA is proposing to require the state to
include the base year emissions inventory information with the BACM and
BACT submittal and as one element of the state's attainment plan due 18
months after reclassification of the area to Serious.
4. Criteria for Effective Regulations To Implement BACM and BACT and
Additional Feasible Measures
As with control measures identified as part of a Moderate area's
attainment control strategy, after a state has identified its BACM and
BACT and additional feasible measures for a particular nonattainment
area, it must implement those measures through a legally enforceable
mechanism to be included in the SIP. As with Moderate area control
measures, the EPA is proposing that in order for the agency to be able
to approve any Serious area control measure and approve it as part of
the SIP, the state will have to provide information to meet the
following four criteria.
First, the base year emissions from the source or group of sources
to which the control measure applies and the future year projected
emissions from those sources once controlled must be quantifiable so
that the projected emissions reductions from the sources can be
attributed to the specific measures being implemented. Once again, it
is important that the emissions from the source category in question
are accurately represented in the base year inventory so that emissions
reductions are properly calculated. In particular, it is especially
important to ensure that both the filterable and condensable components
of PM2.5 are accurately represented in the base year.
Second, the control measures must be enforceable, meaning that they
must specify clear, unambiguous and measurable requirements. The
measurable requirements for larger emitting facilities must include
periodic source testing to establish the capability of such facilities
to achieve the required emission level. Additionally, to verify the
continued performance of the control measure, specific emissions
monitoring programs appropriate for the type of control measure
employed and the level of emissions must be included to verify the
continued performance of the control measure. The control measures and
monitoring program must also have been adopted according to proper
legal procedures.
Third, the results of application of the control measures must be
replicable. This means that where a rule contains procedures for
interpreting, changing or determining compliance with the rule, the
procedures are sufficiently specific and objective so that two
independent entities applying the procedures would obtain the same
result.
Fourth, the control measures must be accountable. For example,
source-specific emission limits must be permanent and must reflect the
assumptions used in the attainment plan for the area, including the
modeling conducted in conjunction with the attainment demonstration.
The attainment plan must establish requirements to track emissions
changes at sources and provide for corrective action if emissions
reductions are not achieved according to the plan.
The EPA seeks comment on these criteria for approval of any control
measures adopted by a state for a Serious area to assure that such
measures are legally enforceable.
[[Page 15413]]
5. Relevance of Prior BACT, LAER and BART Determinations
The EPA believes that BACT or lowest achievable emission rate
(LAER) provisions for new sources (as distinct from BACT for existing
sources), or best available retrofit technology (BART) for existing
sources, could qualify as BACM or BACT for purposes of meeting the
Serious area attainment plan requirements. However, the EPA does not
believe it is appropriate for a state to assume that just because a
certain control technology was determined to meet BACT, LAER, or BART
criteria for a new source, such a control will also automatically meet
the criteria for BACM or BACT or additional feasible measures for
attainment planning purposes because the regulated pollutant or source
applicability may differ and the analyses may be conducted many years
apart. Thus, a state may not simply rely on prior BACT, LAER or BART
analyses for the purposes of showing that a source has also met BACT
for the relevant PM2.5 NAAQS. Rather, the EPA expects that
in Step 2 of either of the agency's proposed approaches to the BACM and
BACT determination process, the state would identify such measures as
``existing measures'' that should be further evaluated as potential
BACM or BACT or additional feasible measures.
6. Multi-State Nonattainment Areas
States that share a multi-state Serious PM2.5
nonattainment area must consult with one another on BACM and BACT and
additional feasible measures that will be required for the
nonattainment area in the different states. This requirement would be
consistent with the overall requirements for BACM and BACT and
additional feasible measures determinations, as all states with Serious
areas need to consider implementing BACM and BACT-level measures that
have been implemented in other states, even if those measures incur
higher costs. The EPA anticipates that states may potentially adopt
controls that differ from state to state, based upon each state's
determination of what qualifies as ``best'' given the mixture of
sources and potential controls in the state portions of relevant
nonattainment areas, subject to EPA approval. If the state can
adequately demonstrate that its chosen BACM and BACT and additional
feasible measures fully meet the EPA's proposed criteria for such
measures, then the agency may consider approving individual state plans
that differ in implementation of control measures.
7. Environmental Justice Considerations for Developing the Attainment
Plan Control Strategy for a Serious PM2.5 Nonattainment Area
The EPA strongly urges states to consider the environmental justice
aspect of any control measures they have identified as BACM and BACT or
additional feasible measures. Because the criteria for determining BACM
and BACT will lead in most cases to the selection of an overall more
stringent control strategy in a Serious area than what RACM and RACT
could provide, an appropriate control strategy for a Serious
nonattainment area will likely implicitly include the best measures for
ensuring that overburdened populations are appropriately protected.
Nonetheless, the EPA encourages states when possible to select BACM and
BACT measures that will result in the least possible burden and
greatest degree of health protection for overburdened populations in
the nonattainment area.
E. Modeling for Attainment Demonstrations
Section IV.E. describes the EPA's proposed attainment demonstration
and modeling requirements for Moderate area plans, and the EPA is
proposing that the same general requirements should apply to Serious
area attainment demonstrations. However, Serious area plans have
additional statutory requirements, which the EPA proposes to address as
described below.
1. Statutory Requirements
Section 189(b) generally requires a state with a designated Serious
nonattainment area to submit an attainment plan for such area. As
discussed earlier, section 189(b)(1)(A) more specifically requires the
state to submit an attainment demonstration including air quality
modeling to establish either: (i) That the area will attain the
relevant NAAQS by the applicable attainment date, or (ii) if the state
is seeking an extension of the attainment date, that it is
impracticable for the area to attain the relevant NAAQS by the
statutory Serious area attainment date. For Serious nonattainment
areas, the attainment date is as expeditiously as practicable, but no
later than the end of the tenth calendar year after designation as
nonattainment. An attainment demonstration that shows that it is
impracticable for the area to attain within this timeframe must also
provide for attainment of the NAAQS by the most expeditious alternative
date practicable, but no later than 5 years after the maximum statutory
Serious area attainment date (based on the criteria specified in
section 188(e)).
Attainment demonstrations are due 18 months after reclassification
if the EPA reclassifies the area to Serious after failure of the area
to attain the applicable Moderate area deadline. Alternatively, section
189(b)(2) requires states with designated Serious nonattainment areas
to submit attainment demonstrations no later than 4 years after
reclassification of the area to Serious if the reclassification occurs
before the Moderate area attainment deadline. However, the EPA is
proposing an approach for determining an appropriate attainment plan
control strategy for a Serious PM2.5 nonattainment area that
would require the state to submit the attainment demonstration for the
area within 18 months after reclassification regardless of when or the
authority under which an area was reclassified to Serious. Sections
VI.A and VI.D of this preamble describe more fully the EPA's proposed
approach for control strategy analyses and due dates for all elements
of a Serious area attainment plan. Section VI.J of this preamble
provides a complete discussion of the EPA's proposed criteria for
granting a Serious area attainment date extension.
2. Attainment Demonstrations for Serious Areas
As described in Section IV.E of this preamble, an attainment
demonstration is a plan that demonstrates how a state will attain the
PM2.5 NAAQS by the applicable attainment date. The EPA is
proposing that the demonstration for Serious areas must consist of: (i)
Technical analyses such as base year and future year modeling of
emissions which identify sources and quantify emissions that are
contributing to violations of the PM2.5 NAAQS; and, (ii)
analyses of future year projected emissions reductions and air quality
improvement resulting from existing (i.e. already-adopted or ``on the
books'') national, regional and local programs, and potential new local
measures needed for attainment, including RACM and RACT and BACM and
BACT controls for the area, as well as other measures either inside the
nonattainment area or outside the nonattainment area but within the
state that could potentially accelerate attainment. Each state with a
Serious nonattainment area must submit an attainment plan with an
attainment demonstration that includes analyses supporting the state's
determination of its proposed attainment date. In all cases, the state
must show that the area
[[Page 15414]]
will attain the NAAQS as expeditiously as practicable, but not later
than the tenth calendar year after designation. In order to establish
that the attainment date is as expeditious as practicable, the state
must explain why the control measures adopted in the attainment plan
provide for the most expeditious attainment and must either: (i) Under
proposed Option 1 for the BACM and BACT determination include all BACM
and BACT controls in the analysis, or (ii) under proposed Option 2 for
BACM and BACT, provide the requisite analysis to show that
implementation of additional emissions controls, including any
potential BACM and BACT, would not advance the attainment date for the
area by at least 1 year if considered collectively.
A state with a Serious nonattainment area can also submit an
impracticability demonstration (under section 189(b)(1)(A)(ii)) as part
of seeking an extension of the attainment date under section 188(e).
The impracticability demonstration for a Serious area would be similar
to an impracticability demonstration for Moderate areas because it must
include air quality modeling which shows that the area will not be able
to attain the PM2.5 NAAQS by the outside statutory
attainment date, which in this case is by the end of the tenth calendar
year following designation. However, in order to support a Serious area
impracticability demonstration, the state must also show (through
modeling) that attainment cannot be reached by the statutory Serious
area attainment date, even if all RACM and RACT and BACM and BACT
controls, as well as other measures either inside the nonattainment
area or outside the nonattainment area but within the state, were
implemented before the attainment date. Moreover, in addition to the
Serious area impracticability demonstration, to support an extension of
the attainment date, the Serious area plan must demonstrate (again,
using air quality modeling) that it provides for attainment by the most
expeditious alternative date practicable employing MSM, as specified in
section 188(e). As a result, the required plan is both an
impracticability demonstration (to justify an extension beyond the
statutory attainment date) and an attainment demonstration which serves
as the basis for proposing an appropriate alternative attainment date.
3. What modeling is required?
States are required to submit air quality modeling in support of an
attainment demonstration for a Serious PM2.5 nonattainment
area. Unlike the impracticability demonstration for Moderate areas
described in section 189(a)(1)(B)(ii), the impracticability
demonstration for Serious areas in section 189(b)(1)(A)(ii) also
requires air quality modeling establishing the most expeditious
alternative attainment date practicable. Therefore, air quality
modeling is a required element in all attainment demonstrations for
Serious areas.
Other than the timing of plan submissions and additional required
elements of a Serious area plan (such as BACM and BACT), the relevant
air quality modeling procedures and guidance for Moderate and Serious
area plans are the same. See Section IV.E. of this preamble for more
details on proposed modeling requirements and guidance for all
PM2.5 nonattainment areas.
4. Will areas reclassified to Serious need to submit two separate
attainment demonstrations?
Under section 189(a)(1)(B), a state is required to submit as part
of an area's Moderate area attainment plan a demonstration that the
area either will attain or cannot practicably attain the NAAQS by the
statutory Moderate area attainment date. Regardless of whether the
state submits an attainment demonstration or an impracticability
demonstration for a Moderate area, if such area is reclassified to
Serious prior to or after failing to attain the applicable NAAQS, the
state is required under section 189(b)(1)(A) to submit a new attainment
demonstration as part of an area's Serious area attainment plan. The
separate statutory requirements for Moderate and Serious nonattainment
areas anticipate two separate attainment plan submissions, and the
EPA's existing guidance in the General Preamble and Addendum further
support this expectation. While the state would be required to submit a
separate Serious area attainment plan, the EPA anticipates that certain
control strategies may build upon those previously adopted and
implemented as part of the Moderate area plan. For example, it could be
the case that an area dominated by woodsmoke emissions could not attain
the standard by the statutory Moderate area attainment date because all
necessary woodstove change-outs could not occur in that timeframe, but
additional woodstove change-outs could occur by the statutory Serious
area attainment date.
5. What future year(s) should be modeled in attainment demonstrations?
A state performing a modeling analysis for an attainment
demonstration or a Serious area impracticability analysis must select a
future year for the analysis. For an attainment demonstration, a state
should select the future modeling year such that all emissions control
measures relied on for attainment will have been implemented by the
beginning of that year. To demonstrate attainment, the modeling results
for the nonattainment area must predict that emissions reductions
implemented by the beginning of the last calendar year preceding the
attainment date will result in PM2.5 concentrations that
meet the level of the standard.\198\
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\198\ Note that for purposes of the PM2.5 NAAQS, a
determination of attainment (or failure to attain), which the EPA is
required to make after the attainment date has passed, is based on
ambient data from the most recent 3 years prior to the attainment
date for the area.
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While states should choose the future modeling year based on a
number of factors, the EPA recommends the last year of the statutory
attainment date as a starting point for modeling for two reasons.
First, a state with a Serious area for which it submits an attainment
date extension request under section 188(e) must show that the area
cannot practicably attain the NAAQS by the end of the tenth calendar
year following designation of the area. Therefore, the appropriate
future modeling year for making such a demonstration would be the tenth
year after designations. Even if a state does not submit (or does not
intend to submit) a Serious area attainment date extension request,
modeling the tenth year is a logical starting point to determine if
attainment by year 10 is likely. If attainment-level concentrations of
PM2.5 are not expected in the tenth calendar year after
designations, then the area must also, as a requirement to receive an
extension of the Serious area attainment date, submit a demonstration
(using air quality modeling) that provides for attainment by the most
expeditious alternative date practicable, but no later than the end of
the fifteenth year after designation, with the implementation of MSM
(see Section VI.J of this preamble for details about MSM
determinations).
Second, even though attainment of any PM2.5 NAAQS is
determined based on 3 years of ambient data, states do not have to
model 2 years before the attainment date to show modeled attainment.
Since the design value is an average of the annual or 98th percentile
value for 3 consecutive years, attainment can still be shown even if
concentrations exceed the NAAQS in one or more of the 3 years used to
determine attainment (as long as the average of the 3 annual values is
less
[[Page 15415]]
than the NAAQS). Therefore, it can be appropriate to model any of the 3
years used to determine attainment. For these reasons, it is
acceptable, and may in fact be most efficient, for a state to begin the
Serious area attainment demonstration process by modeling the final
year of the statutory attainment date to determine future year modeled
PM2.5 concentrations in the tenth year after designations.
Because an area must attain ``as expeditiously as practicable,''
additional considerations are necessary before an attainment date can
be established. For purposes of determining the attainment date that is
as expeditious as practicable, the state must conduct future year
modeling which takes into account growth and known controls (including
any controls that were previously determined to be RACM and RACT for
the area). For example, for an area designated nonattainment for the
2012 PM2.5 NAAQS during the first round of designations and
subsequently reclassified to Serious, a future case scenario for the
year 2025 (10 years after the initial nonattainment designation) would
be needed to examine whether the the BACM and BACT identified by the
state would result in attainment. Under the proposed BACM and BACT
determination Option 1 (where BACM and BACT must be determined
independent of the attainment demonstration for the area), the future
case scenario must include BACM and BACT controls in the analysis plus
any additional measures on sources inside and outside of the
nonattainment area (but within the state) that the state has identified
as feasible to implement by the attainment date. Under proposed Option
2 for determining BACM and BACT (where BACM and BACT is determined
according to what is needed to expeditiously attain the NAAQS), the
future case scenario must show whether implementation of emissions
controls, including all BACM and BACT and additional feasible measures
on sources inside and outside of the nonattainment area (but within the
state), collectively would advance the attainment date by at least 1
year. Note that similar to RACM and RACT, BACM and BACT controls must
be implemented within 4 years after reclassification to Serious
nonattainment. In order to justify an extension of the attainment date
beyond the end of the tenth year after designation, the state must show
that attainment by that date (including the anticipated emissions
reductions from RACM and RACT and additional reasonable measures, and
BACM and BACT and additional feasible measures) would be impracticable.
Any proposed attainment date after the 10 year period must include
modeling of BACM and BACT controls plus the most stringent measures
that are included in the implementation plan of any state and can be
feasibly implemented in the area. The attainment date extension beyond
10 years can be for up to 5 additional years, but the proposed
attainment date must also be shown to be as expeditious as practicable.
Section VI.J of this preamble provides a complete discussion of the
EPA's proposed interpretation of the statutory requirements for a
Serious area attainment date extension under section 188(e).
As with Moderate area attainment demonstrations, the EPA believes
that it is not necessary or reasonable to require states to model each
and every year to determine the appropriate attainment date for a
Serious PM2.5 nonattainment area given the resource demands
associated with modeling.\199\ In some cases it may be reasonable to
model one additional interim year before the maximum statutory
attainment date. However, in most cases, the air quality benefits of an
identified set of reasonable control measures, BACM and BACT and
additional feasible control measures can be estimated through model
sensitivity analyses and the development of transfer factors (factors
to relate tons of emissions reductions in the area to PM2.5
concentration changes in the area). The EPA strongly recommends that
states discuss the selection of the future year(s) to model with their
respective EPA Regional Office as part of the modeling protocol
development process prior to embarking on the modeling.
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\199\ States with Serious areas that request an attainment date
extension beyond 10 years must model the tenth year after
designation of the area as part of an impracticability
demonstration, plus an additional year beyond that which represents
the attainment date.
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6. Attainment Year Motor Vehicle Emissions Budgets
As with Moderate areas, the transportation conformity rule requires
that Serious area attainment plans establish motor vehicle emissions
budgets for the area's attainment year. Therefore, once a Serious
area's attainment date has been established, the state is required to
establish motor vehicle emissions budgets for direct PM2.5
and any relevant PM2.5 precursor for the attainment
year.\200\ A motor vehicle emissions budget for the purposes of a
Serious area PM2.5 attainment plan is that portion of the
total allowable emissions within the nonattainment area allocated to
on-road sources as defined in the submitted attainment plan.\201\ Such
motor vehicle emissions budgets would be calculated using the latest
planning assumptions and the latest approved motor vehicle emissions
model available at the time that the attainment plan is developed.\202\
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\200\ For more information on PM2.5 precursor
requirements, see section 93.102(b)(2)(iv) and (v) of the
transportation conformity rule. See also the May 6, 2005, final
transportation conformity rule that addressed requirements for
PM2.5 precursors. (70 FR 24280).
\201\ A state would also establish motor vehicle emissions
budgets for an area's attainment year. Those budgets would be the
motor vehicle emissions that the SIP establishes as being necessary
to attain the NAAQS.
\202\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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F. RFP Requirements
1. Statutory Requirements
As with Moderate area attainment plans, Serious PM2.5
nonattainment area plans must provide for RFP as required under CAA
section 172(c)(2). Section IV.F of this preamble fully describes the
statutory requirements and overall proposed approaches for states to
fulfill the RFP requirement in the context of Moderate area attainment
plans. The EPA believes that the proposed approaches described for RFP
for Moderate area plans can apply to Serious area attainment plans as
well. The following section offers additional detail about how the EPA
proposes that the approach to RFP should apply specifically to Serious
area attainment plans.
2. Proposed Approach
As with a Moderate area attainment plan, the EPA is generally
proposing that a state must submit an RFP plan as part of any
attainment plan submission for a Serious nonattainment area in order to
satisfy the statutory requirements for RFP. The plan must include a
schedule and an analysis that collectively demonstrate when and through
what control measures emissions from sources in the nonattainment area
will decline from the applicable baseline year to the projected
attainment year. The EPA is proposing that the applicable baseline year
must be the same year as that represented by the latest base year
inventory for the Serious area. The projected attainment year may be up
to the end of the tenth year following designation of the area for a
Serious area
[[Page 15416]]
that can demonstrate attainment pursuant to section 189(b)(1)(A), or up
to the end of the fifteenth year following designation for a Serious
area that is seeking an extension to the statutory attainment date
pursuant to section 188(e).\203\ The RFP analysis must clearly convey
how the schedule for implementing BACM and BACT and any additional
control measures will provide for generally linear progress towards
attainment or, if step-wise progress is more appropriate for the
specific nonattainment area in question, the analysis must convey an
appropriate implementation schedule and must explain why generally
linear progress towards emissions reductions in the area is not
appropriate (e.g., due to the nature of the nonattainment problem and
the types of sources contributing to PM2.5 levels in the
area). For a Serious area that cannot demonstrate attainment by the
statutory Serious area attainment date, the EPA proposes that the state
must include in its RFP analysis the anticipated emissions reductions
expected to be achieved through the implementation of BACM and BACT and
MSM on sources in the nonattainment area. As with RFP plans for
Moderate areas, the EPA proposes that a state must submit one or more
projected emissions inventories as part of the RFP plan for any Serious
PM2.5 nonattainment area following the same guidance that
applies to emissions inventories for attainment plans (see Section VI.B
of this preamble for a complete discussion of emissions inventories for
Serious area attainment plans). These projected inventories must
correspond with the quantitative milestone date(s) for the area as
described in Section VI.H of this preamble. The EPA proposes that motor
vehicle emissions budgets must also be established for direct
PM2.5 and any relevant PM2.5 precursor using the
latest planning assumptions and the latest approved motor vehicle
emissions model available at the time that the Serious area attainment
plan is developed.\204\
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\203\ As noted in Section VI.B of this preamble, depending upon
when the area is reclassified from Moderate to Serious, this base
year inventory may need to be more recent than the inventory
submitted with the Moderate area attainment plan.
\204\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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The EPA seeks comment on all aspects of the agency's proposal for
meeting the statutory RFP requirements as they apply to Serious
nonattainment areas. Furthermore, the EPA seeks comment on the proposed
options described in Section IV.F of this preamble regarding how to
prepare an RFP plan, geographic coverage of emission sources for RFP,
and RFP requirements for multi-state nonattainment areas, which would
also apply to Serious area attainment plans.
G. Quantitative Milestones
The attainment plan for any Serious nonattainment area must include
quantitative milestones pursuant to section 189(c). These quantitative
milestones would be in addition to those identified in the area's
Moderate area attainment plan, and would need to continue to be
achieved every 3 years until the area attains the NAAQS. Specifically,
the Serious area plan for an area that can demonstrate attainment by
the statutory Serious area attainment date would have to contain
quantitative milestones to be achieved by 7.5 years from the area's
date of designation as nonattainment. This date would be 3 years after
the first quantitative milestones for the area, to be met 4.5 years
from designation of the area and 3 years after the Moderate area
attainment plan was due to the EPA. The EPA also proposes and seeks
comment on a requirement that a Serious area plan for an area that can
demonstrate attainment by the statutory Serious area attainment date
must also include quantitative milestones to be reached 10.5 years from
designation, to help assess the state's progress toward attaining the
PM2.5 NAAQS in the event the area fails to attain by the
applicable attainment date. For a Serious area that cannot demonstrate
attainment by the statutory Serious area attainment date, the EPA
proposes that the state must include in the Serious area attainment
plan quantitative milestones to be achieved at years 7.5, 10.5 and 13.5
from the area's date of designation.
The Addendum included guidance that recommended milestones ``should
be addressed by quantifying and comparing the annual incremental
emission reductions which result from implementation of BACM and BACT
(required within 4 years after the area is reclassified as serious) and
from additional measures included in the final serious area SIP to
those reductions which were identified in the SIP as quantitative
milestones necessary to achieve the NAAQS by the applicable attainment
date.'' \205\
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\205\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42016.
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The EPA continues to agree with the fundamental concept conveyed in
the existing guidance, but believes that it is impractical to expect
that a state will always be able to quantify and compare real and
projected emissions reductions, and submit a report to the EPA within
90 days of a given milestone, as required under section 189(c)(2).
Therefore, the EPA proposes that the general proposed approach to
selecting quantitative milestones, described in Section IV.G, should
apply to any attainment plan for a PM2.5 nonattainment area,
independent of its classification. Specifically, the EPA proposes that
states be allowed to select the quantitative milestones that they
identify as appropriate and quantifiable and that will provide for
objective evaluation of progress toward attainment in their Serious
PM2.5 nonattainment area, and that the EPA, in its
attainment plan approval process, will determine if they satisfy the
statutory requirements of section 189(c).
In addition to this general proposed approach for selecting
quantitative milestones and similar to an option proposed for Moderate
area attainment plans, the EPA proposes to require that, at a minimum,
states must include in all attainment plans for Serious
PM2.5 nonattainment areas a measure to confirm that some
specific portion of BACM and BACT for the area has been implemented as
appropriate in order to comply with the statutory requirement at
section 189(b)(1)(B). The EPA acknowledges that the precise
quantifiable metric (e.g., 50 percent of BACM and BACT measures
implemented by milestone date 7.5 years from designation) would need to
be determined on a case-by-case basis, as it would depend upon the date
of reclassification of the area, whether the metric is to be achieved
at year 7.5 or year 10.5 from designation, and the anticipated
implementation timing and nature of the BACM and BACT controls
themselves. Nonetheless, the EPA believes it would be appropriate to
include it as a metric that any state with a Serious nonattainment area
must adopt as a quantitative milestone to demonstrate RFP (and thus
must demonstrate compliance with when they submit their milestone
report), as it derives from a statutory provision that applies to all
Serious areas and thus represents a milestone that all Serious
nonattainment areas must meet.
The EPA seeks comment on these proposed options for interpreting
the statutory quantitative milestone requirements for Serious areas.
H. Contingency Measures
As noted in Section IV.G of this preamble, all PM2.5
nonattainment areas must include in their attainment plans
[[Page 15417]]
contingency measures consistent with section 172(c)(9). Contingency
measures are additional control measures to be implemented in the event
that an area fails to meet RFP requirements or fails to attain the
PM2.5 standard by the applicable attainment date. These
measures must be fully adopted rules or control measures that are ready
to be implemented quickly upon a determination by the EPA that the area
failed to meet RFP or failed to meet the standard by the applicable
attainment date, and such measures are required to take effect without
significant further action by the state or the EPA.
The statutory contingency measure requirement at section 172(c)(9)
is not superseded or subsumed by any requirement under subpart 4, nor
does it apply only to Moderate area attainment plans. Thus, contingency
measures are required for Serious PM2.5 nonattainment areas
as part of a state's Serious area attainment plan submission. The EPA
proposes that the criteria for identifying and selecting contingency
measures for a Serious area attainment plan should be the same as those
for Moderate area plans. Specifically, the EPA proposes that the
following requirements must be met in order for contingency measures to
be approvable as part of a state's Serious area attainment plan
submission:
1. Contingency measures must be fully adopted rules or control
measures that are ready to be implemented quickly upon a determination
by the Administrator of the nonattainment area's failure to meet RFP or
failure to meet the standard by its attainment date.
2. The SIP must contain trigger mechanisms for the contingency
measures, specify a schedule for implementation, and indicate that the
measures will be implemented without significant further action by the
state or by the EPA.
3. Contingency measures must consist of control measures that are
not otherwise included in the control strategy for the SIP, or must
require further implementation of partial measures already included in
the SIP as BACM or BACT, additional feasible measures, or MSM.
4. Contingency measures must provide for emissions reductions
equivalent to 1 year's share of reductions needed to demonstrate
attainment (i.e., the overall needed reductions divided by the number
of years from the base year to the attainment year), or equivalent to 1
year's worth of air quality improvement or emissions reductions
proportional to the overall amount of air quality improvement or
emissions reductions to be achieved by the area's attainment plan.
The EPA further proposes that a state may elect to rely on
contingency measures that achieve emissions reductions on sources
located outside the nonattainment area, but within the state, as well
as from within the nonattainment area, provided that the measures on
sources outside the designated nonattainment area are demonstrated to
produce the appropriate air quality impact within the nonattainment
area.
As with contingency measures for Moderate nonattainment areas, the
EPA believes it appropriate that a state might rely on additional
reductions in the years following a failure to meet RFP requirements or
a failure to attain the NAAQS by the applicable attainment date from
federal or local measures already scheduled for implementation as part
or all of their contingency measures. The EPA could potentially
consider such measures as meeting the contingency measure requirement
as long as they produce emissions reductions in excess of those
required to meet other statutory provisions, such as to meet BACM and
BACT requirements, and they can be relied on to achieve a sufficient
portion of the actual emissions reductions necessary to reduce
emissions in the area while the state develops a new plan to bring the
area into attainment.\206\ As with contingency measures for Moderate
area attainment plans, the EPA proposes that the emissions reductions
associated with contingency measures for Serious area plans must be
equal to approximately 1 year's worth of emissions reductions necessary
to achieve RFP for the area, unless the state adequately demonstrates
that some smaller amount of reductions is appropriate while the state
is revising its attainment plan for the area. The EPA seeks comment on
this requirement.
---------------------------------------------------------------------------
\206\ See LEAN v. EPA, 382 F.3d 575 (5th Cir. 2004).
---------------------------------------------------------------------------
The Addendum provided guidance related specifically to the
selection and implementation of contingency measures for Serious
nonattainment areas. First, the EPA guidance indicated that ``for those
moderate areas reclassified as serious, if all or part of the moderate
area plan contingency measures become part of the required serious area
control measures (i.e., BACM), then additional contingency measures
must be submitted whether or not the previously submitted contingency
measures had already been implemented. Further, the affected states
must ensure that serious areas have adequate contingency measures
considering, among other things, new information about the potential
attainment shortfall for the newly reclassified serious area.'' \207\
The EPA continues to believe that this approach to the statutory
contingency measure requirement is appropriate and proposes to adopt it
for purposes of implementing the PM2.5 NAAQS in Serious
nonattainment areas.
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\207\ Addendum to General Preamble, 59 FR 41988 (August 16,
1994), at 42015.
---------------------------------------------------------------------------
With regard to the timing for implementing contingency measures,
the EPA reiterates that the purpose of contingency measures is to
ensure that corrective measures are put in place automatically at the
time that the EPA makes a determination that an area has failed to meet
RFP or failed to meet the NAAQS by the applicable attainment date. For
any nonattainment area, the EPA is required to determine within 90 days
after receiving a state's RFP demonstration, and within 6 months after
the attainment date for an area, whether the state has met their
statutory obligations for demonstrating RFP or attaining the standard,
as appropriate. As with Moderate areas, the EPA believes that
contingency measures should become effective for Serious areas within
60 days of the EPA making its determination that the area failed to
meet RFP or attain the NAAQS and proposes to require this for purposes
of PM2.5 NAAQS implementation in Serious nonattainment
areas.
Finally, while section 172(b) gives discretion to the Administrator
to establish a deadline for submitting contingency measures up to 3
years from designation of the area, it does not explicitly address the
appropriate submittal date for contingency measures for areas
reclassified to Serious. In the Addendum, the EPA indicated that
``states must submit contingency measures for serious areas or
otherwise demonstrate that adequate measures are in place within 3
years of reclassification.'' \208\ The EPA proposes and seeks comment
on applying this guidance to Serious nonattainment areas for current
and future PM2.5 NAAQS.
---------------------------------------------------------------------------
\208\ Id.
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In addition, as described in Section VI.A, the EPA proposes an
alternative submission deadline for Serious area contingency measures
that would align the contingency measure due date with the Serious area
attainment demonstration due date. If an area is reclassified under the
EPA's discretionary authority, the Serious area
[[Page 15418]]
attainment demonstration is due 4 years from the date of
reclassification; under this alternative proposed approach, contingency
measures would also be due 4 years from the date of reclassification
for such areas. If an area is reclassified under the EPA's mandatory
duty upon failure of the area to attain the NAAQS by the Moderate area
attainment date, then the Serious area attainment demonstration is due
18 months from the date of reclassification; accordingly, under this
alternative proposed approach, contingency measures would also be due
18 months from the date of reclassification for such an area. In either
case, the BACM and BACT provisions for the Serious area would be due at
or before the time contingency measures would be due, which is
appropriate given that the EPA expects a state to consider its BACM and
BACT measures as it develops its contingency measures. The state may
ascertain that measures not otherwise required or necessary for BACM or
BACT may nevertheless be suitable for purposes of contingency measures.
The EPA seeks comment on this alternative approach to setting Serious
area contingency measure due dates.
I. Attainment Dates
As explained earlier, section 188 establishes the attainment dates
for both Moderate and Serious areas. For a Serious area, section
188(c)(2) provides that ``the attainment date shall be as expeditiously
as practicable but no later than the end of the tenth calendar year
beginning after the area's designation as nonattainment.'' \209\ For
example, for an area initially designated as nonattainment effective in
April 2015 that is reclassified to Serious at some future date, the
Serious area attainment date, absent any approved Serious area
attainment date extension, would be no later than December 31, 2025
(the end of the tenth calendar year after designation). As discussed in
Section IV.I, the EPA proposes to interpret the references to
``designation'' in CAA section 188(c) as meaning ``effective date of
designation,'' consistent with the agency's prior approach for
implementing the previous PM2.5 NAAQS under subpart 1 and
other NAAQS.
---------------------------------------------------------------------------
\209\ The EPA believes that there is no real effect on
attainment date determinations due to the small difference in
statutory language in section 188(c) basing the Moderate area
attainment date on the ``sixth calendar year after the area's
designation'' and the Serious area attainment date on the ``tenth
calendar year beginning after the area's designation,'' (emphasis
added).
---------------------------------------------------------------------------
The process for a state to determine the most expeditious
attainment date practicable for a Serious area will depend upon the
final approach selected for determining BACM and BACT for the area.
Therefore the EPA is proposing two approaches for determining the
appropriate attainment date for a Serious area. Under the first
approach, which would correspond to the agency's proposed Option 1 for
determining BACM and BACT--independent of the attainment demonstration
for the area--the state would simply include the control measures
determined to be BACM and BACT for the area in its air quality
modeling, and would report the results of the modeling, including the
earliest projected attainment date.
Under the second proposed approach, which would correspond to the
EPA's proposed Option 2 for determining BACM and BACT--tied to the
attainment needs of the particular nonattainment area--the state would
be required to follow a two-step process for determining the
appropriate attainment date for the area. First, the state would be
required to demonstrate through air quality modeling that the area can
attain the relevant NAAQS by the latest statutory attainment date and
determine which control measures and technologies are needed for the
area to attain by that date. Second, the state would be required to
determine whether implementing any remaining BACM or BACT controls
(i.e., those not needed for attainment by the latest date) or any other
additional controls can cumulatively advance the attainment date for
the area by at least 1 year. In the event that a state determines that
the area can attain the relevant NAAQS earlier through the application
of these other measures, the state must propose the earlier date as
part of the attainment plan submission for the area. This second
approach is similar to the proposed approach for determining the most
expeditious attainment date for a Moderate area.
As with Moderate area attainment dates, when the EPA takes action
to approve the different elements of the attainment plan for the
Serious area, one of the elements that the agency will take action on
will be the state's proposed attainment date for the area. If the EPA
approves an attainment date for the area that is earlier than the
latest date allowed by statute, then the applicable attainment date for
the area will be the approved date. If the state demonstrates that the
Serious area cannot practicably attain the NAAQS by the end of the
tenth calendar year following designation, the state may request a
Serious area attainment date extension as long as certain conditions
are met, as described next in Section VI.J.
J. Attainment Date Extensions
1. Statutory Requirements
As with Moderate areas, the EPA may grant an extension of the
attainment date for a Serious PM2.5 nonattainment area if
certain statutory criteria are met. Specifically, section 188(e)
provides that the EPA may allow one attainment date extension of no
more than 5 years ``upon application by any state . . . if attainment
by the [original Serious area attainment date] would be impracticable,
the state has complied with all requirements and commitments pertaining
to that area in the implementation plan, and the state demonstrates to
the satisfaction of the Administrator that the plan for that area
includes the most stringent measures that are included in the
implementation plan of any state or are achieved in practice in any
state, and can feasibly be implemented in the area.'' In addition to
the required preconditions for such an extension, the statute also
includes factors which the Administrator may use as she considers
whether to grant the extension and the length of the extension,
including ``the nature and extent of nonattainment, the types and
numbers of sources or other emitting activities in the area (including
the influence of uncontrollable natural sources and transboundary
emissions from foreign countries), the population exposed to
concentrations in excess of the standard, the presence and
concentrations of potentially toxic substances in the mix of
particulate emissions in the area, and the technological and economic
feasibility of various control measures.'' \210\
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\210\ Notably, these statutory criteria do not include specific
ambient air quality criteria like the criteria that need to be met
in the year prior to a Moderate area attainment date in order for
the area to qualify for an attainment date extension under section
188(d).
---------------------------------------------------------------------------
2. Proposed Approach
In the Addendum, the EPA generally described the statutory
requirements listed above and expressed an intent to issue guidance on
applying for an extension of the Serious area attainment date, if
appropriate. While ultimately the EPA did not deem it necessary to
issue such guidance, the EPA has interpreted these statutory
requirements through actual exercise of its authority under section
188(e) in past rulemakings for specific PM10 nonattainment
areas. For example, the EPA interpreted section 188(e) in approving an
extension of a Serious area
[[Page 15419]]
attainment date for purposes of the PM10 NAAQS for the
Maricopa area (AZ).\211\ The EPA believes that the steps finalized in
the Maricopa County PM10 Serious area SIP approval notice
provide an appropriate starting point for a proposed regulatory
approach, with some potential modification, for states to meet the
statutory requirements that could apply nationally. The EPA is thus
proposing to require that states adhere to the following steps when
preparing and submitting a request for a Serious area attainment date
extension:
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\211\ Maricopa County PM10 Serious area attainment
date extension, proposal: 65 FR 19964 (April 13, 2000); and final:
67 FR 48718 (July 25, 2002).
---------------------------------------------------------------------------
Step 1: Demonstrate that attainment by the statutory Serious area
attainment date is impracticable. In order to demonstrate
impracticability, the state would have to show that the implementation
of all BACM and BACT and all additional feasible measures required
under section 172(c)(6) will not bring the area into attainment by the
statutory Serious area attainment date (i.e., by no later than the end
of the tenth calendar year after designation).\212\ The statutory
provision for demonstrating impracticability requires that the
demonstration be based on air quality modeling (see section
189(b)(1)(A)). Additional guidance on this demonstration is provided in
Section VI.E of this preamble.
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\212\ This proposed approach parallels the EPA's proposed
approach, described earlier in this preamble, for the
impracticability option for Moderate areas under CAA section
189(a)(1)(B) in which all measures that qualify as RACM and RACT and
all additional reasonable measures are required before a Moderate
area plan could show impracticability of attainment by the statutory
Moderate area attainment date (the end of the sixth calendar year
after designation).
---------------------------------------------------------------------------
Step 2: Comply with all requirements and commitments in the
applicable implementation plan. Similar to the proposed approach
described in Section IV.J of this preamble for Moderate area attainment
date extensions, the EPA proposes to interpret the criterion under
section 188(e) that requires a state to have ``complied with all
requirements and commitments pertaining to that area in the
implementation plan'' simply to mean that the state has implemented the
control measures in the SIP revisions it has submitted to address the
applicable requirements in sections 172 and 189. For a Serious area
attainment date extension request being submitted contemporaneously
with the ``original'' Serious area attainment plan for the area, the
EPA proposes to read section 188(e) not to require the area to have a
fully approved attainment plan that meets the CAA's requirements for
Moderate areas. The agency proposes to base this reading on the plain
language of section 188(e) which requires the state to comply with all
requirements and commitments pertaining to that area in the
implementation plan but does not require that the state comply with all
requirements pertaining to the area in the CAA.\213\ For the same
reason, the EPA also proposes to read this provision not to bar an
extension if all or part of an area's Moderate area plan is disapproved
or has been promulgated as a FIP, provided the area has complied with
all of the requirements in the applicable FIP, or in the applicable SIP
and FIP.
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\213\ This interpretation as applied to section 188(e) for
Serious area attainment date extensions was upheld by the Ninth
Circuit Court of Appeals in Vigil v. Leavitt, 366 F.3d 1025, amended
at 381 F.3d 826 (9th Cir. 2004).
---------------------------------------------------------------------------
However, for a Serious area attainment date extension request being
submitted sometime after submission of an ``original'' Serious area
attainment plan that contained an attainment demonstration meeting the
requirements of section 189(b)(1)(A)(i), the EPA proposes to read
section 188(e) not to require the area to have a fully approved
attainment plan that meets the CAA's requirements for Serious areas,
but to have a fully approved Moderate area attainment plan. The
rationale for this distinction is due to the timing of the Serious area
attainment date extension request under these circumstances, which is
discussed in greater detail later in this section. The EPA believes
that this proposed interpretation of this criterion would apply whether
the area was reclassified to Serious under the EPA's discretionary
authority (section 188(b)(1)) or by operation of law upon failing to
attain by the Moderate area attainment date (section 188(b)(2)).
The EPA also seeks comment on an alternative interpretation of the
implementation plan compliance criterion that would require a state to
have a Moderate area attainment plan fully approved by the EPA, not
just fully implemented by the state, at the time of the Serious area
attainment date extension request, regardless of when such a request is
submitted to the EPA. The EPA believes that one may reasonably argue
that a state seeking an extension of the Serious area attainment date
should have fully implemented all elements of an approved Moderate area
attainment plan. The EPA believes that while such a condition may be
reasonable, generally speaking, there may be circumstances in which a
state submits a Moderate area attainment plan that the EPA is unable to
approve in a timely way, potentially creating a situation in which the
state cannot qualify for a Serious area attainment date extension (due
to its unapproved Moderate area plan) even if the area is reclassified
to Serious and cannot practicably attain by the statutory attainment
date for a Serious area. The EPA seeks comment on this alternate
proposed interpretation of the applicable implementation plan
compliance criterion under section 188(e). Recognizing that a situation
such as that described above may be rare, the agency also seeks comment
on what remedy might be available under the statute if such a situation
comes to pass if the EPA were to finalize this alternative proposed
interpretation of the applicable implementation plan criterion.
Step 3: Demonstrate the inclusion of MSM. To qualify for any
extension of a Serious area attainment date, section 188(e) requires a
state to ``demonstrate to the satisfaction of the Administrator that
the plan for the area includes the most stringent measures that are
included in the implementation plan of any state, or are achieved in
practice in any state, and can feasibly be implemented in the area.''
In its prior guidance in the Addendum, the EPA interpreted the term
``most stringent measure'' (MSM) to mean the maximum degree of emission
reduction that has been required or achieved from a source or source
category in any other attainment plans or in practice in any other
states and that can feasibly be implemented in the area seeking the
extension, such as what LAER represents for new or modified sources
under the NNSR permit program.\214\
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\214\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42010.
---------------------------------------------------------------------------
The agency proposes that a state would need to follow a process for
determining MSM for a Serious nonattainment area that is generally
similar to proposed Option 2 for BACM and BACT described in Section
VI.D of this preamble, which would include exemptions from MSM for
sources in de minimis source categories if such measures did not
collectively advance the attainment date for the area by at least 1
year. The EPA is also proposing an alternative approach for determining
MSM for a Serious nonattainment area that would provide for de minimis
source category exemptions for MSM only for those source categories
that do not contribute significantly to ambient PM2.5
concentrations in the Serious nonattainment area, an approach more
closely aligned with proposed Option 1 for determining BACM and BACT.
[[Page 15420]]
Under proposed approach #1 for MSM, the EPA would prescribe a five-
step process for states to follow when selecting and implementing MSM.
This proposed approach is similar to that used in practice for
approving the PM10 Serious area attainment plan and Serious
area attainment date extension request submitted for Maricopa County
(AZ) in 2000.\215\
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\215\ Maricopa County PM10 Serious area attainment
date extension, 67 FR 48718 (July 25, 2002).
---------------------------------------------------------------------------
The first step of this proposed approach would be for the state to
update as needed the emissions inventory of direct PM2.5 and
PM2.5 precursor sources and source categories in the Serious
nonattainment area required under section 172(c)(3) for any attainment
plan submission. The EPA expects that the state would meet this
inventory requirement as part of its Serious area attainment plan
submittal without any additional work if the state submits the Serious
area attainment date extension request simultaneously with the plan
itself. However, in the event the attainment date extension request is
submitted after the ``original'' Serious area attainment plan for the
area (i.e., toward the end of the Serious area attainment period), then
the EPA proposes to require that the state must submit a more recent,
complete and accurate emissions inventory that meets the same emissions
inventory requirements for Moderate and Serious PM2.5
nonattainment areas pursuant to section 172(c)(3), as well as an
attainment projected inventory as part of the new Serious area
attainment plan for the area. The inventories submitted to support a
Serious area attainment plan must also include point sources meeting
the lower major stationary source threshold in 40 CFR part 51, subpart
A.
The second step in this proposed MSM determination process would
require the state to perform air quality modeling in order to evaluate,
for each of the various source categories included in the emissions
inventory for the area, the impact on PM2.5 concentrations
in excess of the applicable NAAQS in order to determine which
categories are significant for the purposes of adopting MSM. Those
source categories for which such modeling indicates potential control
measures collectively would have only a de minimis effect on advancing
the attainment date for the area could be eliminated from further
consideration. In the context of the EPA's action to approve the
Maricopa County PM10 Serious area attainment plan and
attainment date extension request, the agency finalized an approach for
judging what constitutes a de minimis source category for MSM by
applying a test of whether MSM controls on the allegedly de minimis
sources would result in more expeditious attainment, rather than
applying a test of whether or not requiring the application of controls
for such sources would make the difference between attainment and
nonattainment by the statutory Serious area deadline, as the latter
test implicitly would be met through the controls chosen for
demonstrating attainment by the alternate attainment date for the area.
In the agency's explanation of the proposed approach, the EPA explained
that ``Our responsibility under section 188(e) . . . is to grant the
shortest practicable extension of the attainment date by assuring the
plan provides for attainment as expeditiously as practicable. Thus, one
means of determining an appropriate de minimis level is to determine if
applying MSM to the proposed de minimis source categories would
meaningfully expedite attainment. If it did, then the de minimis level
is too high, and if it did not, then the de minimis level is
appropriate.'' \216\ The EPA thus proposes to determine whether any
source categories should be eliminated from MSM controls through a de
minimis exemption based on a demonstration that collectively applying
MSM controls to such source categories would not advance attainment of
the NAAQS in the area by at least 1 year. This test would presumably
result in a more stringent threshold for what is considered a de
minimis source category for MSM as compared to the threshold for de
minimis source categories for BACM and BACT as described in the EPA's
proposed Option 1 for BACM and BACT determination criteria (see Section
VI.D of this preamble). The EPA proposes and seeks comment on this test
for determining whether any source categories could be found to be de
minimis and thus not subject to MSM controls.
---------------------------------------------------------------------------
\216\ Maricopa County PM10 Serious area attainment
date extension proposal, 65 FR 19964
(April 13, 2000), at page 19969.
---------------------------------------------------------------------------
The third step in the EPA's first proposed approach to determining
MSM for a Serious nonattainment area would involve identifying the
potentially most stringent measures in other implementation plans for
PM2.5 or other NAAQS, or used in practice in other states
for controlling emissions from each of the remaining source categories
listed in the emissions inventory that were not determined to be de
minimis. For each measure, the state would be required to determine its
technological and economic feasibility for sources in the area. The EPA
proposes generally to apply more stringent criteria for determining the
feasibility of potential MSM than that described for BACM and BACT in
Section VI.D. In some situations, MSM could involve increasing the
coverage of measures that were already adopted and implemented as BACM
and BACT (for example, changing out an even greater percentage of
woodstoves in an area, or paving even more roads, if such source
categories were major contributors to the air quality problem in the
nonattainment area).
However, because BACM and BACT represent the ``best'' level of
control feasible for an area, it would be possible for the MSM
requirement to result in no more controls and no more emissions
reductions in an area than result from the implementation of BACM and
BACT. Stated another way, there may be sources or categories for which
no other feasible controls exist beyond what a state has already
adopted as BACM or BACT. Given the strategy in the nonattainment
provisions of the CAA to offset longer attainment timeframes with more
stringent control requirements, the EPA therefore proposes to interpret
the MSM provision in order to increase the potential that it will
result in additional controls beyond the set of measures adopted as
BACM and BACT by requiring a state to reanalyze any measures that were
rejected during the state's BACM and BACT analysis for the area to see
if they are now feasible for the area given the potentially longer
attainment date (up to 5 years after the statutory Serious area
attainment date) or given the changes that have occurred in the interim
that improve the feasibility of previously rejected measures.
The fourth step of this first proposed approach would require the
state to compare the potential MSM for each non-de minimis source
category against the measures, if any, already adopted for that source
category in the Serious nonattainment area to determine if such MSM
would provide any additional reductions.
The fifth step would then require that the plan provide for the
adoption and expeditious implementation of any MSM that is more
stringent than existing measures or, in lieu of adoption, provide a
reasoned justification for rejecting the potential MSM, i.e., provide
an explanation as to why such measures cannot be feasibly implemented
in the area.
[[Page 15421]]
As noted earlier, the EPA expects that this first proposed approach
to determining MSM would be most compatible with the agency's proposed
Option 2 for determining BACM and BACT, described in Section VI.D.
Under proposed Option 2 for BACM and BACT determinations, a state would
be required to implement only those ``best'' control measures necessary
to bring a Serious nonattainment area into attainment expeditiously.
Such an approach to BACM and BACT determinations would not incorporate
an explicit step in the process for a state to exempt de minimis source
categories from consideration for potential control measures. However,
it would allow a state to eliminate any potential BACM or BACT or
additional feasible measures that are not needed to bring a Serious
area into attainment by the statutory attainment date and that cannot,
collectively, advance the attainment date for the area by at least 1
year. Proposed Option 2 for determining BACM and BACT for an area is
thus similar to the proposed approach to MSM described above, in which
a state could eliminate from further consideration those source
categories for which potential control measures collectively would have
only a de minimis effect on advancing the attainment date for the area
(see proposed step 2).
The EPA's proposed Option 1 for BACM and BACT determinations would
include an explicit step in the process for exempting de minimis source
categories from further consideration for potential control measures.
However, under such approach, a state would need to assess whether
emissions of a particular pollutant from a given source category
contributed significantly to PM2.5 concentrations in the
nonattainment area. If the state determined that the source category
contributed only a de minimis amount of emissions, then the state could
exempt the source category from further consideration for potential
control measures. Thus, while it incorporates a step to identify de
minimis source categories, the EPA's proposed Option 1 for BACM and
BACT determinations is not wholly consistent with the agency's proposed
approach #1 for determining MSM.
Therefore, the EPA is also proposing an alternative approach for
determining MSM for a Serious nonattainment area that would be more
compatible with the EPA's proposed approach #1 for determining BACM and
BACT. Under this alternative proposed approach for determining MSM, a
state could exempt de minimis source categories from further
consideration, but de minimis source categories would be identified by
virtue of their lack of significant contribution to PM2.5
levels in the area, not by virtue of whether controlling such sources
categories collectively could expedite attainment of the relevant
NAAQS. In this way, de minimis source categories for MSM would be
defined in a similar way, or subject to a similar ``significant
contribution'' test, as de minimis source categories for BACM and BACT
determinations under proposed Option 1. Thus under proposed approach #2
for MSM, the steps described for determining MSM would generally be the
same as under proposed approach #1, with the exception of step 2.
Rather, the EPA proposes an alternative step 2 in the MSM determination
process in which a state could identify de minimis source categories to
exempt from further control based on an analysis of the particular
contribution made by a given source category to ambient
PM2.5 levels in the nonattainment area. The EPA believes
that defining de minimis source categories and ``significant
contribution'' for determining de minimis source categories would be
equally challenging in the context of MSM determinations as in the
context of BACM and BACT determinations.\217\ However, in the event the
agency finalizes proposed Option 1 for BACM and BACT determinations,
the EPA believes it would be appropriate to finalize proposed approach
#2 for MSM, and would require that a state seeking to exempt from MSM
sources in a given source category apply more stringent criteria for
evaluating whether a certain source category's contributions to the
area's PM2.5 concentrations are indeed de minimis.
---------------------------------------------------------------------------
\217\ See the discussion of de minimis source categories in
Section VI.D in this preamble.
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The EPA believes that either of these proposed approaches for
determining MSM for a Serious nonattainment area would be consistent
with the EPA's guidance in the Addendum to define MSM as those measures
that can ``feasibly be implemented in the relevant area from among
those which are either included in any other SIP or have been achieved
in practice by any other state.'' One of the key features of this
guidance relates to identifying control measures implemented elsewhere,
which is also a key feature of the EPA's proposed process for
identifying RACM and RACT and additional reasonable measures (and BACM
and BACT and additional feasible measures, if necessary) for a
PM2.5 nonattainment area. For these processes, the EPA is
proposing that a state identify potential measures for consideration as
RACM or RACT or additional reasonable measures (or BACM or BACT or
additional feasible measures) by looking at measures implemented by
other states to meet PM2.5 NAAQS or other NAAQS. Thus, a
state seeking to identify MSM should be able to start its process using
with the work already undertaken for the nonattainment area's RACM and
BACM determinations and to make updates to the list of potential
control measures accordingly.
The EPA notes that section 188(e) does not identify a deadline for
a state to implement MSM, while elsewhere the statute establishes a
deadline for implementing RACM and RACT and BACM and BACT (see CAA
sections 189(a)(1)(C) and 189(b)(1)(A), respectively). However, because
the clear intent of section 188(e) is to minimize the length of a
Serious area attainment date extension, the EPA proposes that the
implementation of MSM must be as expeditious as practicable but no
later than 1 year prior to the alternative Serious area attainment date
identified by the state in its extension request.
The EPA seeks comment on whether the two proposed approaches to
determine MSM are sufficiently consistent with the agency's respective
proposed approaches to BACM and BACT determination. The agency also
seeks comment on whether considerations regarding its MSM approach
should influence the final selection of a BACM and BACT approach.
Step 4: Demonstrate attainment by the most expeditious alternative
date practicable. Section 189(b)(1)(A) requires that a Serious area
plan demonstrate attainment, using air quality modeling, by the most
expeditious date practicable after the statutory Serious area
attainment date. This demonstration is the final criterion that must be
met before the EPA may consider granting an extension. The agency's
determination of whether the plan provides for attainment by the most
expeditious date practicable would depend on whether the plan provides
for implementation of BACM and BACT by the statutory implementation
deadline and MSM as expeditiously as practicable. In no case would a
state be able to seek an extension of a Serious area attainment date to
a date more than 5 years past the statutory attainment date for Serious
areas. Section VI.E of this preamble describes the EPA's proposed
requirements for attainment
[[Page 15422]]
demonstration modeling for Serious area attainment plans.
Step 5: Apply for an attainment date extension. The state would
have to apply to the EPA for any extension of a Serious area attainment
date. The request would have to accompany an attainment plan submission
containing an attainment demonstration showing attainment by the most
expeditious alternative date practicable, and the state would need to
submit modeling as part of the attainment demonstration in accordance
with Section VI.E. Furthermore, the state would have to provide the
public reasonable notice and a public hearing on the attainment date
extension request before submitting it to the EPA, as the EPA would
consider it an integral part of the attainment demonstration and part
of the revised SIP submission which is subject to the requirements of
the CAA and federal regulations for public notice and hearing on SIP
revisions.
3. Timing of Extension Request Submittal
The EPA believes that a state may submit a request for an extension
of the Serious area attainment date either at the time the original
Serious area attainment plan is submitted following reclassification of
the area or at a point in time closer to the Serious area attainment
date. In the first case, when taken together with language under
section 189(b)(1)(A)(ii) which describes the possibility of including
an impracticability demonstration in a Serious area attainment plan
that parallels the impracticability demonstration for a Moderate area
attainment plan, section 188(e) appears to set an expectation that a
state may request an extension of the attainment date for a Serious
area when the state initially submits its Serious area plan. Therefore,
the EPA would deem such a request as timely and appropriate.
On the other hand, the EPA also recognizes that a state may prepare
and fully implement a timely Serious area plan that includes modeling
demonstrating attainment no later than the statutory Serious area
attainment date (the end of the tenth calendar year following
designation), and yet may see as the attainment date nears that the
Serious area will in fact fail to attain by its projected attainment
date. While the statute provides a remedy to be instituted immediately
upon failure of a Serious area to attain the standard (through
contingency measures and other measures stipulated in section 189(d)),
the EPA also believes that the criteria of section 188(e) could be
applied after a state submits a Serious area attainment plan but prior
to the area failing to attain, as long as the area had not already been
granted a prior Serious area attainment date extension under section
188(e). In such a case, the EPA believes that it would be acceptable
for a state to submit a Serious area attainment date extension request
similar to that described above (for submissions made simultaneous with
initial Serious area attainment plans) together with a new Serious area
attainment plan meeting all of the statutory requirements that apply to
such plans. In this case, the complete submission would have to be made
in a timely way such that the EPA could fully review the new attainment
plan for the area and the accompanying attainment date extension
request, including the status of compliance with all requirements and
commitments in the Moderate area attainment plan for the area, the
justification for the selection of the alternate attainment date, and
provisions for the implementation of MSM, prior to making its
determination of failure of the area to timely attain the relevant
NAAQS.
The EPA seeks comment on this option, particularly with respect to
whether the criteria proposed above are appropriate in a situation in
which a state seeks a Serious area attainment date extension after
submitting a Serious area attainment plan that initially demonstrated
attainment by the statutory Serious area attainment date. For example,
the EPA seeks comment in particular on whether it would be appropriate
to interpret the section 188(e) requirement for a state to have
``complied with all requirements and commitments pertaining to that
area in the implementation plan'' as referencing those requirements and
commitments contained in the area's Moderate area plan (as proposed
above for areas seeking a Serious area attainment date extension
simultaneous with submittal of their Serious area plan) or whether, for
areas that already submitted Serious area plans demonstrating
attainment, it is more appropriate that the state must have complied
with all requirements and commitments pertaining to the area in the
area's original Serious area attainment plan. The EPA believes this
second interpretation is the more appropriate interpretation as it
pertains to Serious areas seeking an extension of their attainment date
as they approach their statutory Serious area attainment date, and
therefore the agency is proposing and seeking comment on this approach.
The EPA believes that this second interpretation is especially
preferable if the EPA finalizes its proposal that interprets the SIP
compliance requirement for areas seeking an attainment date extension
simultaneous with their Serious area attainment plan submittal to mean
that the state need only have implemented the control measures in the
SIP revisions it has submitted to the EPA to address the CAA
requirements in section 189 (i.e., to mean that the area need not have
a fully approved attainment plan that meets the CAA's requirements for
Serious areas).
The EPA seeks comment on these proposed options for interpreting
and implementing the statutory language at section 188(e) for Serious
area attainment date extensions.
VII. What are the EPA's proposed requirements for attainment plans
under CAA section 189(d) for Serious areas that fail to attain the
NAAQS by the applicable attainment date?
In the event that a Serious area fails to attain the
PM2.5 NAAQS by the applicable attainment date, section
189(d) requires that ``the state in which such area is located shall,
after notice and opportunity for public comment, submit within 12
months after the applicable attainment date, plan revisions which
provide for attainment of the . . . standard and, from the date of such
submission until attainment, for an annual reduction in PM10
or PM10 precursor emissions within the area of not less than
5 percent of the amount of such emissions as reported in the most
recent inventory prepared for such area.''
A state with a Serious nonattainment area subject to section 189(d)
must submit to the EPA its plan to meet the requirements of section
189(d) in the form of a complete attainment plan submission that
contains the following elements: (i) An attainment demonstration and
provisions for the implementation of measures that will achieve annual
emissions reductions of not less than 5 percent from the most recent
emissions inventory for the area for each year until attainment
(section 189(d)); (ii) quantitative milestones that will be used to
measure compliance with the RFP requirement (section 189(c)); and,
(iii) regulation of PM2.5 precursors (in general to meet
attainment and control strategy requirements and as specifically
required for major stationary sources by section 189(e)). Subpart 1
requirements that apply to Serious PM2.5 nonattainment areas
also subject to the requirements of section 189(d) include the
following: (i) A description of the expected annual incremental
reductions
[[Page 15423]]
in emissions that will demonstrate RFP (section 172(c)(2)); (ii)
emissions inventories (section 172(c)(3)); and, (iii) contingency
measures (section 172(c)(9)). A state with a Serious PM2.5
nonattainment area that fails to attain the NAAQS by the applicable
Serious area attainment date must also address any statutory
requirements relevant to Moderate nonattainment areas and Serious
nonattainment areas under sections 172 and 189 of the CAA that have not
already been satisfied. In addition, the EPA must approve a new
attainment date for the area under sections 172(a)(2) and 179(d)(3).
The remainder of this section presents the EPA's proposed
requirements for attainment plan submissions under section 189(d).
A. Plan Due Dates
Section 189(d) requires a state with a Serious PM10
nonattainment area that failed to attain the NAAQS by the applicable
Serious area attainment date to submit a new attainment plan submission
for the area within 12 months after the missed attainment date.
Therefore a state with a nonattainment area subject to section 189(d)
must submit a new attainment plan for the area--with all required
elements of the attainment plan--within 12 months after the missed
attainment date.
B. Emissions Inventory Requirements
As with all other attainment plan submissions required for Moderate
and Serious PM2.5 nonattainment areas, a state must develop
its submission to meet section 189(d) based on ``the most recent
emissions inventory prepared for such [nonattainment] area.'' This
inventory must meet the same requirements that would apply to any other
emissions inventory submitted for a PM2.5 nonattainment area
to meet the requirements of section 172(c)(3), which requires ``a
comprehensive, accurate, and current inventory of actual emissions of
the relevant pollutants'' in the nonattainment area. Therefore the EPA
proposes that the inventory submitted with an attainment plan to meet
section 189(d) requirements must also meet the EPA's proposed
regulatory requirements for such emissions inventories as described
earlier in this preamble under Section IV.B (for Moderate area
attainment plans) and Section VI.B (for Serious area attainment plans).
One important aspect of the emissions inventory required to be
submitted with an attainment plan under section 189(d) is its role as
the basis for calculating the emissions reductions of direct
PM2.5 and PM2.5 precursors necessary to satisfy
the 5 percent annual reduction criteria of section 189(d). For this
reason, the EPA proposes that the ``most recent inventory'' for the
area must not only meet the criteria as that described for a base year
inventory submitted pursuant to section 172(c)(3) and in Section VI.B
of this preamble, but also must fully account for emissions reductions
achieved to date through the implementation of all RACM and RACT, BACM
and BACT and additional reasonable and feasible measures submitted with
the Moderate and original Serious area attainment plans for the area.
In this way, the state will calculate the additional reductions that
the nonattainment area will need beyond those already required in order
to fulfill the requirements of section 189(d) and bring the area into
attainment as expeditiously as practicable.
In order to ensure that the ``most recent inventory'' is
representative of the nonattainment problem in the area current at the
time of the section 189(d) submission, the EPA proposes that the
inventory year must be one of the 3 years from which monitored data was
used to determine that the area failed to attain the PM2.5
NAAQS by the applicable Serious area attainment date. The EPA believes
that associating the inventory with one of these 3 years is reasonable
in light of the fact that some BACM and BACT controls and additional
feasible controls (required under section 172(c)(6)) for sources in the
area may not be implemented until the beginning of the attainment year.
Thus, requiring that a state use an emissions inventory for one of
those 3 years will help ensure that the inventory adequately captures
the emissions reductions already achieved through the prior
implementation of BACM and BACT and additional feasible measures.
The EPA recognizes the additional level of effort that may be
needed to produce an up-to-date emissions inventory for a nonattainment
area, and therefore is proposing and seeking comment on an alternative
approach that would allow a state to select an inventory year earlier
than one of the 3 years from which monitored data were used to
determine that the area failed to attain the NAAQS by the applicable
attainment date. Under this alternative proposed approach, another
inventory year may be included in the plan under specific circumstances
with the submission of a written justification for selecting the
earlier year and in consultation with the appropriate EPA Regional
Office. At a minimum, the state would need to demonstrate that the
inventory for the alternative year adequately incorporates emissions
reductions projected to be achieved through the implementation of BACM
and BACT and additional feasible control measures submitted with the
original Serious area attainment plan for the area. The EPA proposes
that modification of an older inventory to incorporate those emissions
reductions would be an acceptable way to meet this requirement. In
considering use of this option, states could be obligated to achieve a
larger annual reduction than 5 percent if the older inventory has
higher emissions levels than the ``most recent inventory'' for the
area.
The EPA seeks comment on these proposed criteria and options for
emissions inventories to be submitted as part of the attainment plan
due for a Serious area under section 189(d).
C. Pollutants To Be Addressed in the Plan
Section 189(d) requires states to develop a new attainment plan for
an area that failed to attain by the applicable Serious area attainment
date that provides for ``an annual reduction in PM10 or
PM10 precursor emissions within the area of not less than 5
percent of the amount of such emissions'' reported in the latest
emissions inventory for the area. In Section III of this preamble, the
EPA is proposing several options on how a state may evaluate which
PM2.5 precursors to control for purposes of attaining the
NAAQS in a particular nonattainment area. The EPA interprets the
requirements of the CAA generally to allow an air agency to provide a
``precursor demonstration'' that can support a determination that one
or more precursors need not be subject to control requirements in a
given nonattainment area, even if the area has failed to attain the
relevant NAAQS by the applicable Serious area attainment date.
Section III presents three options describing different proposed
approaches to such precursor demonstrations, and requests comment on
each. The discussion for each option describes how states and the EPA
should address precursors for Moderate areas and for Serious areas,
including Serious areas that fail to attain the PM2.5 NAAQS
by the applicable attainment date. This section describes, for each of
the three options, how the given precursor approach would apply to
plans required to be submitted where the area has failed to attain by
the Serious area attainment date.
Option 1: Two independent analyses: (a) An attainment
planning
[[Page 15424]]
analysis demonstrating that control measures for a particular precursor
are not needed for expeditious attainment, meaning that the precursor
can be excluded from measures needed to attain as expeditiously as
practicable for all types of sources; and (b) a section 189(e)
technical demonstration showing that major stationary sources of a
particular precursor do not contribute significantly to levels that
exceed the PM2.5 standard, meaning that the precursor can be
excluded from control requirements for major sources and from NNSR
permitting. Consistent with this approach, for an area subject to the
requirements of section 189(d), the state would need to evaluate
control measures to identify those needed to achieve a minimum 5
percent reduction in emissions of direct PM2.5 or precursors
on an annual basis, and identify those control measures for direct
PM2.5 and all precursors that would bring the area into
attainment as expeditiously as practicable.
Option 2: Single analysis demonstrating that all emissions
of a particular precursor from within the area do not significantly
contribute to PM2.5 levels that exceed the standard, meaning
that control requirements for emissions of the precursor from major
stationary and area sources, as well as mobile sources, would not be
required for expeditious attainment, control requirements for major
sources, or for NNSR permitting. For an area subject to section 189(d)
requirements for which a precursor had previously been demonstrated not
to significantly contribute to PM2.5 levels that exceed the
standard, the air agency would be required to update the precursor
demonstration taking into account any relevant information or technical
tools that had been developed since the demonstration was approved.
Consistent with this approach, if, upon failure to attain, the state
continued to demonstrate that the precursor did not contribute
significantly to PM2.5 concentrations in the area, then the
state would not need to identify or implement any measures to control
that precursor's emissions.
Option 3: An attainment planning analysis demonstrating
that control measures for all types of sources of a particular
precursor are not needed for expeditious attainment also would be
deemed to meet the section 189(e) technical demonstration requirement,
meaning that the state would not need to regulate emissions of the
particular precursor from major stationary sources under the NNSR
permitting program or other control requirements for major stationary
sources. Consistent with this approach, for an area subject to the
requirements of section 189(d), the state would need to evaluate
control measures to identify those needed to achieve a minimum 5
percent reduction in emissions of direct PM2.5 or precursors
on an annual basis, and identify those control measures for direct
PM2.5 and all precursors that would bring the area into
attainment as expeditiously as practicable.
The EPA will finalize its approach to PM2.5 precursors
and clarify the implications for states conducting analyses to identify
measures to satisfy the requirements of section 189(d) after
considering public comment received on this proposal.
D. Attainment Plan Control Strategy
The control strategy to be developed for the attainment plan
submission for a Serious area subject to section 189(d) should place
particular emphasis on control measures that can be implemented
quickly, in order to ensure that the area attains the PM2.5
NAAQS as expeditiously as practicable. The control strategy would need
to include any additional measures that are beyond those already
adopted for the area as RACM and RACT and additional reasonable
measures, or BACM and BACT and additional feasible measures, and that
are necessary to achieve annual reductions in emissions of direct
PM2.5 and PM2.5 precursors from sources in the
area of at least 5 percent of the amount of such emissions reported in
the most recent emissions inventory for the area. The EPA is proposing
to interpret section 189(d) in this way to address the ambiguity of how
the statutory language should apply to the PM2.5 NAAQS, as
section 189(d) requires ``an annual reduction in PM10 or
PM10 precursor emissions . . . as reported in the most
recent inventory prepared for such area.''
1. Proposed Approach
The EPA believes that in light of the important role that
PM2.5 precursors play in the formation of PM2.5,
it is appropriate to require a state to implement control measures for
all types of sources in a Serious nonattainment area subject to section
189(d) to achieve the requisite 5 percent annual reduction in emissions
of both direct PM2.5 and PM2.5 precursors from
sources in that area. Accordingly, the EPA is proposing that, for
direct PM2.5 and for PM2.5 precursors that the
state and the EPA have determined are necessary to be controlled for
purposes of attainment in the area, the attainment plan required by
section 189(d) would have to include control measures that will achieve
at least 5 percent reductions from the latest emissions inventory of
each such pollutant on an annual basis until the area attains the
relevant PM2.5 NAAQS. The EPA believes this is an
appropriate interpretation of the 5 percent requirement of section
189(d) and seeks comment on this proposed approach.
The EPA also proposes and seeks comment on an alternative reading
of the statute that would require a state to achieve 5 percent
reductions of inventoried emissions of either direct PM2.5
or of any relevant PM2.5 precursors. This approach, while
consistent with past guidance on how to interpret section 189(d)
requirements for PM10 NAAQS implementation, could
potentially allow a state to delay the implementation of measures to
control the relevant pollutants. However, paired with the requirement
for the area to reach attainment of the NAAQS as expeditiously as
practicable, the EPA believes that such an interpretation may be
reasonable and seeks comment on this approach.
It is important to note that under implementation of either of the
options presented above, and as described more fully in Section III of
this preamble, the EPA is proposing that in the event that a state has
demonstrated and can continue to demonstrate that emissions of a given
precursor from all sources in a nonattainment area do not contribute
significantly to PM2.5 concentrations in the area, then the
state would not need to achieve 5 percent reductions in emissions of
that precursor even if the nonattainment area becomes subject to the
requirements of section 189(d).
The statute requires that the requisite minimum 5 percent emissions
reductions must be calculated from the total emissions for each
precursor and for direct PM2.5 contained in the most recent
inventory for the area, as described earlier in this section. In
addition, the EPA proposes that these required reductions must then be
achieved every year between the section 189(d) plan submission date and
the new projected attainment date for the area. For example, assume it
is 2025, and a Serious area has failed to attain the 2012
PM2.5 NAAQS within 10 years of designation. Assume also that
the most recent inventory available for an area subject to section
189(d) is for the year 2023. This inventory would serve as the base
inventory for determining the emissions reduction requirement under
section 189(d). If the most recent inventory indicates that emissions
of direct PM2.5 from all sources in the area are 100 tons/
day, then the area would need to reduce emissions of direct
PM2.5
[[Page 15425]]
by 5 percent of the base inventory (in this example, 5 percent of the
2023 base inventory, or 5 tons/day) each year until the area attains
the NAAQS. Thus, in the first year following submission of the section
189(d) plan for the area, emissions of direct PM2.5 could
not exceed 95 tons/day; in the second year, emissions could not exceed
90 tons/day; and so forth.
Although section 189(d) requires that a state develop measures that
will obtain annual emissions reductions of ``not less than 5 percent''
from the most recent inventory, the EPA interprets this language to
authorize states to elect to front-load emissions reductions in earlier
years and still meet the 5 percent per year requirement. The EPA notes
that interpreting the statute in this way will encourage states to
implement measures earlier, where possible, rather than delay
implementation of measures merely to assure that the 5 percent
requirement can be met in later years. Thus, using the example
described above, the annual reduction requirement for the area would be
5 tons/day from a base year emissions level of 100 tons/day. The
required level after year 1 would be 95 tons/day, after year 2 the
level would be 90 tons/day, and so on. If the area reached a level of
81 tons/day by the end of year 3, then by the end of year 4 it would
only need to reduce emissions by 1 ton/day to yield an emissions level
of 80 tons/day. Consistent with its past action to approve a Serious
area attainment plan for the San Joaquin Valley (CA) PM10
nonattainment area under section 189(d), the EPA therefore proposes and
seeks comment on an approach to allow states to carry forward any
emissions reductions beyond the required minimum 5 percent in a given
year to the next year as a means to encourage states to achieve
emissions reductions as quickly as possible.\218\
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\218\ 69 FR 30006 (May 26, 2004).
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The EPA also proposes to clarify its interpretation of the
statutory language under section 189(d) that requires a state to submit
a new attainment plan to achieve annual reductions ``from the date of
such submission until attainment,'' to mean annual reductions beginning
from the due date of such submission until the new projected attainment
date for the area based on the new or additional control measures
identified to achieve at least 5 percent emissions reductions annually.
This proposed clarification is intended to make clear that even if a
state is late in submitting its section 189(d) plan, the area must
still achieve its annual 5 percent emissions reductions beginning from
the past due date for the section 189(d) plan submission. Because
attainment dates for PM2.5 nonattainment areas established
under subpart 4 occur at the end of the calendar year, any section
189(d) plan, which is required within 12 months of the missed
attainment date for the area, would also be due by the end of the
calendar year.
2. Additional Guidance on Section 189(d) Control Measures
The EPA believes that an appropriate starting point for a state to
identify measures to achieve the requisite minimum 5 percent annual
emissions reductions of direct PM2.5 and PM2.5
precursors is the list of potential control measures initially required
as part of the RACM and RACT determination for the area, then updated
as part of the required BACM and BACT determination for the area. The
EPA anticipates that a state should be able to rely on much of the work
it previously undertook to develop this list of potential control
measures and analyze their technological and economic feasibility, and
the time required to implement them. However, for purposes of meeting
the requirements of section 189(d), the EPA recommends that the state
first identify any additional potential measures not previously
identified for the area, and then analyze any new or additional
measures that the state has not already adopted in a previous
attainment plan for the area. The EPA expects that such an analysis to
identify new control measures would necessarily take into account
recent technological advances in control technologies, the possibility
of a greater availability of funding to expand implementation of
control measures for area sources, and the additional time the area
will have to attain the PM2.5 NAAQS under sections 189(d)
and 179(d)(3).
In addition, a state may include in the section 189(d) plan control
strategy for the area any control measures triggered as contingency
measures upon the EPA's determination that area failed to attain the
PM2.5 NAAQS by the applicable attainment date. In order to
be included as control measures that will help the area meet its
requisite minimum 5 percent reductions in direct PM2.5 and
PM2.5 precursor emissions, such measures would have to meet
the same requirements as all other approvable control measures for
being quantifiable, enforceable, replicable and accountable. The EPA
believes that reliance on such measures is appropriate given the short
timeline provided for in the statute for states to revise and submit
their SIP revisions (12 months from the missed attainment date) and the
fact that the contingency measures included in the prior attainment
plan for the area under section 172(c)(9) must be activated once the
EPA publishes its finding of the area's failure to attain the NAAQS by
the applicable attainment date. If contingency measures from the
Serious area attainment plan are relied on in the new attainment
demonstration as part of the control strategy, the state will need to
submit additional contingency measures for the section 189(d)
attainment plan submission.
3. Control Strategy Submission Requirements
To ensure that attainment plan submissions contain the necessary
supporting information for the EPA to review and approve the state's
new control strategy to achieve at least 5 percent reductions in
emissions of direct PM2.5 and significant PM2.5
precursors, the EPA proposes to require under the authority of section
301(a) that a state must submit the following information as part of
its section 189(d) plan submission:
A list of all emissions source categories, sources and
activities in the nonattainment area (for multi-state nonattainment
areas, this would include source categories, sources and activities
from all states which make up the area);
For each source category, source or activity in the
nonattainment area, an inventory of direct PM2.5 and all
PM2.5 precursor emissions;
For each source category, source or activity in the
nonattainment area, a comprehensive list of potential control measures
considered by the state for those sources in the nonattainment area;
\219\
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\219\ Menu of Control Measures document available at http://www.epa.gov/air/criteria.html.
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For each potential control measure considered by the state
but eliminated from further consideration due to a determination by the
state that the control measure or technology was not technologically
feasible, a narrative explanation and quantitative or qualitative
supporting documentation to justify the state's conclusion;
For each technologically feasible emission control measure
or technology, the state must provide the following information
relevant to economic feasibility: (i) the control efficiency by
pollutant; (ii) the possible emission reductions by pollutant; (iii)
the estimated cost per ton of pollutant reduced; and, (iv) a
determination of whether the measure is economically
[[Page 15426]]
feasible, with narrative explanation and quantitative supporting
documentation to justify the state's conclusion;
For each technologically and economically feasible
emission control measure or technology, the date by which the
technology or measure could be implemented.
As with other PM2.5 attainment plan submissions, the EPA
believes that it is incumbent on the state to ensure that the
information needed for the EPA to evaluate the state's analysis of new
control measures needed to achieve annual 5 percent reductions is
presented separately as part of the control strategy analysis and in a
format that provides transparency, consistency and the ability for
another party to evaluate the state's analysis effectively and to
duplicate the state's results. For this reason, the EPA is including
the section 189(d) plan base year emissions inventory information as a
necessary part of the control strategy submittal and as one element of
the state's section 189(d) plan due 12 months after the missed
attainment date for the area. In addition, the EPA proposes that the
state must provide information as part of any attainment plan submitted
to meet the requirements of section 189(d) consistent with the criteria
described in Section VI.D.5 of this preamble to ensure that a state
adopts effective regulations to implement the control measures
identified as being needed to meet those requirements. Specifically,
all control measures must be quantifiable, enforceable, replicable and
accountable.
The section 189(d) requirement to reduce emissions by 5 percent per
year is in effect a fixed level of RFP to be achieved annually.
Accordingly, just as quantitative milestones are used to track progress
with RFP requirements, the EPA proposes that the state would be
required to submit quantitative milestone reports to describe the
area's progress in meeting the 5 percent annual emissions reduction
requirement under section 189(d). See Section VII.G of this preamble
for more details.
E. Modeling for Attainment Demonstrations
Section 189(d) requires a state with a Serious nonattainment area
that failed to attain the relevant NAAQS by the applicable Serious area
attainment date to submit a new attainment plan for such area within 12
months after the missed attainment date. The EPA is proposing that the
same general requirements for attainment demonstrations and modeling
that apply to Moderate area plans and Serious area plans due under
sections 189(a) and 189(b) should also apply to section 189(d)
attainment plans. However, the EPA is proposing additional requirements
specific to plans states submitted pursuant to section 189(d) as
described below.
1. Attainment Demonstrations for Serious Areas That Fail To Attain the
NAAQS by the Applicable Attainment Date
The EPA is proposing that the attainment demonstration for Serious
areas subject to section 189(d) requirements must consist of: (i)
technical analyses such as base year and future year modeling of
emissions which identify sources and quantify their emissions that are
contributing to violations of the PM2.5 NAAQS; and, (ii)
analyses of future year projected emissions reductions and air quality
improvement resulting from national, regional and local programs
already implemented as part of previous Moderate and/or Serious area
attainment plans for the area (including reasonable control measures,
BACM and BACT and additional feasible measures), and additional
measures needed for expeditious attainment, including measures needed
to achieve 5 percent emissions reductions on an annual basis. Each
state with a nonattainment area subject to the requirements of section
189(d) must submit an attainment plan with an attainment demonstration
that includes analyses supporting the state's determination of its
proposed new attainment date. In all cases, the state must show that
the area will attain the NAAQS as expeditiously as practicable.
2. What modeling is required?
The EPA proposes that states are required to submit air quality
modeling in support of an attainment demonstration for a nonattainment
area subject to the requirements of section 189(d). The modeling
demonstration must show how and when the area will attain the NAAQS.
Other than the timing of plan submissions and requirement to achieve 5
percent emissions reductions in direct PM2.5 and
PM2.5 precursors, the relevant air quality modeling
procedures and guidance for all PM2.5 nonattainment area
plans are the same. See Sections IV.E. and VI.E of this preamble for
more details on proposed modeling requirements and guidance for
Moderate and Serious PM2.5 nonattainment areas,
respectively.
3. What future year(s) should be modeled in attainment demonstrations?
As discussed more fully in Section VII.I of this preamble, the EPA
must establish a new attainment date for a PM2.5
nonattainment area subject to section 189(d) and must do so according
to the provisions of sections 179(d)(3) and 172(a)(2), which require
that the new attainment date must be as expeditious as practicable, but
no later than 5 years from the date of publication in the Federal
Register of the EPA's determination that the area failed to attain the
relevant NAAQS. The EPA may extend the attainment date by up to 5
additional years (thus to 10 years from the date of publication of the
notice of finding of failure to attain by the applicable attainment
date for the area) if the agency deems it appropriate ``considering the
severity of nonattainment and the availability and feasibility of
pollution control measures.''
For purposes of determining the attainment date that is as
expeditious as practicable, the state must conduct future year modeling
which takes into account emissions growth, known controls (including
any controls that were previously determined to be RACM or RACT or
additional reasonable measures, or BACM or BACT or additional feasible
measures for the area), the 5 percent per year emissions reductions
required by section 189(d), plus any other emissions controls that are
needed for expeditious attainment of the NAAQS. A state performing a
modeling analysis for a plan submitted under section 189(d) must select
a future modeling year such that all emissions control measures relied
on for attainment will have been implemented by the beginning of that
year. To demonstrate attainment, the modeling results for the
nonattainment area must predict that emissions reductions implemented
by the beginning of the last calendar year preceding the attainment
date will result in PM2.5 concentrations that meet the level
of the standard.\220\
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\220\ Note that for purposes of the PM2.5 NAAQS, a
determination of attainment (or failure to attain), which the EPA is
required to make after the attainment date has passed, is based on
an average of the most recent 3 years of ambient data prior to the
area's attainment date.
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For a PM2.5 nonattainment area subject to section
189(d), the EPA expects that the state will adopt any control measures
necessary to demonstrate expeditious attainment within 5 years of the
area failing to attain the NAAQS by the applicable Serious area
attainment date.
4. Attainment Year Motor Vehicle Emissions Budgets
As with all other PM2.5 NAAQS attainment plans, the
transportation
[[Page 15427]]
conformity rule requires that attainment plans for areas subject to
section 189(d) establish motor vehicle emissions budgets for the area's
attainment year. Therefore, for such an area, the state would first
determine the new attainment date as described in Section VII.I of this
preamble. Once an area's attainment date has been established, the
state would establish motor vehicle emissions budgets for direct
PM2.5 and any relevant PM2.5 precursor for the
attainment year.\221\ A motor vehicle emissions budget for the purposes
of a PM2.5 attainment plan is that portion of the total
allowable emissions within the nonattainment area allocated to on-road
sources as defined in the submitted attainment plan.\222\ Such motor
vehicle emissions budgets would be calculated using the latest planning
assumptions and the latest approved motor vehicle emissions model
available at the time that the attainment plan is developed.\223\
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\221\ For more information on PM2.5 precursor
requirements, see section 93.102(b)(2)(iv) and (v) of the
transportation conformity rule. See also the May 6, 2005, final
transportation conformity rule that addressed requirements for
PM2.5 precursors. (70 FR 24280).
\222\ A state would also establish motor vehicle emissions
budgets for an area's attainment year. Those budgets would be the
motor vehicle emissions that the SIP establishes as being necessary
to attain the NAAQS.
\223\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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The EPA seeks comment on these proposed attainment demonstration
and modeling requirements for new attainment plans due for Serious
areas subject to section 189(d).
F. RFP Requirements
As with other PM2.5 attainment plans, a plan submitted
to meet the requirements of section 189(d) must provide for RFP as
required under sections 172(c)(2) and 189(c)(1). Section 171(1) defines
RFP as ``such annual incremental reductions in emissions of the
relevant air pollution as are required by this part or may reasonably
be required by the Administrator for the purpose of ensuring attainment
of the applicable [NAAQS] by the applicable attainment date.'' The
purpose of RFP requirements is to assure that a state is making
progress towards attainment on an annual basis through the attainment
plan, rather than deferring emissions reductions until just before the
attainment date for the area. This requirement is similar to, though
less prescriptive than, the requirement under section 189(d) for 5
percent emissions reductions of direct PM2.5 or
PM2.5 precursors from the most recent emissions inventory on
an annual basis until the area attains. Therefore, the EPA proposes to
determine that a state has satisfied the RFP requirement if the state
submits an approvable control strategy under section 189(d) that
demonstrates that the state will achieve at least 5 percent reductions
in direct PM2.5 and PM2.5 precursor emissions
from sources in the area annually until attainment.
The EPA proposes that motor vehicle emissions budgets must also be
established as part of any RFP plan for direct PM2.5 and for
any relevant PM2.5 precursor using the latest planning
assumptions and the latest approved motor vehicle emissions model
available at the time that the plan is developed for a Serious area
subject to 189(d).\224\
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\224\ If an area includes re-entrained road dust in the motor
vehicle emissions budget, the latest approved version of AP-42
should be used unless the EPA has approved an alternative model for
the area.
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The EPA seeks comment on this proposed approach related to RFP
requirements for new attainment plans due under section 189(d).
G. Quantitative Milestones
The revised attainment plan for any Serious nonattainment area that
fails to attain the relevant PM2.5 NAAQS by the applicable
attainment date must include quantitative milestones pursuant to
section 189(c). These quantitative milestones would be additional to
those previously identified in the Moderate area and original Serious
area attainment plans, and would need to reflect the projected
emissions reductions or air quality improvements expected through the
implementation of specific control measures identified to achieve the
minimum 5 percent annual reductions required under section 189(d). Such
milestones would need to be achieved every 3 years until the area
attains the relevant NAAQS, such that the EPA proposes that, at a
minimum, quantitative milestones selected for an attainment plan
submitted under section 189(d) would need to demonstrate a reduction of
at least 15 percent in emissions of direct PM2.5 and
significant precursors below those emissions reported in the most
recent inventory for the area.
The section 189(d) plan for an area that failed to attain the
standard by the applicable Serious area attainment date would have to
contain quantitative milestones to be achieved by 13.5 years from the
area's date of designation and every 3 years thereafter until the
area's new projected attainment date. In the event a state is
developing a revised attainment plan pursuant to section 189(d) that
will be due sometime after 13.5 years following designation of the
area, the EPA proposes to allow the state to submit quantitative
milestones beginning for the year 16.5 from designation and every 3
years thereafter until the area's projected attainment date.
The EPA believes that its proposed requirements for quantitative
milestones, described in Sections IV.G and VI.G of this preamble,
should also apply to quantitative milestones submitted with any revised
attainment plan pursuant to section 189(d), and thus proposes and seeks
comment on the agency's proposed milestone requirements for application
to attainment plans due under section 189(d).
H. Contingency Measures
All PM2.5 attainment plans, including plans for areas
subject to section 189(d), must contain contingency measures that are
consistent with section 172(c)(9). Section VI.H of this preamble
describes the EPA's proposed criteria for contingency measures for a
Serious area attainment plan, and the agency proposes that contingency
measures for a section 189(d) plan must meet the same criteria. The EPA
proposes that the emissions reductions associated with contingency
measures for section 189(d) plans must be at least 5 percent of direct
PM2.5 and significant PM2.5 precursor emissions
as reported in the most recent inventory for the area. The EPA believes
this requirement would appropriately align the proposed requirement for
selecting contingency measures with the agency's proposed approach to
RFP for these areas. In other words, if RFP for an area is equivalent
to about 1 year's worth of emissions reductions, or 5 percent emissions
reductions in direct PM2.5 and PM2.5 precursors,
then the adopted contingency measures should likewise achieve about 1
year's worth of emissions reductions, or 5 percent emissions reductions
in direct PM2.5 and PM2.5 precursors.
The EPA recognizes that identifying contingency measures for a
Serious PM2.5 nonattainment area that failed to attain the
relevant NAAQS by the applicable attainment date may be challenging for
a state that should already have fully implemented all control measures
identified as ``reasonable'' and ``best,'' and potentially ``most
stringent,'' in addition to identifying new control measures to achieve
the requisite minimum 5 percent reductions in direct PM2.5
and significant PM2.5 precursor emissions
[[Page 15428]]
necessary for expeditious attainment. Nonetheless, given the statutory
language of section 172(c)(9), the EPA seeks comment on applying the
same proposed requirements for contingency measures for section 189(d)
plans, and on the agency's proposed approach for calculating the
emissions reductions that such measures must be able to achieve.
I. Attainment Dates
As previously discussed, section 189(d) requires a minimum 5
percent annual reduction in emissions of direct PM2.5 and
PM2.5 precursors until the area attains the relevant NAAQS.
However, neither section 189(d) nor other sections in subpart 4
explicitly establish or provide the authority to establish a new
attainment date for the area; other subpart 4 attainment date
provisions for Moderate or Serious areas are likewise not applicable to
areas in this situation. Therefore, once an area is beyond the
attainment dates that Congress specified in subpart 4 for the
PM10 NAAQS, the EPA must look to the existing provisions of
the CAA to provide authority for a new attainment date. Sections
179(d)(3) and 172(a)(2) provide generally applicable attainment dates
that fill the gap in the statute left for areas subject to the
requirements of section 189(d). Thus, for a PM2.5
nonattainment area subject to section 189(d) requirements, the EPA must
establish a new attainment date, and must do so according to the
provisions of section 179(d)(3) and 172(a)(2). The EPA has followed
this same approach in the past for PM10 nonattainment areas
governed by subpart 4 nonattainment requirements.\225\
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\225\ For example, see the Federal Register notice from June 6,
2007 (72 FR 31183) in which the EPA found that the Phoenix
PM10 Serious nonattainment area failed to attain the
standard by the 2006 attainment date.
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The new attainment date must be as expeditious as practicable, but
no later than 5 years from the date of publication in the Federal
Register of the EPA's determination that the area failed to attain the
relevant NAAQS. The EPA may extend the attainment date by up to 5
additional years (thus to 10 years from the date of publication of the
notice of finding of failure to attain by the applicable attainment
date for the area) if the agency deems it appropriate ``considering the
severity of nonattainment and the availability and feasibility of
pollution control measures.'' For a PM2.5 nonattainment area
subject to section 189(d), the EPA expects that the state will adopt
any control measures necessary to demonstrate expeditious attainment
within 5 years of the area failing to attain the NAAQS by the
applicable Serious area attainment date.
As discussed earlier in this section, the EPA will consider the
state's attainment demonstration and proposed attainment date for the
area, in addition to the state's revised control strategy and the
relevant facts and circumstances, in order to identify the most
expeditious attainment date practicable for the area.
The EPA seeks comment on this proposal for interpreting the
statutory requirements under section 189(d) for a Serious area that
fails to attain the PM2.5 NAAQS by the applicable attainment
date.
VIII. What are the EPA's proposed NNSR permitting requirements?
A. Statutory Requirements for NSR
Section 110(a)(2)(C) of the CAA requires states to include in their
SIPs a preconstruction review permitting program that regulates the
construction and modification of stationary sources as necessary to
ensure that NAAQS are achieved. To address the regulation of the larger
pollutant-emitting sources (defined as major stationary sources),
Congress provided specific permitting requirements in the CAA in parts
C and D of title I. The requirements for preconstruction permits under
parts C and D of the CAA are commonly known collectively as the major
NSR program because they apply specifically to the preconstruction
review and permitting of new major stationary sources, and major
modifications at existing sources. As explained in Sections VIII.A.1
and 2 of this preamble, the preconstruction review of each new and
modified major stationary source generally is carried out on a
pollutant-specific basis and the requirements with regard to each
pollutant apply based on whether the area in which the proposed major
source or major modification would locate is designated attainment (or
unclassifiable) or nonattainment for that pollutant at the time the
permit is issued.
1. PSD
Part C of title I of the CAA (hereafter referred to simply as part
C) contains implementation plan requirements that apply to new major
stationary sources and major modifications in areas designated
attainment or unclassifiable for any NAAQS. These requirements
constitute the PSD program. Pursuant to part C, the EPA has adopted PSD
regulations at 40 CFR 51.166 (minimum requirements for an approvable
state PSD program in the SIP) and 40 CFR 52.21 (the federal PSD
program, applicable in areas where the state does not have an EPA-
approved PSD program in its SIP). The EPA last amended the PSD
regulations for PM2.5 on January 15, 2013, in the final rule
revising the PM2.5 NAAQS.\226\ This proposal does not relate
to the PSD program, nor does it propose further changes to the PSD
regulations. Any future revisions to the PSD regulations for
PM2.5 would be done through a separate notice-and-comment
rulemaking.
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\226\ More information on the PSD requirements for
PM2.5 as well as the public comments and the EPA's
responses to those comments and the related issues for which
comments were received is contained in the January 15, 2013 Federal
Register document (78 FR 3086, beginning at page 3251).
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2. NNSR
Part D of title I of the CAA (hereafter referred to as part D)
contains implementation plan requirements for nonattainment areas,
which include the requirements for permitting new major stationary
sources and major modifications in designated nonattainment areas,
referred to as the NNSR program. As noted earlier, part D contains
several subparts that include various requirements for addressing
nonattainment areas. Subpart 1 addresses plan requirements for
nonattainment areas generally, including section 172(c)(5) which
requires preconstruction and operating permits for new major stationary
sources and major modifications in nonattainment areas. Section 173
outlines the minimum statutory requirements for a state's NNSR permit
program and serves as the basis for the EPA's NNSR regulations for
PM2.5 as promulgated in the 2008 PM2.5 NSR Rule.
Subpart 4 was added to part D as part of the 1990 CAA Amendments and
includes additional plan provisions for designated PM10
nonattainment areas. Relevant here, section 189(a)(1)(A) of subpart 4
requires states to include in their implementation plan a permit
program addressing major stationary sources of PM10 that
meets the requirements under section 173 of subpart 1. Subpart 4 also
includes some additional preconstruction review requirements for which,
to date, the EPA has promulgated NSR regulations applying only to major
stationary sources of PM10 in PM10 nonattainment
areas. The specific NNSR requirements contained in both subparts 1 and
4 are described below including the changes to the NNSR regulations
needed to address PM2.5 specifically that the EPA is
proposing in this notice.
[[Page 15429]]
B. Federal NNSR Regulations
Federal regulations pertaining to the preconstruction permitting of
new major stationary sources and major modifications in areas
designated nonattainment are contained at 40 CFR 51.165; part 51,
appendix S; and, Sec. 52.24. An approved NNSR program in a state's
implementation plan must, at a minimum, meet the program requirements
set forth in the federal NNSR requirements at 40 CFR 51.165, which for
PM2.5 are currently based on changes made under the 2008
PM2.5 NSR Rule. States are required to adopt regulations
consistent with those plan requirements and submit them to the EPA for
approval as part of their SIP within a period of time consistent with
the schedule prescribed by the CAA.
The EPA interprets the requirement established under section
110(a)(2)(C) of the CAA for states to regulate the construction and
modification of sources to apply in nonattainment areas as of the
effective date of a new nonattainment area designation.\227\ Although
section 110(a)(2)(C) does not contain specific requirements a state
must follow for issuing major source permits during the interim period
between effective date of designation and the date when a state has an
EPA-approved NNSR program, the EPA regulation at 40 CFR 52.24(k)
authorizes states to apply 40 CFR part 51, Appendix S, known as the
Emission Offset Interpretative Ruling, during the interim period.
228 229
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\227\ See the Federal Register published on November 29, 2005
(70 FR 71612, 71677 and 71678).
\228\ States with designated PM2.5 nonattainment
areas were required to submit SIPs satisfying the requirements of
the 2008 PM2.5 NSR Implementation Rule by May 16, 2011, 3
years from the date of publication of that rule. See 73 FR 28321
(May 16, 2008), at page 28342. Such approved state programs can
continue to be implemented to issue permits to new major stationary
sources and major modifications until the state's revised program
containing the subpart 4 NNSR provisions promulgated in this
rulemaking is approved under the applicable SIP.
\229\ Appendix S was originally promulgated in 1976 to address
whether, and to what extent, new and modified sources would be
allowed to construct in nonattainment areas whose attainment
deadlines had already passed, in light of the regulatory requirement
that new or modified sources be disapproved where the source would
interfere with attainment of the NAAQS (41 FR 55524 (December 21
1976)). When Congress added the part D provisions in the 1977 CAA
Amendments, it also added the requirement that SIPs contain NNSR
provisions as set forth in Part D. Additionally, Congress provided
that Appendix S would govern preconstruction permitting in
nonattainment areas lacking approved part D SIPs before a
construction ban went into effect. When Congress removed the
construction ban via the 1990 CAA Amendments (except as provided for
in section 110(n)(3)) it left in place the use of the interim NNSR
program under Appendix S.
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Accordingly, states with newly designated nonattainment areas for
the revised primary PM2.5 NAAQS have two possible means by
which they can implement NNSR requirements for PM2.5
following the effective date of designations and until the EPA approves
a SIP submission meeting the NNSR requirements for PM2.5
promulgated in this rule under subpart 4. First, any state that has an
approved NNSR program for PM2.5 can continue to apply those
permitting requirements in the interim. Second, states that lack any
approved NNSR program for PM2.5 may rely upon the NNSR
provisions in Appendix S until the EPA approves a SIP submission from
the state to address PM2.5 in order to ensure that proposed
new major stationary sources and major modifications for
PM2.5 in newly designated PM2.5 nonattainment
areas undergo the appropriate type of preconstruction review in the
interim.
1. General Applicability
New major stationary sources are subject to the NNSR requirements
when they are major for the pollutant for which an area is designated
nonattainment. See 40 CFR 51.165(a)(2)(i). With regard to major
modifications, NNSR applies to proposed physical changes or changes in
the method of operation of an existing stationary source that (1) is
major for the nonattainment pollutant (or a precursor for that
pollutant) and (2) results in both a significant emissions increase and
a significant net emissions increase of that nonattainment pollutant
(or a precursor for that pollutant).\230\
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\230\ As will be explained in ensuing discussions, the
nonattainment pollutant and any applicable precursors for that
pollutant are considered separately for NNSR applicability purposes.
See 40 CFR 51.165(a)(1)(v)(A), (a)(2)(ii)A).
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For each proposed major new source and major modification, the
general NNSR requirements that are required to be included in a state's
SIP include: (i) the installation and continuous operation of pollution
control technology that complies with the LAER; (ii) the acquisition of
creditable emissions reductions to adequately offset the proposed
emissions increase of the nonattainment pollutant; and, (iii) a
demonstration of compliance with other analyses as required under
section 173 of the CAA.\231\ These NNSR requirements must be satisfied
by a major new source or major modification as a prerequisite for
receipt of a construction permit and apply as of the effective date of
designation of an area as nonattainment for the pollutant.
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\231\ The basic NNSR requirements are set forth in section 173
of subpart 1. Subpart 4 adds a more stringent definition of ``major
source'' for PM10 sources in PM10
nonattainment areas classified as Serious and sets forth provisions
for the regulation and potential exemption of major sources of
PM10 precursors in PM10 nonattainment areas.
Until the decision in NRDC v. EPA was issued, the additional subpart
4 requirements had not been directly applied with regard to
PM2.5.
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2. Historical Overview of NNSR for PM10 and PM2.5
NAAQS
Following the adoption of new PM NAAQS based on the PM10
indicator in 1987 (replacing the original Total Suspended Particulate
indicator), the EPA announced that it did not intend to designate areas
as nonattainment for PM10. As a result, the EPA initially
determined that part D, which at that point consisted only of generally
applicable requirements, did not apply to the PM10
NAAQS.\232\ Thus, nonattainment area requirements, including the NNSR
program, did not initially apply with respect to PM10.
Consequently, all new major stationary sources and major modifications
of PM10 were required to undergo PSD review as a
prerequisite for construction or modification.
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\232\ At the time the EPA promulgated the new PM10
NAAQS, part D of the CAA did not include subpart 4. See 52 FR 24672
(July 1, 1987).
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The approach for implementing the NNSR program for PM changed when
in 1990 Congress established a new subpart 4 specifically to address
implementation plan requirements for PM10 nonattainment
areas, including new preconstruction permit requirements for major
stationary sources and major modifications with respect to
PM10 and PM10 precursors. Moreover, Congress
created new PM10 nonattainment areas through designations
that became effective upon enactment of the 1990 Amendments on November
15, 1990.\233\ In section 189(a)(2)(A), Congress also required states
to submit the necessary NNSR permit program SIP revisions for these
areas to the EPA by June 30, 1992.
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\233\ See section 107(d)(4)(B) of the CAA. The EPA subsequently
published a list of the statutorily created PM10 areas in
a Federal Register document at 55 FR 45799 (October 31, 1990).
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In a letter to its Regional Offices dated March 11, 1991,\234\ the
EPA initially indicated that states should implement such new
requirements by operation of law, without the need for formal
rulemaking by the EPA to establish the necessary requirements for
states to adopt. In the General Preamble, the EPA offered states
additional guidance and described the EPA's preliminary views on how
the states and the EPA should interpret various provisions of the 1990
[[Page 15430]]
Amendments, primarily those provisions concerning planning and control
measure requirements for the attainment of the NAAQS in nonattainment
areas. In a 2005 final rule, the EPA formally amended the NNSR
regulations to incorporate the requirements contained in subpart 4 of
part D of the 1990 CAA Amendments concerning PM10
nonattainment areas. \235\
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\234\ The EPA memorandum titled ``New Source Review (NSR)
Program Transition Guidance,'' signed by John S. Seitz, Director,
Office of Air Quality Planning & Standards.
\235\ See ``Final Rule to Implement Certain Aspects of the 1990
Amendments Relating to New Source Review and Prevention of
Significant Deterioration as They Apply in Carbon Monoxide,
Particulate Matter and Ozone NAAQS.'' 70 FR 71611 (November 29,
2005).
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The EPA revised the PM NAAQS in 1997, establishing new annual and
24-hour NAAQS using PM2.5 particles as a new indicator,
while retaining the NAAQS for PM10.\236\ In 2006, the EPA
again revised the suite of PM NAAQS by tightening the 24-hour
PM2.5 standards and retaining the level of the annual
PM2.5 standards.\237\ In 2008, the EPA issued the
PM2.5 NSR Rule that established various provisions ensuring
that proposed new major stationary sources or major modifications of
sources of direct PM2.5 emissions or emissions of applicable
PM2.5 precursors would be required to undergo
preconstruction review.\238\ The EPA included specific provisions in
the 2008 PM2.5 NSR Rule to apply when such sources are
located in a designated PM2.5 nonattainment area. Unlike the
NNSR requirements for PM10 developed under subpart 4, the
EPA determined that the applicable implementation requirements for the
PM2.5 NAAQS were contained in the general nonattainment
provisions under subpart 1.
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\236\ See 62 FR 38652 (July 18, 1997).
\237\ See 71 FR 61144 (October 17, 2006).
\238\ See 73 FR 28321 (May 16, 2008).
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With regard to NSR applicability for PM2.5 precursors in
the 2008 PM2.5 NSR Rule, the EPA recognized NOX,
SO2, VOC and ammonia as precursors of PM2.5 in
the scientific sense (because those pollutants under the appropriate
conditions can contribute to the formation of PM2.5 in the
ambient air) but did not require that states subject all of these
precursors to control as part of the attainment plan or NSR permitting
requirements applicable to a given nonattainment area.\239\ Instead,
based on the authority in section 302(g) of the CAA, the EPA
established the initial presumptions for nonattainment areas that
SO2 and NOX should be regulated precursors for
PM2.5, but VOC and ammonia need not be regulated precursors.
The EPA or the states could rebut the initial presumptions regarding
NOX, VOC or ammonia on an area-by-area basis with a
demonstration approved by the Administrator and thus reverse any of
those presumptions in the state's implementation plan for that
area.\240\
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\239\ See 72 FR 20589.
\240\ In the 2008 PM2.5 NSR Rule, the EPA concluded
that SO2 should be regulated as a precursor for
PM2.5 in all areas. See 73 FR 28327.
---------------------------------------------------------------------------
As described above in Section II.C of this preamble, in January
2013 the court in NRDC v. EPA held that the EPA erred in implementing
the PM2.5 NAAQS pursuant only to the general implementation
requirements in subpart 1, rather than also to the implementation
requirements specific to particulate matter in subpart 4. Accordingly,
the court directed the EPA to comply with the requirements of subpart 4
when developing implementing regulations for PM2.5
nonattainment areas.
The court decision, requiring that the EPA implement the
PM2.5 NAAQS consistent with the requirements of subpart 4,
clearly has specific implications for implementing the NNSR program for
PM2.5. Two provisions of subpart 4 impose additional
requirements on the existing NNSR program requirements for
PM2.5. The first relates to the definition of ``major
stationary source.'' Section 188(b) provides that some areas initially
designated as Moderate areas for PM10 subsequently may be
reclassified as Serious areas. For any PM10 nonattainment
area reclassified as a Serious area, section 189(b)(3) provides that a
major stationary source of PM10 be defined to include any
stationary source or group of stationary sources located within a
contiguous area and under common control that emits or has the
potential to emit at least 70 tpy of PM10. In accordance
with the statute, the EPA is proposing to establish a major source
emissions threshold for stationary sources of PM2.5 that
satisfies the intent of section 189(b)(3).
The second relevant subpart 4 provision governs the treatment of
major sources of PM10 precursors. As previously explained in
Section III.A of this preamble, the court specifically criticized the
EPA's prior establishment of the rebuttable presumptions for addressing
PM2.5 precursors, specifically citing the requirement of
section 189(e). Section 189(e) requires that the control requirements
in the plan applicable to major stationary sources of PM10
must also apply to major stationary sources of PM10
precursors. Section 189(e) also provides that states may elect not to
impose control requirements on major stationary sources of
PM10 precursor emissions if such emissions do not contribute
significantly to ambient PM10 concentrations that exceed the
standard in the PM10 nonattainment area. Section 189(e)
requires that the EPA must make this determination, and thus the EPA
must approve the decisions of a state that elects to use this provision
to exempt any major stationary sources of PM2.5 precursors
from controls in its attainment plan or NNSR program.
The court's observation that the EPA's prior presumptions regarding
precursors were inconsistent with the explicit requirements of section
189(e) that major sources of all PM2.5 precursors are
subject to control requirements thus necessitates that the agency
revise the NNSR regulations governing precursors for PM2.5.
As explained in greater detail later in this section, the EPA is
proposing different potential options to make the necessary changes to
the NNSR regulations in order to address the precursor requirements
contained in subpart 4.
C. What are the changes the EPA is proposing for NNSR for PM2.5
nonattainment areas?
In this section, the EPA presents for comment certain proposed
revisions to the NNSR regulations as well as alternative approaches for
incorporating the subpart 4 requirements into the NNSR regulations for
PM2.5. The proposed changes would affect the existing
regulations at 40 CFR 51.165 and part 51 Appendix S. The agency does
not intend to propose any changes to the regulations at 40 CFR 52.24,
which provide the authorization for states to issue NNSR permits to
major new sources and major modifications ``during the period between
the date of designation as nonattainment and the date the NSR permit
program meeting the requirements of part D is approved.''
1. What are the changes the EPA is proposing for the NNSR requirements
for PM2.5 at 40 CFR 51.165?
As explained above, the existing NNSR regulations applicable to
PM2.5 are based solely on the permit requirements contained
in section 173 of subpart 1. In subpart 4, section 189(a)(1)(A)
requires states to include in their SIPs for PM10
nonattainment areas a permit program meeting the requirements of
section 173; however, other provisions in subpart 4 add additional
requirements for the NNSR permit program. Those additional provisions
concern (i) the definition of ``major stationary source'' in
nonattainment areas classified as Serious areas, and (ii) control
[[Page 15431]]
requirements for applicable major stationary sources of PM10
precursors. While those particular requirements in subpart 4 refer
specifically to PM10, the EPA is proposing to add similar
requirements for PM2.5 in accordance with the court's
holding in NRDC v. EPA that subpart 4 also governs implementation of
the PM2.5 NAAQS.
a. Definition of ``major stationary source'' in Serious PM2.5
nonattainment areas. In Section III.A of this preamble, the EPA
indicated its intention to propose new provisions based on the
requirements in subpart 4 for reclassifying certain PM2.5
nonattainment areas as Serious areas. Because the NNSR regulations for
PM2.5 set forth in the 2008 PM2.5 NSR Rule were
developed pursuant to subpart 1, which does not provide for the
classification of designated nonattainment areas, the EPA has not yet
developed regulations to address subpart 4 requirements concerning
nonattainment areas classified as Serious. With respect to NNSR,
section 189(b)(3) provides that, for any PM10 nonattainment
area classified as Serious, the major source threshold with regard to
the terms ``major source'' and ``major stationary source'' shall be 70
tpy of PM10. Accordingly, the EPA is proposing to amend the
NNSR regulations at 40 CFR 51.165 consistent with this provision to
establish a major source threshold for new major stationary sources and
major modifications in PM2.5 nonattainment areas classified
as Serious consistent with subpart 4. The EPA is proposing to set the
major source threshold for direct PM2.5 emissions at 70 tpy.
See proposed 40 CFR 51.165(a)(1)(iv)(A)(1)(vii).
While the court decision did not mandate that the EPA define
``major source'' and ``major stationary source'' for PM2.5
at a threshold of 70 tpy of PM2.5 emissions for areas
reclassified as Serious, the most straightforward and consistent
application of section 189(b)(3) to PM2.5 nonattainment
areas is to establish the same numerical threshold for Serious
PM2.5 nonattainment areas as that which applies to Serious
PM10 nonattainment areas. Moderate nonattainment areas for
both PM10 and PM2.5 are already subject to the
same major source thresholds by statute, so the EPA believes that it is
also reasonable to establish the threshold for PM2.5 in
Serious areas at the same level as the threshold that applies to
PM10 in Serious areas. For the reasons explained below, the
EPA believes that potential alternative approaches to setting the major
source threshold for Serious PM2.5 nonattainment areas could
have significant drawbacks. Nevertheless, the EPA is proposing and
requesting comments on other possible thresholds for Serious areas.
A possible alternative approach would be to promulgate a
PM2.5 major source threshold lower than 70 tpy of
PM2.5 emissions, recognizing that PM2.5 is a
subset of PM10. Generally, any source's PM2.5
emissions will be a fraction of that source's PM10
emissions. However, determining the appropriate major source emissions
threshold for PM2.5 that would be equivalent to 70 tpy of
PM10 on a national basis is problematic because, while
PM2.5 is generally a subset of PM10, there is not
a consistent ratio of PM2.5 to PM10 emissions for
all stationary sources. Combustion sources, such as industrial and
commercial boilers that burn fossil fuels, and selected industrial
processes emit primarily finer particles within the PM2.5
size range, while other industrial processes--typically involving
crushing and grinding operations--tend to emit more coarse particles in
the PM10 size range. While the PM10:
PM2.5 ratio for most sources decreases when the overall
emissions of PM are controlled, the quantitative difference between
PM2.5 emissions and PM10 emissions from specific
sources can still be significant, thus making a national
PM2.5 major source threshold based on a single ratio
difficult to define. The EPA seeks comments on possible ways in which a
PM2.5 emissions rate different from the statutory 70 tpy
rate for PM10 emissions can be established, taking into
account variations in the PM10: PM2.5 ratio for
different source categories and activities.
Accordingly, while the EPA seeks comment on this alternative
approach, because of the associated limitations just described, the
first option (i.e., a major source threshold of 70 tpy of
PM2.5 emissions for stationary sources proposing to
construct or modify in PM2.5 nonattainment areas
reclassified as Serious) represents the agency's preferred approach.
b. Control requirements for new major stationary sources and major
modifications of PM2.5 precursors. The second key provision contained
in subpart 4 that is not contained in subpart 1 relates to the control
of major stationary sources and major modifications of precursor
pollutants. Section 189(e) provides that, with respect to NNSR, the
control requirements applicable to major stationary sources of
PM10 also apply to major stationary sources of
PM10 precursors, except that major stationary sources of a
particular precursor may be exempt from the control requirements that
apply to major stationary sources of PM10 if the state can
demonstrate (based on guidance provided by the EPA) that the precursor
emissions from those sources do not contribute significantly to ambient
PM10 concentrations that exceed the standard in the
nonattainment area.
The specific ``control requirements'' for new or modified major
stationary sources of PM2.5 are contained in section 173 of
the CAA (outlining requirements for the state permit program required
to be submitted in a state plan under section 189(a)(1)(A)) and
189(b)(3) (establishing a major source threshold for sources in Serious
areas). Consistent with these requirements, the EPA is proposing a
series of revisions to address PM2.5 precursors in the NNSR
regulations at 40 CFR 51.165, including: Revision of the definition of
``regulated NSR pollutant'' to require regulation under the permitting
program of all PM2.5 precursors; the establishment of major
stationary source thresholds (for both Moderate areas and Serious
areas) for all PM2.5 precursors; and, a provision for an
exemption from the NNSR requirements, pursuant to section 189(e) of the
CAA, for major stationary sources of any PM2.5 precursor
where such sources do not contribute significantly to ambient
concentrations of PM2.5 that exceed the standard in a
particular nonattainment area. As described in greater detail below,
the EPA is not at this time proposing any new significant emissions
rates for the PM2.5 precursors.
As described in Section VIII.A.2.b of this preamble, the NNSR
regulations at 40 CFR 51.165 currently require states to regulate new
major stationary sources and major modifications of SO2 and
NOX as precursors under the NNSR requirements for
PM2.5.\241\ Optionally, a state may avoid regulating new
major stationary sources and major modifications of NOX
under the NNSR requirements for PM2.5 if that state
demonstrates to the satisfaction of the EPA that NOX is not
a significant contributor to PM2.5 concentrations in a
particular PM2.5 nonattainment area. Similarly, the existing
regulations provide that a state may opt to regulate new major
stationary sources and major modifications of VOC or ammonia under the
NNSR requirements for PM2.5 if that state demonstrates to
the satisfaction of the EPA that VOC or ammonia are precursors for
PM2.5 that need to be controlled in a particular
[[Page 15432]]
PM2.5 nonattainment area.\242\ In accordance with the
court's statement that section 189(e) requires all PM2.5
precursors to be addressed, the EPA is proposing to revise the NNSR
regulations to require that new major stationary sources and major
modifications of SO2, NOX, VOC and ammonia meet
the NNSR requirements for PM2.5 in PM2.5
nonattainment areas. In doing so, the EPA believes that it is necessary
to propose several revisions to 40 CFR 51.165 to ensure that the NNSR
requirements for PM2.5 adequately address the regulated
precursors consistent with the requirements of subpart 4.
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\241\ See the definition of ``regulated NSR pollutant'' at
existing 40 CFR 51.165(a)(1)(xxxvii)(C)(2) and (3).
\242\ Ibid at (a)(1)(xxxvii)(C)(3) and (4).
---------------------------------------------------------------------------
First, the EPA is proposing to revise the regulations at 40 CFR
51.165 to ensure that new major stationary sources and major
modifications of the four scientific precursors for PM2.5
are subject to the same requirements under the NNSR regulations that
apply to new major stationary sources and major modifications of direct
PM2.5 emissions. As explained earlier in this preamble, the
court decision in NRDC vs. EPA concluded that section 189(e)
``expressly governs precursor presumptions'' and thus necessitates that
the EPA revise its existing provisions in the NNSR rules that indicate
that VOC and ammonia are not regulated PM2.5 precursors. The
EPA is thus proposing to revise the NNSR definition of ``regulated NSR
pollutant'' to ensure that the NNSR regulations are consistent in
establishing that SO2, NOX, VOC and ammonia are
all regulated PM2.5 precursors for purposes of NNSR
requirements, except under certain conditions explained below. See
proposed 40 CFR 51.165(a)(1)(xxxvii)(C)(2).
While section 189(e) generally requires that major stationary
sources of PM2.5 precursors must apply the control
requirements (including those for NNSR) for major stationary sources of
direct PM2.5 emissions, the section also provides for an
exemption from such requirements for any precursor for which ``the
Administrator determines that such sources do not contribute
significantly'' to the levels of PM2.5 that exceed the
standard in the nonattainment area. Section 189(e) further authorizes
the EPA to issue guidelines concerning the application of the exemption
process.
In Section III of this preamble, the EPA described the agency's
proposed approaches for interpreting requirements for states to control
PM2.5 precursors in their attainment plans for the
PM2.5 NAAQS, which includes several proposed options to
enable states to exempt a precursor from the attainment plan control
requirements (including NNSR) for a particular PM2.5
nonattainment area with the appropriate factual and analytical basis.
In summary, the options included: (i) Separate analyses to determine
which precursors are subject to the control requirements for attainment
plans and which precursors are subject to the control requirements for
NNSR for PM2.5; (ii) a technical demonstration showing that
all sources of a particular precursor do not significantly contribute
to the PM2.5 levels that exceed the standard in an area,
thus exempting the precursor from control under both the attainment
plan and NNSR programs; and, (iii) one analysis to determine whether
control measures for a precursor are not needed for expeditious
attainment for purposes of the attainment plan, which would also define
the precursors that should be addressed for NNSR for PM2.5.
Accompanying the description of each of the above options, Section
III.C of this preamble discusses the potential analytical requirements
for any proposed demonstration that any particular precursor should be
exempted from the control requirements for PM2.5 in a given
nonattainment area. The EPA is requesting comments on the three
precursor options and the technical approaches for requesting a
precursor exemption. Any comments received will be considered in
developing the agency's final policy for addressing PM2.5
precursors under the NNSR program for PM2.5.
The second proposed change with regard to the nonattainment area
control requirements for PM2.5 precursors involves the
definition of ``major stationary source'' as it relates specifically to
precursors. The EPA is proposing to revise the definition of ``major
stationary source'' contained in the NNSR regulations to ensure that
new sources that emit major amounts of any PM2.5 precursor
that the state is regulating in the attainment plan for the area are
appropriately considered major stationary sources subject to the NNSR
requirements for PM2.5. See proposed 40 CFR
51.165(a)(1)(iv)(A)(1). The proposed change concerning the regulation
of precursors for PM2.5 is being accomplished by adding to
the term ``regulated NSR pollutant'' the phrase ``(as defined in
paragraph (a)(1)(xxxvii) of this section).'' It should be noted that
the definition of ``major modification'' already contains this phrase.
As described above, the EPA is also proposing to revise the definition
of ``regulated NSR pollutant'' to clarify that four precursors are
being regulated for PM2.5 in nonattainment areas for
PM2.5. The EPA is proposing to set the major source
threshold for each PM2.5 precursor (SO2,
NOX, VOC and ammonia) at 100 tpy of each precursor for
sources locating in Moderate areas, and 70 tpy of any precursor for
sources locating in Serious areas. See proposed 40 CFR
51.165(a)(1)(iv)(A)(1) and (a)(1)(viii), respectively. For example, in
order to be a major source for purposes of the PM2.5 NAAQS,
the source would need to emit at least 100 tpy of PM2.5
emissions or at least 100 tpy of any individual PM2.5
precursor that is a regulated precursor in a Moderate PM2.5
nonattainment area. The individual treatment of pollutants and
precursors for applicability purposes is consistent with the EPA's
policy as explained in previous rulemakings.\243\
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\243\ ``Different pollutants, including precursors, are not
summed to determine applicability.'' See 73 FR 28231 (May 16, 2008),
at page 28331.
---------------------------------------------------------------------------
In proposing to set the major source threshold for each
PM2.5 precursor at 100 tpy for Moderate areas, the EPA is
following the precedent established in the 2008 PM2.5 NSR
Rule in which the agency set the same 100 tpy major source threshold
for PM2.5 and each of its precursors (at that time
SO2 and NOX).\244\ As the EPA stated in that 2008
notice, sections 169 and 302(j) of the CAA contain definitions of
``major emitting facility'' and ``major stationary source'' that apply
to programs implemented under subpart 1, which contain the PSD and NNSR
program requirements, respectively.\245\ Those definitions also apply
to programs implemented under subpart 4 to the extent that they
regulate areas classified as Moderate PM2.5 nonattainment
areas, as subpart 4 does not establish a different threshold for such
areas. This proposal to set the same 100 tpy major source thresholds
for sources of PM2.5 emissions and applicable
PM2.5 precursor emissions is also consistent with the
requirements of section 189(e), which make the control requirements
applicable to major stationary sources of PM10 also
applicable to major stationary sources of applicable PM10
precursors.\246\
---------------------------------------------------------------------------
\244\ Ibid.
\245\ Ibid.
\246\ See 57 FR 13498 (April 16, 1992), at page 13538.
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As noted above, section 189(b)(3) sets a lower major source
threshold of 70 tpy of PM10 emissions for sources locating
in PM10 nonattainment areas reclassified as Serious. Because
subpart 4 NNSR requirements must be applied to PM2.5, the
EPA must set a lower major source
[[Page 15433]]
threshold for PM2.5, pursuant to section 189(b)(3), in
PM2.5 nonattainment areas that are reclassified as Serious
areas. Thus, the EPA's preferred approach proposed above is to set a
major source threshold of 70 tpy of PM2.5 emissions for
sources in PM2.5 nonattainment areas reclassified as
Serious.
Consistent with this proposal, the EPA is also proposing to set the
major source threshold for Serious areas for each precursor at 70 tpy
of that particular precursor. As noted above, section 189(e) makes the
control requirements for major stationary sources of PM10
also applicable to major stationary sources of PM10
precursors; thus, in accordance with the provision of the statute, the
control requirements applicable to major stationary sources of
PM2.5 emissions are also applicable to major stationary
sources of PM2.5 precursors. Accordingly, the EPA must
develop a major source threshold for PM2.5 precursors that
is consistent with the threshold for direct PM2.5 that will
apply in PM2.5 nonattainment areas reclassified as Serious.
See proposed 40 CFR 51.165(a)(1)(iv)(1)(viii).
The EPA's proposal to set a major source threshold of 70 tpy for
Serious areas for each PM2.5 precursor is also consistent
with the approach the EPA has taken for establishing a major source
threshold for each PM10 precursor under subpart 4. In the
Addendum to the General Preamble offering guidance as to how to apply
the new subpart 4 requirements in Serious areas, the EPA indicated that
it interpreted the statute as applying the 70 tpy threshold to sources
of PM10 precursors.\247\
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\247\ See Addendum to the General Preamble, 59 FR 41998 (August
16, 1994), at page 42012 (defining major point sources in Serious
areas as ``sources with the potential to emit at least 70 tons per
year of PM10 (or PM10 precursors) as required
in sections 189(b)(3) and 189(e) of the Act'').
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The EPA also solicits comments on the appropriateness of setting
the precursor major source thresholds at a different rate, particularly
if, as alternatively proposed above, the agency defines ``major
stationary source'' for sources of direct PM2.5 in Serious
PM2.5 nonattainment areas at a rate lower than 70 tpy of
PM2.5 emissions. For example, if the agency sets the major
source threshold at 60 tpy of PM2.5 emissions in Serious
PM2.5 nonattainment areas, the agency would also consider
setting the major source threshold for each PM2.5 precursor
at 60 tpy of that particular precursor.
Moreover, the EPA believes that a reasonable argument can be made
that whatever threshold is set for PM2.5 emissions, the same
level would be too low to be regarded as ``major'' for each precursor
when considering the effects that such precursor sources could have on
ambient PM2.5 concentrations. The EPA previously analyzed
the relationship between emissions of SO2 and NOX
and the formation of secondary PM2.5 in the ambient air
expressly for purposes of determining an appropriate ratio for allowing
interprecursor offsets for PM2.5. Those studies resulted in
the EPA providing in the 2008 PM2.5 NSR Rule ``preferred''
ratios for both SO2 and NOX, whereby a source
could obtain reductions of a PM2.5 precursor to offset an
increase of direct PM2.5 emissions or another
PM2.5 precursor based on the ``preferred'' offset
ratios.\248\ In brief, the preferred ratios were as follows: For
NOX-to-primary PM2.5: 200 to 1 (NOX
tons to PM2.5 tons) for areas in the eastern U.S, and 100 to
1 for areas in the western U.S.; and for SO2-to-primary
PM2.5: 40 to 1 (SO2 tons for PM2.5
tons). In each case, the ratio illustrates that it requires
considerably more precursor emissions than direct PM2.5
emissions to result in a particular ambient concentration of
PM2.5. It should be noted that at that time the EPA did not
consider using the preferred ratios for the purpose of adjusting the
major source thresholds or significant emissions rates for
SO2 and NOX when regulating them as
PM2.5 precursors.
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\248\ The technical assessment, with details on data and
modeling inputs, was fully described in a technical memo titled
``Details on Technical Assessment to Develop Interpollutant Trading
Ratios for PM2.5 Offsets,'' which was placed in the
docket to the 2008 final rule. See also 73 FR 28321 (May 16, 2008),
at page 28339.
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The preferred ratios as presented in the 2008 notice were later
challenged in a petition for reconsideration and the EPA withdrew them
via an EPA memorandum issued in 2011.\249\ In withdrawing the preferred
ratios, the EPA cited several concerns. First, it was determined that
the preferred ratios were not sufficiently conservative to be
representative of conditions in all areas of the country. Second, the
EPA determined that the preferred ratios were not adequate for
addressing the precursor relationship to ambient PM2.5
concentrations for the short-term (daily) averaging period.\250\ In
addition, the EPA believes that the overall analysis conducted for the
2008 notice generally illustrates that the threshold for defining
``major'' for either SO2 or NOX as precursors for
PM2.5 could reasonably be set at an emissions rate
considerably higher than 70 tpy of that particular precursor and be
equally protective of air quality as the 70 tpy threshold applied to
PM2.5 emissions.
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\249\ Memorandum from Gina McCarthy, then EPA Assistant
Administrator, dated July 21, 2011, titled ``Revised Policy to
Address Reconsideration of Interpollutant Trading Provisions for
Fine Particles (PM2.5)'' and sent to Regional Air
Division Directors.
\250\ Nevertheless, while the ratios are no longer considered
appropriate to use presumptively to meet the NNSR requirements for
emissions offsets, a state may still conduct its own analysis and
propose area-specific ratios for EPA approval on a case-by-case
basis for interpollutant offset trading.
---------------------------------------------------------------------------
Although the statutory definition at section 189(b)(3) applicable
to PM10 does not explicitly apply to other pollutants, the
EPA is considering the possibility that it may not have the legal
authority to set a higher major source threshold for PM2.5
precursors, even if it were technically justified. As previously noted,
section 189(e), as interpreted in light of the court decision in NRDC
v. EPA, requires that the same control requirements applicable to major
stationary sources of PM2.5 also apply to major stationary
sources of PM2.5 precursors. Courts have determined in other
contexts that the term ``controls'' under the CAA includes NSR
requirements, and in particular includes major source thresholds as
specified in the statute.\251\ Thus, if the holding of South Coast
directs the EPA's actions, section 189(e) must be read to require the
same major source threshold be applied to PM2.5 precursors
as applies to direct emissions of PM2.5.
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\251\ See South Coast Air Quality Management District v. EPA,
472 F.3d 882, 900-902 (D.C. Cir. 2006) (holding that ``controls'' in
section 172(e) anti-backsliding provision include NSR requirements
such as LAER, offset ratios, and major source thresholds).
---------------------------------------------------------------------------
This conclusion is also consistent with the limited legislative
history on this issue. A House (of Representatives) Report accompanying
the 1990 amendments to the CAA described the effects of adding section
189(b)(3) to include the requirement that ``new or modified sources
emitting 70 tons or more per year of VOC will be subject to new source
review requirements.'' \252\ Thus, Congress seems to have contemplated
that the same major source threshold would apply to sources of
PM2.5 emissions and PM2.5 precursors in Serious
areas.
---------------------------------------------------------------------------
\252\ H.R. Rep. 101-490.
---------------------------------------------------------------------------
The EPA does not believe that a sufficient technical basis exists
at this time to enable the agency to propose specific higher major
source thresholds for any of the four PM2.5 precursors
presumptively regulated in PM2.5 nonattainment areas. The
EPA intends to continue its analysis of the relationship between each
precursor and ambient PM2.5 concentrations with the
possibility that higher major source thresholds for specific precursors
could be established in the future. In the meantime, the agency
solicits comments
[[Page 15434]]
on the general appropriateness of setting higher major source
thresholds for one or more PM2.5 precursors in
PM2.5 nonattainment areas, as well as legal and technical
considerations that should be made as part the EPA's future analysis of
NNSR requirements with respect to PM2.5 precursors.
c. Significant emissions rates for PM2.5 precursors. As explained
above, a modification to an existing major stationary source of a
nonattainment pollutant such as PM2.5 is a major
modification and subject to the NNSR requirements for that pollutant
when the source proposes to make a physical or operational change that
results in both a significant emissions increase and a significant net
emissions increase of that nonattainment pollutant. With regard to
PM2.5 precursors, a modification to a major stationary
source of any such precursor is likewise a major modification subject
to the NNSR requirements for PM2.5 when the source proposes
a physical or operational change resulting in a significant net
emissions increase of that precursor. The EPA defined ``significant''
for SO2 and NOX as PM2.5 precursors in
the 2008 PM2.5 NSR Rule. For both precursors, the EPA set
the significant emissions rate for each pollutant when it is regulated
as a precursor to PM2.5 at 40 tpy, the same level as the
existing significant emissions rate for the pollutant as independently
regulated as a criteria pollutant for purposes of the SO2
and NO2 NAAQS.\253\ Also, in the preamble to the 2008
PM2.5 NSR Rule, the EPA indicated that it would consider 40
tpy for VOC as a PM2.5 precursor; however, that rate was not
codified in any of the NSR regulations because the regulations provided
that VOC was generally presumed not to be a precursor to
PM2.5. Instead, the agency explained that any state making a
demonstration that VOC should be treated as a PM2.5
precursor in a particular nonattainment area ``would be required to
adopt the 40-tpy significant emissions rate unless it demonstrated that
a more stringent significant emissions rate (lower rate) is more
appropriate.'' \254\
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\253\ See the Federal Register published on May 16, 2008 (73 FR
28321, 28333 and 28334); and existing 40 CFR 51.165(a)(1)(x)(A).
\254\ See the Federal Register published on May 16, 2008 (73 FR
28321 and 28333).
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The 2008 PM2.5 NSR Rule codified the presumption that
ammonia, like VOC, need not be regulated as a PM2.5
precursor and the EPA did not set a significant emissions rate for
ammonia. Instead, the agency indicated that it was allowing states that
determine that ammonia significantly contributes to PM2.5
concentrations in a given PM2.5 nonattainment area to set
the significant emissions rate for ammonia based on information
developed for each individual attainment plan.\255\
---------------------------------------------------------------------------
\255\ Ibid.
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As explained in the 2008 PM2.5 NSR Rule, the EPA set the
significant emissions rates for the presumed PM2.5
precursors at the levels for those pollutants already included in NSR
programs. The EPA explained that the use of the existing rates where
the PM2.5 precursor is also regulated as a separate criteria
pollutant harmonizes the NSR program for PM2.5 with the NSR
programs for those other criteria pollutants. The agency further
explained that this approach for setting the significant emissions
rates for PM2.5 precursors follows the precedent for setting
the significant emissions rate for NOX as a precursor to
ozone, where the same 40 tpy threshold was used for NOX
emissions as both a criteria pollutant (NO2) and a precursor
for ozone.\256\
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\256\ See 73 FR 28321 (May 16, 2008), at page 28334.
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Nevertheless, the EPA gave some consideration in the development of
the 2008 PM2.5 NSR Rule to setting the significant emissions
rates for the individual PM2.5 precursors at different
levels based on the effect of each precursor on ambient
PM2.5 concentrations. The EPA concluded that it did not have
adequate data on the impacts of precursor emissions from individual
sources to override the administrative advantages of setting the
significant emissions rates for SO2, NOX and VOC
for purposes of the PM2.5 NSR program at the same levels
that are already used for other purposes in the major NSR program for
other NAAQS. The EPA continues to believe, however, that when more data
are available, these data could provide a reasonable basis for
considering subsequent changes to the significant emissions rates for
each PM2.5 precursor for purposes of implementing the
PM2.5 NAAQS, whereby the significant emissions rates for the
individual PM2.5 precursors could more realistically reflect
the effect that each precursor has on ambient PM2.5
concentrations.
The EPA is currently undertaking a separate rulemaking for both
NNSR and PSD in which it intends to include a technical analysis of
each PM2.5 precursor to better understand the relationship
of emissions of each precursor to ambient PM2.5
concentrations. The agency intends to consider the results of that
analysis and other factors and may propose new significant emissions
rates accordingly for SO2 and NOX as
PM2.5 precursors. The EPA also intends to propose individual
significant emissions rates for VOC and ammonia as PM2.5
precursors at that time. Thus, the EPA is not proposing any changes to
the existing significant emissions rates for SO2 and
NOX as PM2.5 precursors in this document.
It is the EPA's expectation that any new or revised significant
emissions rates for the individual PM2.5 precursors will
become effective in that separate rulemaking not long after the date of
that final rule, allowing states to adopt and use them in their own
NNSR regulations once the EPA approves their individual SIPs. However,
in the event that the timing of that rule does not allow ample time for
states to rely on it to adopt any new or revised significant emissions
rates in their rules, it was explained earlier that individual
significant emissions rates already exist for SO2 and
NOX at 40 tpy. Additionally, the significant emissions rate
for VOC was identified as 40 tpy in the 2008 PM2.5 NSR Rule
notice (though not in the final regulations), but the EPA is proposing
to add that precursor and emissions rate to the list of
PM2.5 precursors. See proposed 40 CFR 51.165(a)(1)(x)(A).
Hence, only the ammonia significant emissions rate would remain to be
defined by each state that needs to control major stationary sources of
ammonia as part of their NNSR program.
d. Transition provisions for PM2.5. The CAA requires proposed major
stationary sources and major modifications to meet major NSR permitting
requirements that apply on the basis of the area's attainment
designation.\257\ Accordingly, the EPA's longstanding interpretation of
the CAA is that a proposed new major stationary source or major
modification must satisfy the appropriate major NSR requirements (PSD
vs. NNSR) for a particular pollutant that are in effect on the date
that a permit is issued to the source, rather than the requirements
that may have been applicable when the permit application was
submitted.\258\
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\257\ Compare CAA section 165(a) (permitting requirements for
sources locating in attainment and unclassifiable areas) with
sections 172(c)(5) and 173 (permitting requirements for sources
locating in nonattainment areas).
\258\ See Memorandum from John S. Seitz, Director, EPA Office of
Air Quality Planning and Standards, on March 11, 1991, titled ``New
Source Review (NSR) Transitional Guidance,'' Attachment p. 6, sent
to Regional Air Division Directors.
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In the final 2012 PM NAAQS rule, the EPA established a
grandfathering provision that would enable some proposed new and
modified sources
[[Page 15435]]
that had already submitted a PSD application prior to the effective
date of the revised primary annual PM2.5 NAAQS to continue
being reviewed under the pre-existing PSD requirements for
PM2.5. This provision applies where the PSD program
continues to be the applicable set of major NSR requirements for the
area of concern. In response to the EPA's proposal to add this
grandfathering provision for certain PSD permit applications pending
upon the effective date of the new NAAQS, the EPA received comments
concerning the need for a transition period for implementing the NNSR
requirements in newly designated PM2.5 nonattainment areas
as a result of the tightening of the primary annual PM2.5
NAAQS.\259\ The commenters recommended that the EPA establish a
grandfathering provision to enable pending permit applications to
continue under review for the pre-existing requirements. A subset of
the commenters recommended that grandfathering be accomplished by
establishing an effective date for designations 1 year after initial
publication in the Federal Register. Presumably, these commenters
believed that by delaying the effective date of any new nonattainment
designations for the primary annual PM2.5 NAAQS, sources
with pending PSD permit applications could continue to be reviewed
under the PSD permitting requirements rather than the NNSR requirements
for PM2.5.
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\259\ See 78 FR 3086 (January 15, 2013), at page 3263.
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In the final 2012 PM NAAQS rule, the EPA expressed its disagreement
with those commenters, explaining that the obligation to adopt new
provisions under a state's NNSR program will not apply with regard to
the revised NAAQS until such time as an area is designated
nonattainment, and beginning on the effective date of the new area
designations for PM2.5 proposed new and modified major
sources would be required to meet the applicable NNSR requirements for
PM2.5.\260\ However, the EPA further indicated that it would
continue to consider the need to establish a grandfathering provision
under the NNSR program for PM2.5, and would propose such
provision, if appropriate, as part of a subsequent NSR implementation
rulemaking with additional opportunity for public comment.\261\
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\260\ The applicable NNSR requirements would be either the NNSR
requirements for PM2.5 in the state's existing SIP or the
requirements found at 40 CFR part 51 Appendix S, where a state's SIP
does not currently include NNSR requirements for PM2.5.
States will be required to submit to the EPA for approval SIP
revisions containing the amended NNSR program requirements for
PM2.5 contained in the final PM2.5 NAAQS
implementation rule being proposed in this notice, but those
additional requirements will not apply in states with SIPs that
include NNSR requirements for PM2.5 until the EPA
approves the SIP revision. See ibid.
\261\ Ibid.
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After further considering the issue during the development of this
proposal, the EPA has decided not to propose a grandfathering provision
that would apply to pending PSD permit applications that were submitted
but not approved prior to the effective date of the new nonattainment
designations for the 2012 primary annual PM2.5 NAAQS. The
EPA does not believe it would be acceptable for the EPA or a state to
issue a PSD permit, instead of a NNSR permit, with regard to a
particular pollutant for which an area is designated nonattainment on
the date the permit is to be issued. Instead, if the PSD permit has not
been issued by the effective date of the new nonattainment designation,
then the applicant should be required to withdraw that part of the
permit application that addresses the nonattainment pollutant and
submit an application that satisfies the applicable NNSR or minor NSR
requirements in effect in the implementation plan on the date the
permit will be issued. Given adverse conditions that already exist in a
nonattainment area and the congressional directive to reach attainment
as expeditiously as practicable, construction at a major stationary
source that significantly increases emissions in such an area should be
expected to address NNSR requirements, even if this could cause delay
to the permit applicant.
As explained in Section VIII.D of this preamble, states will have
18 months from the date of the new nonattainment designations to revise
their existing NNSR programs or establish new programs in accordance
with the applicable requirements under subpart 4. Where the area was
already designated nonattainment for any prior PM2.5 NAAQS
before the effective date of designations for the 2012 NAAQS, the state
should continue to apply the NNSR requirements contained in the
approved SIP to issue the final permit addressing all PM2.5
NAAQS until the new SIP revisions required by this rule are approved.
In areas already designated nonattainment for any PM2.5
NAAQS but lacking an approved NNSR program that applies to
PM2.5, the requirements of Appendix S may continue to be
applied for issuing permits in that area. However, any changes to the
Appendix S requirements that the EPA may make via this rulemaking must
be implemented in any area that applies Appendix S once these revisions
become effective. Section VIII.C.2 that follows discusses the possible
changes to the NNSR requirements in Appendix S that the agency is
proposing in this action.
The EPA is not proposing to add any grandfathering provisions that
would apply to changes in NNSR permitting requirements in areas that
the EPA may already have designated nonattainment for PM2.5
at the time the source submitted a permit application. For reasons
similar to those identified above in cases where an area designation
changes, the EPA generally believes that major sources that would
contribute to the air quality in an area that is not meeting the NAAQS
for a particular pollutant should be expected to address the most
current requirements that apply in the nonattainment area. The agency
acknowledges it is possible that a proposed new or modified source may
need to address additional precursor control requirements that did not
apply when a permit application was submitted once the EPA's final rule
is promulgated and the appropriate revisions are approved into a
state's NNSR SIP. However, based on the terms of section 189(e) of the
CAA, the EPA generally believes that those requirements should be
addressed in pending permit applications unless the air agency has
determined, and the EPA has approved such demonstration, that major
stationary sources of that precursor do not contribute significantly to
PM2.5 levels in the nonattainment area. Nevertheless, the
agency recognizes that there may be certain circumstances where
proposed construction might be delayed and an applicant may feel
fundamental fairness would support exempting a particular pending
permit from newly established requirements; therefore, the EPA seeks
comment on what circumstances, if any, would justify a grandfathering
provision for pending nonattainment NSR permits similar to the
grandfathering provision promulgated in the final 2012 PM NAAQS Rule
for PSD permitting purposes. See 40 CFR 51.166(i)(10) 52.21(i)(11). In
addition, the EPA requests comment on how such a grandfathering
provision would be consistent with the relevant provisions of the CAA.
The EPA does not believe the statutory deadline in section 165(c) that
forms part of the EPA's basis for grandfathering in the PSD context is
applicable to NNSR permit decisions.
2. What are the changes the EPA is proposing in Appendix S?
As described above, 40 CFR 52.24(k) provides that the Emission
Offset
[[Page 15436]]
Interpretative Ruling, 50 CFR part 51, Appendix S, shall govern permits
to construct and operate for which a NNSR permit application is
submitted between the effective date of designation as nonattainment
and the date a state's NSR permit program meeting the requirements of
part D is approved and effective. The EPA is considering a range of
options concerning how and whether to address the proposed subpart 4
requirements in the interim NNSR program requirements contained in
Appendix S.
Permitting requirements for new major stationary sources and major
modifications in PM2.5 nonattainment areas were originally
added to Appendix S in the 2008 PM2.5 NSR Rule. The
amendments generally followed the NNSR requirement contained in subpart
1 of part D. However, in the 2008 PM2.5 NSR Rule, the EPA
determined that, in light of the transitional function of Appendix S,
it would be appropriate to regulate PM2.5 precursors under
Appendix S in a manner that differed slightly from the regulatory
approach taken in 40 CFR 51.165.
As explained in Section VIII.B.2 of this preamble, under the
existing requirements for NNSR plans at 40 CFR 51.165, SO2
is regulated as a PM2.5 precursor, NOX is
presumed to be a regulated PM2.5 precursor, and VOC and
ammonia are presumed not to be regulated precursors (with either states
or the EPA having authority to rebut any such presumption for a
particular nonattainment area). However, in developing Appendix S, the
EPA determined that it would be premature to presume that
NOX is a regulated PM2.5 precursor in all
PM2.5 nonattainment areas that proposed new major sources
and major modifications in those areas should be required to address as
a prerequisite to obtaining a NNSR permit, while at the same time the
states were in the process of determining whether in fact
NOX emissions contribute significantly to ambient
PM2.5 concentrations in those areas. Accordingly, the EPA
decided to delay implementing any control requirements for
NOX as a PM2.5 precursor until the states
completed the necessary analyses to determine the need for
NOX controls as part of their SIP revisions addressing the
revised PM2.5 NAAQS. Thus, the existing NNSR requirements
for PM2.5 under Appendix S do not contain a requirement for
proposed sources to consider the control of NOX emissions as
a PM2.5 precursor. Moreover, as states presumptively did not
need to regulate VOC and ammonia in accordance with the 2008
PM2.5 NSR Rule in 40 CFR 51.165, the EPA similarly did not
require sources seeking permits pursuant to the Appendix S requirements
to address those precursors.
As an interim measure to facilitate permitting while states develop
NNSR rules for PM2.5, the EPA believes that the NNSR
requirements under Appendix S need not be identical to those governing
states' development of approvable programs pursuant to subpart 4, which
requires regulation of all PM2.5 precursors unless a state
provides, and the EPA approves, a demonstration that such control is
not necessary for major stationary sources in the area under section
189(e). This is reasonable because the EPA anticipates that many states
may be able to demonstrate to the EPA that there is not a need to
regulate one or more PM2.5 precursors from major stationary
sources in a given nonattainment area, as described in Section III of
this preamble.
Accordingly, the EPA is proposing to revise the definition of
regulated NSR pollutant as contained in Appendix S to provide for the
regulation of some precursors during the transition period, but not
others. Specifically, for reasons explained below, the EPA is proposing
to require that both SO2 and NOX be considered
regulated PM2.5 precursors in Appendix S and is proposing a
significant emissions rate of 40 tpy for NOX as a
PM2.5 precursor. See proposed Sections II.A.31(iii)(b) and
II.A.10(i) of Appendix S, respectively. However, this proposal would
not provide states the option of submitting a demonstration that could
relieve them of the obligation to regulate SO2 and
NOX as PM2.5 precursors during the transition
period. The EPA believes that it is not necessary or efficient to
expend effort on such a demonstration for the transitional program,
when states are developing the demonstration for submittal with the
NNSR SIP submission that, when approved, would replace the Appendix S
transitional program for that area.
The EPA is proposing to include SO2 and NOX
in Appendix S based on the principle that the national application of a
transition program should correspond to the general expectation of what
the prevailing regulation of precursors will ultimately be when SIPs
are submitted. Although such expectations are uncertain at this time,
it is nonetheless appropriate to base the transition program on them.
The EPA believes it is likely in many cases that states will determine
that emissions of VOC and/or ammonia do not contribute significantly to
PM2.5 concentrations in the affected PM2.5
nonattainment area, although such determinations should be made on a
case-by-case basis for individual PM2.5 nonattainment areas.
On the other hand, the EPA expects that the cases where
NOX does not contribute significantly to PM2.5
concentrations in the affected PM2.5 nonattainment area will
be few in number. Accordingly, given this likelihood, the EPA believes
that it is reasonable to require the regulation of SO2 and
NOX as PM2.5 precursors during the interim period
when states are developing their PM2.5 attainment plans for
newly designated areas (including the necessary revisions to the NNSR
programs based on subpart 4). An added benefit of this proposed
approach is that it will also ensure that states using the permitting
requirements contained in Appendix S will regulate the same precursors
that are required to be regulated in states that have already adopted
NNSR for PM2.5 based on the 2008 PM2.5 NSR Rule.
The EPA seeks comment on this approach as part of this proposal.
As one alternative approach that the EPA is presenting for public
comment, the agency is proposing to amend Appendix S to regulate not
only SO2 and NOX, but also VOC and ammonia, as
PM2.5 precursors that must be controlled during this interim
period. This alternative would more closely match the basic NNSR
program requirements of subpart 4, which indicate that states should
regulate precursors from major stationary sources in the nonattainment
area unless the EPA has determined that such emissions do not
significantly contribute to violations of the NAAQS in the area.
However, it would require states to control new major stationary
sources and major modifications of each PM2.5 precursor
during the interim period prior to submission of the required SIP
revisions without the benefit of first allowing states to determine
whether the control of each precursor is warranted. The EPA does not
prefer this option for amending Appendix S as an interim NNSR program;
however, the EPA is seeking comment on the approach to address the
policy and legal implications associated with it. This alternative,
while being proposed for comment, is not shown in the proposed
regulatory text.
Another alternative that the agency is proposing for comment is for
the EPA to establish a phased-in process for regulating
PM2.5 precursors in the NNSR program whereby states would
initially require sources issued a permit to control only
SO2 and NOX as PM2.5 precursors (as
under the preferred option), with a second requirement to later require
sources issued a permit
[[Page 15437]]
after the prescribed date (e.g., the date on which SIP revisions based
on subpart 4 requirements are due) to control emissions of VOC and
ammonia as well. For each precursor, the requirement to control would
apply to major stationary sources of that particular precursor. The EPA
believes that by phasing in the requirement to address all precursors,
states that are ultimately able to demonstrate to the EPA's
satisfaction that VOC and/or ammonia do not need to be subject to
control under the NNSR requirements for PM2.5, but that have
not yet submitted such demonstration, will have ample time to make the
necessary demonstration and will not have to control such precursors
even temporarily. At the same time, the phase-in provision could
address concerns about delays in SIP submittal or approval in states
with PM2.5 nonattainment areas in which VOC and ammonia need
to be regulated. Such delays could result in prolonged exclusion of
these precursors from control requirements beyond the time when an EPA-
approved state NNSR program is expected to be in place. This
alternative, while being proposed for comment, is not shown in the
proposed regulatory text.
Separately, the EPA is proposing to amend Appendix S by revising
the definition of ``major stationary source'' to include a separate
PM2.5 major source threshold applicable to new major
stationary sources and major modifications in PM2.5
nonattainment areas reclassified as Serious areas. See proposed section
II.A.4(i)(a)(7). Inclusion of the new definition is not an immediate
concern for the revised 2012 primary annual PM2.5 NAAQS or
any future revision to the PM2.5 NAAQS because the possible
reclassification of any Moderate area to a Serious area will not occur
for several years and states are required to submit their SIP revisions
addressing NNSR requirements prior to such time. There is a
possibility, however, that existing PM2.5 nonattainment
areas (for the 1997 and/or 2006 PM2.5 NAAQS) could be
reclassified as Serious areas sooner. States that still do not have
approved NNSR programs addressing PM2.5 would be without the
appropriate NNSR provisions to address new major stationary sources and
major modifications in those Serious areas until they submit revisions
to their existing programs and the EPA approves those revisions. The
EPA solicits comments on this proposal to incorporate a definition of
``major stationary source'' for PM2.5 nonattainment areas
reclassified as Serious.
The EPA is not proposing any Appendix S provisions for
grandfathering proposed new and modified sources from newly established
permit requirements applicable to PM2.5 nonattainment areas.
The EPA generally believes that it would not be appropriate to
grandfather sources from requirements that apply in areas that are not
meeting the NAAQS. Nevertheless, the EPA seeks comment on possible
circumstances where grandfathering, similar to the grandfathering
provision established for pending PSD permits under the final 2012 p.m.
NAAQS Rule, may be appropriate with respect to changes made to Appendix
S.
D. Plan Due Dates
For Moderate areas, section 189(a)(2)(B) requires that states make
an attainment plan submission satisfying the requirements contained
therein, including applicable NNSR programs for PM10 (and
PM2.5), to the EPA for approval within 18 months of an area
being designated nonattainment. The agency recognizes that this
submittal date represents a considerably earlier date than anticipated
when it issued the final 2012 p.m. NAAQS rule.\262\ However as the CAA
requires, the EPA will apply the 18 month deadline from the effective
date of designation of a Moderate PM2.5 nonattainment area
for the submission of any applicable NNSR program revisions for
PM2.5 as included in any final implementation rule.
---------------------------------------------------------------------------
\262\ Ibid.
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In the event a Moderate area is reclassified as a Serious
PM2.5 nonattainment area, it will be required to implement
the NNSR program with a ``major stationary source'' threshold of 70
tons per year (per CAA section 189(b)(3)). However, the CAA does not
specify a deadline for the state's submittal of any NNSR program
revisions (e.g., to lower the major stationary source threshold from
100 tpy to 70 tpy) that would be needed to implement the program in a
Serious area. Pursuant to the EPA's gap-filling authority in CAA
section 301(a), and to effectuate the statutory control requirements in
section 189 of the CAA, the EPA proposes to require the state to submit
these NNSR SIP revisions no later than 18 months from the effective
date of final reclassification of the area as a Serious nonattainment
area. This timeframe is consistent with the 18 month timeframe required
for submittal of certain Serious area plan elements, and it is
consistent with the 18 month time for submittal of Moderate area plan
revisions. We also request comment on a 12-month timeframe for
submittal of the NNSR revisions for Serious areas. An approach that
requires the NNSR revisions to be submitted on the same 18-month
schedule as other Serious area plan elements is expected to be more
administratively efficient than one that would require the NNSR
revisions on a different schedule. On the other hand, this type of
revision to the NNSR regulations may be relatively straightforward and
potentially could be completed within 12 months of the reclassification
date, thereby assuring that new major sources or modified major sources
in the area will be subject to the lower statutory major source
thresholds expeditiously. The EPA requests comment on both the proposed
18-month timeframe for submission of the NNSR SIP revisions for Serious
areas and the alternative 12-month option.
E. Avoidance of Dual Review for PSD and NNSR for PM2.5
Because the EPA designates nonattainment areas for the primary
annual and 24-hour PM2.5 NAAQS independently, some areas
ultimately may be designated nonattainment for one of these standards
and unclassifiable/attainment or attainment for another. This may raise
concerns that the sources locating in such an area may be subject to
both PSD and NSSR for the same pollutant. In the preamble to the final
2012 p.m. NAAQS rule, the EPA explained that the existing PSD
regulations resolved this issue.\263\ Specifically, the PSD regulations
at 40 CFR 51.166(i)(2) and 52.21(i)(2) provide that the PSD
requirements do not apply to a major stationary source or major
modification with respect to a pollutant when ``as to that pollutant,
the source or modification is located in an area designated as
nonattainment . . . .'' \264\ [emphasis added]. This policy was
explained in the preamble to the final rule promulgating the revised
primary annual PM2.5 NAAQS.\265\ The EPA is simply
reiterating in this action the agency's policy for addressing NSR
applicability for areas that may be designated nonattainment for one
averaging period and attainment or unclassifiable for another averaging
[[Page 15438]]
period. Thus, for PM2.5 only the NNSR requirements would
apply with regard to major stationary sources of PM2.5
locating in that nonattainment area.
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\263\ See ibid.
\264\ The policy for applying the PSD exemption is clear with
regard to the federal PSD program at 40 CFR 52.21; however, the
requirements for a SIP-approved PSD program state that ``[t]he plan
may provide . . .'' Accordingly, a state may choose to apply a
different applicability strategy if it so wishes.
\265\ Ibid.
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IX. What other proposed requirements would apply in PM2.5
nonattainment areas?
A. Waivers Under Section 188(f)
1. Statutory Requirements and Existing Guidance
Section 188(f) of the CAA provides a means for the EPA to waive a
specific date for attainment and certain control and planning
requirements for PM2.5 nonattainment areas if certain
conditions are met in the nonattainment area. Specifically, the statute
provides that: ``The Administrator may, on a case-by-case basis, waive
any requirement applicable to any Serious Area . . . where the
Administrator determines that anthropogenic sources of PM10
do not contribute significantly to the violation of the PM10
standard in the area.'' In addition, ``the Administrator may also waive
a specific date for attainment of the [PM10] standard where
the Administrator determines that nonanthropogenic sources of
PM10 contribute significantly to the violation of the
PM10 standard in the area.'' In the Addendum, the EPA
provided extensive guidance on how the agency interpreted section
188(f) and how it intended to apply the statutory waiver provisions for
purposes of implementing the PM10 NAAQS.\266\ At this time,
the EPA is not proposing to revise the guidance presented in the
Addendum with respect to section 188(f), but the agency requests
comment on whether the existing guidance in the Addendum is appropriate
when implementing the current and any future PM2.5 NAAQS.
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\266\ 59 FR 41998 (August 16, 1994), at page 42004.
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2. Relationship Between the CAA Section 188(f) Waiver Provisions and
the EPA's Exceptional Events Rule
On March 22, 2007, the EPA promulgated the ``Treatment of Data
Influenced by Exceptional Events; Final Rule'' (72 FR 13560), known as
the Exceptional Events Rule, pursuant to the 2005 amendment of CAA
section 319.\267\ The Exceptional Events Rule provides a mechanism by
which the EPA can concur with an air agency's request to exclude from
regulatory decisions air quality monitoring data determined by the EPA
to have been affected by exceptional events.\268\ The Exceptional
Events Rule applies to all NAAQS pollutants, including
PM2.5. Section 188(f) and the Exceptional Events Rule
provide separate mechanisms by which states and/or other air agencies
can seek to have event-influenced monitoring data excluded from certain
regulatory requirements or decisions associated with the PM NAAQS
implementation process, under appropriate circumstances. This section
explains the EPA's views on how these two mechanisms can operate.
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\267\ Section 319 of the CAA, as amended by section 6013 of the
Safe Accountable Flexible Efficient-Transportation Equity Act: A
Legacy for Users (SAFE-TEA-LU) of 2005, required the EPA to propose
and promulgate regulations governing the review and handling of air
quality monitoring data influenced by exceptional events.
\268\ References to ``air agencies'' are meant to include state,
local and tribal air agencies responsible for implementing the
Exceptional Events Rule.
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The Exceptional Events Rule addresses elevated emissions from
specific events that influence monitored air quality concentrations.
The EPA's regulations at 40 CFR 50.1(j) define an ``exceptional event''
as one that ``affects air quality, is not reasonably controllable or
preventable, is an event caused by human activity that is unlikely to
recur at a particular location or a natural event, and is determined by
the Administrator in accordance with 40 CFR 50.14 to be an exceptional
event.'' Further, 40 CFR 50.1(j) explicitly provides that exceptional
events do ``. . . not include stagnation of air masses or
meteorological inversions, a meteorological event involving high
temperatures or lack of precipitation, or air pollution relating to
source noncompliance.'' At 40 CFR 50.1(k), the EPA's regulations define
a ``natural event'' as an event in which human activity plays little or
no direct causal role to the event in question.\269\ The Exceptional
Events Rule allows the EPA to exclude from regulatory decisions air
quality monitoring data that it determines to have been influenced by
emissions that result from exceptional events. Air quality monitoring
data that the EPA determines to have been influenced by an exceptional
event under the procedural steps, substantive criteria, and schedule
specified in the Exceptional Events Rule may be excluded from
regulatory decisions such as initial area designations decisions and
decisions associated with implementing the PM2.5 NAAQS such
as clean data determinations, evaluation of attainment demonstrations,
and discretionary or mandatory reclassifications of nonattainment areas
from Moderate to Serious. While the EPA may agree with an air agency's
request to exclude event-influenced air quality monitoring data from
regulatory decisions, these regulatory actions require the EPA to
provide an opportunity for public comment on the claimed exceptional
event and all supporting data prior to the EPA taking final agency
action.
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\269\ The EPA will generally consider human activity to have
played little or no direct role in causing emissions of the dust
generated by high wind for purposes of the regulatory definition of
``natural event'' if contributing anthropogenic sources of the dust
are reasonably controlled at the time of the event, regardless of
the amount of dust coming from these reasonably controlled
anthropogenic sources, and thus the event could be considered a
natural event. In such cases, the EPA believes that it would
generally be a reasonable interpretation of its regulations to find
that the anthropogenic source had ``little'' direct causal role. If
anthropogenic sources of windblown dust that are reasonably
controllable but that did not have those reasonable controls applied
at the time of the high wind event have contributed significantly to
a measured concentration, then the event would not be considered a
natural event. See preamble to the Exceptional Events Rule at 72 FR
13560 (March 22, 2007), footnote 11 on page 13566.
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If wildfire is a potential contributor to exceedances of the NAAQS
and exceptional events, the EPA urges state and local agencies to
coordinate with the land management agencies, as appropriate, in
developing plans and appropriate public communications regarding public
safety and reducing exposure. This action can directly help states meet
their Exceptional Events Rule obligation whereby ``states must provide
public notice, public education, and must provide for implementation of
reasonable measures to protect public health when an event occurs.''
When wildfire impacts are significant in a particular area, air
agencies and communities may be able to lessen the impacts of wildfires
by working collaboratively with land managers and land owners to employ
various mitigation measures including taking steps to minimize fuel
loading in areas vulnerable to fire.\270\
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\270\ Because of previously expressed stakeholder feedback
regarding implementation of the Exceptional Events Rule and specific
stakeholder concerns regarding the analyses that can be used to
support wildfire-related exceptional event demonstrations, the EPA
intends to propose revisions to the Exceptional Events Rule in a
future notice-and-comment rulemaking and will solicit public comment
at that time. Depending on the nature and scope of any interstate
emissions events affecting downwind air quality, the EPA may be able
to assist states in developing approvable exceptional events
demonstrations.
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The EPA notes that there could be some potential overlap between
the application of the Exceptional Events Rule and section 188(f). The
EPA believes that this potential for overlap can best be addressed by
considering the applicability of the Exceptional Events Rule and
section 188(f) in sequence. Thus, the EPA recommends
[[Page 15439]]
that air agencies first consider whether the monitored air quality data
on specific days were influenced by an exceptional event. If the air
agency requests and the EPA agrees with this request and determines
that the monitored air quality data should be excluded from
consideration in regulatory decisions, then using the provisions in the
Exceptional Events Rule could address the situation adequately.
Thereafter, if the air agency determines that the waiver provisions of
section 188(f) may also be applicable, then the EPA can evaluate that
question based on the remaining data that are representative for the
area in question.
B. Conformity Requirements
1. What requirements apply to both transportation and general
conformity?
a. What are transportation and general conformity? Conformity is
required under CAA section 176(c) to ensure that federal actions are
consistent with (``conform to'') the purpose of the SIP. Conformity to
the purpose of the SIP means that federal activities will not cause new
air quality violations, worsen existing violations, or delay timely
attainment of the relevant NAAQS or interim reductions and milestones.
Conformity applies to areas that are designated nonattainment, and
those nonattainment areas redesignated to attainment with a CAA section
175A maintenance plan after 1990 (``maintenance areas'').
The EPA's Transportation Conformity Rule (40 CFR 51.390 and part
93, subpart A) establishes the criteria and procedures for determining
whether transportation activities conform to the SIP. These activities
include adopting, funding or approving transportation plans,
transportation improvement programs (TIPs) and federally supported
highway and transit projects. The EPA first promulgated the
Transportation Conformity Rule on November 24, 1993 (58 FR 62188), and
subsequently published several amendments. For example, the EPA
published a final rule on July 1, 2004 (69 FR 40004) that provided
conformity procedures for state and local agencies under the 1997
PM2.5 NAAQS, among other things. On May 6, 2005 (70 FR
24280) the EPA published a final rule that addressed transportation
conformity requirements for PM2.5 precursors.\271\ The EPA
published another final rule on March 24, 2010 (75 FR 14260) that
addressed additional requirements for the 2006 PM2.5 NAAQS.
Finally, the EPA published a final rule on March 14, 2012 (77 FR 14979)
that restructured portions of the transportation conformity rule so
that they would clearly apply to nonattainment and maintenance areas
for new and revised NAAQS, including the 2012 PM2.5 NAAQS.
All of these rules apply to the current PM2.5 NAAQS
including the 1997 PM2.5 NAAQS, the 2006 24-hour
PM2.5 NAAQS and the 2012 primary annual PM2.5
NAAQS and will apply to future PM2.5 NAAQS. For further
information on conformity rulemakings, policy guidance and outreach
materials, see the EPA's Web site at http://www.epa.gov/otaq/stateresources/transconf/index.htm. The EPA may issue future
transportation conformity guidance as needed to implement the 2012
primary annual PM2.5 NAAQS.
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\271\ This final rule was not challenged or affected in any way
by the January 2013 D.C. Circuit Court decision requiring the EPA to
implement the PM2.5 NAAQS pursuant to subpart 4 of the
CAA.
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With regard to general conformity, the EPA first promulgated
general conformity regulations in November 1993 (40 CFR part 51,
subpart W, 40 CFR part 93, subpart B). Subsequently the EPA finalized
revisions to the general conformity regulations on April 5, 2010 (75 FR
17254). Besides ensuring that federal actions not covered by the
transportation conformity rule will not interfere with the SIP, the
general conformity program also fosters communications between federal
agencies and state/local air quality agencies, provides for public
notification of and access to federal agency conformity determinations
and allows for air quality review of individual federal actions. More
information on the general conformity program is available at http://www.epa.gov/air/genconform/.
b. Why is the EPA discussing transportation and general conformity
in this proposed rulemaking? The EPA is discussing transportation and
general conformity in this proposed rulemaking in order to provide
affected parties with information on when conformity must be
implemented after nonattainment areas are designated for a new or
revised PM2.5 NAAQS. At this time the EPA is using the 2012
PM2.5 NAAQS as an example. The agency is also discussing how
it plans to make the transition from demonstrating conformity for the
1997 annual PM2.5 NAAQS to the 2012 primary annual
PM2.5 NAAQS because this transition is unique in that the
1997 annual PM2.5 NAAQS was retained as a secondary NAAQS.
The information presented here is consistent with existing conformity
regulations and statutory provisions that are not addressed by this
PM2.5 implementation rulemaking. Affected parties would
include state and local transportation and air quality agencies,
metropolitan planning organizations (MPOs), and federal agencies
including the U.S. Department of Transportation (DOT), the U.S.
Department of Defense, the U.S. Department of Interior and the U.S.
Department of Agriculture.
c. When would transportation and general conformity apply to areas
designated nonattainment for the 2012 primary annual PM2.5 NAAQS?
Transportation and general conformity apply 1 year after the effective
date of nonattainment designations for a new or revised
PM2.5 NAAQS including the 2012 primary annual
PM2.5 NAAQS. This is because CAA section 176(c)(6) provides
a 1-year grace period from the effective date of initial designations
for any new NAAQS before transportation and general conformity apply in
areas newly designated nonattainment for a specific pollutant and
NAAQS. With regard to general conformity, the EPA's April 2010
revisions to its general conformity regulations (see 75 FR 17277; April
5, 2010) apply the same 1-year grace period for purposes of general
conformity.
With regard to transportation conformity, the conformity grace
period applies to all areas designated nonattainment for a new or
revised PM2.5 NAAQS including the 2012 primary annual
PM2.5 NAAQS. The requirements differ depending on whether
the nonattainment area is within or adjacent to a MPO designated under
23 U.S.C. 134. Within 1 year after the effective date of the initial
nonattainment designation for a given pollutant and NAAQS, the MPOs and
DOT must make a conformity determination with regard to that pollutant
and standard for all of the transportation plans and TIPs in the
nonattainment area. The conformity requirements for surrounding ``donut
areas,'' including the application of the 1-year conformity grace
period, are generally the same as those for metropolitan areas.\272\
For the purposes of the implementation of the 2012 PM2.5
NAAQS, MPOs and any adjacent donut areas in a 2012 PM2.5
NAAQS nonattainment area must continue to meet conformity requirements
during the grace period for any other applicable NAAQS, including the
1997 annual PM2.5 NAAQS and the 2006 24-hour
PM2.5 NAAQS. If, at the end of the grace period for the 2012
annual PM2.5 NAAQS, the MPO and DOT have not made a
transportation plan and TIP
[[Page 15440]]
conformity determination for that NAAQS, the area would be in a
conformity ``lapse.'' During a conformity lapse, only certain projects
can receive additional federal funding or approvals to proceed. The
practical impact of a conformity lapse will vary from area to area.
Finally, the 1-year conformity grace period also applies to project
level conformity determinations.
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\272\ For the purposes of transportation conformity, a ``donut''
area is the geographic area outside a metropolitan planning area
boundary, but inside a designated nonattainment or maintenance area
boundary that includes an MPO (40 CFR 93.101).
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Isolated rural nonattainment and maintenance areas are areas that
do not contain or are not part of an MPO (40 CFR 93.101). Conformity
requirements for isolated rural nonattainment and maintenance areas can
be found at 40 CFR 93.109(g). One year after the effective date of the
initial nonattainment designation for a given pollutant and NAAQS,
conformity requirements with regard to that pollutant and standard
would apply in any nonattainment areas that are isolated rural areas.
Per the transportation conformity rule, an isolated rural area would be
required to make a transportation conformity determination only at the
point when a transportation project needs funding or approval. This
project level conformity determination may occur significantly after
the 1-year grace period has ended. See the EPA's July 1, 2004 final
rule for further background on how the EPA has implemented this
conformity grace period in metropolitan, donut and isolated rural areas
(69 FR 40008; July 1, 2014; see also 69 FR 40009, 40010, 40011, 40012,
40013 and 40014).
d. How will transportation and general conformity apply with regard
to the 1997 annual PM2.5 NAAQS, which was retained as a secondary
NAAQS? In the final 2012 p.m. NAAQS rule the EPA established a new
health-based primary annual PM2.5 NAAQS of 12.0 [mu]g/m\3\.
In that same action the EPA retained the 1997 annual PM2.5
NAAQS of 15.0 [mu]g/m\3\ as a secondary NAAQS to protect against
certain welfare effects. In the 1997 PM2.5 designations rule
(70 FR 944; January 5, 2005), the EPA designated areas nonattainment
for both the 1997 primary and secondary annual PM2.5 NAAQS
(which have identical levels of 15.0 [mu]g/m\3\). Designations for the
2012 primary annual PM2.5 NAAQS were made in January 2015
(80 FR 2205; January 15, 2015). This action did not make any changes to
the designations that apply for the 1997 secondary annual
PM2.5 standard. Therefore, at this time, all areas
designated nonattainment in 2005 for the 1997 annual PM2.5
standard are considered as having been designated nonattainment for
both the 1997 primary annual PM2.5 NAAQS and for the 1997
secondary annual PM2.5 NAAQS where such distinctions are
made below. Similarly, for any 1997 PM2.5 nonattainment
areas that have approved redesignation requests for attainment of the
1997 PM2.5 NAAQS, the redesignation applies to both the
primary and secondary standards of the 1997 PM2.5 NAAQS. A
discussion of how transportation and general conformity apply in this
situation follows.
CAA section 176(c)(5) establishes that conformity applies to: a
nonattainment area and each pollutant for which the area is designated
as a nonattainment area; and an area that was designated as a
nonattainment area but that was later redesignated by the Administrator
as an attainment area and that is required to develop a maintenance
plan under CAA section 7505a with respect to the specific pollutant for
which the area was designated nonattainment. Section 176(c)(5) is clear
that transportation and general conformity apply in nonattainment areas
and in areas that have been redesignated to attainment and are required
to develop a maintenance plan under section 175A.
Section 175A(a) establishes the requirements for areas that are
required to submit a maintenance plan as one of the requirements that
must be fulfilled in order for an area to be redesignated to
attainment.
Section 175A(a) requires nonattainment areas for primary NAAQS to
submit maintenance plans in order to be redesignated, and such plans
must ensure maintenance of the standard for at least 10 years after
redesignation. Section 175A(a) does not require nonattainment areas for
secondary NAAQS to submit maintenance plans in order to be designated
to attainment. Therefore, the EPA concludes that transportation and
general conformity do not apply in areas that have been redesignated
for any secondary NAAQS, such as the 1997 secondary annual
PM2.5 NAAQS, since conformity does not apply in areas that
have been redesignated without maintenance plans.
Elsewhere in this notice, the EPA is proposing options for revoking
the 1997 primary annual PM2.5 NAAQS, which has been replaced
by the more health protective 2012 primary annual PM2.5
NAAQS. If the EPA finalizes an option that results in the revocation of
the 1997 primary annual PM2.5 NAAQS, nonattainment and
maintenance areas would not be required to make transportation or
general conformity determinations for the 1997 primary annual
PM2.5 NAAQS after the effective date of the revocation of
the 1997 primary annual NAAQS. The revocation would leave designations
in place for the 1997 secondary annual NAAQS. Any area that is
designated as nonattainment for the 1997 secondary annual NAAQS would
have to continue to make transportation and general conformity
determinations for that NAAQS as conformity applies in nonattainment
areas for secondary NAAQS.
However, for any area that has been redesignated to attainment for
the 1997 secondary NAAQS and is not designated nonattainment for the
2012 primary annual PM2.5 NAAQS, the relevant planning
organization will not have to make conformity determinations for any
annual PM2.5 NAAQS after the effective date of the
revocation of the 1997 primary annual PM2.5 NAAQS because,
as discussed above, the CAA does not require maintenance areas for
secondary NAAQS to make conformity determinations. This means that if
the EPA finalizes any of the options for revoking the 1997 primary
annual PM2.5 NAAQS, after the effective date of the
revocation, areas redesignated to attainment for the 1997 secondary
annual PM2.5 NAAQS will no longer be required to make
transportation plan, TIP, or project-level transportation conformity
determinations for that NAAQS. In addition, federal agencies will no
longer be required to make general conformity determinations for that
NAAQS. Areas that remain designated nonattainment for the 1997
secondary annual PM2.5 NAAQS will continue to make
transportation plan, TIP, and project-level conformity determinations
for that NAAQS and federal agencies will be required to continue to
make general conformity determinations for that NAAQS in these areas
until such time as they attain that NAAQS and are redesignated to
attainment.
e. What impact will the implementation of a new or revised PM2.5
NAAQS such as the 2012 PM2.5 NAAQS have on a state's transportation
and/or general conformity SIP? As long as the EPA does not make
specific changes to its transportation or general conformity
regulations states should not need to revise their transportation and/
or general conformity SIPs. The EPA is not proposing any changes to its
transportation conformity regulations. The EPA is proposing to change
the de minimis levels in its general conformity regulations as
discussed in Section IX.B.2.b. of this preamble. States with a general
conformity SIP should evaluate the need to revise those SIPs if this
change is finalized. States with new nonattainment areas may also need
to revise conformity SIPs in order to
[[Page 15441]]
ensure the state regulations apply in any newly designated areas.
However, if this is the first time that transportation conformity
will apply in a state, such a state is required by the statute and EPA
regulations to submit a SIP revision that addresses three specific
transportation conformity requirements that address consultation
procedures and written commitments to control or mitigation measures
associated with conformity determinations for transportation plans,
TIPs or projects (40 CFR 51.390). Additional information and guidance
can be found in the EPA's ``Guidance for Developing Transportation
Conformity State Implementation Plans'' (http://www.epa.gov/otaq/stateresources/transconf/policy/420b09001.pdf).
2. What additional requirements apply to general conformity?
a. What de minimis emissions levels will apply for direct PM2.5 and
its precursors?
Federal actions estimated to have an annual net emissions increase
less than the de minimis levels established in the general conformity
regulations are not required to demonstrate conformity under those
regulations. For direct PM2.5 and its precursors
(SO2, NOX, VOC and ammonia), the existing de
minimis emissions levels are set forth in the EPA's general conformity
regulations at 40 CFR 93.153(b)(1). Those levels were based on the
definition of a major stationary source for nonattainment NSR programs
as established by sections 182, 183 and 302 of the CAA. The EPA
believes it is appropriate to continue this practice for implementing
the current and any future PM2.5 NAAQS.
However, because the definition of precursors currently in the
general conformity regulations at 40 CFR 93.152(b)(1) does not reflect
the elimination of rebuttable presumptions for certain PM2.5
precursors, the EPA is proposing changes to these conformity provisions
to make them consistent with the agency's revised precursor
requirements. Specifically, the current definition of precursors for
PM2.5 in the general conformity regulations reflects the
rebuttable presumptions for VOC and ammonia finalized in the 2007
PM2.5 Implementation Rule (72 FR 20583; April 25, 2007). It
also does not reflect the subpart 4 definitions for ``major source''
and ``major stationary source'' that apply for Serious PM2.5
nonattainment areas. Therefore, through this proposal the EPA proposes
to change the PM2.5 precursor de minimis levels currently in
40 CFR 93.153(b)(1) to be consistent with the statutory requirements
for major stationary source thresholds under subpart 4 and any relevant
changes being proposed in Section III of this preamble. The EPA
proposes to set the de minimis levels that apply to direct
PM2.5 and PM2.5 precursors for PM2.5
nonattainment areas for purposes of general conformity as identified in
Table 3 below.
Table 3--General Conformity De Minimis Emission Levels for PM2.5 Precursors
----------------------------------------------------------------------------------------------------------------
Tons/year in moderate PM2.5
Type of emission nonattainment areas and all Tons/year in Serious PM2.5
maintenance areas nonattainment areas
----------------------------------------------------------------------------------------------------------------
Direct emissions.................................. 100 70
SO2............................................... 100 70
NOX............................................... 100 70
VOC............................................... 100 70
Ammonia........................................... 100 70
----------------------------------------------------------------------------------------------------------------
b. Are there any other impacts related to general conformity based
on implementation of the 2012 PM2.5 NAAQS? The EPA is not proposing any
other revisions to the general conformity regulations at this time.
However, as states develop SIP revisions for the 2012 and future
PM2.5 NAAQS, the agency recommends that state and local air
quality agencies work with federal agencies with large facilities
(e.g., commercial airports, ports and large military bases) that are
subject to the general conformity regulations to establish an emissions
budget for those facilities in order to facilitate future conformity
determinations under the conformity regulations. Such a budget could be
used by federal agencies in determining conformity or identifying
mitigation measures if the budget level is included and identified in
the SIP.
Significant tracts of land under federal management may also be
included in nonattainment area boundaries. The role of fire in these
areas should be assessed and emissions budgets developed in concert
with those federal land management agencies. In such areas the EPA
encourages states to consider in any baseline, modeling and SIP
attainment inventory used and/or submitted to include emissions
expected from projects subject to general conformity, including
emissions from wildland fire that may be reasonably expected in the
area. Where appropriate, states may consider developing plans for
addressing wildland fuels in collaboration with land managers and
owners. Information is available from DOI and USDA Forest Service on
the ecological role of fire and on smoke management programs and basic
smoke management practices.\273\
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\273\ USDA Forest Service and Natural Resources Conservation
Service, Basic Smoke Management Practices Tech Note, October 2011,
http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1046311.pdf.
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C. Clean Data Policy
This section describes the ongoing status of the EPA's Clean Data
Policy and proposes provisions applicable to any determinations of
attainment under current and future PM2.5 NAAQS. This
section also sets forth the regulatory consequences of an EPA
determination, made after notice and comment rulemaking, that an area
designated nonattainment for a PM2.5 standard has air
quality attaining that standard. Upon such a determination by the EPA,
the state's requirement for the area to submit the separate required
elements of an attainment plan (including an attainment demonstration,
but not the emissions inventory requirement), shall be suspended until
such time as the area is redesignated to attainment, at which time the
requirements no longer apply. If the EPA determines that the area,
after reaching attainment, has again violated that PM2.5
NAAQS, the requirements are again applicable. The following discussion
of this interpretation, known as the EPA's Clean Data Policy, explains
the basis for the EPA's interpretation and is relevant to all
PM2.5 NAAQS under subpart 4.
1. What is a clean data determination?
The EPA's interpretation of the CAA applies when the agency, after
notice-and-comment rulemaking, issues a ``clean data determination''
(CDD), in
[[Page 15442]]
which it determines that a specific nonattainment area has attained the
relevant standard. For such areas, the EPA interprets the CAA as
suspending the state requirements to submit to the EPA the planning
elements of an attainment plan related to attaining the NAAQS for as
long as the area continues to attain the standard.\274\ These planning
elements generally include reasonable further progress (RFP)
requirements, attainment demonstrations, RACM and RACT, nonattainment
area contingency measures, and other state planning requirements
related to the attainment of the NAAQS.\275\ The suspension of the
obligation to submit applies regardless of when the plan submissions
are due. The CDD does not suspend CAA requirements that are independent
of helping the area achieve attainment, such as the requirements to
submit an emissions inventory and nonattainment new source review
requirements.
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\274\ In the context of CDDs, the EPA distinguishes between
attainment planning requirements of the CAA, which relate to the
attainment demonstration for an area and related control measures
for bringing an area into attainment for a given NAAQS as
expeditiously as practicable, and other types of requirements, such
as permitting requirements under the NNSR program, and any specific
control requirements independent of those strictly needed to ensure
timely attainment of a given NAAQS.
\275\ See December 14, 2004 memorandum from Stephen D. Page,
Director, EPA Office of Air Quality Planning and Standards, to Air
Division Directors, EPA Regions I-X, entitled ``Clean Data Policy
for the Fine Particle National Ambient Air Quality Standards.''
Available at: http://www.epa.gov/airquality/urbanair/sipstatus/docs/pm25_clean_data_policy_14dec2004.pdf.
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The emissions inventory is a basic compilation of information used
to characterize the sources of emissions of the nonattainment area.
Section 172(c)(3), the statutory provision requiring submission of an
emissions inventory, is not tied to attainment of the NAAQS, unlike the
attainment planning provisions which are suspended by a CDD. A base
year inventory continues to be relevant to a nonattainment area that is
attaining the NAAQS and has obtained a CDD because, for example, the
inventory is a necessary component to an approvable redesignation
request. In addition, in the event the air quality in the area exceeds
the standard in a subsequent year, the state would be obligated to
submit an attainment demonstration and other planning elements for the
area, and a base year inventory would need to be available immediately
in order for the state to submit an approvable attainment plan
expeditiously. Similarly, the new source review requirement is not
suspended because section 172(c)(5) is not tied to attainment of the
NAAQS, and an area with a CDD is still designated nonattainment. NNSR
permitting is required in each nonattainment area until the area is
redesignated to attainment.'' For the past two decades, and for many
NAAQS, the EPA has consistently applied its Clean Data Policy
interpretation to attainment-related provisions of subparts 1, 2 and 4
of Part D, Title I of the CAA. The Clean Data Policy is the subject of
several EPA memoranda and regulations and numerous individual
rulemakings published in the Federal Register. These rulemakings have
applied the interpretation to a broad spectrum of NAAQS, including the
1-hour and 1997 ozone standards, PM10, 1997 and 2006
PM2.5 standards and the carbon monoxide (CO) and lead
standards. The D.C. Circuit has upheld the Clean Data Policy
interpretation as embodied in the EPA's 8-hour ozone Implementation
Rule, 40 CFR 51.918.\276\ NRDC v. EPA, 571 F. 3d 1245 (D.C. Cir. 2009).
Other U.S. Circuit Courts of Appeals that have considered and reviewed
the EPA's Clean Data Policy interpretation have upheld it and the
rulemakings applying the EPA's interpretation. Sierra Club v. EPA, 99
F.3d 1551 (10th Cir. 1996); Sierra Club v. EPA, 375 F. 3d 537 (7th Cir.
2004); Our Children's Earth Foundation v. EPA, N. 04-73032 (9th Cir.
June 28, 2005) (memorandum opinion); Latino Issues Forum, v. EPA, Nos.
06-75831 and 08-71238 (9th Cir. March 2, 2009) (memorandum opinion).
The EPA incorporated its Clean Data Policy interpretation in both its
1997 8-hour ozone implementation rule and in its remanded 2007
PM2.5 Implementation Rule in 40 CFR 51.1004(c). See the
Federal Register published on April 25, 2007 (72 FR 20583, 20585 and
20665. The D.C. Circuit, in its January 4, 2013 decision remanding the
PM2.5 implementation rule, did not address the merits of
that regulation or the EPA's existing interpretation of the statutory
provisions as they pertained to the EPA's Clean Data Policy.
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\276\ ``The EPA's Final Rule to implement the 8-hour Ozone
National Ambient Air Quality Standard--Phase 2 (Phase 2 Final
Rule).'' See the Federal Register published on November 29, 2005 (70
FR 71612, 71645 and 71646).
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The EPA has previously articulated its Clean Data Policy
interpretation under subpart 4 in implementing the PM10
standard. See, e.g., 75 FR 27944 (May 19, 2010) (determination of
attainment of the PM10 standard in Coso Junction,
California); 71 FR 13021 (March 14, 2006) (Yuma, Arizona area); 71 FR
40023 (July 14, 2006) (Weirton, West Virginia area); 71 FR 44920
(August 8, 2006) (Rillito, Arizona area); 71 FR 63642 (October 30,
2006) (San Joaquin Valley, California area) 72 FR 14422 (March 28,
2007) (Miami, Arizona area). In the EPA's proposed and final
rulemakings determining that the San Joaquin Valley nonattainment area
attained the PM10 standard, the EPA set forth at length its
rationale for applying the Clean Data Policy to PM10 under
subpart 4. 71 FR at 63643-45. The Ninth Circuit upheld the EPA's final
rulemaking, and specifically the EPA's Clean Data Policy, in the
context of subpart 4. Latino Issues Forum v. EPA, supra. Nos. 06-75831
and 08-71238 (9th Cir. March 2, 2009) (memorandum opinion). In
rejecting the petitioner's challenge to the Clean Data Policy under
subpart 4 for PM10, the Ninth Circuit stated, ``As the EPA
explained, if an area is in compliance with PM10 standards,
then further progress for the purpose of ensuring attainment is not
necessary.'' Thus the EPA has previously established its interpretation
that, under subpart 4, a clean data determination suspends the
obligations to submit an attainment demonstration, RACM/RACT, RFP and
quantitative milestones, contingency measures, and other measures
related to attainment. The EPA is proposing to codify this
interpretation in this implementation rule for the PM2.5
NAAQS.
As with its Clean Data Policy interpretation for 8-hour ozone,
which the EPA embodied in a regulation that was upheld by the D.C.
Circuit in NRDC v. EPA, 571 F. 3d 1245 (D.C. Cir. 2009), the EPA
intends to embody its interpretation for the Clean Data Policy for
current and future PM2.5 NAAQS in a regulation as part of
this proposed rulemaking. This interpretation complies with the D.C.
Circuit's ruling (NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 2013)) that both
subparts 1 and subpart 4 apply to implementation, and reflects the
interpretation upheld by the Latino Issues Forum Court. Latino Issues
Forum v. EPA, supra. Nos. 06-75831 and 08-71238 (9th Cir. March 2,
2009) (memorandum opinion). Under this proposed regulation, if the EPA
determines, after notice-and-comment rulemaking, that an area has
attained the applicable PM2.5 NAAQS based on the most recent
3 years of complete, quality-assured data meeting the requirements of
40 CFR part 50, Appendix N, the area's obligation to submit the
following Moderate or Serious area attainment-related planning
requirements is suspended for so long as the area continues to attain
the PM2.5 standard: (i) the part D, subpart 4 and subpart 1
[[Page 15443]]
obligation to provide an attainment demonstration pursuant to section
189(a)(1)(B); (ii) the RACM and RACT provisions of section
189(a)(1)(C); (iii) the RFP and quantitative milestones provisions of
section 189(c); and, (iv) related attainment demonstration, RACM and
RACT, RFP and contingency measure provisions requirements of subpart 1,
section 172.
A final determination of attainment, also known as a clean data
determination, would not constitute a redesignation to attainment under
CAA section 107(d)(3). The state would still have to meet the statutory
requirements for redesignation in order to be redesignated to
attainment. A determination of attainment for purposes of the Clean
Data Policy is also not linked to any particular attainment deadline,
and is not necessarily equivalent to a determination that an area has
attained the standard by its applicable attainment deadline, e.g.,
under section 189(c).
2. Planning Requirements Suspended With a CDD
a. Control measure requirements for Moderate areas. Both sections
172(c)(1) and 189(a)(1)(C) require ``provisions to assure that
reasonably available control measures'' (i.e., RACM) are implemented in
a nonattainment area. Reasonably available control technology (i.e.,
RACT) is a subset of RACM. The General Preamble states that the EPA
interprets section 172(c)(1) so that RACM requirements are a
``component'' of an area's attainment demonstration.\277\ Thus, for the
same reason the obligation to submit an attainment demonstration is
suspended, the requirement for a state to submit RACM is suspended if
the nonattainment area reaches attainment. For PM2.5, the
EPA has consistently interpreted this provision to require only
implementation of potential RACM that could contribute to RFP or to
timely attainment (General Preamble, 57 FR 13498). Thus, where an area
is already attaining the standard, no additional RACM are required, but
all measures adopted into the SIP prior to attainment would
remain.\278\ The EPA is interpreting section 189(a)(1)(C) consistent
with its interpretation of section 172(c)(1).
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\277\ 57 FR 13498 (April 16, 1992), at page 13560.
\278\ The EPA's interpretation that the statute requires
implementation only of RACM that would advance attainment was upheld
by the Fifth Circuit Court (Sierra Club v. EPA, 314 F.3d 735, 743-
745 (5th Cir. 2002), and by the D.C. Circuit Court (Sierra Club v.
EPA, 294 F.3d 155, 162-163 (D.C. Cir. 2002)).
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b. RFP and quantitative milestones. The EPA has long interpreted
the provisions of part D, subpart 1 of the CAA (sections 171 and 172)
as not requiring the submission of RFP for an area already attaining
the PM10 NAAQS. For an area that is attaining, showing that
the state will make RFP towards attainment ``will, therefore, have no
meaning at that point.'' \279\ Section 189(c)(1) states that: ``Plan
revisions demonstrating attainment submitted to the Administrator for
approval under this subpart shall contain quantitative milestones which
are to be achieved every 3 years until the area is redesignated
attainment and which demonstrate reasonable further progress, as
defined in section [171(1)] of this title, toward attainment by the
applicable date.''
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\279\ 57 FR 13498 (April 16, 1992), at page 13564. See 71 FR
40952 (July 19, 2006) and 71 FR 63642 (October 30, 2006) (proposed
and final determination of attainment for San Joaquin Valley); 75 FR
13710 (March 23, 2010) and 75 FR 27944 (May 19, 2010) (proposed and
final determination of attainment for Coso Junction).
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With respect to RFP, section 171(1) states that, for purposes of
part D, RFP ``means such annual incremental reductions in emissions of
the relevant air pollutant as are required by this part or may
reasonably be required by the Administrator for the purpose of ensuring
attainment of the applicable NAAQS by the applicable date.'' 42 U.S.C.
7501(1). Thus, whether dealing with the general RFP requirement of
section 172(c)(2), the ozone-specific RFP requirements of sections
182(b) and (c), or the specific RFP requirements for PM10
areas of part D, subpart 4, section 189(c)(1), the stated purpose of
RFP is to ensure attainment by the applicable attainment date. Although
section 189(c) states that revisions shall contain milestones which are
to be achieved until the area is redesignated to attainment, such
milestones are designed to show reasonable further progress ``toward
attainment by the applicable attainment date,'' as defined by section
171. Thus, it is clear that once the area has attained the standard, no
further milestones are necessary or meaningful. This interpretation is
supported by language in section 189(c)(3), which mandates that a state
that fails to achieve a milestone must submit a plan that assures that
the state will achieve the next milestone or attain the NAAQS if there
is no next milestone. Thus, section 189(c)(3) itself assumes that the
requirement to submit and achieve milestones does not continue after
attainment of the NAAQS.
In the General Preamble, the EPA noted with respect to section
189(c) that the purpose of the milestone requirement is ``to provide
for emission reductions adequate to achieve the standards by the
applicable attainment date (H.R. Rep. No. 490 101st Cong., 2d Sess. 267
(1990)).'' 57 FR 13498 (April 16, 1992), at page 13539. If an area has
in fact attained the standard, the stated purpose of the RFP
requirement will have already been fulfilled.\280\ Similarly, the
requirements of section 189(c)(2) with respect to milestones no longer
apply so long as an area has attained the standard. Section 189(c)(2)
provides in relevant part that: Not later than 90 days after the date
on which a milestone applicable to the area occurs, each State in which
all or part of such area is located shall submit to the Administrator a
demonstration . . . that the milestone has been met.
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\280\ Thus, the EPA believes that it is a distinction without a
difference that section 189(c)(1) speaks of the RFP requirement as
one to be achieved until an area is ``redesignated attainment,'' as
opposed to section 172(c)(2), which is silent on the period to which
the requirement pertains, or the ozone nonattainment area RFP
requirements in sections 182(b)(1) or 182(c)(2), which refer to the
RFP requirements as applying until the ``attainment date,'' since
section 189(c)(1) defines RFP by reference to section 171(1) of the
CAA. Reference to section 171(1) clarifies that, as with the general
RFP requirements in section 172(c)(2) and the ozone-specific
requirements of section 182(b)(1) and 182(c)(2), the PM-specific
requirements may only be required ``for the purpose of ensuring
attainment of the applicable national ambient air quality standard
by the applicable date.'' 42 U.S.C. 7501(1). As discussed in the
text of this proposed rulemaking, the EPA interprets the subpart 4
RFP requirements, in light of the definition of RFP in section
171(1), and its incorporation into section 189(c)(1), to no longer
apply once the EPA makes a determination that the standard has been
attained.
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Where the area has attained the standard and there are no further
milestones, there is no further requirement to make a submission
showing that such milestones have been met. This is consistent with the
position that the EPA took with respect to the general RFP requirement
of section 172(c)(2) in the General Preamble and in the May 10, 1995
Seitz memorandum \281\ with respect to the requirements of sections
182(b) and (c). In the Seitz memorandum, the EPA also noted that
section 182(g), the milestone requirement of subpart 2, which is
analogous to provisions in section 189(c), is suspended upon a
determination that an area has attained. The memorandum, citing
additional provisions related to attainment
[[Page 15444]]
demonstration and RFP requirements, stated:
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\281\ Memorandum from John S. Seitz, titled ``Reasonable Further
Progress, Attainment Demonstration, and Related Requirements for
Ozone Nonattainment Areas Meeting the Ozone National Ambient Air
Quality Standard,'' (Seitz Memo). May 10, 1995.
Inasmuch as each of these requirements is linked with the
attainment demonstration or RFP requirements of section 182(b)(1) or
182(c)(2), if an area is not subject to the requirement to submit
the underlying attainment demonstration or RFP plan, it need not
---------------------------------------------------------------------------
submit the related SIP submission either. (Seitz memo, page 4).
c. Contingency measures. Other SIP submission requirements are
linked with these attainment demonstration and RFP requirements, and
similar reasoning applies to them. These requirements include the
contingency measure requirements of sections 172(c)(9). The EPA has
interpreted the obligation to submit contingency measure requirements
of sections 172(c)(9) as suspended when an area has attained the
standard because those ``contingency measures are directed at ensuring
RFP and attainment by the applicable date.'' 57 FR at 13564; see also
Seitz memo at pgs. 5-6.
Section 172(c)(9) provides that: ``SIPs in nonattainment areas
shall provide for the implementation of specific measures to be
undertaken if the area fails to make reasonable further progress, or to
attain the [NAAQS] by the attainment date applicable under this part.
Such measures shall be included in the plan revision as contingency
measures to take effect in any such case without further action by the
state or the EPA.''
The contingency measure requirement is inextricably tied to the RFP
and attainment demonstration requirements. Contingency measures are
implemented if RFP targets are not achieved, or if attainment is not
realized by the attainment date. Where an area has already achieved
attainment and continues to do so it has no need to rely on contingency
measures to come into attainment or to make further progress to
attainment. As the EPA stated in the General Preamble: ``The section
172(c)(9) requirements for contingency measures are directed at
ensuring RFP and attainment by the applicable date.'' See 57 FR 13564.
d. Attainment demonstrations. With respect to the attainment
demonstration requirements of section 172(c) and section 189(a)(1)(B),
the EPA proposes to find that, as with the RFP requirements, if an area
is already monitoring attainment of the standard, there is no need for
an area to make a further submission containing additional measures to
achieve attainment. The plain language of section 189(a)(1)(B) requires
that the attainment plan provide for ``a demonstration (including air
quality modeling) that the [SIP] will provide for attainment by the
applicable attainment date . . . .'' Where the area has attained the
standard, such a demonstration no longer serves a purpose. This
interpretation is consistent with the interpretation of the section
172(c) requirements provided by the EPA in the General Preamble, the
Page memo, and the section 182(b) and (c) requirements set forth in the
Seitz memo.\282\ As the EPA stated in the General Preamble, no other
measures to provide for attainment would be needed by areas seeking
redesignation to attainment since ``attainment will have been reached''
(57 FR at 13564). See also Latino Issues Forum, v. EPA, Nos. 06-75831
and 08-71238 (9th Cir.), Memorandum Opinion, March 2, 2009.
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\282\ Memorandum from Stephen D. Page titled ``Clean Data Policy
for the Fine Particle National Ambient Air Quality Standards'' are
equally pertinent to all NAAQS. December 14, 2004.
---------------------------------------------------------------------------
e. Control measure requirements for Serious areas. Under proposed
Option 1 for BACM and BACT determinations, described in Section VI.D of
this preamble, BACM and BACT for sources in the nonattainment area
would be determined independent of the attainment needs of the area,
and thus the requirement for BACM and BACT would not be considered an
attainment planning requirement. Therefore, under such an approach, a
determination of attainment (i.e., a clean data determination) would
not suspend the obligation to submit any applicable outstanding BACM
and BACT requirements. Under proposed Option 2 for BACM and BACT
determinations, BACM and BACT would be identified based on the specific
attainment needs of the area, thus tying the BACM and BACT requirement
directly to attainment planning for the area. Consistent with this
second proposed approach for determining BACM and BACT, issuance of a
CDD would therefore also suspend BACM and BACT requirements.
In addition, for a Serious area that failed to attain the relevant
PM2.5 NAAQS by the applicable attainment date and that is
therefore subject to the annual 5 percent emissions reduction
requirement under section 189(d), but is nevertheless now attaining the
relevant NAAQS, the EPA believes that the Clean Data Policy may apply
to the obligations of the state to make an attainment plan submission
to meet the requirements of section 189(d). Once such an area is
attaining the relevant NAAQS, a clean data determination would suspend
the section 189(d) submission requirement.
3. Planning Requirements Not Suspended With a CDD
For Moderate nonattainment areas, the planning elements that are
not suspended with a clean data determination are: Emissions
inventories, nonattainment new source review including 189(e) control
requirements for major stationary source precursors, and conformity.
For Serious nonattainment areas, the planning elements not suspended
with a clean data determination are: Emissions inventories,
nonattainment NSR including section 189(e) control requirements for
major stationary sources of PM2.5 precursors, the Most
Stringent Measures (MSM) requirements (if the area has elected to seek
an extension of the attainment date under section 188(e)), and
conformity. In addition, for a Serious PM2.5 nonattainment
area, if the EPA finalizes proposed Option 1 for BACM and BACT
determinations, in which BACM and BACT would be determined independent
of the attainment needs for the area, then the requirement for
implementation of BACM and BACT would not be considered an attainment
planning requirement and would thus not be suspended with a clean data
determination for the area.
4. Violations of the NAAQS After a CDD
The suspension of the state's obligations to submit attainment plan
elements such as provisions for RACM and RACT, RFP and quantitative
milestones, contingency measures, an attainment demonstration and other
related attainment planning requirements exists only for as long as the
area continues to monitor attainment of the relevant NAAQS prior to
redesignation. If the EPA determines, after notice-and-comment
rulemaking but prior to redesignation, that the area has monitored a
violation of the relevant NAAQS, the basis for the suspension of the
requirements no longer exists. In that case, the area would again be
subject to the requirement to submit the pertinent attainment plan
elements or SIP revisions and would need to address those requirements.
Thus, a final determination that the area need not currently submit one
of the required attainment plan elements amounts to no more than a
suspension of the obligation to make the submission for so long as the
area continues to attain the standard. Only if and when the EPA
redesignates the area to attainment under section 107(d)(3) would the
area be permanently relieved of these attainment plan submission
obligations.
[[Page 15445]]
Upon the EPA's determination that an area is currently attaining
the applicable PM2.5 standard, the EPA proposes that the
obligations to submit attainment planning provisions to meet the
requirements for an attainment plan for the PM2.5 NAAQS,
including RFP plans, RACM and RACT, quantitative milestones,
contingency measures and an attainment demonstration are suspended for
as long as the area continues to monitor attainment of the applicable
PM2.5 standards. If in the future, prior to redesignation of
the nonattainment area to attainment, the EPA determines after notice-
and-comment rulemaking that the area again violates the applicable
PM2.5 standard, then the basis for suspending the obligation
of the state to make one or more of these submissions would no longer
exist and these attainment plan elements would again be due. Since all
attainment planning requirements had been suspended for this area and
the area attained by its attainment date, the CAA attainment plan
contingency measures would not apply at the time of the NAAQS
violation. In addition, because the area did not have a maintenance
plan, the CAA section 175A maintenance plan contingency measures would
also not apply. When an area violates after a CDD, and the statutory
submission date has passed, CAA section 110(k)(5) applies, requiring
that if the EPA finds that the applicable implementation plan is
substantially inadequate to attain or maintain the NAAQS, the
Administrator shall establish a reasonable deadline (not to exceed 18
months) for a state to submit a SIP plan revision.
D. Section 179B/International Border Areas
The EPA recognizes that some states are affected not only by local
and regional sources of PM2.5 and PM2.5
precursors, but also international sources that can contribute to an
area's PM2.5 NAAQS nonattainment status. As discussed in
Section II of this preamble, direct PM2.5 and more
importantly PM2.5 precursors can be transported long
distances and can be found in the air thousands of miles from where the
emissions occurred and the particles were formed. Nitrates and sulfates
formed from NOX and SO2 emissions are generally
transported over wide areas leading to substantial background
contributions to NAAQS violations in urban areas. Organic carbon, which
has both a primary and secondary component, can also be transported,
but to a far lesser degree. In general, higher concentrations of
elemental carbon and crustal matter are found closer to the sources of
these emissions.
Section 179B of the CAA, entitled ``International Border Areas,''
applies to areas that could attain the relevant NAAQS by the statutory
attainment date ``but for'' emissions emanating from outside the U.S.
Specifically, section 179B(a) provides that the EPA shall approve an
attainment plan for such an area if: (i) the attainment plan meets all
other applicable requirements of the CAA, and (ii) the submitting state
can satisfactorily demonstrate that ``but for emissions emanating from
outside of the United States,'' the area would attain and maintain the
relevant NAAQS. In addition, section 179B(d) applies specifically to
PM10 NAAQS (which would include the PM2.5 NAAQS)
and provides that if a state demonstrates that an area would have
timely attained the NAAQS but for emissions emanating from outside the
U.S., then the area is not subject to the mandatory reclassification
element of section 188(b)(2) for Moderate areas that fails to attain
the PM10 NAAQS by the applicable attainment date.
Under section 179B, areas affected by emissions from outside the
U.S. continue to have attainment plan obligations. First, even if the
area is impacted by emissions from outside the U.S., that fact does not
affect the designation of the area. An area that is violating the
relevant NAAQS, even if emissions from outside the U.S. contribute to
that violation, will be designated nonattainment. Section 179B does not
affect designation. Second, as a result of that designation, the state
is required to meet the applicable attainment plan requirements for the
relevant NAAQS. Section 179B does not negate the attainment plan
requirements, it only eliminates the obligation for an attainment
demonstration that demonstrates attainment and maintenance of the
NAAQS, and elimination of that obligation is conditioned upon the state
meeting all other attainment plan requirements.
Under section 179B, states remain obligated to meet the attainment
plan requirements other than the requirement to demonstrate timely
attainment. The applicable requirements for an attainment plan for
PM2.5 include those requirements that apply to a Moderate
area attainment plan, including an emissions inventory, RACM and RACT
measures, RFP and quantitative milestones, and contingency measures.
The Addendum includes a discussion of the applicable attainment plan
requirements in the context of developing a SIP subject to section
179B. In it, the EPA clarified that ``RACM/RACT must be implemented to
the extent necessary to demonstrate attainment by the applicable
attainment date if emissions emanating from outside the U.S. were not
included in the analysis.'' \283\ The EPA further encouraged states
``to reduce emissions beyond the minimum necessary to satisfy the `but
for' test in order to reduce the PM concentrations to which their
populations are exposed''.\284\ However, the EPA acknowledged that ``if
. . . States . . . were also required, because of contributions to
PM10 violations caused by foreign emissions, to shoulder
more of a regulatory and economic burden than States not similarly
affected . . . such a requirement would unfairly penalize States
containing international border areas and effectively undermine the
purpose of section 179B. Indeed, to the extent an affected State can
satisfactorily demonstrate that implementation of such measures clearly
would not advance the attainment date, EPA and the state could conclude
they are unreasonable and hence do not constitute RACM.'' \285\
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\283\ Addendum to the General Preamble, 59 FR 41998 (August 16,
1994), at page 42001.
\284\ Ibid.
\285\ Ibid.
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The EPA has considered this past interpretation of RACM and RACT
requirements in the context of section 179B attainment plans for
PM2.5 NAAQS and no longer views it as appropriate or
consistent with the agency's guidance that encourages states ``to
reduce emissions beyond the minimum necessary to satisfy the `but for'
test in order to reduce the PM10 concentrations to which
their populations are exposed.'' \286\ That is, given that the primary
purpose of an attainment plan is to achieve emission reductions so that
people living in a nonattainment area receive the public health
protection intended by the NAAQS, adopting an interpretation that would
allow those people to continue to be subjected to levels of
PM2.5 above the NAAQS that the state could reasonably
reduce--in this case not to attainment level, but to a level below the
current level--would be antithetical to the objectives of the CAA. In
addition, as with all other Moderate PM2.5 nonattainment
areas, the EPA interprets the provisions of section 172(c)(6) to
require that such areas must implement all additional reasonable
measures that it can implement through the sixth calendar year
following designation of the area, in addition to those measures
meeting
[[Page 15446]]
the definition of RACM and RACT, in order to make progress toward
attainment after the end of the fourth year following designation.
---------------------------------------------------------------------------
\286\ Ibid.
---------------------------------------------------------------------------
Therefore, the EPA is proposing and seeking comment on two proposed
approaches that would give greater clarity to the agency's existing
interpretation of control strategy requirements for Moderate area
attainment plans to be approved under section 179B. The first proposed
interpretation would clarify that the control strategy for an area that
could attain by the Moderate area attainment date, ``but for'' foreign
emissions of direct PM2.5 or its precursors, must include
all control measures identified by the state to be technologically and
economically feasible and implementable on sources in the area by the
end of the sixth calendar year following designation of the area, thus
satisfying requirements for RACM and RACT and additional reasonable
measures, with a possible exception for any such measures that
collectively would not be effective in reducing ambient
PM2.5 levels in the area. This interpretation would closely
align the EPA's interpretation of what constitutes a reasonable control
strategy for a Moderate area attainment plan submitted pursuant to
section 179B with the EPA's proposed interpretation of what constitutes
a reasonable control strategy for a Moderate area attainment plan
submitted pursuant to section 189(a)(1) for an area that cannot
practicably attain by the statutory Moderate area attainment date.
More specifically, under the first proposed approach for
identifying appropriate control measures on sources in a Moderate
PM2.5 nonattainment area that could attain the NAAQS ``but
for'' foreign emissions, the EPA is proposing that the state would be
required to implement all technologically and economically feasible
measures that can be implemented on sources in the area by the end of
the sixth calendar year following designation of the area in order to
ensure that the area makes reasonable progress toward attaining the
standard even if such measures are not expected to yield attainment by
the statutory Moderate area attainment date. However, because the EPA
recognizes that it may not be reasonable to require that a state
implement those technologically and economically feasible control
measures that collectively will not effectively reduce ambient
PM2.5 concentrations, the agency is proposing to allow the
state not to implement such measures if it can demonstrate that
collectively they will not be effective in reducing PM2.5
levels in the area. The EPA seeks comment on this proposed approach for
Moderate PM2.5 nonattainment areas potentially subject to an
attainment demonstration waiver under section 179B, and seeks comment
on an alternative proposed approach that would not allow such an
exception based on the collective effectiveness of otherwise
``reasonable'' measures. This alternative proposed option parallels a
similar option described in Section IV.D in this preamble for Moderate
PM2.5 nonattainment areas that cannot practicably attain the
NAAQS by the latest statutory attainment date for the area.
The EPA also seeks comment on a distinct, second proposed approach
for interpreting what would constitute an acceptable control strategy
for sources in an area for which a state is seeking an attainment plan
approval under section 179B. Under this second option, a state would
need to demonstrate that its selected control measures for a Moderate
nonattainment area would achieve reductions in PM2.5 levels
that exceeded the applicable NAAQS in proportion to their contribution
to overall PM2.5 levels. For example, if monitors in a
Moderate nonattainment area reveal that the area is exceeding the 2012
PM2.5 NAAQS of 12 [mu]g/m\3\ by 2 [mu]g/m\3\, for a total of
14 [mu]g/m\3\, and the state concludes that foreign sources are
contributing 3 [mu]g/m\3\, then the state would be responsible for the
remaining 11 [mu]g/m\3\ and would need to implement enough reasonable
control measures to achieve reductions in monitored ambient
PM2.5 concentrations equal to (11/14)*2 [mu]g/m\3\ or 1.6
[mu]g/m\3\. The EPA recognizes that this approach could require a high
level of precision to be able to quantify accurately contributions from
sources inside and outside the nonattainment area as well as projected
emission reductions to be achieved with the implementation of each
potential control measure for sources inside the area. However, the
agency believes that such precision may be justified to support any
``but for'' demonstration submitted to the EPA and to support any
claims that a state should only be required to implement a subset of
otherwise ``reasonable'' control measures on sources of direct
PM2.5 emissions or emissions of PM2.5 precursors
located in the nonattainment area.
The EPA seeks comment on these two approaches to clarify what
constitutes a reasonable control strategy in the context of a SIP
submitted pursuant to section 179B. The EPA is also proposing
regulations for the PM2.5 NAAQS consistent with the existing
guidance with respect to requirements for RFP and quantitative
milestones and contingency measures for areas seeking Moderate area
attainment plan approval under section 179B. The General Preamble
states that:
In international border areas, EPA will not require the
contingency measures for PM10 to be implemented after the
area fails to attain if EPA determines that the area would have
attained the NAAQS, but for emissions emanating from outside the
U.S. However, the EPA will require contingency measures to be
implemented if it determines that the area failed to make RFP in
achieving the required reductions in PM10 emissions from
sources within the U.S., or if the area does not, in fact, obtain
the emission reductions that were necessary to demonstrate timely
attainment of the NAAQS, but for emissions emanating from outside
the U.S.\287\
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\287\ Ibid.
The EPA is proposing that this interpretation of section 179B(a)(1)
with respect to contingency measures and RFP requirements should apply
to Moderate nonattainment areas for the PM2.5 NAAQS.
Specifically, the EPA proposes that as part of any Moderate area
attainment plan submitted under section 179B, a state must include an
RFP plan developed consistent with proposed Option 2 for RFP analyses
for Moderate nonattainment areas that cannot practicably attain the
relevant NAAQS by the statutory attainment date, described in Section
IV.F of this preamble. Furthermore, the state must include as part of
any attainment plan submission made for such an area contingency
measures that can be implemented without significant effort in the
event the EPA finds that such area failed to meet RFP requirements. The
contingency measures should achieve approximately 1 year's worth of
emissions reductions as calculated by the state for purposes of the RFP
analysis. In addition, the EPA proposes that the state must identify
quantitative milestones for the area to be achieved 4.5 years and 7.5
years from the date of designation of the area. The EPA proposes to
apply the same proposed requirements for establishing and reporting on
quantitative milestones for Moderate nonattainment areas seeking
attainment date waivers under section 179B as for all other Moderate
nonattainment areas, described fully in Section IV.G of this preamble.
The agency seeks comment on these proposed requirements for Moderate
area plans submitted pursuant to section 179B.
The EPA has historically evaluated section 179B ``but for''
demonstrations on a case-by-case basis, based on the
[[Page 15447]]
individual circumstances and data provided by the submitting state.
These demonstrations have included information such as ambient air
quality monitoring data, modeling scenarios, emissions inventory data
and meteorological or satellite data.\288\ The Moderate area attainment
demonstration modeling and other elements of the attainment
demonstration must show timely attainment of the NAAQS but for the
emissions from outside of the U.S. Section 179B does not, however,
provide authority to exclude monitoring data influenced by
international transport from regulatory determinations related to
attainment and nonattainment. Thus, even if the EPA approves a section
179B ``but for'' demonstration for an area, the area would continue to
be designated as nonattainment and subject to the applicable
requirements, including nonattainment new source review, conformity and
other measures prescribed for nonattainment areas by the CAA. Section
179B requires states to continue to meet attainment plan requirements,
notwithstanding the contribution of emissions from sources outside the
U.S., in order to provide the public health protection intended by the
NAAQS. However, if the EPA approves a ``but for'' demonstration for a
Moderate nonattainment area, the area would not be subject to
reclassification for failure to attain by the applicable attainment
date as explained earlier.
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\288\ Ibid. The Addendum includes further examples of
information a state may present for the EPA to consider as part of
the ``but for'' demonstration, including additional monitors in
international border areas, more detailed emissions inventories, and
speciation data that identifies PM2.5 components from
foreign sources.
---------------------------------------------------------------------------
Although monitor data cannot be excluded for a determination of
whether an area has attained based solely on the fact the data are
affected by emissions from outside the U.S., such data may be excluded
from consideration if they were significantly influenced by exceptional
events under section 319(b)(3) of the CAA. Where international
transport of emissions contributes to an exceedance or violation and
comes from natural sources such as wildfires, and otherwise meets the
criteria contained in the EPA's Exceptional Events Rule, it can be
addressed by that rule.\289\ Specifically, if the EPA concurs with an
air agency's request to exclude affected data, the event-influenced
data are officially noted and removed from the data set used to
calculate official design values. Because of previously expressed
stakeholder feedback regarding implementation of the Exceptional Events
Rule and specific stakeholder concerns regarding the analyses that can
be used to support wildfire-related exceptional event demonstrations,
the EPA intends to propose revisions to the Exceptional Events Rule in
a future notice-and-comment rulemaking and will solicit public comment
at that time. The EPA has approved PM2.5 wildfire influenced
exceptional events demonstrations in the past, which are posted on the
agency's Exceptional Events Rule Web site.\290\
---------------------------------------------------------------------------
\289\ See 40 CFR 50.14.
\290\ The EPA's Exceptional Events Rule Web site is located at:
http://www.epa.gov/ttn/analysis/exevents.htm.
---------------------------------------------------------------------------
Depending on the nature and scope of international emissions events
affecting air quality in the U.S., the EPA may be able to assist states
in developing approvable exceptional events demonstrations. More
generally, the EPA believes that the best approach for evaluating the
potential impacts of international transport on nonattainment is for
states to work with the EPA on a case-by-case basis to determine the
most appropriate information and analytical methods for each area's
unique situation. The EPA will work with states that are developing
attainment plans for which section 179B is relevant, and ensure the
states have the benefit of the EPA's understanding of international
transport of PM2.5 and PM2.5 precursors.
E. Enforcement and Compliance
Section 172(c)(6) in subpart 1 of the CAA requires nonattainment
SIPs to ``include enforceable emission limitations, and such other
control measures, means or techniques . . . as well as schedules and
timetables for compliance, as may be necessary or appropriate to
provide for attainment.'' In the remanded 2007 PM2.5
Implementation Rule, the EPA described the general elements that
characterize an enforceable SIP regulation, recognizing that
enforceable SIP regulations may address the elements in different ways
depending on the type of source category being regulated. The agency
continues to believe and hereby proposes that in general, in order for
a SIP regulation to be enforceable, it must clearly spell out which
sources or source types are subject to its requirements and what its
requirements (e.g., emission limits or work practices) are. An
enforceable regulation would also specify the timeframes within which
these requirements must be met, and definitively state the
recordkeeping and monitoring requirements appropriate to the type of
sources being regulated. The recordkeeping and monitoring requirements
would have to be sufficient to enable the state or the EPA to determine
whether the source is complying with the emission limit on a continuous
basis. An enforceable regulation would also contain test procedures in
order to determine whether sources are in compliance.
The EPA continues to believe that complete and effective
regulations that ensure compliance with an applicable emissions limit
would have to include requirements for both performance testing of
emissions and ongoing monitoring of the compliance performance of
control measures, and the agency proposes to require that SIP
regulations that establish emission limits include the following:
(a) Indicator(s) of compliance--the pollutant or pollutants of
interest (e.g., filterable and condensable PM2.5) and the
applicable units of measurement for expressing compliance (e.g., ng/J
of heat input, lb/hr);
(b) Test method--reference to a specific EPA or other published set
of sample collection and analytical procedures, equipment design and
performance criteria, and the calculations providing data in units of
the indicator of compliance (Section IX.K of this preamble presents a
discussion of specific test methods for condensable PM2.5
emissions);
(c) Averaging time--the minimum length of each required test run
and the requirement to average the results of the test runs (e.g.,
three runs) representing a specified period of time (e.g., 8 hours);
and,
(d) Frequency--the maximum time between emissions or performance
tests (e.g., within 30 days of facility start-up and once each
successive quarter, every 6-month period, or yearly).
In order to be complete with regard to compliance monitoring
provisions, the EPA proposes that regulations adopted into the SIP must
include the following critical elements:
(a) Indicator(s) of performance--the parameter or parameters
measured or observed for demonstrating proper operation of the
pollution control measure or compliance with the applicable emissions
limitation or standard. Indicators of performance could include direct
or predicted emissions measurements, process or control device (and
capture system) operational parametric values that correspond to
compliance with efficiency or emissions limits, and recorded findings
of verification of work practice activities, raw material or fuel
pollutant content, or design
[[Page 15448]]
characteristics. Indicators could be expressed as a single maximum or
minimum value, a function of process variables (e.g., within a range of
pressure drops), a particular operational or work practice status
(e.g., a damper position, completion of a waste recovery task), raw
material or fuel pollutant content, or an interdependency between two
or more variables;
(b) Measurement technique--the means used to gather and record
information of or about the indicators of performance. The components
of the measurement technique include the detector type or analytical
method, location and installation specifications, inspection
procedures, and quality assurance and quality control measures.
Examples of measurement approaches include continuous emissions
monitoring systems (CEMS), continuous opacity monitoring systems
(COMS), continuous parametric monitoring systems (CPMS), performance
testing, vendor or laboratory analytical data, and manual inspections
and data collection that include making records of process conditions,
raw materials or fuel specifications, or work practices. Directly
enforceable emission measurements, such as PM CEMs, are preferred
wherever feasible. Where COMS are feasible, it should be clear that
opacity is a directly enforceable standard, not merely an indicator of
compliance;
(c) Averaging time--the period over which to average data to verify
compliance with the emissions limitation or standard or proper
operation of the pollution control measure. Examples of averaging time
include a 3-hour average in units of the emissions limitation, a 30-day
rolling average emissions value, a daily average of a control device
operational parametric range, periodic (e.g., monthly, annual) average
of raw materials or fuel pollutant content, and an instantaneous alarm;
(d) Monitoring frequency--the number of monitoring data values
recorded over a specified time interval. Examples of monitoring
frequencies include at least one data value every 15 minutes for CEMS
or CPMS, at least every 10 seconds for COMS, upon receipt or
application of raw materials or fuel to the process, or at least once
per operating day (or week, month, etc.) for performance testing, work
practice verification, or equipment design inspections; and,
(e) Reporting and record retention requirements--criteria for
retaining monitoring and test data in an electronic form and periodic
electronic reporting of information as needed to the compliance office.
Electronic record retention and submission have been widely adopted,
and the EPA believes that such readily accessible documentation could
be used by state, federal and other analysts to spot trends and non-
compliance more easily than if these entities conducted reviews of
paper documents. The EPA also recommends that compliance reports be
made available online so that the general public can readily access the
information without the need to submit Freedom of Information Act
(FOIA) requests to the EPA. The EPA is in the process of revising
federal rules to make similar requirements apply.
The EPA continues to believe that approval of regulations adopted
into SIPs would have to ensure that these critical elements are present
and clearly defined to be approvable. In particular, the compliance
obligations, including emissions limits and other applicable
requirements, would need to be representative of and accountable to the
assumptions used in a state's attainment demonstration. This
accountability would include the ability to transfer the applicable
regulatory requirements to a title V operating permit subject to the
EPA and public review.\291\
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\291\ Under the title V regulations, sources have an obligation
to include in their title V permit applications, among other
components, all emissions of pollutants for which the source is
major, and all emissions of regulated air pollutants. See, e.g., 40
CFR 70.5(c)(3). The definition of regulated air pollutant in 40 CFR
70.2 includes any pollutant for which a NAAQS has been promulgated,
including PM2.5.
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The EPA seeks comment on the elements proposed to be required to
ensure that regulations adopted into a SIP are enforceable.
F. Efforts To Encourage a Multi-Pollutant Approach When Developing
PM2.5 Attainment Plans
1. General Guidance
From a planning and resource perspective, the EPA believes that it
can be efficient for states to develop integrated control strategies
that address multiple pollutants rather than separate strategies for
each pollutant or NAAQS individually. An integrated air quality control
strategy that reduces multiple pollutants can help ensure that
reductions are efficiently achieved and produce the greatest overall
air quality benefits. For example, it is widely known that certain
control measures that reduce emissions of NOX and VOC, and
thus reduce ambient PM2.5 levels, can also result in reduced
ambient concentrations of ground-level ozone.\292\ Many VOC are also
hazardous air pollutants (HAP), so a control strategy for a
PM2.5 nonattainment area that reduces VOC emissions may
provide the additional benefit of reducing air toxics. It is also
widely known that many sources of PM2.5 also emit toxic
metals as particulates, so controlling directly emitted
PM2.5 emissions from these sources would also reduce the
emissions of toxic metals. In addition, due to expected changes in
meteorology resulting from climate change, the EPA encourages states to
assess climate change and air pollution together and account for the
potential effects of climate change in their multi-pollutant planning
efforts.
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\292\ For a list of potential control measures for
PM2.5 and PM2.5 precursors, see http://www.epa.gov/air/pdfs/MenuOfControlMeasures.pdf.
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In June 2007, the EPA's CAA Advisory Committee (CAAAC) recommended
that the agency allow states to integrate SIP requirements and other
air quality goals into a comprehensive plan.\293\ The recommended plan
would demonstrate attainment/maintenance of multiple NAAQS, accomplish
sector-based reductions, realize risk reductions of HAPs and make
improvements in visibility. It could also be structured to integrate
programs addressing land use, transportation, energy and climate.
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\293\ Recommendations to the Clean Air Act Advisory Committee:
Phase II, June 2007, http://www2.epa.gov/caaac/caaac-reports.
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The EPA has encouraged states to take a multi-pollutant approach to
managing air quality.\294\ Specifically, the agency has encouraged
states to involve all stakeholders when planning to meet air quality
standards and to provide a basic outline for how local jurisdiction(s)
could address air pollutants in an integrated manner.
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\294\ Memorandum from Stephen D. Page to Regional Air Division
Directors, ``Consideration of Multiple Pollutants in Control
Strategy Development.'' August 10, 2005.
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While the agency encourages states to develop multi-pollutant
plans, it recognizes that the requirement for the agency to review and,
as necessary, revise NAAQS every 5 years, which can trigger new
statutory attainment plan submission and attainment dates, as well as
the ever-evolving understanding of pollutants and many control programs
that may be available to reduce emissions, can sometimes make such
efforts challenging. For example, under the current law, the 2007
submission date for Regional Haze SIPs has already passed while RACT
SIPs for nonattainment areas classified as Moderate or higher for the
2008 ozone NAAQS were due more than 2 years before the due date for
Moderate area
[[Page 15449]]
attainment plans for areas designated nonattainment for the 2012 annual
PM2.5 NAAQS. Although it is not feasible to integrate fully
these planning requirements, states could potentially use common
databases and modeling tools for all three SIP submissions for these
different requirements and rely on similar control measures as
appropriate. Furthermore, as states develop plans to meet any current
or future PM2.5 NAAQS, they may wish to modify existing
plans for implementing the ozone NAAQS or other NAAQS, or for regional
haze, as they consider strategies more comprehensively. However, it is
important to note that states and the EPA must continue to meet all the
CAA mandated planning and program elements for individual NAAQS. The
EPA seeks comment on alternative approaches to integrate the planning
requirements for multiple NAAQS and other CAA programs that are
promulgated at different times.
2. What is the EPA doing beyond encouraging states to integrate their
air quality planning activities to the extent feasible?
Ideally, an air quality management plan (AQMP) is a set of
pollution reduction strategies/planning activities for an area
demonstrating: attainment/maintenance of one or more NAAQS; risk
reductions from HAPs; improvements in visibility and ecosystem health;
and, integration of land use, transportation, energy and climate
activities in the area. Three areas in the country--North Carolina, New
York and the City of St. Louis (involving both Missouri and Illinois)--
participated in an EPA-led pilot effort to develop multi-pollutant
AQMPs. The pilot projects provided lessons regarding AQMP development
that should prove useful to other areas interested in better
integrating their air quality planning. The areas' initial AQMPs and
other materials are available on the EPA's Web site.\295\
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\295\ See http://www.epa.gov/air/aqmp/.
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Implementation of the 2012 PM2.5 NAAQS provides an
opportunity for states to consider how to use a multi-pollutant
approach from the beginning of their planning process. The EPA
recommends that states and tribes wishing to take a comprehensive
approach consider the following activities:
Develop models for the attainment demonstration that
include previously implemented or planned measures to reduce
PM2.5 precursors and secondary fine particles, ozone
precursors, pollutants that contribute to regional haze and, where
appropriate, air toxics and any potential negative impacts on
ecosystems;
Conduct an integrated assessment of the impact that
controls have on ambient levels of PM2.5, ozone, regional
haze, and, where applicable, air toxics, greenhouse gases, ecosystem
protection and environmental justice to identify those controls with
the greatest potential co-benefits; and,
Use common data bases and analytical tools, where
possible.
The EPA is requesting comment on what incentives or assistance the
agency might be able to provide to encourage states to integrate their
planning activities.
3. Multi-Pollutant Assessments/One-Atmosphere Modeling
A multi-pollutant assessment, or one-atmosphere modeling, is
conducted with a single air quality model that is capable of simulating
transport and formation of multiple pollutants simultaneously.\296\ For
example, this type of model can simulate formation and deposition
involving pollutants associated with PM2.5, ozone and
regional haze, and it can include algorithms simulating gas phase
chemistry, aqueous phase chemistry, aerosol formation and acid
deposition. This type of model could also include the formation and
deposition of key air toxics and the chemical interactions that occur
with these individual toxic species to produce PM2.5 and
ozone.
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\296\ Depending on the context, ``multi-pollutant'' can be
defined in different ways. In this context the agency is defining
multi-pollutant modeling as simultaneous modeling of
PM2.5, ozone, key air toxics, and regional haze. Future
multi-pollutant models may include the ability to model a broader
array of air toxics as well as greenhouse gases.
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Multi-pollutant assessments are recommended for PM2.5
attainment demonstrations because the formation and transport of VOC
and NOX are closely related to the formation of both ozone
and regional haze. There is often a positive correlation between
measured secondary particulate matter and ozone. Many of the same
factors affecting PM2.5 concentrations also affect ozone
concentrations because similarities exist in sources of precursors for
both pollutants. For example, emissions of NOX may lead to
formation of nitrates, which affect both ambient PM2.5 and
ozone levels and impair visibility. Many VOC (such as toluene) are air
toxics and may also be sources of precursors for both organic particles
and ozone. In addition, the presence of ozone itself may be an
important factor affecting secondary particle formation.
Because of these relationships, models and data analysis intended
to address PM2.5 could be beneficial for use in addressing
ozone and visibility impairment. When performing a multi-pollutant
assessment, the modeling should take into account previously
implemented or planned measures to reduce PM2.5, ozone, and
regional haze. States that undertake multi-pollutant assessments as
part of their attainment demonstration should consider assessing the
impact of their PM2.5 strategies on ozone and visibility
impairment to ensure that optimal emission reduction strategies are
developed for the three programs to the extent possible. This could
facilitate addressing all of these pollutants in a more cost effective
manner.
States may also find it desirable to assess the impact of
PM2.5, ozone, and/or regional haze control strategies on
toxic air pollutants regulated under the CAA or under state air toxic
initiatives. Given the relationships that exist between air toxics and
the formation of PM2.5 and ozone, states may find that
controls can be selected to meet goals for PM2.5 and/or
ozone attainment as well as those of specific air toxic programs.
G. Measures To Ensure Appropriate Protections for Overburdened
Populations
1. Review of PM NAAQS and At-Risk Populations
As discussed in Section II of this preamble, when the EPA sets a
primary NAAQS, the CAA directs the Administrator to establish a
standard that is ``requisite'' to protect public health with ``an
adequate margin of safety.'' \297\ In setting the NAAQS, the EPA
considers available, relevant scientific information on the health
effects that may occur in the general
[[Page 15450]]
population, as well as specific groups within the general population
that are at increased risk for experiencing adverse pollutant-related
health effects (i.e., at-risk populations).\298\ These groups could
exhibit a greater risk of pollutant-related health effects than the
general population for a number of reasons including being adversely
affected at lower pollutant concentrations, experiencing a larger
health impact at a given pollutant concentration, and/or being exposed
to higher pollutant concentrations than the general population. Thus,
the NAAQS review process inherently takes into consideration certain
environmental justice factors as part of the standard-setting process.
In setting a secondary standard, the CAA directs the Administrator to
establish a standard that ``is requisite to protect the public welfare
from any known or anticipated adverse effects.''
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\297\ The requirement that primary standards provide an adequate
margin of safety was intended to address uncertainties associated
with inconclusive scientific and technical information available at
the time of standard setting. It was also intended to provide a
reasonable degree of protection against hazards that research has
not yet identified. Both kinds of uncertainties are components of
the risk associated with pollution at concentrations below those at
which human health effects can be said to occur with reasonable
scientific certainty. Thus, in selecting primary standards that
provide an adequate margin of safety, the EPA Administrator is
seeking not only to prevent pollution levels that have been
demonstrated to be harmful but also to prevent lower pollutant
levels that may pose an unacceptable risk of harm, even if the risk
is not precisely identified as to nature or degree. The CAA does not
require the Administrator to establish a primary NAAQS at a zero-
risk level or at background concentration levels, but rather at a
level that reduces risk sufficiently so as to protect public health
with an adequate margin of safety.
\298\ The legislative history of section 109 of the CAA
indicates that a primary standard is to be set at the ``maximum
permissible ambient air level . . . which will protect the health of
any [sensitive] group of the population'' and that for this purpose
``reference should be made to a representative sample of persons
comprising the sensitive group rather than to a single person in
such a group.''
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Section 109(d) of the CAA requires the EPA to periodically review
(every 5 years) the science upon which the standards are based and the
standards themselves. As discussed elsewhere in this proposal, in its
2012 review of the PM NAAQS, the EPA revised the primary annual
PM2.5 standard by lowering the level to 12.0 micrograms per
cubic meter ([mu]g/m\3\) so as to provide increased protection against
health effects associated with long- and short-term PM2.5
exposures.\299\ The agency also revised the form of the primary annual
PM2.5 standard to eliminate the spatial averaging provisions
to avoid potential disproportionate impacts on at-risk populations. In
conjunction with these revisions, the EPA retained the primary 24-hour
PM2.5 standard, as revised in 2006 (71 FR 61144, October 17,
2006), to provide supplemental protection against health effects
associated with short-term PM2.5 exposures, especially in
areas with high peak PM2.5 concentrations. This suite of
primary annual PM2.5 standards provides increased public
health protection, including the health of at-risk populations which
include children, older adults, persons with pre-existing health and
lung disease, and persons of lower socioeconomic status, against a
broad range of PM2.5-related effects that include premature
mortality, increased hospital admissions and emergency department
visits, and development of chronic respiratory disease.\300\
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\299\ 78 FR 3086 (January 15, 2013).
\300\ In the final 2012 p.m. NAAQS rule, based on information
presented in the Integrated Science Assessment for Particulate
Matter (U.S. EPA, 2009, sections 2.2.1 and 8.1.7), the EPA made a
finding that persons with lower socioeconomic status are at
increased risk for experiencing adverse health effects related to PM
exposures (78 FR 3085, January 15, 2013, at page 3104). Persons with
lower socioeconomic status (SES) have been generally found to have a
higher prevalence of pre-existing diseases, limited access to
medical treatment, and increased nutritional deficiencies, which can
increase this population's risk to PM-related effects (77 FR 38911,
June 29, 2012).
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In addition, the Policy Assessment (U.S. EPA, 2011a, p. 2-60)
observed that the highest concentrations of PM2.5 in an area
tend to be measured at monitors located in areas where the surrounding
populations are more likely to live below the poverty line and to have
higher percentages of minorities. The EPA directed states to relocate a
limited number of existing monitors to near-roadway sites in large
urban areas. Both of these revisions were informed by scientific
evidence that underscored the potentially disproportionate exposure to
high PM2.5 concentrations and therefore disproportionate
risk to low-income and minority populations.
2. Relationship Between Direct PM2.5 Emissions and
PM2.5 Precursor Emissions Reductions and At-Risk Populations
Sources of direct PM emissions have their greatest impact on
PM2.5 concentrations and public health in the general
vicinity of the source (e.g., within 10 miles), while sources of
precursor emissions can contribute to PM2.5 concentrations
more than 100 miles away and are considered to have a more regional
impact. To date, state PM2.5 attainment plans have generally
relied to a greater extent on reductions of precursor pollutants rather
than on reductions of direct PM2.5 emissions. Studies show,
however, that on a per ton basis, the reduction of a ton of direct
PM2.5 emissions leads to greater health benefits than the
reduction of a ton of SO2 or NOX.\301\
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\301\ See Fann, N., Fulcher, C., and B. Hubbell, 2009. The
Influence of location, source, and emission type in estimates of the
human health benefits of reducing a ton of air pollution. Air
Quality, Atmosphere & Health. Volume 2, Number 3, 169-176, June
2009. See also Fann et. al., 2011. Maximizing health benefits and
minimizing inequality: incorporating local-scale data in the design
and evaluation of air quality policies. Society for Risk Analysis,
vol. 31, no. 6, p. 908-922, June 2011.
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The process for developing attainment plans for the current and
future PM2.5 NAAQS presents a potential opportunity to
target the health protections afforded by the NAAQS, as the EPA expects
that attainment for the 2012 PM2.5 NAAQS and future
PM2.5 NAAQS in nonattainment areas with the most severe
pollution problems may need to give greater emphasis to reducing direct
PM2.5 emissions in combination with efforts already underway
to further reduce precursor emissions. Placing greater emphasis on
reducing emissions from sources of direct PM2.5 (e.g.,
certain industrial facilities located in more densely populated areas;
areas with high motor vehicle and other diesel engine emissions, such
as rail yards and near major roadways; and, areas with high wood smoke
emissions) could provide the added benefit of reducing exposure to
PM2.5 in low-income and minority communities.
With this in mind, the EPA is seeking comment on additional ways
that air agencies can provide public health protection specifically for
overburdened populations when preparing attainment plans for the
PM2.5 NAAQS. The discussion that follows provides some
examples of points in the attainment plan development process at which
a state could assess opportunities for providing such additional
protections, and examples of what those additional protections might
look like.
3. Options for States To Consider To Ensure Appropriate Protections
From PM2.5 Exposure for Overburdened Populations
The EPA believes that states have sufficient flexibility and
discretion under the CAA in implementing their attainment strategies to
focus resources on controlling those sources of emissions that directly
and adversely affect low-income and other at risk populations. By
reducing impacts on at-risk populations, states can maximize health
benefits, thereby creating greater net benefits for the state in a
cost-effective manner.\302\ In addition, reducing adverse impacts to
low-income and minority populations advances the environmental justice
goal of fair treatment for these populations.
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\302\ Wesson, K., Fann, N., Morris, M, Fox, T., Hubbell, T.,
2010. A multipollutant, risk-based approach to air quality
management. Case study for Detroit. Atmospheric Pollution Research,
1, 296-304. The study compared air quality control strategies and
concluded that the multi-pollutant, risk-based approach was able to
produce approximately two times greater monetized benefits through
avoided health impacts and was more cost effective than a pollutant-
by-pollutant approach.
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There are a number of actions that states could take to focus
resources in this way. Some of these actions can help identify areas
where additional ambient monitoring may be needed in low income and
overburdened communities.
[[Page 15451]]
Such information can be used to support updates to the state's annual
monitoring plan. Examples of actions to support updates to the annual
monitoring plan include:
Develop databases and online mapping tools that enable
users (including state staff, public, and the regulated community) to
understand where sources of direct PM2.5 emissions are
located and where new or modified sources of emissions could have
potential impacts on low income and other overburdened communities;
Incorporate existing mapping tools which identify target
areas in the attainment plan development process and related actions;
and,
Analyze emissions data, ambient data, and available
modeling to identify potential unmonitored PM2.5 hotspots in
areas with a high percentage of low income, minority or indigenous
persons (see Section IV.E of this preamble for further discussion of
this option).
Once target areas for addressing these sensitive population needs
within a nonattainment area have been identified, the state could
consider taking any of the following actions which help target
emissions reductions that may be needed to attain the PM2.5
NAAQS:
Prioritize the selection of control measures that target
reductions of direct PM2.5, particularly from sources
located in ``at-risk'' areas as part of the state's RACM and RACT
analysis (for Moderate nonattainment areas) or BACM and BACT analysis
(for Serious nonattainment areas), as well as other measures needed to
demonstrate attainment (see Sections IV.D and VI.D, respectively, of
this preamble for further discussion of this option);
Improve the understanding of the potential impact of minor
sources by improving or generating an emissions inventory for such
minor sources, including sources that are not currently required to
report emissions, to generate options on how emissions can be reduced
in the target area;
Design voluntary programs to reduce VMT and mobile source-
related PM2.5 emissions (e.g., diesel retrofits);
Incorporate environmental justice criteria into the
alternatives analysis to ensure appropriate siting and require
cumulative impact studies for proposed projects;
Eliminate exemptions from and/or raise thresholds for
minor source permitting;
Develop a list of potential supplemental environmental
projects (SEPs) \303\ that could be applied in the target area; and,
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\303\ For more information on SEPs, go to www2.epa.gov/enforcement/supplemental-environmental-projects-sep.
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Prioritize targeted enforcement strategies.
In addition to the above, states could increase opportunities for
meaningful involvement of community groups in attainment plan
development, annual monitoring network plan reviews, and permitting
processes \304\ for at-risk and minority populations by taking the
following steps:
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\304\ See 78 FR 27220 (May 9, 2013) notice of availability,
``EPA Activities To Promote Environmental Justice in the Permit
Application Process.''
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Develop advisory boards and/or develop enhanced notice-
and-comment requirements for low income and minority communities to
assure meaningful involvement relative to projects that impact their
communities;
Provide special notice of important actions affecting
target areas in appropriate languages and with attention to cultural
barriers;
Provide advance notification for low income and minority
communities of upcoming opportunities for public comment on SIPs,
ambient air monitoring plans, and other relevant actions;
Maintain multi-lingual Web sites and offer translators for
public meetings and hearings;
Coordinate with the state's EJ coordinator to assist with
outreach efforts; and,
Provide states with appropriate federal EJ guidance tools.
The EPA is seeking comment on these examples and whether and how
the EPA might provide recommendations to states preparing attainment
plans for the 2012 and any future PM2.5 NAAQS on additional
ways to ensure equal protections for overburdened populations.
H. Tribal Issues
The 1998 Tribal Air Rule (TAR) (40 CFR part 49), which implements
section 301(d) of the CAA, gives tribes the option of developing TIPs.
Specifically, the TAR provides for the tribes to be treated in the same
manner as a state in implementing certain sections of the CAA. However,
tribes are not required to develop implementation plans. The EPA
determined in the TAR that it was inappropriate to treat tribes in a
manner similar to a state with regard to specific plan submittal and
implementation deadlines for NAAQS-related requirements, including, but
not limited to, such deadlines in CAA sections 110(a)(1), 172(a)(2),
182 187, and 191. See 40 CFR 49.4(a). In addition, the EPA determined
it was not appropriate to treat tribes similarly to states with respect
to provisions of the CAA requiring as a condition of program approval
the demonstration of criminal enforcement authority or providing for
the delegation of such criminal enforcement authority. See 40 CFR
49.4(g). To the extent a tribe is precluded from asserting criminal
enforcement authority, the federal government will exercise primary
criminal enforcement responsibility. See 40 CFR 49.8. In such
circumstances, tribes seeking approval for CAA programs provide
potential investigative leads to an appropriate federal enforcement
agency.
If a tribe elects to do a TIP, the agency will work with the tribe
to develop an appropriate schedule which meets the needs of the tribe,
and which does not interfere with the attainment of the NAAQS in other
jurisdictions. The tribe developing a TIP can work with the EPA
Regional Office on the appropriateness of addressing RFP and other
substantive SIP requirements that may or may not be appropriate for the
tribe's situation.
The CAA and the TAR provide tribes opportunities and flexibility
for the tribe in the preparation of a TIP to address the NAAQS. If a
tribe elects to develop a TIP, the TAR offers flexibility for the tribe
to identify and implement on a case-by-case basis only those CAA
programs or reasonably severable program elements needed to address
their specific air quality problems. In the TAR, the EPA described this
flexible implementation approach as a modular approach. Each tribe may
evaluate the particular activities, including potential sources of air
pollution within the exterior boundaries of its reservation (or within
non-reservation areas for which it has demonstrated jurisdiction),
which cause or contribute to its air pollution problem. A tribe may
adopt measures for controlling those sources of PM2.5-
related emissions, as long as the elements of the TIP are reasonably
severable from the package of elements that can be included in a whole
TIP. A TIP must include regulations designed to solve specific air
quality problems for which the tribe is seeking the EPA's approval, as
well as a demonstration that the tribal air agency has the authority
from the tribal government to develop and run their program, the
capability to enforce their rules, and the resources to implement the
program they adopt. In addition, the tribe must receive an eligibility
determination from the EPA to be treated in the same manner as a state
for the particular
[[Page 15452]]
matter at issue and to receive authorization from the EPA to run a CAA
program.
The EPA would review and approve, where appropriate, these partial
TIPs as one step of an overall air quality plan to attain the NAAQS. A
tribe may step in later to add other elements to the plan, or the EPA
may step in to fill gaps in the air quality plan as necessary or
appropriate. In approving a TIP, the agency would evaluate whether the
plan appropriately coordinates with the overall air quality plan for an
area when tribal lands are part of a multi-jurisdictional area.
Because many PM2.5 nonattainment areas will include
multiple jurisdictions, and in some cases both Indian country and state
lands, it is particularly important for the tribes and the states to
work together to coordinate their planning efforts. States need to
incorporate Indian country emissions in their base emissions
inventories if Indian country is part of an attainment or nonattainment
area.\305\ Tribes and states should coordinate their planning
activities as appropriate to ensure that neither is adversely affecting
attainment of the NAAQS in the area as a whole. Coordinated planning in
these areas will help ensure that the planning decisions made by the
states and tribes complement each other and that the nonattainment area
makes reasonable progress toward attainment and ultimately attains the
applicable PM2.5 NAAQS. In reviewing and approving
individual TIPs and SIPs, the EPA will determine if together they are
consistent with the overall air quality needs of an area.
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\305\ On January 17, 2014, the United States Court of Appeals
for the District of Columbia Circuit issued a decision vacating the
EPA's 2011 rule entitled ``Review of New Sources and Modifications
in Indian Country'' (76 FR 38748, July 1, 2011) with respect to non-
reservation areas of Indian country (See, Oklahoma Department of
Environmental Quality v. EPA, 740 F.3d 185 (D.C. Cir. 2014)). Under
the court's reasoning, with respect to CAA state implementation
plans, a state has primary regulatory jurisdiction in non-
reservation areas of Indian country (i.e., Indian allotments located
outside of reservations and dependent Indian communities) within its
geographic boundaries unless the EPA or a tribe has demonstrated
that a tribe has jurisdiction over a particular area of non-
reservation Indian country within the state.
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To date, very few tribes have submitted for the EPA's approval TIPs
covering areas over which they have jurisdiction. In the absence of a
TIP, the EPA is authorized under the TAR to implement CAA programs in
such areas as necessary or appropriate. For example, an unhealthy air
quality situation on an Indian reservation may require the EPA to
develop a FIP to reduce emissions from sources on the reservation.
Likewise, if the agency determines that sources in an area under tribal
jurisdiction could interfere with a larger nonattainment area meeting
the NAAQS by its attainment date, it would develop a FIP for those
sources in consultation with the tribe, as necessary or appropriate.
States have an obligation to notify other states in advance of any
public hearing(s) on their state plans if such plans will significantly
impact such other states. 40 CFR 51.102(d)(5). Under section 301(d) of
the CAA and the TAR, tribes may become eligible to be treated in a
manner similar to states (TAS) for this purpose. Affected tribes with
this status must also be informed of the contents of such state plans
and given access to the documentation supporting these plans. In
addition to this mandated process, the EPA encourages states to extend
the same notice to all affected tribes, regardless of their TAS status.
Executive Orders and the EPA's Indian policies generally call for
the EPA to coordinate and consult with tribes on matters that affect
tribes. Executive Order 13175, titled, ``Consultation and Coordination
with Indian Tribal Governments'' requires the EPA to develop a process
to ensure ``meaningful and timely input by tribal officials in the
development of regulatory policies that have Tribal implications.'' In
addition, the EPA's policies include the agency's 1984 Indian Policy
relating to Indian tribes and implementation of federal environmental
programs, the April 10, 2009, Office of Air Quality Planning and
Standards guidance ``Consulting with Indian Tribal Governments,'' and
the ``EPA Policy on Consultation and Coordination With Indian Tribes.''
Consistent with these policies, the EPA intends to meet with tribes on
activities potentially affecting the attainment and maintenance of the
current and future PM2.5 NAAQS in Indian country, including
agency actions on SIPs. As such, it would be helpful for states to work
with tribes with land that is part of the same air quality area during
the SIP development process and to coordinate with tribes as they
develop their SIPs.
I. Voluntary Programs for Reducing Ambient PM2.5
1. PM Advance Program
The EPA believes there are significant advantages for states,
tribes and local agencies to take steps to reduce direct
PM2.5 emissions and emissions of PM2.5 precursors
as early as possible. First and foremost, early reductions help to
achieve cleaner air sooner, and help to ensure continued health
protection. Second, early steps could help an area avoid a
nonattainment designation in the first place, or for an area eventually
designated as nonattainment, early reductions could help bring the area
back into attainment sooner, which may lead to qualifying for a CDD and
subsequent suspension of attainment planning requirements as described
in Section IX.C of this preamble. In addition, early action to improve
air quality can help an eventual nonattainment area, particularly an
area that has never been designated nonattainment before, to establish
working relationships between key stakeholders. The EPA's expectation
is that early actions to reduce emissions in such areas would be less
resource-intensive than actions taken once a nonattainment designation
has been made, since at that point the implementation of controls would
need to occur in conjunction with actions to comply with other
requirements such as nonattainment NSR and transportation conformity.
In January 2013, the EPA began a new early emissions reduction
program for attainment areas called ``PM Advance,'' which is much like
the related ``Ozone Advance'' program that began in April 2012.
Additional information about the PM Advance program for the annual and
24-hour PM2.5 NAAQS is provided in a separate guidance
document that is available at http://www.epa.gov/ozonepmadvance.
2. Residential Wood Smoke Programs
The EPA recognizes that residential wood smoke is a concern for
many nonattainment areas. The EPA estimates that wood stoves, hydronic
heaters and fireplaces emit more than 345,000 tons of PM2.5
into the air throughout the country each year--mostly during the winter
months. Residential wood smoke can increase fine particle pollution to
levels that cause significant health concerns (e.g., asthma attacks,
heart attacks, premature death). Wood smoke causes many counties
throughout the U.S. to either exceed the national health-based
standards for fine particles, or places them on the cusp of exceeding
the standards. Because wood stoves, hydronic heaters and other similar
appliances can be used around the clock in residential areas, they can
cause significant and varying health and quality of life issues.
To reduce fine particle pollution, many PM2.5
nonattainment areas will need to address residential wood smoke. The
EPA has developed the ``Strategies for Reducing Residential Wood
Smoke''
[[Page 15453]]
document that provides education and outreach tools, information on
regulatory approaches to reduce wood smoke, as well as information
about voluntary programs that communities around the country have
used.\306\ In addition, it includes methods for calculating emissions
reductions, funding ideas and the basic components of a wood smoke
reduction plan that can be adopted into a SIP as an enforceable control
measure.\307\ To access the document, go to http://epa.gov/burnwise/pdfs/strategies.pdf. For more information on the EPA's wood smoke
reduction program, visit http://www.epa.gov/burnwise.
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\306\ On February 3, 2015, the EPA strengthened the New Source
Performance Standards (NSPS) for new residential wood heaters and
established NSPS for other new wood heaters, including outdoor and
indoor wood-fired boilers (also known as hydronic heaters). The
standards will reduce emissions of direct PM2.5 as well
as carbon monoxide, VOC, air toxics (including formaldehyde, benzene
and polycyclic organic matter), and black carbon. See http://www2.epa.gov/residential-wood-heaters/new-source-performance-standards-new-residential-wood-heaters-new.
\307\ For further guidance on incorporating voluntary measures
into a SIP, see ``Incorporating Emerging and Voluntary Measures in a
State Implementation Plan (SIP).'' U.S. EPA. Office of Air and
Radiation. September 2004. Available at http://www.epa.gov/ttn/caaa/t1/memoranda/evm_ievm_g.pdf.
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J. Improved Stationary Source Emissions Monitoring
1. Background
For purposes of demonstrating compliance with the EPA's air quality
regulatory requirements, the EPA, air agencies, and sources rely on two
basic types of monitoring: ambient air quality monitoring and
stationary source emissions monitoring. Ambient air quality monitoring,
as discussed in Section II of this preamble, entails collecting and
measuring samples of criteria pollutants in ambient air to evaluate air
quality as compared to clean air standards and historical information.
Stationary source emissions monitoring, on the other hand, entails
collecting and using measurement data (or other information) from
individual stationary sources to demonstrate compliance with emissions
standards, to assess process or control device performance, or to
verify work practices. While ambient air quality monitoring is used to
assess compliance with the NAAQS, stationary source emissions
monitoring is used to assess compliance with source-specific
regulations under programs like the New Source Performance Standards
(NSPS), the National Emissions Standards for Hazardous Air Pollutants
(NESHAP), the compliance assurance monitoring (CAM) program, the title
V air operating permits program, and the acid deposition control
program, as well as specific SIP control measures.\308\
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\308\ Regulations governing the implementation of these programs
are located at 40 CFR parts 60, 61, 63, 64, 70, 71 and 75.
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Accurate stationary source emissions monitoring is critical for
purposes of developing accurate emissions inventories and in order to
identify appropriate control measures to reduce emissions from
stationary sources. In addition, after control measures are in place,
stationary source emissions monitoring provides process and control
device performance information to the facility operator so that
appropriate corrective action can be taken if emission levels exceed
applicable thresholds. Thus, appropriate stationary source emissions
monitoring requirements, like the control measures with which they are
associated, are a fundamental element of an approvable attainment plan.
By way of example, in a limited study on improving stationary
source emissions monitoring, the EPA found that revising the
measurement technique at a stationary source could provide information
to the facility operator to take corrective action that could
potentially reduce emissions up to 15 percent, and that increasing
monitoring frequency at the facility could provide information that
could be used to inform corrective actions that could yield potential
stationary source emissions reductions of up to 13
percent.309 310 Implementation of stationary source
emissions monitoring improvements could thus lead to actions to achieve
additional emissions reductions not only at individual sources but also
in the nonattainment areas where these sources are located.
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\309\ Impact of Improved Monitoring on PM2.5
Emissions, memorandum from L. Barr and K. Schaffner, RTI
International, to B. Parker, U.S. Environmental Protection Agency.
December 2003.
\310\ As discussed in Section IX.E of this preamble, emissions
monitoring has four essential components: (i) indicator(s) of
performance; (ii) measurement technique(s); (iii) monitoring
frequency; and, (iv) averaging time.
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2. Guidance To Help Improve Stationary Source Emissions Monitoring
Because of the important role that effective stationary source
emissions monitoring can play in informing the development of
attainment strategies for PM2.5 NAAQS nonattainment areas,
the EPA is interested in applied best practices for stationary source
emissions monitoring that could be included in guidance for other
stationary sources and air agencies. The EPA seeks to gather
information about ways to make the source emissions monitoring data
collection process easier and more transparent. The EPA therefore seeks
appropriate examples and supporting data from individual sources and
air agencies with experience in this area to inform such future
guidance. The EPA also seeks comment on the specific topics and
questions that follow, which the agency may address in future guidance
related to improved source monitoring. Specifically:
(1) Based on your experience, in which cases do you believe
improved monitoring techniques are more appropriate than visual
emissions (VE) techniques for monitoring compliance with
PM2.5 (or PM, in general) emissions limits? Please identify
monitoring techniques that you would recommend in lieu of VE, and
describe the instances in which VE remains appropriate.
(2) Based on your experience, are bag leak detection systems, PM
continuous parameter monitoring systems (CPMS), or PM continuous
emissions monitoring systems (CEMS) reliable, cost-effective methods
for monitoring compliance with PM emissions? Please provide additional
information on reliability and cost to support your position.
(3) Will increasing the frequency of VE observations resolve the
issue of applicability of VE techniques for monitoring compliance with
PM2.5 emissions? In other words, are there situations in
which increased VE frequency (i.e., daily versus weekly) would be
expected to have no impact on compliance with PM2.5 emission
limits? If so, please provide relevant data and explanation of such
situations.
(4) Should the EPA consider mandating through rulemaking the use of
alternatives to VE techniques for monitoring compliance with
PM2.5 and PM emissions limits in certain situations and
applications? If so, in what cases?
(5) Should the EPA's effort with regard to the use of improved
monitoring techniques in lieu of VE monitoring be focused on applicable
requirements established/relied upon for compliance with the
PM2.5 NAAQS, or should the agency more broadly address other
applicable requirements where VE techniques are commonly used (e.g., to
estimate TSP and PM10 emissions)?
(6) Should the EPA consider mandating through rulemaking the use of
alternatives to continuous opacity monitoring systems (COMS) for
monitoring compliance with PM2.5 and PM emissions limits in
certain situations and applications? If so, in what cases?
[[Page 15454]]
(7) In its study published in 2003, the EPA identified stationary
source emission reduction techniques that air agencies should consider
when developing their potential list of control measures for a
PM2.5 NAAQS nonattainment area.\311\ Specifically, the EPA
identified improved measurement techniques and increased monitoring
frequency as practices that could better inform sources and air
agencies of excess emissions from individual sources which, if
responded to more quickly, could yield significant reductions and
assist in bringing the area into attainment for the NAAQS. Please
comment on whether these techniques remain appropriate, given that they
were based on the best technical information available at the time. Are
there ways to improve the methodologies described in the study?
---------------------------------------------------------------------------
\311\ Ibid.
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(8) Please submit any examples of improved stationary source
emissions monitoring, including a description of the measure,
monitoring data, etc.
(9) Please submit any other methodologies--complete with equations
and explanations--for estimating emissions reductions due to improved
monitoring.
The EPA will continue to explore and implement innovative, cost-
effective ideas that offer tangible incentives for improved source
monitoring to be adopted as part of the associated emissions
limitations that will help achieve additional reductions from
stationary sources and bring areas into attainment for the
PM2.5 NAAQS in a timely way.
K. Stationary Source Test Methods for Emissions of Condensable PM2.5
1. Background
As discussed in Section II of this preamble, direct
PM2.5 comprises of two components: Filterable
PM2.5 and condensable PM2.5 emissions. Accurate
test methods for quantifying filterable PM emissions have been
available for air agencies and states to apply since the early 1970s.
In addition, controls have improved over the past 40 years and most
sources now achieve substantially lower emissions than required by
state and federal emissions limits. With the filterable portion of
PM2.5 emissions being relatively well controlled, the
condensable portion of PM2.5 emissions now represents a
larger share of overall PM2.5 emissions for several
categories of stationary sources. However, accurate test methods for
condensable PM2.5 emissions have only been recently
developed and approved by the EPA. Thus, many states may have
stationary source emission limits adopted into their existing SIPs
based only on filterable PM2.5 emissions or based on
outdated methods for measuring or estimating condensable
PM2.5 emissions.
The following discussion focuses on current test methods for
quantifying condensable PM2.5 emissions and the EPA's
proposed requirements for states developing control strategies for
PM2.5 nonattainment areas.
2. Test Methods for Condensable PM From Stationary Sources
Since January 1, 2011, the EPA has required that states take into
consideration condensable PM2.5 emissions when establishing
emission limits for stationary sources as part of any control strategy
for PM2.5 NAAQS nonattainment areas.\312\ This date
coincided with the effective date of the agency's revisions to test
methods for measuring filterable PM10 emissions from
stationary sources (Method 201A) and for measuring condensable PM
emissions from stationary sources (Method 202).\313\ The revisions
increased the precision of Method 202 and improved the consistency in
the measurements obtained between source tests performed under
different regulatory authorities.
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\312\ 72 FR 20586 (April 25, 2007).
\313\ 75 FR 80118 (December 21, 2010).
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In the preamble to the 2007 PM2.5 Implementation Rule,
the EPA explained that the use of the (then anticipated) revisions to
the EPA Method 201A combined with Method 202 to obtain measured source
specific emissions of PM2.5 would improve the quality of
emissions inventories for stationary sources and would aid in the
development of a more reliable attainment strategy, as sources that may
have a considerable amount of condensable PM2.5 emissions
could be better characterized with the new methods. The EPA continues
to believe that using these improved test methods can help identify
sources of direct PM2.5 emissions which, if better
controlled, can help to bring a PM2.5 nonattainment area
into attainment. Likewise, use of these test methods may help a state
identify sources whose condensable emissions may have been incorrectly
estimated and therefore may not provide meaningful PM2.5
control opportunities.
3. Proposed SIP Requirements for Test Methods For Condensable
PM2.5 Emissions
The EPA proposes to require that, where a state needs to adopt
control measures for direct PM2.5 from sources in a
nonattainment area, the state must specify PM2.5 emission
limits in its SIP that include both filterable and condensable
emissions. In addition, compliance testing of those sources must
include measurement of condensable emissions (such as through the use
of Method 202). Under this proposal, any new or revised emission limit
used as a control measure to bring an area into attainment for any
current or future PM2.5 NAAQS must use methods that measure
PM2.5 or total PM including both filterable and condensable
particulate matter. Existing emission limitations that are not being
revised as part of a Moderate area or Serious area attainment plan can
remain as filterable PM or whatever test method is used by the state
for compliance determination. In these cases, the acceptability of
existing stationary source test methods for PM2.5 attainment
plans will depend upon what is required under the state's current test
methods for PM emissions. The EPA believes that this proposed
requirement is appropriate because the addition of the condensable
portion of PM2.5 to filterable PM2.5 may increase
direct PM2.5 emissions by a factor of five or more, and the
use of test methods that only measure filterable emissions potentially
limit the control measures available for developing cost effective
strategies to achieve attainment of the PM2.5 NAAQS.
The EPA seeks comment on this proposed requirement for states to
quantify condensable PM2.5 emissions in their attainment
plans for PM2.5 nonattainment areas.
X. What is the EPA proposing with respect to revoking the 1997 primary
annual PM2.5 NAAQS?
A. Background
If the 1997 primary annual PM2.5 NAAQS were to remain in
place after conformity requirements begin to apply for the 2012 primary
annual PM2.5 NAAQS (1 year after the effective date of
designations), a number of federal agencies, metropolitan planning
organizations (MPOs) and other state, local, and federal transportation
and air quality agencies in areas that are currently designated
nonattainment or maintenance for the 1997 annual PM2.5 NAAQS
and will be designated nonattainment for the 2012 primary annual NAAQS
would be required to implement conformity requirements for both annual
PM2.5 NAAQS concurrently. Additionally, some areas would
also be implementing conformity requirements for the 2006 24-hour
PM2.5
[[Page 15455]]
NAAQS, and two areas remain subject to conformity requirements for the
1997 24-hour PM2.5 NAAQS. This could lead to unnecessary
complexity for transportation conformity determinations, especially if
an area's boundaries for the various PM2.5 NAAQS differ from
one another and the same test of conformity cannot be used for all of
the PM2.5 NAAQS. Even where an area's boundaries are
unchanged, different analysis years under the conformity rules may be
required for each PM2.5 NAAQS. It could also lead to general
conformity determinations being made in areas that are attainment for
the 2012 primary annual PM2.5 NAAQS. Finally, state and
local air quality agencies would be required to continue attainment
planning activities for the 1997 primary annual PM2.5 NAAQS
even if they had air quality data that resulted in their being
designated attainment for the 2012 primary annual PM2.5
NAAQS.
The EPA believes that it is more important and consistent with CAA
requirements to determine conformity for the new 2012 primary annual
PM2.5 NAAQS, which is more stringent and thus more
protective of health than the 1997 PM2.5 NAAQS. This section
therefore describes the EPA's proposed approaches for transitioning
from the 1997 primary annual PM2.5 NAAQS to the 2012 primary
annual PM2.5 NAAQS. This section discusses a number of
options for revoking the 1997 primary annual PM2.5 NAAQS and
addresses anti-backsliding requirements that would apply, as
appropriate, under each of the revocation options. The EPA is not
proposing to revoke the 1997 secondary annual PM2.5 NAAQS in
this action because that NAAQS has been retained in order to prevent
certain welfare effects associated with PM2.5.\314\
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\314\ 78 FR 3086 (January 15, 2013).
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The proposed options are framed in the context of the CAA
requirements that apply to NAAQS transitions to ensure that states and
nonattainment areas continue to make progress and do not reverse
progress, or backslide, from improvements already made in air quality.
The CAA contains several provisions indicating congressional intent not
to allow a state to alter or remove provisions from an approved
attainment plan if the revision would reduce air quality protection.
Section 193 of the CAA prohibits modification of a control requirement
in effect or required to be adopted as of November 15, 1990 (the date
of enactment of the 1990 CAA Amendments), unless such a modification
would ensure equivalent or greater emissions reductions. Section
172(e), which addresses relaxations of a NAAQS, requires protections
for areas that have not attained a NAAQS prior to a relaxation by
requiring controls which are at least as stringent as the controls
applicable in nonattainment areas prior to any such relaxation. Section
110(l) provides that a SIP revision cannot be approved if it will
interfere with attainment or other CAA requirements. Under section
175A(d), an area that is redesignated to attainment may, with an
appropriate showing of no interference, cease to implement a measure
that is contained in the SIP at the time of redesignation, but only if
that measure is retained as a contingency measure in the area's
maintenance plan.315 316
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\315\ Nonattainment areas that were redesignated to attainment
with an approved section 175A maintenance plan are referred to
throughout this document as ``maintenance areas.''
\316\ Unimplemented requirements in the SIP or those shown to be
unnecessary for maintenance can be shifted to the contingency
measures portion of the SIP upon redesignation. See ``Procedures for
Processing Requests to Redesignate Areas to Attainment,'' Memorandum
from John Calcagni, Director, Air Quality Management Division,
September 4, 1992; ``State Implementation Plan (SIP) Requirements
for Areas Submitting Requests for Redesignation to Attainment of the
Ozone and Carbon Monoxide (CO) National Ambient Air Quality
Standards (NAAQS) On or After November 15, 1992,'' Memorandum from
Michael H. Shapiro, Acting Assistant Administrator for Air and
Radiation, September 17, 1993. As discussed elsewhere in this
document, an exception is made for NNSR, which can be removed from
the SIP completely and need not be retained as a contingency measure
after redesignation to attainment.
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The transition from the 1997 to the 2012 primary annual
PM2.5 NAAQS is a straightforward tightening of the level
with little change in the form of the standard, so it is unambiguous
that the 2012 primary annual PM2.5 NAAQS is more stringent
than the 1997 primary annual PM2.5 NAAQS. In the final 2012
PM NAAQS rule the EPA eliminated the provisions that allowed for an
area to use spatial averaging of monitoring data to determine whether
or not it is attaining the 1997, 2012 and any future annual
PM2.5 NAAQS.\317\ Eliminating spatial averaging provides
additional protection for populations that may be at a greater risk to
exposures of elevated levels of PM2.5. In these
circumstances where the annual PM2.5 NAAQS has clearly been
strengthened, section 172(e) on its face does not apply. The EPA's
interpretation that anti-backsliding provisions consistent with the
purposes of section 172(e) by analogy should apply as upheld by the
court in South Coast as appropriate in the absence of statutory
provisions addressing tightened air quality standards. In proposing
anti-backsliding requirements that would apply as appropriate to the
options that are being considered, the EPA seeks to apply the
principles of section 172(e).\318\
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\317\ See the Federal Register published on January 15, 2013 (78
FR 3085, 3124, 3125, 3126, 3137 and 3229).
\318\ South Coast Air Quality Management District v. EPA, 472
F.3d 882 (D.C. Cir. 2006).
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B. History of Revocation of Other NAAQS
The EPA has either adopted or has proposed to adopt transition
policies for other NAAQS, including the policies for the transitions
from:
The 1-hour ozone NAAQS to the 1997 ozone NAAQS;
The 1997 ozone NAAQS to the 2008 ozone NAAQS;
The prior lead NAAQS to the 2008 lead NAAQS; and,
The prior sulfur dioxide (SO2) NAAQS to the
2010 SO2 NAAQS.
It is important to note that for all previous NAAQS transitions,
the EPA has used revocation to reduce the burden associated with
implementing a NAAQS that has been replaced with a more stringent
NAAQS.
In its Phase 1 Rule for the transition from the 1-hour ozone NAAQS
to the 1997 ozone NAAQS, the EPA stated that the 1-hour ozone NAAQS
would be revoked (i.e., no longer apply) 1 year after the effective
date of initial area designations for the 1997 ozone NAAQS. The EPA
also included anti-backsliding requirements in the Phase 1 Rule to
address the transition between the two standards.
The Phase 1 Rule for implementation of the 1997 ozone NAAQS was the
subject of legal challenges, and the resulting court decision in South
Coast upheld the EPA's authority to revoke the 1-hour ozone NAAQS as
long as adequate anti-backsliding measures were retained to prevent
backsliding.\319\ The decision directed the EPA to provide additional
1-hour ozone NAAQS anti-backsliding requirements for NNSR, section 185
fees, and section 172(c)(9) and 182(c)(9) contingency measures for
failure to attain the 1-hour ozone NAAQS by the applicable attainment
date or to make reasonable further progress toward attainment of that
standard, in addition to the anti-backsliding measures contained in the
Phase 1 rule.\320\
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\319\ South Coast Air Quality Management District v. EPA, 472
F.3d 882 (D.C. Cir. 2006).
\320\ For a more complete discussion of the requirements for the
transition from the 1-hour ozone NAAQS to the 1997 ozone NAAQS, see
the Federal Register dated April 30, 2004 (69 FR 23951, 23969,
23970, 23971, 23972, 23973, 23974, 23975, 23976, 23977, 23978,
23979, 23980, 23981, 23982, 23983, 23984, 23985, 23986, 23987, 23988
and 23989).
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[[Page 15456]]
As part of its final SIP requirements rule for the 2008 ozone
NAAQS, the EPA included requirements for the transition from the 1997
ozone NAAQS to the 2008 ozone NAAQS.\321\ In developing that
rulemaking, the EPA built upon its experience in implementing the Phase
1 rule for the transition from the 1-hour ozone NAAQS to the 1997 ozone
NAAQS and the decision in the South Coast litigation. The EPA revoked
the 1997 ozone NAAQS on the effective date of the final SIP
requirements rule and finalized anti-backsliding requirements
consistent with the implementation of the court decision for the
previous ozone transition that would apply in areas designated
nonattainment for the 1997 ozone NAAQS at the time of revocation.\322\
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\321\ See the published proposal at 78 FR 34178 (June 6, 2013)
and the final SIP requirements rule for the 2008 ozone NAAQS at
http://www.epa.gov/groundlevelozone/implement.html.
\322\ Ibid.
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It should be noted that as part of the transition from the 1997
ozone NAAQS to the 2008 ozone NAAQS, the EPA revoked the 1997 ozone
NAAQS for transportation conformity purposes only in a separate action
related to classifications for the 2008 ozone NAAQS that was finalized
prior to the time that the full implementation rule had been
proposed.\323\ The EPA took this action because the D.C. Circuit Court
in litigation on the transportation conformity rule and in its decision
in the South Coast litigation affirmed that the use of motor vehicle
emissions budgets that have been approved or found adequate for use in
transportation conformity determinations for the prior NAAQS must be
used in transportation conformity determinations for the new NAAQS
until a state submits motor vehicle emissions budgets for the new NAAQS
and those budgets are either found adequate or are
approved.324 325 These cases seemed to indicate that the use
of these existing budgets until new budgets are available is the
appropriate anti-backsliding measure with respect to transportation
conformity to support revocation for that purpose.\326\ It should be
noted, however, that the revocation of the 1997 ozone NAAQS for
transportation conformity purposes was the subject of litigation in the
D.C. Circuit Court.\327\ The court issued its decision on December 23,
2014, and held that the EPA lacked authority to revoke the 1997 ozone
NAAQS only for transportation conformity purposes because for areas
that remain designated as nonattainment or maintenance for the 1997
ozone NAAQS, CAA section 176(c) requires transportation conformity
determinations in nonattainment and maintenance areas.
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\323\ 77 FR 30160 (May 21, 2012).
\324\ See South Coast Air Quality Management District v. EPA,
472 F.3d 882 (D.C. Cir. 2006).
\325\ 40 CFR 93.101 defines ``motor vehicle emissions budget''
as ``that portion of the total allowable emissions defined in the
submitted or approved control strategy implementation plan revision
or maintenance plan for a certain date for the purpose of meeting
reasonable further progress milestones or demonstrating attainment
or maintenance of the NAAQS, for any criteria pollutant or its
precursors, allocated to highway and transit vehicle use and
emissions.''
\326\ In addition, the Court affirmed that conformity
determinations need not be made for a revoked standard.
\327\ NRDC v. EPA, No. 12-1321 (D.C. Cir.) (challenging EPA
actions taken at 77 FR 30160 (May 21, 2012)).
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Following promulgation of the 2008 lead NAAQS and 2010
SO2 NAAQS, the EPA revoked the prior lead and SO2
NAAQS for all purposes in areas that had attained the prior NAAQS and
had been redesignated to attainment, as well as in areas that had
initially been designated as attainment for those NAAQS. The EPA
retained the prior NAAQS in areas that had not yet attained those NAAQS
until those areas had an approved attainment plan for the revised
NAAQS. Because the EPA revoked the prior lead and SO2 NAAQS
in areas that had been redesignated to attainment for those NAAQS, the
EPA primarily relied on the CAA's anti-backsliding provisions found in
sections 110(l) and 193 in order to provide anti-backsliding
protection.\328\
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\328\ For details on the requirements for the lead NAAQS and the
SO2 NAAQS, respectively, see 73 FR 66964 (November 12,
2008), at page 67043; and 75 FR 35519 (June 22, 2010), at page
35580.
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In developing the options for revoking the 1997 primary annual
PM2.5 NAAQS contained in this proposal, the EPA has drawn
from these prior anti-backsliding approaches.
C. Proposed Options for Revocation and Related Anti-Backsliding
Requirements for the 1997 Primary Annual PM2.5 NAAQS
The EPA is proposing and seeking comment on two options for
revoking the 1997 primary annual PM2.5 NAAQS and is seeking
comment on whether to revoke the NAAQS at the current time. Under
either of the options to revoke the 1997 NAAQS, revocation would take
effect no sooner than 1 year after the effective date of designations
for the 2012 primary annual PM2.5 NAAQS. One of these
options would provide for revocation at a later date for some areas.
After revocation of the 1997 primary annual PM2.5 NAAQS,
the designations (and the classifications associated with those
designations) for that standard would no longer be in effect, and the
designations that would remain in effect would be those for the 1997
secondary annual PM2.5 NAAQS, the 2006 primary and secondary
24-hour PM2.5 NAAQS and the 2012 primary annual
PM2.5 NAAQS. However, the EPA would retain the listing of
the designated nonattainment areas for the revoked 1997 primary annual
PM2.5 NAAQS in 40 CFR part 81, for the sole purpose of
identifying the anti-backsliding requirements that may apply to the
areas at the time of revocation. Accordingly, such references to
historical designations for the revoked standard should not be viewed
as current designations under CAA section 107(d).
For any proposed option that allows for revocation in nonattainment
areas for the 1997 primary annual PM2.5 NAAQS, the EPA is
also proposing anti-backsliding provisions to ensure that in these
areas: (i) There is protection against degradation of air quality
(e.g., the areas do not backslide in terms of air quality
improvements); (ii) the areas continue to make progress toward
attainment of the new, more stringent 2012 primary annual
PM2.5 NAAQS; and, (iii) there is consistency with the
PM2.5 NAAQS implementation framework outlined in subpart 4
of part D, title I of the CAA. At the current time, there are 14 areas
that continue to be designated as nonattainment for the 1997 annual
PM2.5 NAAQS; however all but 2 of these areas have 2011-2013
air quality data showing that they are attaining that NAAQS. Therefore,
the EPA expects many of these current nonattainment areas will be
eligible to seek redesignation to attainment prior to any revocation.
The EPA is proposing and seeking comment on the following two options:
Option 1: Revoke the 1997 primary annual PM2.5
NAAQS for all purposes in attainment areas for that NAAQS 1 year after
the effective date of the designations for the 2012 primary annual
PM2.5 NAAQS; or,
Option 2: Revoke the 1997 primary annual PM2.5
NAAQS for all purposes in all nonattainment and attainment areas for
that NAAQS 1 year after the effective date of the designations for the
2012 primary annual PM2.5 NAAQS.
More details on the proposed options and associated rationale are
included below.
[[Page 15457]]
1. Option 1: Revoke the 1997 Primary Annual PM2.5 NAAQS for
All Purposes in Attainment Areas for That NAAQS 1 Year After the
Effective Date of the Designations for the 2012 Primary Annual
PM2.5 NAAQS
The EPA's first proposed option would revoke the 1997 primary
annual PM2.5 NAAQS for all purposes in areas that are
designated as attainment for that NAAQS 1 year after the effective date
of designations for the 2012 primary annual PM2.5 NAAQS, as
well as in future areas that are redesignated as attainment areas after
the initial revocation. The areas addressed by this option are those
that were originally designated as attainment areas for the 1997
primary PM2.5 NAAQS and those that were originally
designated as nonattainment but have since or will in the future be
redesignated to attainment for that NAAQS. Under this option, the EPA
would not revoke the 1997 primary annual PM2.5 NAAQS in any
area that is designated nonattainment for that NAAQS.
Areas that are designated nonattainment for the 1997 annual
PM2.5 NAAQS at the time of the initial revocation would be
required to continue to meet all applicable requirements for such
NAAQS, and could continue to seek redesignation to attainment for the
1997 primary annual PM2.5 NAAQS. For example, even if the
revocation were to become effective in April 2016, redesignations could
continue to be approved after that date. For such areas, the effective
date of the revocation would be the effective date of the area's
redesignation to attainment for the 1997 annual PM2.5 NAAQS.
The EPA notes that under proposed Option 1 it is unnecessary to
propose anti-backsliding requirements for the 1997 primary annual
PM2.5 NAAQS, since Option 1 would only revoke this NAAQS in
attainment areas. Anti-backsliding requirements are not applicable to
attainment areas (i.e., for former nonattainment areas that have been
redesignated to attainment the EPA has already determined through the
redesignation process and approval of maintenance plans that all
applicable requirements for the 1997 primary annual PM2.5
NAAQS--including anti-backsliding requirements--have been fulfilled and
areas that have always been designated attainment for this NAAQS).
For areas that were initially designated as attainment for both the
1997 and 2012 annual PM2.5 NAAQS the EPA is proposing that
the approved PSD SIPs for these areas satisfy the obligation to submit
an approvable maintenance plan for the 2012 primary annual
PM2.5 NAAQS under section 110(a)(1).
The EPA also notes that areas designated nonattainment for the 2012
primary annual PM2.5 NAAQS would be required to comply with
applicable conformity requirements beginning 1 year after the effective
date of designations for that NAAQS. For transportation conformity
purposes these requirements would include using adequate or approved
motor vehicle emissions budgets for the 1997 annual PM2.5
NAAQS where they exist until the area has approved or adequate budgets
for the 2012 primary annual PM2.5 NAAQS.\329\ The use of
such budgets serves as the appropriate anti-backsliding measure for
transportation conformity purposes.
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\329\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests required by 40 CFR 93.109(c)(3) and 40 CFR
93.119(b).
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In general, Option 1 builds upon the EPA's practice in the
transition from the 1-hour to the 1997 ozone NAAQS in that areas will
not only be able to be redesignated to attainment up to the date of the
initial revocation, but any remaining nonattainment areas will be able
to be redesignated after the initial revocations occur 1 year after the
effective date of designations.\330\ This approach is also consistent
with the approach established for the transition from the prior lead
and SO2 NAAQS to the current lead and SO2 NAAQS.
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\330\ Although section 51.905(a) specified that the anti-
backsliding requirements ``attached'' at the time of designation for
the 1997 ozone NAAQS, areas were still able to redesignate to
attainment for the 1-hour ozone NAAQS up to the date of revocation
of that standard.
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2. Option 2: Revoke the 1997 Primary Annual PM2.5 NAAQS for
All Purposes in All Nonattainment and Attainment Areas for That NAAQS 1
Year After the Effective Date of Designations for the 2012 Primary
Annual PM2.5 NAAQS
Under this second proposed option, the EPA would revoke the 1997
primary annual PM2.5 NAAQS for all purposes in all
nonattainment and attainment areas 1 year after the effective date of
designations for the 2012 primary annual PM2.5 NAAQS. The
requirements for revoking the 1997 primary annual NAAQS in attainment
areas for that NAAQS are discussed under proposed Option 1. However,
revoking the 1997 primary annual PM2.5 NAAQS in
nonattainment areas for that NAAQS would require anti-backsliding
measures. Therefore, the EPA is proposing the following anti-
backsliding measures for any designated nonattainment areas that exist
for the 1997 primary annual PM2.5 NAAQS upon the effective
date of the proposed revocation:
For areas designated attainment for the 2012 primary
annual PM2.5 NAAQS and nonattainment for the 1997 primary
annual PM2.5 NAAQS, the EPA's preferred proposed option is
not to require these areas to adopt any outstanding applicable
requirements for the revoked 1997 primary annual PM2.5
standard. However, the EPA proposes that the approved PSD SIPs for
these areas satisfy the obligation to submit an approvable maintenance
plan for the 2012 primary annual PM2.5 NAAQS under section
110(a)(1).
For these same areas (i.e., those designated attainment
for the 2012 primary annual PM2.5 NAAQS and nonattainment
for the 1997 primary annual PM2.5 NAAQS), the EPA is also
proposing an alternative anti-backsliding option where these areas
would be required to show maintenance for the 2012 primary annual
PM2.5 NAAQS. This maintenance showing would be due 3 years
after the effective date of designations for the 2012 primary annual
PM2.5 NAAQS. The maintenance showing would contain a
demonstration of continued maintenance of the 2012 primary annual
PM2.5 NAAQS in the area for 10 years from the effective date
of the area's designation as attainment for the 2012 primary annual
PM2.5 NAAQS. The EPA would take further action to specify
the elements of such a maintenance showing should the agency require it
in the final rule. For areas designated nonattainment for the 2012
primary annual PM2.5 NAAQS and also designated nonattainment
for the 1997 annual PM2.5 NAAQS, the EPA is proposing that
these areas continue to implement their approved SIPs for the 1997
annual PM2.5 NAAQS and fulfill any outstanding requirements,
and that they comply with the applicable requirements for the current
2012 primary annual PM2.5 NAAQS. For example, at some time
in the future there may be an area that is reclassified as Serious for
the 1997 PM2.5 NAAQS while also classified as Moderate for
the 2012 PM2.5 NAAQS. In such an area, the lower Serious
area major source threshold of 70 tpy (PTE) would apply. In addition to
these proposed requirements, if a state seeks to revise any measure
already approved into its SIP for a nonattainment area for the 1997
annual PM2.5 NAAQS, the state must meet the requirements of
sections 110(l) and 193, if applicable.
The EPA notes that Option 2 for 2012 attainment/1997 nonattainment
would
[[Page 15458]]
be similar to the approach to revocation of the 1-hour ozone NAAQS
consistent with court decisions and the approach to revocation of the
1997 ozone NAAQS in the final 2008 ozone NAAQS SIP requirements
rule.\331\ The EPA also notes that areas designated nonattainment for
the 2012 primary annual PM2.5 NAAQS would be required to
comply with applicable conformity requirements beginning 1 year after
the effective date of designations for that NAAQS. For transportation
conformity purposes these requirements would include using adequate or
approved motor vehicle emissions budgets for the 1997 annual
PM2.5 NAAQS where they exist until the area has approved or
adequate budgets for the 2012 primary annual PM2.5
NAAQS.\332\ The use of such budgets serves as the appropriate anti-
backsliding measure for transportation conformity purposes. Further
details regarding this option and associated rationale are in Section
X.D of this preamble.
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\331\ See the final SIP requirements rule for the 2008 ozone
NAAQS at http://www.epa.gov/groundlevelozone/implement.
\332\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests required by 40 CFR 93.109(c)(3) and 40 CFR
93.119(b).
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Lastly, the EPA requests comment on the possible approach of not
revoking the 1997 primary annual PM2.5 NAAQS at this time.
Under this concept, the EPA would not revoke the 1997 primary annual
PM2.5 NAAQS for any purpose at this time. As a result, all
nonattainment and maintenance areas would be required to continue
planning activities associated with the 1997 annual PM2.5
NAAQS such as submitting attainment SIPs and maintenance plans, NNSR,
and transportation and general conformity requirements for the 1997
primary annual PM2.5 NAAQS, in addition to any new
requirements associated with the more health-protective 2012 primary
annual PM2.5 NAAQS. Under this approach the EPA would not
have to establish any anti-backsliding requirements.
The EPA again notes that if this approach were finalized it would
be the first time that the EPA has not taken some action to reduce the
burden associated with implementing a NAAQS that has been replaced with
a more stringent NAAQS.\333\ If the EPA were to finalize this approach,
it would result in state and local agencies being required to implement
the requirements associated with two primary annual PM2.5
NAAQS. These agencies would be required to continue attainment planning
activities for the 1997 primary annual PM2.5 NAAQS even if
they had air quality data that resulted in their being designated
attainment for the 2012 primary annual PM2.5 NAAQS. State,
local and federal agencies would be required to continue to make
transportation and general conformity determinations for the less
protective 1997 primary annual PM2.5 NAAQS.
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\333\ As discussed in Section IX.B of this preamble, the EPA has
taken action to revoke previous ozone, SO2 and lead NAAQS
when the previous NAAQS has been revised.
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D. Discussion of Options
Until the 1997 primary annual PM2.5 NAAQS is revoked,
that NAAQS remains in effect, in parallel with the 2012 primary annual
PM2.5 NAAQS, and continues to apply independently and by its
own terms. The EPA believes that all of the proposed options to revoke
the 1997 primary annual PM2.5 NAAQS are consistent with the
CAA and previous precedent in transitioning from a previous NAAQS to a
new, more stringent NAAQS, and would ensure that attainment areas
continue to attain the revoked NAAQS into the future. If the 1997
primary annual PM2.5 NAAQS is revoked, the EPA is proposing
that the anti-backsliding requirements for the 1997 primary annual
PM2.5 NAAQS, as proposed in this rulemaking, will become
applicable. However, the EPA notes that most of the areas that were
initially designated as nonattainment for the 1997 primary annual
PM2.5 NAAQS where the NAAQS would be revoked have already
been redesignated to attainment (i.e., they are maintenance areas) or
could qualify for redesignation based on current air quality data, and
in such cases their approved maintenance plan for the 1997 primary
annual PM2.5 would prevent backsliding.\334\ Under Option 2
there would be a limited number of nonattainment areas where the 1997
primary annual NAAQS would be revoked and where anti-backsliding
measures would be required. Under all of the proposed options,
conformity would apply in areas that are designated nonattainment for
the more health protective 2012 primary annual PM2.5 NAAQS.
In the case of transportation conformity, adequate or approved motor
vehicle emissions budgets for the 1997 primary annual PM2.5
NAAQS would be used in conformity determinations until motor vehicle
emissions budgets for the 2012 primary annual PM2.5 NAAQS
are found adequate or are approved. Once a NAAQS is revoked in a
nonattainment area, the EPA would not designate or redesignate areas
for that NAAQS after the revocation of that NAAQS except as described
in Option 1. The extent of continued implementation of a revoked
standard derives from administration of anti-backsliding requirements
for that standard.
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\334\ Based on 2011-13 air quality data, many of the areas that
were initially designated nonattainment for the 1997 annual
PM2.5 NAAQS will have already met the 1997 annual
PM2.5 NAAQS and will have been redesignated to attainment
by the time it is revoked (projected to be in or around April 2016),
and thus after revocation of the 1997 primary annual
PM2.5 NAAQS, the number of areas with 1997 anti-
backsliding requirements will be correspondingly reduced.
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Under Option 1, the 1997 primary annual PM2.5 NAAQS
would be revoked only in areas that have attained the 1997 annual
PM2.5 NAAQS and have been redesignated to attainment with an
approved section 175A maintenance plan for the 1997 primary annual
PM2.5 NAAQS; under Option 2, many of the areas where the
1997 primary annual NAAQS would be revoked would have been redesignated
to attainment with an approved maintenance plan. The EPA also
anticipates that states will continue to request that areas be
redesignated to attainment and the EPA will continue to act on those
requests under Option 2. As a result the EPA anticipates that a number
of such requests will be approved prior to the point in time that the
EPA has proposed for the revocations to become effective (i.e., 1 year
after the effective date of designations for the 2012 primary annual
PM2.5 NAAQS). Therefore, the number of nonattainment areas
for the 1997 primary annual PM2.5 NAAQS will continue to
decrease and fewer areas will be required to comply with anti-
backsliding requirements, and a correspondingly larger number of areas
will be required to continue to implement their approved section 175A
maintenance plan for the 1997 primary annual PM2.5 NAAQS.
It should also be noted that, for either proposed option, after the
effective date of any revocation of the 1997 primary annual
PM2.5 NAAQS, transportation and general conformity
determinations would continue to be required in areas that are
designated nonattainment for the 1997 secondary annual PM2.5
NAAQS until such areas are redesignated to attainment pursuant to the
requirements of section 107(d)(3). Areas that are initially designated
as nonattainment for the 2012 primary annual NAAQS are subject to
transportation and general conformity requirements after the end of the
grace period that ends 1 year after the effective date of designations
for the 2012 primary annual PM2.5 NAAQS. See further
information for how conformity will be implemented for the 2012
PM2.5 NAAQS in Section IX.B of this preamble. Under Options
1 and 2 the
[[Page 15459]]
timing that the EPA is proposing means that any area that was
previously a 1997 annual PM2.5 NAAQS nonattainment area, but
has been redesignated to attainment for the 1997 annual
PM2.5 NAAQS by the time of revocation of the 1997 primary
annual PM2.5 NAAQS (e.g., April 2016 for most areas), will
not be subject to the anti-backsliding requirements for the 1997 annual
PM2.5 NAAQS. This is because when an area has been
redesignated to attainment for a PM2.5 NAAQS while that
NAAQS is in effect, it has fulfilled all applicable requirements for
that NAAQS, including applicable anti-backsliding requirements for the
1997 annual PM2.5 NAAQS. The area is, therefore, not subject
to anti-backsliding requirements for the revoked 1997 primary annual
PM2.5 NAAQS. These areas are required instead to implement
their approved CAA section 175A maintenance plan for the 1997 primary
annual PM2.5 NAAQS and implement a PSD program for this
NAAQS, if they are designated attainment for the 2012 primary annual
PM2.5 NAAQS.335 336 Revisions to the approved
maintenance plan can only be made if the revisions meet the
requirements of section 110(l) and, if applicable, section 193. The EPA
proposes that these areas not be required to submit a second 10-year
maintenance plan for the 1997 primary annual PM2.5 NAAQS
because there is no justification for additional maintenance plan
burdens to be imposed on these areas solely because at one time they
were designated nonattainment under the revoked 1997 primary annual
PM2.5 NAAQS. Not requiring a second 10-year maintenance plan
for these areas would help to minimize the burden associated with
preparing SIPs for a succession of NAAQS of increasing stringency.
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\335\ Areas initially designated as attainment for the 1997
annual PM2.5 NAAQS would also be required to continue to
implement a PSD program unless an area was designated nonattainment
for the 2012 primary annual PM2.5 NAAQS. Such an area
would be required to implement a NNSR program for that NAAQS.
\336\ Areas designated nonattainment for the 2012 primary annual
PM2.5 NAAQS would implement a NNSR program for that
NAAQS.
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As explained previously, for areas redesignated to attainment under
Options 1 and 2, the section 175A maintenance plan for the 1997 primary
annual PM2.5 NAAQS satisfies the anti-backsliding
requirements of these areas. The EPA believes that for these areas any
further 110(a)(1) maintenance plan requirement under the 2012 primary
annual PM2.5 NAAQS for areas designated attainment for that
NAAQS would be unnecessarily burdensome.
For Option 2, the EPA is applying a general principle to apply
transition requirements depending on how the area is designated--
attainment or nonattainment--for the 2012 primary annual
PM2.5 NAAQS, while taking into account the area's status
with respect to the 1997 primary annual PM2.5 NAAQS. For
those areas which have already incorporated measures into their
approved SIPs that satisfy the nonattainment requirements for that
standard, section 110(l) functions to require continued implementation
of such measures unless revised in accordance with its provisions.
Under Option 2, the EPA is proposing as one alternative that areas
designated attainment for the 2012 primary annual PM2.5
NAAQS and nonattainment for the 1997 annual PM2.5 NAAQS (as
of revocation of the 1997 primary annual PM2.5 NAAQS) not be
required to adopt any outstanding applicable requirements for the
revoked 1997 primary annual standard. This approach is similar to the
approach followed in the transition from the 1-hour ozone NAAQS to the
1997 ozone NAAQS. However, instead of submitting a maintenance plan the
EPA is also proposing that the approved PSD SIPs for these areas
satisfy the obligation to submit an approvable maintenance plan for the
2012 primary annual PM2.5 NAAQS under section 110(a)(1).
This is similar to what the EPA finalized for the transition from the
1997 ozone NAAQS to the 2008 ozone NAAQS.\337\ The EPA's rationale for
this approach is as follows: Areas designated attainment for the 2012
primary annual PM2.5 NAAQS and nonattainment for the 1997
primary annual PM2.5 NAAQS (as of revocation of the 1997
primary annual PM2.5 NAAQS) have already attained the most
stringent existing standard. These areas thus have developed
nonattainment plans that in combination with federal measures and
emissions controls in upwind areas have produced sufficient emissions
reductions to achieve the more protective 2012 primary annual
PM2.5 NAAQS. They remain subject to the 1997 nonattainment
area requirements already approved into the SIP, which can be revised
only upon a showing that such revision is consistent with sections
110(l) and 193, if applicable. At this time, and given the succession
of NAAQS of increasing stringency that has occurred, the EPA believes
that the burden of developing an approvable maintenance plan for the
2012 primary annual PM2.5 NAAQS would outweigh any
compensating benefit for an area that is already attaining that more
stringent NAAQS and that is subject to prior nonattainment requirements
which are already incorporated into the SIP.
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\337\ See the the final SIP requirements rule for the 2008 ozone
NAAQS at http://www.epa.gov/groundlevelozone/implement.html.
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Under Option 2, the EPA is also proposing, for areas that are
attainment for the 2012 primary annual PM2.5 NAAQS, that the
NNSR anti-backsliding requirement(s) for the 1997 annual
PM2.5 NAAQS cease to apply, since PSD will then be in
effect. The state may request that the corresponding NSR requirements
be removed entirely, rather than be retained in the SIP as a
maintenance plan contingency measure.\338\ Areas that are designated
nonattainment for the more stringent 2012 primary annual
PM2.5 NAAQS will be subject to NNSR and other nonattainment
requirements for their classification under the more stringent 2012
primary annual PM2.5 NAAQS.
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\338\ See 40 CFR 51.905(a)(3), the comparable provision for
transitions from the 1-hour NAAQS to the 1997 ozone NAAQS, which
allows such areas to request that the 1-hour NNSR provisions be
removed from the SIP.
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The revocation of the 1-hour ozone NAAQS and the associated anti-
backsliding provisions were the subject of past litigation. In its
December 2006 decision on that challenge, as modified following
rehearing, the Court held with respect to the anti-backsliding approach
for conformity that 1-hour ozone motor vehicle emissions budgets must
be used in transportation conformity determinations for the more
protective 1997 ozone NAAQS where such SIP motor vehicle emissions
budgets have been found adequate or approved, until SIP motor vehicle
emissions budgets for the 1997 ozone NAAQS are available.\339\ In
addition, the Court affirmed more broadly that in order for
transportation conformity determinations to fulfill the requirements of
CAA section 176(c)(1), motor vehicle emissions budgets for a prior
NAAQS must be used in transportation conformity determinations under a
revised NAAQS until emissions budgets for the revised NAAQS are either
found adequate or are approved, but that conformity determinations need
not be made for a revoked standard. Therefore, areas designated
nonattainment for the 2012 primary annual PM2.5 NAAQS that
have adequate or approved SIP budgets for the 1997 annual
PM2.5 NAAQS must continue to use such budgets in
transportation conformity determinations until budgets for the
[[Page 15460]]
2012 primary annual PM2.5 NAAQS are found adequate or are
approved.\340\
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\339\ See South Coast Air Quality Management District v. EPA,
472 F.3d at 882 (D.C. Cir. 2006).
\340\ Areas that do not have adequate or approved motor vehicle
emissions budgets for the 1997 annual PM2.5 NAAQS or the
2006 24-hour PM2.5 NAAQS would use one of the two interim
emissions tests requied by 40 CFR 93.109(c)(3) and 40 CRR 93.119(b).
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With regard to general conformity, the D.C. Circuit Court did not
address the need for specific anti-backsliding measures in its initial
decision or in the modified decision on the South Coast litigation.
Therefore, if the EPA finalizes either Option 1 or 2 and revokes the
1997 primary annual PM2.5 NAAQS, general conformity
determinations will be required in nonattainment areas for the 2012
primary annual NAAQS as required by section 176(c)(5) to ensure that
the action of federal agencies do not cause a violation of that NAAQS,
make an existing violation worse or delay timely attainment of the
NAAQS or an interim milestone.\341\ The EPA believes that revoking the
1997 primary annual PM2.5 NAAQS under Option 1 or 2 is
logical because it would result in only one primary annual
PM2.5 NAAQS--the 2012 primary annual PM2.5
NAAQS--applying for purposes of transportation and general conformity
in most areas, after the end of the 1-year conformity grace period that
applies to newly designated nonattainment areas. (CAA section
176(c)(6)).
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\341\ It should be noted that some areas will remain designated
nonattainment for 1997 secondary annual PM2.5 NAAQS. Such
areas will remain subject to transportation and general conformity
for that NAAQS until such time that they are redesignated to
attainment for that NAAQS pursuant to the requirements of section
107(d)(3).
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Areas that are attaining the more health protective 2012 primary
annual PM2.5 NAAQS would no longer have to expend resources
to make conformity determinations for any of the current primary annual
PM2.5 NAAQS after the 1997 primary annual PM2.5
NAAQS is revoked and the area is redesignated as attainment for the
1997 secondary annual PM2.5 NAAQS. Some of these areas would
be required to continue to make conformity determinations for the 2006
24-hour PM2.5 NAAQS and based on 2011-13 air quality data
two areas would be required to make conformity determinations for the
1997 24-hour PM2.5 NAAQS. It should be noted that any areas
that are attaining the more health protective 2012 primary annual NAAQS
are also necessarily attaining the less stringent 1997 annual
PM2.5 NAAQS by a wide margin. Therefore, the options of this
proposal would provide a seamless transition from demonstrating
conformity for the 1997 annual PM2.5 NAAQS to demonstrating
conformity for the more stringent 2012 primary annual PM2.5
NAAQS.
Areas designated nonattainment for the 2012 primary annual
PM2.5 NAAQS will likely need the full 1-year grace period
provided in section 176(c)(6) to complete the required initial
transportation conformity determination. Those areas that were
designated as either nonattainment or maintenance for the 1997 annual
PM2.5 NAAQS at the time of designation as nonattainment for
the 2012 primary annual PM2.5 NAAQS will need certainty as
to the specific requirements for that conformity determination. For
example they need to know what analysis years must be addressed and, if
the boundaries for the PM2.5 NAAQS are different, they need
to know whether to address conformity for both areas and which test or
tests would apply.
The EPA seeks comment on the options proposed in the preceding
discussion regarding revoking the 1997 primary annual PM2.5
standard, as well as on whether the agency should take no action to
revoke the standard as this time.
XI. Environmental Justice Considerations
The EPA believes the human health or environmental risk addressed
by this action will not have disproportionately high and adverse human
health or environmental effects on minority, low-income, or indigenous
populations because it would not negatively affect the level of
protection provided to human health or the environment under the
PM2.5 NAAQS. When promulgated, these proposed regulations
will clarify the state implementation plan requirements and the NNSR
permitting requirements to be met by states in order to attain the
PM2.5 NAAQS as expeditiously as practicable. These
requirements are designed to protect all segments of the general
population. The EPA included specific discussion in this preamble about
actions that could be considered for the protection of minority, low-
income or indigenous populations in Section IV.D.6 on Moderate area
attainment plan control strategies; Section VI.D.7 on Serious area
attainment plan control strategies; and Section IX.G, measures to
ensure appropriate protections for overburdened populations. In
addition, as part of the consultation activities conducted in
developing this rule, the EPA participated in training and outreach
activities with representatives from environmental justice
organizations in a March 2014 conference held in Research Triangle
Park, NC titled, ``Clean Air Act Rulemaking and Permitting Training for
EJ Communities.'' These proposed regulations are designed to protect
and enhance the health and safety of these and other populations, and
they will not adversely affect the health or safety of minority, low-
income or indigenous populations.
XII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review
This action is a significant regulatory action that was submitted
to the Office of Management and Budget (OMB) for review because it
raises novel policy issues. Any changes made in response to OMB
recommendations have been documented in the docket.\342\
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\342\ Note that a regulatory impact analysis evaluating the
costs and benefits associated with attaining the 2012
PM2.5 NAAQS was released at the time the NAAQS review was
finalized. See ``Regulatory Impact Analysis for the Final Revisions
to the National Ambient Air Quality Standards for Particulate
Matter.'' U.S. Environmental Protection Agency, Office of Air
Quality and Planning Standards, Health and Environmental Impacts
Division, February 28, 2013. EPA-452/R-12-005.
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B. Paperwork Reduction Act (PRA)
The information collection activities in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the PRA. The Information Collection Request (ICR) document
prepared by the EPA has been assigned the EPA ICR number 2258.03, OMB
Control No. 2060-0611. You can find a copy of the ICR in the docket for
this rule, and it is briefly summarized here.
The EPA is proposing this PM2.5 NAAQS SIP Requirements
Rule to describe the CAA requirements that must be met by states with
nonattainment areas required to develop attainment plans for attaining
and maintaining the NAAQS. The intended effect of the SIP Requirements
Rule is to provide certainty to states regarding their planning
obligations such that states may begin SIP development. Only states
with nonattainment areas are required to submit SIPs under this rule.
For purposes of analysis of the estimated paperwork burden, the EPA
assumed there were 21 existing nonattainment areas for the 1997 and
2006 PM2.5 NAAQS, and 15 hypothetical, newly-designated
nonattainment areas.\343\ The attainment
[[Page 15461]]
plan requirements would appear as 40 CFR 51.1000 through 51.1015 which
implement CAA subsections 172(c)(1) and (2), and 189(a)(1)(B) and (C),
189(b)(1)(A) and (B) and 189(c). Some states have new nonattainment
areas and some states should already have information from emission
sources, as facilities should have provided this information to meet
1997 and 2006 PM2.5 NAAQS SIP requirements, operating
permits and/or emissions reporting requirements. Such information does
not generally reveal the details of production processes. But, to the
extent it may, confidential business information for the affected
facilities is protected. Specifically, submissions of emissions and
control efficiency information that is confidential, proprietary and
trade secret and is not emission data is protected from disclosure
under the requirements of subsections 503(e) and 114(c) of the CAA.
---------------------------------------------------------------------------
\343\ These hypothetical nonattainment areas were developed
based on 2010-12 air quality data and state recommendations. Actual
nonattainment designations and boundaries are based on the most
recent, complete air quality data available.
---------------------------------------------------------------------------
The annual state burden for this information collection for the 15
hypothetical newly designated 2012 PM2.5 nonattainment
areas, averaged over the first 3 years of this ICR, is estimated to be
a total of 54,000 labor hours per year at an annual labor cost of $3.2
million (present value) over the 3-year period, or approximately
$649,000 per state for the 5 state respondents. The average annual
reporting burden is approximately 3,600 hours per response, with
approximately 3 responses per state for 15 state responses. There are
no capital or operating and maintenance costs associated with the
proposed rule requirements. Burden is defined at 5 CFR 1320.3(b).
The annual state burden for this information collection for the 21
existing nonattainment areas for the 1997 and 2006 PM2.5
NAAQS, averaged over the first 3 years of this ICR, is estimated to be
a total of 43,400 labor hours per year at an annual labor cost of $2.6
million (present value) over the 3-year period, or approximately
$370,000 per state for the 7 state respondents. The average annual
reporting burden is approximately 2,000 hours per response, with
approximately 3 responses per state for 21 state responses. There are
no capital or operating and maintenance costs associated with the
proposed rule requirements. Burden is defined at 5 CFR 1320.3(b).
An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in 40 CFR are listed in 40 CFR part 9.
Submit your comments on the agency's need for this information, the
accuracy of the provided burden estimates and any suggested methods for
minimizing respondent burden to the EPA using the docket identified at
the beginning of this rule. You may also send your ICR-related comments
to OMB's Office of Information and Regulatory Affairs via email to
oria_submissions@omb.eop.gov, Attention: Desk Officer for the EPA.
Since OMB is required to make a decision concerning the ICR between 30
and 60 days after receipt, OMB must receive comments no later than
April 22, 2015. The EPA will respond to any ICR-related comments in the
final rule.
C. Regulatory Flexibility Act
The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any regulation subject
to notice-and-comment rulemaking requirements under the Administrative
Procedures Act or any other statute unless the agency certifies the
rule will not have a significant economic impact on a substantial
number of small entities. Small entities include small businesses,
small organizations and small governmental jurisdictions.
For purposes of assessing the impacts of this rule on small
entities, small entity is defined as: (1) A small business as defined
in the Small Business Administration's (SBA) regulations at 13 CFR
121.201; (2) a small governmental jurisdiction that is a government of
a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
After considering the economic impacts of this proposed rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. This
proposed rule will not impose any requirements directly on small
entities. Entities potentially affected directly by this proposal
include state, local and tribal governments and none of these
governments are small governments. Other types of small entities are
not directly subject to the requirements of this rule. The EPA
continues to be interested in the potential impacts of the proposed
rule on small entities and welcomes comments on issues related to such
impacts.
D. Unfunded Mandates Reform Act (UMRA)
This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action imposes no enforceable duty on any
state, local or tribal governments or the private sector. The CAA
imposes the obligation for states to submit attainment plans to
implement the PM2.5 NAAQS. In this rule, the EPA is
clarifying those requirements. Therefore, this action is not subject to
the requirements of sections 202, 203, and 205 of the UMRA.
E. Executive Order 13132: Federalism
This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government, as
specified in Executive Order 13132. The requirement to submit
attainment plans to meet a PM2.5 NAAQS is imposed by the
CAA. This proposed rule, if made final, would interpret those
requirements as they apply to current and future PM2.5
NAAQS. Thus, Executive Order 13132 does not apply to these proposed
regulations.
In the spirit of Executive Order 13132 and consistent with the EPA
policy to promote communications between the EPA and state and local
governments, the EPA specifically solicits comments on this proposed
action from state and local officials. In addition, the EPA intends to
meet with organizations representing state and local officials during
the comment period for this action.
F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This proposed action does not have tribal implications, as
specified in Executive Order 13175 (65 FR 67249, November 9, 2000). It
would not have a substantial direct effect on one or more Indian
tribes. Furthermore, these proposed regulation revisions do not affect
the relationship or distribution of power and responsibilities between
the federal government and Indian tribes. The CAA and the TAR establish
the relationship of the federal government and tribes in characterizing
air quality and developing plans to attain the NAAQS, and these
revisions to the regulations do nothing to modify that
[[Page 15462]]
relationship. Thus, Executive Order 13175 does not apply to this
action.
Although Executive Order 13175 does not apply to this action, the
EPA solicits comment on this proposed action from tribal officials. The
EPA also intends to offer to consult with any tribal government to
discuss this proposal.
G. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks
The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. This action is not subject to
Executive Order 13045 because it implements a previously promulgated
health or safety-based federal standard established pursuant to the
CAA.
These proposed regulatory provisions are designed to help implement
the current and future PM2.5 NAAQS, promulgated to protect
the health and welfare of individuals, including children, who are
susceptible to the adverse effects of exposure to unhealthy levels of
ambient PM2.5.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action is not a ``significant energy action'' as defined in
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not
likely to have a significant adverse effect on the supply,
distribution, or use of energy.
I. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272
note) directs the EPA to use voluntary consensus standards in its
regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures and business practices) that are developed or
adopted by voluntary consensus standards bodies. NTTAA directs the EPA
to provide Congress, through OMB, explanations when the agency decides
not to use available and applicable voluntary consensus standards.
This proposed rulemaking does not involve technical standards.
Therefore, the EPA is not considering the use of any voluntary
consensus standards.
J. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations
The EPA believes the human health or environmental risk addressed
by this action will not have disproportionately high and adverse human
health or environmental effects on minority, low-income, or indigenous
populations. The results of this evaluation are contained in Section XI
of this preamble.
K. Determination Under Section 307(d)
Pursuant to sections 307(d)(1)(E) and 307(d)(1)(V) of the CAA, the
Administrator proposes to determine that this action is subject to the
provisions of section 307(d). Under section 307(d)(1)(V), the
provisions of section 307(d) apply to ``such other actions as the
Administrator may determine.''
Statutory Authority
The statutory authority for this action is provided by 42 U.S.C.
7403, 7407, 7410, and 7601.
List of Subjects
40 CFR Part 50
Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.
40 CFR Part 51
Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.
40 CFR Part 93
Environmental protection, Air pollution control, Intergovernmental
relations, Particulate matter.
Dated: March 10, 2015.
Gina McCarthy,
Administrator.
For the reasons stated in the preamble, Title 40, Chapter I of the
Code of Federal Regulations is proposed to be amended as follows:
PART 50--NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY
STANDARDS
0
1. The authority citation for part 50 continues to read as follows:
Authority: 42 U.S.C. 7401, et seq.
0
2. In Sec. 50.13, add paragraph (d) to read as follows:
Sec. 50.13 National primary and secondary ambient air quality
standards for PM2.5.
* * * * *
(d) The standards set forth in this section will remain applicable
to all areas notwithstanding the promulgation of the 2012 primary
annual PM2.5 national ambient air quality standards (NAAQS)
in Sec. 50.18. The 1997 primary annual PM2.5 NAAQS set
forth in this section will no longer apply to an area 1 year after the
effective date of the designation of that area, pursuant to section 107
of the Clean Air Act, for the primary annual PM2.5 NAAQS set
forth in Sec. 50.18; except that for areas designated nonattainment
for the 1997 annual PM2.5 NAAQS set forth in this section as
of 1 year after the effective date of the designations for the primary
annual PM2.5 NAAQS established in Sec. 50.18, the
requirements applicable to the 1997 annual PM2.5 NAAQS set
forth in this section will apply until the effective date of an area's
redesignation to attainment for the 1997 annual NAAQS pursuant to the
requirements of section 107 of the Clean Air Act. The 1997 secondary
annual PM2.5 NAAQS and the 1997 24-hour PM2.5
NAAQS shall remain in effect.
PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF
IMPLEMENTATION PLANS
0
3. The authority citation for part 51 continues to read as follows:
Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.
Subpart I--Review of New Sources and Modifications
0
4. In Sec. 51.165:
0
a. Revise paragraphs (a)(1)(iv)(A)(1), (a)(1)(x)(A), and
(a)(1)(xxxvii)(C)(2);
0
b. Remove paragraphs (a)(1)(xxxvii)(C)(3), and (4); and
0
d. Revise paragraphs (a)(2)(i) and (a)(2)(ii)(A).
The revisions read as follows:
Sec. 51.165 Permit requirements.
(a) * * *
(1) * * *
(iv)(A) * * *
(1) Any stationary source of air pollutants that emits, or has the
potential to emit, 100 tons per year or more of any regulated NSR
pollutant (as defined in paragraph (a)(1)(xxxvii) of this section),
except that lower emissions thresholds shall apply in areas subject to
subpart 2, subpart 3, or subpart 4 of part D, title I of the Act,
according to paragraphs (a)(1)(iv)(A)(1)(i) through (viii) of this
section.
(i) 50 tons per year of volatile organic compounds in any serious
ozone nonattainment area.
[[Page 15463]]
(ii) 50 tons per year of volatile organic compounds in an area
within an ozone transport region, except for any severe or extreme
ozone nonattainment area.
(iii) 25 tons per year of volatile organic compounds in any severe
ozone nonattainment area.
(iv) 10 tons per year of volatile organic compounds in any extreme
ozone nonattainment area.
(v) 50 tons per year of carbon monoxide in any serious
nonattainment area for carbon monoxide, where stationary sources
contribute significantly to carbon monoxide levels in the area (as
determined under rules issued by the Administrator).
(vi) 70 tons per year of PM10 in any serious
nonattainment area for PM10.
(vii) 70 tons per year of PM2.5 in any serious
nonattainment area for PM2.5.
(viii) 70 tons per year of any precursor for PM2.5 in
any serious nonattainment area for PM2.5.
* * * * *
(x)(A) Significant means, in reference to a net emissions increase
or the potential of a source to emit any of the following pollutants, a
rate of emissions that would equal or exceed any of the following
rates:
Pollutant Emission Rate
Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40 tpy
of sulfur dioxide emissions; 40 tpy of nitrogen oxide emissions; 40 tpy
of VOC emissions;
* * * * *
(xxxvii) * * *
(C) * * *
(2) Sulfur dioxide, nitrogen oxides, volatile organic compounds and
ammonia are precursors to PM2.5 in any PM2.5
nonattainment area, unless the State demonstrates to the
Administrator's satisfaction or the EPA demonstrates that major
stationary sources of a particular precursor do not contribute
significantly to PM2.5 levels that exceed the
PM2.5 ambient standards in a particular area.
* * * * *
(2) Applicability procedures. (i) Each plan shall adopt a
preconstruction review program to satisfy the requirements of sections
172(c)(5) and 173 of the Act for any area designated nonattainment for
any national ambient air quality standard under subpart C of 40 CFR
part 81. Such a program shall apply to any new major stationary source
or major modification that is major for the pollutant (as defined in
paragraph (a)(1)(xxxvii) of this section) for which the area is
designated nonattainment under section 107(d)(1)(A)(i) of the Act, if
the stationary source or modification would locate anywhere in the
designated nonattainment area. Different pollutants, including
individual precursors, are not summed to determine applicability of a
major stationary source or major modification.
(ii) * * *
(A) Except as otherwise provided in paragraphs (a)(2)(iii) and (iv)
of this section, and consistent with the definition of major
modification contained in paragraph (a)(1)(v)(A) of this section, a
project is a major modification for a regulated NSR pollutant (as
defined in paragraph (a)(1)(xxxvii) of this section), if it causes two
types of emissions increases--a significant emissions increase (as
defined in paragraph (a)(1)(xxvii) of this section), and a significant
net emissions increase (as defined in paragraphs (a)(1)(vi) and (x) of
this section). The project is not a major modification if it does not
cause a significant emissions increase. If the project causes a
significant emissions increase, then the project is a major
modification only if it also results in a significant net emissions
increase.
* * * * *
0
5. In Appendix S to part 51:
0
a. Revise paragraph II.A.4.(i)(a) introductory text;
0
b. Add paragraphs II.A.4.(a)(7) and (8); and
0
c. Revise paragraphs II.A.10.(i) and II.A.31.(ii)(b)(2).
The revisions and addition read as follows:
Appendix S to Part 51--Emission Offset Interpretative Ruling
* * * * *
II. * * *
A. * * *
4. (i) * * *
(a) Any stationary source of air pollutants which emits, or has
the potential to emit, 100 tons per year or more of a regulated NSR
pollutant (as defined in paragraph II.A.31 of this Ruling), subject
to regulation under the Act, except that lower emissions thresholds
shall apply in areas subject to subpart 2, subpart 3, or subpart 4
of part D, title I of the Act, according to paragraphs
II.A.4(i)(a)(1) through (6) of this ruling.
* * * * *
(7) 70 tons per year of PM2.5 in any serious
nonattainment area for PM2.5.
(8) 70 tons per year of any PM2.5 precursor (as
defined in paragraph II.A.31 of this Ruling) in any Serious
nonattainment area for PM2.5.
* * * * *
10. (i) Significant means, in reference to a net emissions
increase or the potential of a source to emit any of the following
pollutants, a rate of emissions that would equal or exceed any of
the following rates:
Pollutant and Emissions Rate
Carbon monoxide: 100 tons per year (tpy)
Nitrogen oxides: 40 tpy
Sulfur dioxide: 40 tpy
Ozone: 40 tpy of volatile organic compounds or nitrogen oxides
Lead: 0.6 tpy
Particulate matter: 25 tpy of particulate matter emissions
PM10: 15 tpy
PM2.5: 10 tpy of direct PM2.5 emissions; 40
tpy of sulfur dioxide emissions; 40 tpy of nitrogen oxides emissions
* * * * *
31. * * *
(ii) * * *
(b) * * *
(2) Sulfur dioxide and nitrogen oxides are precursors to
PM2.5 in all PM2.5 nonattainment areas.
* * * * *
0
6. Revise subpart Z to read as follows:
Subpart Z--Provisions for Implementation of PM2.5
National Ambient Air Quality Standards
Sec.
51.1000 Definitions.
51.1001 Applicability of part 51.
51.1002 Classifications.
51.1003 Attainment plan submittals and due dates.
51.1004 Attainment dates.
51.1005 Attainment date extensions.
51.1006 Requirements for demonstrating insignificant contribution of
PM2.5 precursors.
51.1007 Requirements for de minimis source category determinations
for direct PM2.5 and PM2.5 precursors.
51.1008 Emissions inventory requirements.
51.1009 Moderate area attainment plan control strategy requirements.
51.1010 Serious area attainment plan control strategy requirements.
51.1011 Attainment demonstration and modeling requirements.
51.1012 Reasonable further progress (RFP) requirements.
51.1013 Quantitative milestone requirements.
51.1014 Contingency measures requirements.
51.1015 Clean data requirements.
Sec. 51.1000 Definitions.
The following definitions apply for purposes of this subpart. Any
term not defined herein shall have the meaning as defined in 40 CFR
51.100 or Clean Air Act section 302.
Act means the Clean Air Act as codified at 42 U.S.C. 7401-7671q
(2003).
[[Page 15464]]
Additional feasible measure is any control measure that otherwise
meets the definition of ``best available control measure'' (BACM) but
can only be implemented in whole or in part beginning 4 years after the
date of reclassification of an area as Serious and no later than the
statutory attainment date for the area.
Additional reasonable measure is any control measure that otherwise
meets the definition of ``reasonably available control measure'' (RACM)
but can only be implemented in whole or in part during the period
beginning 4 years after the date of designation of a nonattainment area
and no later than the end of the sixth calendar year following the date
of designation of the area.
Applicable annual standard is the annual PM2.5 NAAQS
established, revised, or retained as a result of a particular
PM2.5 NAAQS review.
Applicable attainment date means the latest statutory date by which
an area is required to attain a particular PM2.5 NAAQS,
unless EPA has approved an attainment plan for the area to attain such
NAAQS, in which case the applicable attainment date is the date
approved under such attainment plan. If EPA grants an extension of an
approved attainment date, then the applicable attainment date for the
area shall be the extended date.
Applicable 24-hour standard is the 24-hour PM2.5 NAAQS
established, revised, or retained as a result of a particular
PM2.5 NAAQS review.
Attainment projected inventory means the projected emissions of
direct PM2.5 and all PM2.5 precursors from
sources included in the base year inventory, and from any additional
sources of such emissions expected within the boundaries of the
nonattainment area by the projected attainment date for the area.
Base year inventory means the actual emissions of direct
PM2.5 and all PM2.5 precursors from all sources
within the boundaries of a nonattainment area in one of the 3 years
used for purposes of designations or another technically appropriate
year.
Benchmark RFP analysis means the analysis submitted as part of the
RFP plan for a PM2.5 nonattainment area that requires
generally linear emissions reductions in direct PM2.5 and in
each PM2.5 precursor from the base year through the
projected attainment year.
Best available control measure (BACM) is any technologically and
economically feasible control measure that can be implemented in whole
or in part within 4 years after the date of reclassification of a
PM2.5 nonattainment area and that generally can achieve
greater permanent and enforceable emissions reductions in direct
PM2.5 emissions and/or emissions of PM2.5
precursors from sources in the area than can be achieved through the
implementation of RACM on the same source(s). BACM includes best
available control technology (BACT).
Date of designation means the effective date of a PM2.5
area designation as promulgated by the Administrator.
Date of reclassification means the effective date of a
PM2.5 area reclassification from Moderate to Serious as
promulgated by the Administrator.
Direct PM2.5 emissions means solid particles emitted directly from
an air emissions source or activity, or gaseous emissions or liquid
droplets from an air emissions source or activity which condense to
form particulate matter at ambient temperatures. Direct
PM2.5 emissions include filterable and condensable
PM2.5 emissions composed of elemental carbon, directly
emitted organic carbon, directly emitted sulfate, directly emitted
nitrate, and other inorganic particles (including but not limited to
crustal material, metals, and sea salt).
Existing control measure means any federally enforceable national,
state, or local control measure that results in reductions in direct
PM2.5 emissions or emissions of PM2.5 precursors
in a nonattainment area in that state.
Implemented means adopted by the state and fully approved into the
SIP by EPA for the nonattainment area; built, installed, and/or
otherwise physically manifested; and, fully complied with by the
affected sources.
Most stringent measure (MSM) is any permanent and enforceable
control measure that achieves the most stringent emissions reductions
in direct PM2.5 emissions and/or emissions of
PM2.5 precursors from among those control measures which are
either included in any other SIP for any NAAQS or have been achieved in
practice by any state and that can feasibly be implemented in the
relevant PM2.5 NAAQS nonattainment area.
PM2.5 design value (DV) for a PM2.5 nonattainment area
is the highest of the three-year average concentrations calculated for
the ambient air quality monitors in the area, in accordance with 40 CFR
part 50, appendix N.
PM2.5 NAAQS are the fine particulate matter National Ambient Air
Quality Standards codified at 40 CFR part 50.
PM2.5 precursors are sulfur dioxide (SO2), oxides of
nitrogen (NOX), volatile organic compounds (VOC), and
ammonia (NH3).
Reasonably available control measure (RACM) is any technologically
and economically feasible measure that can be implemented in whole or
in part within 4 years after the date of designation of a
PM2.5 nonattainment area and that achieves permanent and
enforceable reductions in direct PM2.5 emissions and/or
PM2.5 precursor emissions from sources in the area. RACM
includes reasonably available control technology (RACT).
Reasonable further progress (RFP) means such annual incremental
reductions in emissions of direct PM2.5 and PM2.5
precursors regulated in the attainment plan as are required for the
purpose of ensuring attainment of the applicable PM2.5 NAAQS
in a nonattainment area by the applicable attainment date.
Subpart 1 means subpart 1 of part D of title I of the Act.
Subpart 4 means subpart 4 of part D of title I of the Act.
Sec. 51.1001 Applicability of part 51.
The provisions in subparts A through X of this part apply to areas
for purposes of the PM2.5 NAAQS to the extent they are not
inconsistent with the provisions of this subpart.
Sec. 51.1002 Classifications.
(a) Initial classification as Moderate PM2.5 nonattainment area.
Any area designated nonattainment for a PM2.5 NAAQS shall be
classified at the time of such designation, by operation of law, as a
Moderate PM2.5 nonattainment area.
(b) Reclassification as Serious PM2.5 nonattainment area. A
Moderate nonattainment area shall be reclassified to Serious under the
following circumstances:
(1) The EPA shall reclassify as Serious through notice-and-comment
rulemaking any Moderate PM2.5 nonattainment area that the
EPA determines cannot practicably attain a particular PM2.5
NAAQS by the applicable Moderate area attainment date.
(2) A Moderate PM2.5 nonattainment area shall be
reclassified by operation of law as a Serious nonattainment area if the
EPA finds through notice-and-comment rulemaking that the area failed to
attain a particular PM2.5 NAAQS by the applicable Moderate
area attainment date.
Sec. 51.1003 Attainment plan submittals and due dates.
(a) Nonattainment areas initially classified as Moderate.
(1) For any area designated as nonattainment and initially
classified as Moderate for a PM2.5 NAAQS, the
[[Page 15465]]
state(s) shall submit a Moderate area attainment plan that meets all of
the following requirements:
(i) Emissions inventory requirements set forth at Sec.
51.1008(a)(1);
(ii) Emissions inventory requirements set forth at Sec.
51.1008(a)(2);
(iii) Moderate area attainment plan control strategy requirements
set forth at Sec. 51.1009;
(iv) Attainment demonstration and modeling requirements set forth
at Sec. 51.1011;
(v) Reasonable Further Progress (RFP) requirements set forth at
Sec. 51.1012;
(vi) Quantitative milestone requirements set forth at Sec.
51.1013;
(vii) Contingency measure requirements set forth at Sec. 51.1014;
and,
(viii) Nonattainment new source review plan requirements pursuant
to section 189(a)(1)(A) and section 172(c)(5) of the CAA.
(2) The state(s) shall submit its Moderate area attainment plan to
EPA no later than 18 months from the date of designation of the area.
(b) Nonattainment areas reclassified to Serious.
(1) For any nonattainment area reclassified to Serious for a
PM2.5 NAAQS under Sec. 51.1002(b), in addition to meeting
the Moderate area attainment plan submittal requirements set forth at
Sec. 51.1003(a), the state(s) shall submit a Serious area attainment
plan that meets all of the following requirements:
(i) Emissions inventory requirements set forth at Sec.
51.1008(b)(1);
(ii) Emissions inventory requirements set forth at Sec.
51.1008(b)(2);
(iii) Serious area attainment plan control strategy requirements
set forth at Sec. 51.1010;
(iv) Attainment demonstration and modeling requirements set forth
at Sec. 51.1011;
(v) Reasonable Further Progress (RFP) requirements set forth at
Sec. 51.1012;
(vi) Quantitative milestone requirements set forth at Sec.
51.1013;
(vii) Contingency measure requirements set forth at Sec. 51.1014;
and,
(viii) Nonattainment new source review plan requirements pursuant
to section 189(b)(3) and section 172(c)(5) of the CAA.
(2) The state(s) shall submit its Serious area attainment plan to
EPA according to the following schedule:
(i) For any nonattainment area reclassified to Serious for a
particular PM2.5 NAAQS under Sec. 51.1002(b)(1), the
state(s) shall submit to EPA the portion of the Serious area attainment
plan that meets the requirements set forth at paragraphs (b)(1)(i),
(iii) and (viii) of this section no later than 18 months from the date
of reclassification. The state(s) shall submit to EPA the portion of
the Serious area attainment plan that meets the requirements set forth
at paragraphs (b)(1)(ii) and (b)(1)(iv) through (vii) of this section
to EPA no later than 4 years from the date of reclassification.
(ii) For any nonattainment area reclassified to Serious for a
particular PM2.5 NAAQS under Sec. 51.1002(b)(2), the
state(s) shall submit to EPA a Serious area attainment plan meeting the
requirements set forth at paragraphs (b)(1)(i) through (viii) of this
section no later than 18 months from the date of reclassification.
(iii) If the state(s) submits to EPA a request for a Serious area
attainment date extension simultaneous with the Serious area attainment
plan due under paragraph (b)(1) of this section, such a plan shall meet
the most stringent measure (MSM) requirements set forth at Sec.
51.1010(b) in addition to the BACM and BACT and additional feasible
measure requirements set forth at Sec. 51.1010(a).
(c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain the PM2.5 NAAQS by the applicable Serious
area attainment date.
(1) For any Serious nonattainment area that fails to attain a
particular PM2.5 NAAQS by the applicable Serious area
attainment date, the state(s) shall submit a revised Serious area
attainment plan that demonstrates that the area annually will achieve
at least 5 percent reductions in emissions of direct PM2.5
and PM2.5 precursors based on the most recent emissions
inventory for the area and that meets the following requirements:
(i) Emissions inventory requirements set forth at Sec.
51.1008(c)(1);
(ii) Emissions inventory requirements set forth at Sec.
51.1008(c)(2);
(iii) Demonstration of attainment and modeling requirements set
forth at Sec. 51.1011;
(iv) Reasonable Further Progress (RFP) requirements set forth at
Sec. 51.1012;
(v) Quantitative milestone requirements set forth at Sec. 51.1013;
and,
(vi) Contingency measure requirements set forth at Sec. 51.1014.
(2) The state(s) shall submit to EPA the revised attainment plan
meeting the requirements set forth at paragraphs (c)(1)(i) through (vi)
of this section no later than 12 months from the missed applicable
Serious area attainment date.
(d) Any attainment plan submitted to EPA under this section shall
establish motor vehicle emissions budgets for the projected attainment
year for the area, if applicable. The state shall develop such budgets
according to the requirements of the transportation conformity rule as
they apply to PM2.5 nonattainment areas (40 CFR part 93).
Sec. 51.1004 Attainment dates.
(a) The state shall submit a projected attainment date as part of
its attainment plan submission under Sec. 51.1003 for any
PM2.5 NAAQS nonattainment area located in whole or in part
within its boundaries. The state shall justify the projected attainment
date for each such nonattainment area (or portion of a nonattainment
area) as part of the demonstration of attainment developed and
submitted according to the requirements set forth at Sec. 51.1011 and
according to the following:
(1) Nonattainment areas initially classified as Moderate.
(i) Except for nonattainment areas that meet the criterion under
paragraph (a)(1)(ii) of this section, the projected attainment date for
a Moderate PM2.5 nonattainment area shall be as expeditious
as practicable with the implementation of all control measures required
under Sec. 51.1009 and may be as late as the end of the sixth calendar
year after the date of designation if the state demonstrates that the
implementation of certain control measures that qualify as RACM or RACT
or additional reasonable measures, but that are not necessary for
demonstrating attainment by the end of the sixth calendar year after
the date of designation, will not collectively advance the attainment
date by at least 1 year.
(ii) The projected attainment date for a Moderate PM2.5
nonattainment area which the state demonstrates cannot practicably
attain the applicable PM2.5 NAAQS by the end of the sixth
calendar year after the date of designation of the area with the
implementation of all control measures required under Sec. 51.1009
shall be such date unless and until the area is reclassified as Serious
according to Sec. 51.1002.
(2) Nonattainment areas reclassified to Serious.
(i) Except for nonattainment areas that meet the criterion under
paragraph (a)(2)(ii) of this section, the projected attainment date for
a Serious PM2.5 nonattainment area shall be as expeditious
as practicable with the implementation of all control measures required
under Sec. 51.1010 but no later than the end of the tenth calendar
year after the date of designation.
[ALTERNATIVE PROPOSED REGULATORY TEXT]
(i) Except for nonattainment areas that meet the criterion under
paragraph (a)(2)(ii) of this section, the projected attainment date for
a Serious PM2.5 nonattainment area shall be as
[[Page 15466]]
expeditious as practicable with the implementation of all control
measures required under Sec. 51.1010 and may be as late as the end of
the tenth calendar year after the date of designation if the state
demonstrates that the implementation of certain control measures that
qualify as BACM or BACT or additional feasible measures, but that are
not necessary for demonstrating attainment by the end of the tenth
calendar year after the date of designation, will not collectively
advance the attainment date by at least 1 year.]
(ii) A state that submits an attainment plan that demonstrates that
a Serious PM2.5 nonattainment area cannot practicably attain
the PM2.5 NAAQS by the end of the tenth calendar year
following the date of designation of the area with the implementation
of all control measures required under Sec. 51.1010(a) must request an
extension of the Serious area attainment date consistent with Sec.
51.1005(b). The request must propose a projected attainment date for
the nonattainment area that is as expeditious as practicable, but no
later than the end of the fifteenth calendar year from the date of
designation of the area.
(3) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain by the applicable Serious area attainment date. The
projected attainment date for a Serious PM2.5 nonattainment
area that failed to attain the PM2.5 NAAQS by the applicable
Serious area attainment date shall be as expeditious as practicable
based on annual reductions in direct PM2.5 and significant
PM2.5 precursor emissions within the area of not less than 5
percent of the amount of such emissions as reported in the most recent
emissions inventory prepared for the area, but no later than 5 years
following the missed Serious area attainment date.
(b) Except for attainment plans that meet the conditions of
paragraphs (a)(1)(ii) or (a)(3) of this section, the Administrator
shall approve an attainment date at the same time and in the same
manner in which the Administrator approves the attainment plan for the
area.
(1) In accordance with paragraph (a)(1)(ii) of this section, if a
state demonstrates that a Moderate PM2.5 nonattainment area
cannot practicably attain the PM2.5 NAAQS by the end of the
sixth calendar year following the date of designation of the area, EPA
shall proceed under the provisions of Sec. 51.1002(b)(1) to reclassify
the area to Serious through notice-and-comment rulemaking.
(2) In accordance with paragraph (a)(3) of this section, if a
Serious PM2.5 nonattainment area fails to attain the
PM2.5 NAAQS by the applicable Serious area attainment date,
EPA will proceed to establish a new attainment date through a direct
final action published in the Federal Register.
Sec. 51.1005 Attainment date extensions.
(a) Nonattainment areas initially classified as Moderate.
(1) A state with a Moderate PM2.5 nonattainment area may
apply for a 1-year attainment date extension for the area if the
following conditions are met in the year preceding the applicable
attainment date for the area:
(i) The state has complied with all requirements and commitments
pertaining to the area in the applicable implementation plan;
(ii) For an area designated nonattainment for a particular 24-hour
PM2.5 NAAQS for which the state seeks an attainment date
extension, the 98th percentile concentration at each monitor in the
area for the calendar year prior to the applicable attainment date is
less than or equal to the level of the applicable 24-hour standard
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N);
(iii) For an area designated nonattainment for a particular annual
PM2.5 NAAQS for which the state seeks an attainment date
extension, the annual average concentration at each monitor in the area
for the calendar year prior to the applicable attainment date is less
than or equal to the level of the applicable annual standard
(calculated according to the data analysis requirements in 40 CFR part
50, appendix N).
(2) The applicable implementation plan for a Moderate
PM2.5 nonattainment area for which a state seeks an
attainment date extension is the plan submitted to EPA to meet the
requirements of Sec. 51.1003(a).
(3) For a Moderate PM2.5 nonattainment area, the
requesting state (or states) shall submit a written request by February
28 of the year following the applicable attainment date for the area.
(4) A state with a Moderate area that received an initial 1-year
attainment date extension may apply for a second 1-year attainment date
extension for the area if the state meets the conditions described in
paragraph (a)(1) of this section in the year preceding the approved
attainment date.
(b) Nonattainment areas reclassified as Serious.
(1) A state may apply for one attainment date extension not to
exceed 5 years for a Serious nonattainment area if the following
conditions are met:
(i) The state demonstrates that attainment of the applicable
PM2.5 NAAQS by the approved attainment date for the area
would be impracticable or, in the absence of an approved attainment
date, attainment of the applicable PM2.5 NAAQS by the
applicable statutory attainment date for the area would be
impracticable;
(ii) The state has complied with all requirements and commitments
pertaining to the area in the applicable implementation plan; and,
(iii) The state demonstrates that the attainment plan for the area
includes the most stringent measures (MSM) that are included in the
attainment plan of any state or are achieved in practice in any state,
and can feasibly be implemented in the area consistent with Sec.
51.1010(b).
(2) At the time of application for an attainment date extension,
the state shall submit to EPA a Serious area attainment plan that meets
the following requirements:
(i) Emissions inventory requirements set forth at Sec. 51.1008(b);
(ii) Most stringent measures (MSM) requirement described under
paragraph (b)(1)(iii) of this section and Sec. 51.1010(b);
(iii) Attainment demonstration and modeling requirements set forth
at Sec. 51.1011 that justify the state's conclusion under paragraph
(b)(1)(i) of this section;
(iv) Reasonable Further Progress (RFP) requirements set forth at
Sec. 51.1012;
(v) Quantitative milestone requirements set forth at Sec. 51.1013;
and,
(vi) Contingency measure requirements set forth at Sec. 51.1014.
(3) The applicable implementation plan for a Serious
PM2.5 nonattainment area for which a state seeks an
attainment date extension under Sec. 51.1004(a)(2)(ii) is the plan
submitted to EPA to meet the requirements set forth at Sec.
51.1003(a).
(4) The applicable implementation plan for a Serious
PM2.5 nonattainment area for which a state seeks an
attainment date extension under Sec. 51.1004(a)(2)(i) is the plan
submitted to EPA to meet the requirements set forth at Sec.
51.1003(b)(1).
(5) A state applying for an attainment date extension for a Serious
nonattainment area under Sec. 51.1004(a)(2)(ii) shall submit to EPA a
request for an extension at the same time as it submits the Serious
area attainment plan due under Sec. 51.1003(b)(1).
(6) A state applying for an attainment date extension for a Serious
nonattainment area subsequent to submitting an initial Serious area
attainment plan that demonstrated
[[Page 15467]]
attainment of the NAAQS by the applicable attainment date consistent
with Sec. 51.1004(a)(2)(i) at the time of submittal may apply for such
an extension no later than 60 calendar days prior to the approved
attainment date for the area or, in the absence of an approved
attainment date, no later than 60 calendar days prior to the applicable
statutory attainment date for the area.
(c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain by the applicable Serious area attainment date. If a
Serious area fails to attain a particular PM2.5 NAAQS by the
applicable Serious area attainment date, the area is then subject to
the requirements of section 189(d) of the Act, and, for this reason,
the state is prohibited from requesting an extension of the applicable
Serious area attainment date for such area.
(d) For any attainment date extension request submitted pursuant to
this section, the requesting state (or states) shall submit a written
request and evidence of compliance with these regulations which
includes both of the following:
(i) Evidence that all control measures submitted in the applicable
attainment plan have been implemented, and
(ii) Evidence that the area has made emission reduction progress
that represents reasonable further progress toward timely attainment of
the applicable PM2.5 NAAQS.
(e) For a PM2.5 nonattainment area located in two or
more states or jurisdictions, all states and/or jurisdictions in which
such area is located shall submit separate attainment date extension
requests for the area consistent with the requirements set forth at
paragraph (d) of this section.
Sec. 51.1006 Requirements for demonstrating insignificant
contribution of PM2.5 precursors.
(a) For purposes of determining that a particular PM2.5
precursor does not contribute significantly to ambient PM2.5
concentrations in a PM2.5 nonattainment area, the state
shall conduct a technical analysis that accounts for all emissions of
such PM2.5 precursor from all sources located within the
area.
(b) The state shall submit results and supporting documentation for
any technical analyses conducted pursuant to paragraph (a) of this
section as part of any attainment plan for the area.
Sec. 51.1007 Requirements for de minimis source category
determinations for direct PM2.5 and PM2.5
precursors.
(a) All categories of sources of direct PM2.5 emissions
and of emissions of PM2.5 precursors in a PM2.5
nonattainment area shall be considered non-de minimis unless and until
the state conducts a technical analysis to determine whether a
particular source category may qualify for a presumptive de minimis
source category exemption from evaluation for potential control
measures due to its minimal contribution to the ambient
PM2.5 concentrations in the area.
(b) The state shall define source categories for stationary sources
classified under the North American Industry Classification System
(NAICS) at the level represented by four (4) digits or fewer.
(c) The state shall define a single source category for on-road
mobile sources, including on-road vehicles and engines, and a single
source category for nonroad mobile sources, including nonroad engines,
equipment, and vehicles, or may define a single source category for all
mobile sources in the aggregate.
Sec. 51.1008 Emissions inventory requirements.
(a) For any nonattainment area initially classified as Moderate,
the state shall submit to EPA all of the following:
(1) A base year inventory for the nonattainment area for all
emissions sources that meets the following minimum criteria:
(i) The inventory year shall be one of the 3 years used for
designations or another technically appropriate inventory year if
justified by the state in the plan submission.
(ii) The inventory shall include actual emissions of all sources
within the nonattainment area.
(iii) The emissions values shall be either annual total emissions
or average-season-day emissions. The state shall include as part of the
plan a rationale for providing annual or seasonal emissions.
(iv) The inventory shall include direct PM2.5 emissions
and emissions of all PM2.5 precursors.
(v) The state shall report emissions as point sources according to
the point source emissions thresholds of the Air Emissions Reporting
Rule (AERR), 40 CFR part 51, subpart A.
(vi) The detail of the emissions inventory shall be consistent with
the data elements required by 40 CFR part 51, subpart A.
(2) An attainment projected inventory for the nonattainment area
that meets the following minimum criteria:
(i) The year of the projected inventory shall be the most
expeditious year for which attainment is demonstrated by the modeled
attainment plan.
(ii) The emissions values shall be projected emissions of the same
sources included in the base year inventory for the nonattainment area
(i.e., those only within the nonattainment area). The state shall
include in this inventory projected emissions growth and contraction
from both controls and other causes during the relevant period.
(iii) The temporal period of emissions shall be the same temporal
period (annual or average-season-day) as the base year inventory for
the nonattainment area.
(iv) Consistent with the base year inventory for the nonattainment
area, the inventory shall include direct PM2.5 emissions and
emissions of all PM2.5 precursors.
(v) The same sources reported as point sources in the base year
inventory for the nonattainment area shall be provided as point sources
in the attainment projected inventory for the nonattainment area.
Nonpoint and mobile source projected emissions shall be provided using
the same detail (e.g., state, county, and process codes) as the base
year inventory.
(vi) The same detail of the emissions included shall be consistent
with the level of detail in the base year inventory (i.e., as required
by 40 CFR part 41, subpart A).
(b) For any nonattainment area reclassified as Serious, the state
shall submit to EPA all of the following:
(1) For purposes of meeting the emissions inventory requirements of
CAA section 172(c)(3), a base year inventory for the nonattainment area
for all emissions sources that meets the requirements listed under
paragraph (a)(1) of this section, and in addition, uses the Serious
area definition of a major source listed under Sec.
51.165(a)(1)(iv)(A)(vii) and (viii) in determining sources to include
as point sources.
(2) An attainment projected inventory for the nonattainment area
that meets the criteria listed under paragraph (a)(2) of this section.
(c) Serious nonattainment areas subject to CAA section 189(d) for
failing to attain a PM2.5 NAAQS by the applicable Serious
area attainment date. No later than 12 months after EPA finds through
notice-and-comment rulemaking that a Serious nonattainment area, or
portion thereof contained within a state's borders, fails to attain a
PM2.5 NAAQS by the applicable attainment date and thus
becomes subject to the requirements under CAA section 189(d), the state
shall submit to EPA all of the following:
(1) For purposes of meeting the emissions inventory requirements of
[[Page 15468]]
CAA section 172(c)(3), a base year inventory for the nonattainment area
for all emissions sources that meets the requirements listed under
paragraph (a)(1) of this section, and in addition, uses the Serious
area definition of a major source listed under Sec.
51.165(a)(1)(iv)(A)(vii) and (viii) in determining sources to include
as point sources.
(2) An attainment projected inventory for the nonattainment area as
defined by Sec. 51.1000(e) and that meets the criteria listed under
paragraph (a)(2) of this section.
Sec. 51.1009 Moderate area attainment plan control strategy
requirements.
(a) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located in any Moderate PM2.5 nonattainment area
or portion thereof located within the state consistent with the
following:
(1) The state shall identify all sources of direct PM2.5
emissions and all sources of emissions of PM2.5 precursors
in the nonattainment area in accordance with the emissions inventory
requirements of Sec. 51.1008(a);
(2) The state shall identify all potential control measures to
reduce emissions from all sources of direct PM2.5 emissions
and all sources of emissions of PM2.5 precursors in the
nonattainment area identified under paragraph (a)(1) of this section.
(i) The state may elect not to identify potential control measures
to reduce emissions from any sources of a particular PM2.5
precursor if the state demonstrates that all sources of such
PM2.5 precursor contribute insignificantly to ambient
PM2.5 concentrations in the area under Sec. 51.1006.
(ii) The state may elect not to identify potential control measures
to reduce emissions from sources in any source category of direct
PM2.5 emissions or emissions of PM2.5 precursors
determined to be a de minimis source category under Sec. 51.1007.
(3) For any potential control measure identified under paragraph
(a)(2) of this section, the state may make a demonstration that such
measure is not technologically or economically feasible to implement in
whole or in part by the end of the sixth calendar year following the
date of designation of the area, and the state may eliminate such whole
or partial measure from further consideration under this paragraph.
(i) For purposes of evaluating the technological feasibility of a
potential control measure, the state may consider factors including but
not limited to a source's processes and operating procedures, raw
materials, physical plant layout, and potential environmental impacts
such as increased water pollution, waste disposal, and energy
requirements.
(ii) For purposes of evaluating the economic feasibility of a
potential control measure, the state may consider factors including but
not limited to capital costs, operating and maintenance costs, and cost
effectiveness of the measure.
(iii) The state must submit to EPA as part of its Moderate area
attainment plan a detailed written justification for eliminating from
further consideration any potential control measure identified under
paragraph (a)(2) of this section on the basis of technological or
economic infeasibility.
(4) The state shall use air quality modeling that meets the
requirements of Sec. 51.1011(a) and that accounts for emissions
reductions estimated due to all technologically and economically
feasible control measures identified for sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors in the Moderate PM2.5 nonattainment area to
demonstrate that the area can attain the applicable PM2.5
NAAQS as expeditiously as practicable but no later than the end of the
sixth year following the date of designation of the area, or to
demonstrate that the Moderate PM2.5 nonattainment area
cannot practicably attain the applicable PM2.5 NAAQS by such
date.
(i) If the state demonstrates through air quality modeling that the
area can attain the applicable PM2.5 NAAQS by the end of the
sixth calendar year following the date of designation of the area, the
state shall adopt and implement all technologically and economically
feasible control measures identified under paragraph (a)(3) of this
section that are necessary to bring the area into attainment by such
date. The state shall also adopt and implement all other
technologically and economically feasible measures identified under
paragraph (a)(3) of this section that, when considered collectively,
would advance the attainment date for the area by at least 1 year.
(A) Any control measure identified for adoption and implementation
under this paragraph that can be implemented in whole or in part by 4
years after the date of designation of the Moderate PM2.5
nonattainment area shall be considered RACM for the area. Any such
control measure that is also a control technology shall be considered
RACT for the area.
(B) Any control measure identified for adoption and implementation
under this paragraph that can only be implemented in whole or in part
during the period beginning 4 years after the date of designation of
the Moderate PM2.5 nonattainment area and the beginning of
the calendar year containing the applicable attainment date for the
area shall be considered an additional reasonable measure for the area.
(ii) If the state demonstrates through air quality modeling that
the area cannot practicably attain the applicable PM2.5
NAAQS by the end of the sixth calendar year following the date of
designation of the area, the state shall adopt all technologically and
economically feasible control measures identified under paragraph
(a)(3) of this section unless the state makes a demonstration that one
or more such measures, when considered collectively, would have minimal
effect on reducing ambient PM2.5 concentrations in the area.
(A) Any control measure identified for adoption and implementation
under this paragraph that can be implemented in whole or in part by 4
years after the date of designation of the Moderate PM2.5
nonattainment area shall be considered RACM for the area. Any such
control measure that is also a control technology shall be considered
RACT for the area.
(B) Any control measure identified for adoption and implementation
under this paragraph that can only be implemented in whole or in part
during the period beginning 4 years after the date of designation of
the Moderate PM2.5 nonattainment area through the end of the
sixth calendar year following the date of designation of the area shall
be considered an additional reasonable measure for the area.
(b) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located outside the Moderate PM2.5 nonattainment
area, or portion thereof, located within the state if doing so is
necessary to provide for attainment or will expedite attainment of the
applicable PM2.5 NAAQS in such area.
(c) For control measures on sources of direct PM2.5
emissions in the form of source emissions limitations, the state shall
establish such limitations taking into account the filterable and
condensable fractions of such emissions.
[[Page 15469]]
Sec. 51.1010 Serious area attainment plan control strategy
requirements.
[PROPOSED REGULATORY TEXT FOR OPTION 1:
(a) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located in any Serious PM2.5 nonattainment area
or portion thereof located within the state to yield a control strategy
for the area that is more stringent than that developed for the area
when it was classified as Moderate, and consistent with the following:
(1) The state shall identify all sources of direct PM2.5
emissions and all sources of emissions of PM2.5 precursors
in the nonattainment area in accordance with the emissions inventory
requirements of Sec. 51.1008(b);
(2) The state shall identify all potential control measures to
reduce emissions from all sources of direct PM2.5 emissions
and sources of emissions of PM2.5 precursors in the
nonattainment area identified under paragraph (a)(1) of this section.
(i) The state shall survey other NAAQS nonattainment areas in the
U.S. and identify any measures not previously identified by the state
during the development of the Moderate area attainment plan for the
area.
(ii) The state may elect not to identify potential control measures
to reduce emissions from any sources of a particular PM2.5
precursor if the state demonstrates that all sources of such
PM2.5 precursor contribute insignificantly to ambient
PM2.5 concentrations in the area under Sec. 51.1006.
(iii) The state may elect not to identify potential control
measures to reduce emissions from sources in any source category of
direct PM2.5 emissions or emissions of PM2.5
precursors determined to be a de minimis source category under Sec.
51.1007.
(3) The state may make a demonstration that any measure identified
under paragraph (a)(2) of this section is not technologically or
economically feasible to implement in whole or in part by the end of
the tenth calendar year following the date of designation of the area,
and may eliminate such whole or partial measure from further
consideration under this paragraph.
(i) For purposes of evaluating the technological feasibility of a
potential control measure, the state may consider factors including but
not limited to a source's processes and operating procedures, raw
materials, physical plant layout, and potential environmental impacts
such as increased water pollution, waste disposal, and energy
requirements.
(ii) For purposes of evaluating the economic feasibility of a
potential control measure, the state may consider capital costs,
operating and maintenance costs, and cost effectiveness of the measure.
(iii) The state shall submit to EPA as part of its Serious area
attainment plan submission a detailed written justification for
eliminating from further consideration any potential control measure
identified under paragraph (a)(2) of this section on the basis of
technological or economic infeasibility. The state shall provide as
part of its written justification an explanation of how its criteria
for determining the technological and economic feasibility of potential
control measures under paragraphs (a)(3)(i) and (ii) of this section
are more stringent than its criteria for determining the technological
and economic feasibility of potential control measures under Sec.
51.1009(a)(3)(i) and (ii) for the same sources in the PM2.5
nonattainment area.
(4) Except as provided under paragraph (a)(3) of this section, the
state shall adopt and implement all potential control measures
identified under paragraph (a)(2) of this section.
(i) Any control measure that can be implemented in whole or in part
by the end of the fourth year following the date of reclassification of
the area to Serious shall be considered a best available control
measure for the area. Any such control measure that is also a control
technology for a stationary source in the area shall be considered a
best available control technology for the area.
(ii) Any control measure that can be implemented in whole or in
part between the end of the fourth year following the date of
reclassification of the area to Serious and the applicable attainment
date for the area shall be considered an additional feasible measure.
(5) The state shall use air quality modeling that meets the
requirements of Sec. 51.1011(b) and that accounts for emissions
reductions estimated due to all best available control measures,
including best available control technologies, and additional feasible
measures identified for sources of direct PM2.5 emissions
and sources of emissions of PM2.5 precursors in the area to
demonstrate that the area can attain the PM2.5 NAAQS as
expeditiously as practicable but no later than the end of the tenth
calendar year following the date of designation of the area, or to
demonstrate that the Serious PM2.5 nonattainment area cannot
practicably attain the applicable PM2.5 NAAQS by such date.]
[PROPOSED REGULATORY TEXT FOR OPTION 2:
(a) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located in any Serious PM2.5 nonattainment area
or portion thereof located within the state to yield a control strategy
for the area that is more stringent than that developed for the area
when it was classified as Moderate, and consistent with the following:
(1) The state shall identify all sources of direct PM2.5
emissions and sources of emissions of PM2.5 precursors in
the nonattainment area in accordance with the emissions inventory
requirements of Sec. 51.1008;
(2) The state shall identify all potential control measures to
reduce emissions from all sources of direct PM2.5 emissions
and sources of emissions of PM2.5 precursors in the
nonattainment area identified under paragraph (a)(1) of this section.
(i) The state shall survey other NAAQS nonattainment areas in the
U.S. and identify any measures not previously identified by the state
during the development of the Moderate area attainment plan for the
area.
(ii) The state may elect not to identify potential control measures
to reduce emissions from any sources of a particular PM2.5
precursor if the state demonstrates that all sources of such
PM2.5 precursor contribute insignificantly to ambient
PM2.5 concentrations in the area under Sec. 51.1006.
(3) The state may make a demonstration that a measure identified
under paragraph (a)(2) of this section is not technologically or
economically feasible to implement in whole or in part by the end of
the tenth calendar year following the date of designation of the area,
and may eliminate such whole or partial measure from further
consideration under this paragraph.
(i) For purposes of evaluating the technological feasibility of a
potential control measure, the state may consider factors including but
not limited to a source's processes and operating procedures, raw
materials, physical plant layout, and potential environmental impacts
such as increased water pollution, waste disposal, and energy
requirements.
(ii) For purposes of evaluating the economic feasibility of a
potential control measure, the state may consider
[[Page 15470]]
capital costs, operating and maintenance costs, and cost effectiveness
of the measure.
(iii) The state shall submit to EPA as part of its Serious area
attainment plan submission a detailed written justification for
eliminating from further consideration any potential control measure
identified under paragraph (a)(2) of this section on the basis of
technological or economic infeasibility. The state shall provide as
part of its written justification an explanation of how its criteria
for determining the technological and economic feasibility of potential
control measures under paragraphs (a)(3)(i) and (ii) of this section
are more stringent than its criteria for determining the technological
and economic feasibility of potential control measures under Sec.
51.1009(a)(3)(i) and (ii) for the same sources in the PM2.5
nonattainment area.
(4) The state shall use air quality modeling that meets the
requirements of Sec. 51.1011(b) and that accounts for emissions
reductions estimated due to all technologically and economically
feasible control measures identified for sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors in the area to demonstrate that the area can attain the
applicable PM2.5 NAAQS as expeditiously as practicable but
no later than the end of the tenth calendar year following the date of
designation of the area, or to demonstrate that the Serious
PM2.5 nonattainment area cannot practicably attain the
applicable PM2.5 NAAQS by such date.
(5) For a Serious PM2.5 nonattainment area which air
quality modeling demonstrates that the area can attain the applicable
PM2.5 NAAQS by the end of the tenth calendar year following
the date of designation of the area, the state shall adopt and
implement all technologically and economically feasible control
measures needed to bring the area into attainment by such date and
additionally any other such measures that, when considered
collectively, would advance the attainment date for the area by at
least 1 year.
(i) Any control measure that can be implemented in whole or in part
by the end of the fourth year following the date of reclassification of
the area to Serious shall be considered a best available control
measure for the area. Any such control measure that is also a control
technology for a stationary source in the area shall be considered a
best available control technology for the area.
(ii) Any control measure that can only be implemented in whole or
in part between the end of the fourth year following the date of
reclassification of the area to Serious and the applicable attainment
date for the area shall be considered an additional feasible measure.]
(b) For a Serious PM2.5 nonattainment area which air
quality modeling demonstrates cannot practicably attain the applicable
PM2.5 NAAQS by the end of the tenth calendar year following
the date of designation of the area, the state shall identify, adopt,
and implement the most stringent control measures that are included in
the attainment plan for any state or are achieved in practice in any
state, and can be feasibly implemented in the area, consistent with the
following:
(1) The state shall identify all sources of direct PM2.5
emissions and sources of emissions of PM2.5 precursors in
the nonattainment area in accordance with the emissions inventory
requirements of Sec. 51.1008(b).
(2) The state shall identify all potential control measures to
reduce emissions from all sources of direct PM2.5 emissions
and sources of emissions of PM2.5 precursors in the
nonattainment area identified under paragraph (a)(1) of this section
and not otherwise determined to contribute insignificantly to ambient
PM2.5 concentrations in the area according to Sec. 51.1006
or to be de minimis according to Sec. 51.1007.
(i) The state shall survey other NAAQS nonattainment areas in the
U.S. and identify the most stringent measures adopted into any SIP for
any NAAQS or used in practice to control emissions from any non-de
minimis source categories.
(ii) The state shall reanalyze any measures previously rejected by
the state during the development of any Moderate area or Serious area
attainment plan control strategy for the area, unless the extension
request is made at the same time as the Serious area attainment plan
required after the area is reclassified in accordance with Sec.
51.1005(b)(5).
(3) The state may make a demonstration that a measure identified
under paragraph (b)(2) of this section is not technologically or
economically feasible to implement in whole or in part by 5 years after
the applicable attainment date for the area, and may eliminate such
whole or partial measure from further consideration under this
paragraph.
(i) For purposes of evaluating the technological feasibility of a
potential control measure, the state may consider factors including but
not limited to a source's processes and operating procedures, raw
materials, physical plant layout, and potential environmental impacts
such as increased water pollution, waste disposal, and energy
requirements.
(ii) For purposes of evaluating the economic feasibility of a
potential control measure, the state may consider capital costs,
operating and maintenance costs, and cost effectiveness of the measure.
(iii) The state shall submit to EPA as part of its Serious area
attainment plan submission a detailed written justification for
eliminating from further consideration any potential control measure
identified under paragraph (b)(2) of this section on the basis of
technological or economic infeasibility. The state shall provide as
part of its written justification an explanation of how its criteria
for determining the technological and economic feasibility of potential
control measures under paragraphs (b)(3)(i) and (ii) of this section
are more stringent than its criteria for determining the technological
and economic feasibility of potential control measures under paragraphs
(a)(3)(i) and (ii) of this section and under Sec. 51.1009(a)(3)(i) and
(ii) for the same sources in the PM2.5 nonattainment area.
(4) Except as provided under paragraph (b)(3) of this section, the
state shall adopt and implement all control measures identified under
paragraph (b)(2) of this section that may achieve greater emissions
reductions from any non-de minimis sources of direct PM2.5
emissions or sources of emissions of PM2.5 precursors in the
area than previously adopted measures have achieved and that shall
achieve attainment as expeditiously as practicable but no later than 5
years after the applicable attainment date for the area.
(c) The state shall identify, adopt, and implement control
measures, including control technologies, on sources of direct
PM2.5 emissions and sources of emissions of PM2.5
precursors located outside the Serious PM2.5 nonattainment
area or portion thereof, located within the state if doing so will
expedite attainment of the applicable PM2.5 NAAQS within the
area.
(d) For control measures on sources of direct PM2.5
emissions in the form of source emissions limitations, the state shall
establish such limitations taking into account the filterable and
condensable fractions of such emissions.
Sec. 51.1011 Attainment demonstration and modeling requirements.
(a) Nonattainment areas initially classified as Moderate. The
attainment demonstration due to EPA as part of any
[[Page 15471]]
Moderate area attainment plan required under Sec. 51.1003(a) shall
meet all of the following criteria:
(1) The attainment demonstration shall show the projected
attainment date for the Moderate nonattainment area that is as
expeditious as practicable in accordance with the requirements of Sec.
51.1004(a)(1).
(2) The attainment demonstration shall meet the requirements of
Appendix W of this part and shall include inventory data, modeling
results, and emission reduction analyses on which the state has based
its projected attainment date.
(3) The base year for the emissions inventory required for an
attainment demonstration under this paragraph shall be one of the 3
years used for designations or another technically appropriate
inventory year if justified by the state in the plan submission.
(4) The control strategies modeled as part of the attainment
demonstration shall be consistent with the following as applicable:
(i) For a Moderate area that can demonstrate attainment of the
applicable PM2.5 NAAQS no later than the end of the sixth
calendar year following the date of designation of the area with the
implementation of RACM and RACT and additional reasonable measures, the
control strategies modeled as part of the attainment demonstration
shall be consistent with control strategy requirements under Sec.
51.1009(a).
(ii) For a Moderate area that cannot practicably attain the
applicable PM2.5 NAAQS by the end of the sixth calendar year
following the date of designation of the area with the implementation
of RACM and RACT and additional reasonable measures, the control
strategies modeled as part of the attainment demonstration shall be
consistent with control strategy requirements under Sec. 51.1009(b).
(5) The attainment demonstration and supporting air quality
modeling should be consistent with the most current version of EPA's
PM2.5 attainment demonstration modeling guidance.
(6) Required time frame for obtaining emissions reductions. For
each Moderate nonattainment area, the attainment plan must provide for
implementation of all control measures needed for attainment as
expeditiously as practicable. All control measures in the attainment
demonstration must be implemented no later than the beginning of the
year prior to the attainment date, notwithstanding RACM implementation
deadline requirements in Sec. 51.1009.
(b) Nonattainment areas reclassified as Serious. The attainment
demonstration due to EPA as part of a Serious area attainment plan
required under Sec. 51.1003(b) shall meet all of the following
criteria:
(1) The attainment demonstration shall show the projected
attainment date for the Serious nonattainment area that is as
expeditious as practicable in accordance with the requirements of Sec.
51.1004(a)(2).
(2) The attainment demonstration shall meet the requirements of
Appendix W of this part and shall include inventory data, modeling
results, and emission reduction analyses on which the state has based
its projected attainment date.
(3) The base year for the emissions inventories required for
attainment demonstrations under this paragraph shall be one of the 3
years used for designations or another technically appropriate
inventory year if justified by the state in the plan submission.
(4) The control strategies modeled as part of the attainment
demonstration shall be consistent with the following as applicable:
(i) For a Serious area that can demonstrate attainment of the
applicable PM2.5 NAAQS no later than the end of the tenth
calendar year following the date of designation of the area with the
implementation of best available control measures (BACM), including
best available control technologies (BACT), and additional feasible
measures, the control strategies modeled as part of the attainment
demonstration shall be consistent with control strategy requirements
under Sec. 51.1010(a).
(ii) For a Serious area that cannot practicably attain the
applicable PM2.5 NAAQS by the end of the tenth calendar year
following the date of designation of the area with the implementation
of best available control measures (BACM), including best available
control technologies (BACT), and additional feasible measures, the
control strategies modeled as part of the attainment demonstration
shall be consistent with control strategy requirements under Sec.
51.1010(b).
(5) The attainment demonstration and supporting air quality
modeling should be consistent with the most current version of EPA's
PM2.5 attainment demonstration modeling guidance.
(6) Required timeframe for obtaining emissions reductions. For each
Serious nonattainment area, the attainment plan must provide for
implementation of all control measures needed for attainment as
expeditiously as practicable. All control measures must be implemented
no later than the beginning of the year prior to the attainment date,
notwithstanding BACM implementation deadline requirements in Sec.
51.1010.
Sec. 51.1012 Reasonable further progress (RFP) requirements.
(a) Consistent with CAA section 172(c)(2), the state shall submit
in each attainment plan for a PM2.5 nonattainment area a
plan that demonstrates that the area will achieve, on an annual basis,
reasonable further progress (RFP) in reducing emissions of direct
PM2.5 and any PM2.5 precursors from sources in
the area that the state has determined are necessary to be controlled
in order for the area to attain the applicable PM2.5 NAAQS
as expeditiously as practicable. The RFP plan shall include all of the
following:
(1) A description of each control measure adopted by the state to
satisfy the control strategy requirements of Sec. 51.1009 (for
Moderate area attainment plans) or Sec. 51.1010 (for Serious area
attainment plans), as appropriate, and the projected reductions in
direct PM2.5 emissions and emissions of PM2.5
precursors that each control measure will achieve by the projected
attainment date for the area.
(2) A schedule for implementing the measures described in paragraph
(a)(1) of this section.
(3) An analysis that demonstrates that by the end of the calendar
year for each milestone date for the area determined in accordance with
Sec. 51.1013(a), emissions will be at a level that reflects generally
linear progress in reducing emissions on an annual basis between the
base year and the attainment year.
(b) Except as provided under paragraph (c) of this section, the RFP
analysis required under paragraph (a)(3) of this section shall include,
at a minimum, a benchmark RFP analysis, and may include an alternative
RFP analysis, consistent with the following:
(1) The base year for the RFP emissions inventory shall be one of
the 3 years used for designations or another technically appropriate
inventory year if justified by the state in the plan submission.
(2) In the benchmark RFP analysis, the state must identify direct
PM2.5 emissions and PM2.5 precursors regulated in
the control strategy for the area and specify target emission reduction
levels to be achieved during the milestone years. In developing the
benchmark RFP analysis, the state must develop emissions inventory
information for the area and calculate the following:
(i) For direct PM2.5 emissions and each PM2.5
precursor addressed in the control strategy, the full implementation
reduction is calculated by subtracting
[[Page 15472]]
the full implementation inventory from the base year inventory.
(ii) The ``milestone date fraction'' is the ratio of the number of
years from the base year to the milestone year divided by the number of
years from the baseline year to the full implementation year.
(iii) For direct PM2.5 emissions and each
PM2.5 attainment plan precursor addressed in the attainment
strategy, a benchmark emission reduction is calculated by multiplying
the full implementation reduction by the milestone date fraction.
(iv) The benchmark emission level in the milestone year is
calculated for direct PM2.5 emissions and each
PM2.5 precursor by subtracting the benchmark emission
reduction from the base year emission level.
(v) In comparing inventories between the base year and future years
for direct PM2.5 emissions and emissions of PM2.5
precursors, the inventories must be derived for sources located within
the nonattainment area.
(vi) For purposes of establishing motor vehicle emissions budgets
for transportation conformity purposes (as required in 40 CFR part 93)
for a PM2.5 nonattainment area, the state shall include in
its RFP submittal an inventory of on-road mobile source emissions in
the nonattainment area for each milestone year.
(3) The RFP analysis must demonstrate that emissions for the
milestone year are either:
(i) At levels that are roughly equivalent to the benchmark emission
levels for direct PM2.5 emissions and emissions of
PM2.5 precursors addressed in the attainment plan; or
(ii) At levels included in an alternative RFP analysis that
projects generally equivalent improvement in air quality by the
milestone year as would be achieved under the benchmark RFP plan.
(iii) The equivalence of an alternative RFP analysis to the
corresponding benchmark analysis must be determined by comparing the
expected air quality changes from the two analyses at the design value
monitor location. This comparison must use the information developed
for the attainment plan to assess the relationship between emissions
reductions of the direct PM2.5 emissions and emissions of
PM2.5 precursors addressed in the control strategy for the
area and the ambient air quality improvement.
(c) For an attainment plan submittal that demonstrates that a
Moderate PM2.5 nonattainment area cannot practicably attain
the applicable PM2.5 NAAQS by the end of the sixth calendar
year following the effective date of designation of the area with the
implementation of control measures as required under Sec. 51.1009, the
RFP analysis required under paragraph (a)(3) of this section shall
demonstrate generally linear emissions reductions in direct
PM2.5 emissions and emissions of PM2.5 precursors
projected from the Moderate area control strategy determined according
to Sec. 51.1008 for each milestone year.
(d) For a multi-state or multi-jurisdictional nonattainment area,
the RFP plans for each state represented in the nonattainment area
shall demonstrate RFP on the basis of common multi-state inventories.
The states or jurisdictions within which the area is located must
provide a coordinated RFP plan. Each state in a multi-state
nonattainment area must ensure that the sources within its boundaries
comply with enforceable emission levels and other requirements that in
combination with the reductions planned in other state(s) within the
nonattainment area will provide for attainment as expeditiously as
practicable and demonstrate RFP consistent with these regulations.
Sec. 51.1013 Quantitative milestone requirements.
(a) Consistent with CAA section 189(c)(1), the state must submit in
each attainment plan for a PM2.5 nonattainment area specific
quantitative milestones that demonstrate reasonable further progress
toward attainment of the applicable PM2.5 NAAQS in the area
and that meet the following requirements:
(1) Nonattainment areas initially classified as Moderate.
(i) For an attainment plan submittal that demonstrates that a
Moderate PM2.5 nonattainment area can attain the applicable
PM2.5 NAAQS by the end of the sixth calendar year following
the date of designation of the area or earlier with the implementation
of control measures as required under Sec. 51.1009, the state shall
submit quantitative milestones to be achieved no later than a milestone
date of 4.5 years from the date of designation of the area.
(ii) For an attainment plan submittal that demonstrates that a
Moderate PM2.5 nonattainment area cannot practicably attain
the applicable PM2.5 NAAQS by the end of the sixth calendar
year following the effective date of designation of the area with the
implementation of control measures as required under Sec. 51.1009, the
state shall submit quantitative milestones to be achieved no later than
milestone dates of 4.5 years and 7.5 years, respectively, from the date
of designation of the area.
(iii) The state shall select quantitative milestones that coincide
with the milestone due dates specified in paragraphs (a)(1)(i) and (ii)
of this section, as applicable, and that provide for objective
evaluation of emissions reductions and/or air quality improvements
representing progress toward attainment of the applicable
PM2.5 NAAQS in the area, including, at a minimum, a
milestone that all control measures identified and adopted as RACM and
RACT for the area will be fully implemented within 4 years after the
date of designation.
(2) Nonattainment areas reclassified to Serious.
(i) For an attainment plan submittal that demonstrates that a
Serious PM2.5 nonattainment area can attain a particular
PM2.5 NAAQS by the end of the tenth calendar year following
the effective date of designation of the area with the implementation
of control measures as required under Sec. 51.1010(a), the state shall
submit quantitative milestones to be achieved no later than milestone
dates of 7.5 years and 10.5 years, respectively, from the date of
designation of the area.
(ii) For an attainment plan submittal that demonstrates that a
Serious PM2.5 nonattainment area cannot practicably attain a
particular PM2.5 NAAQS by the end of the tenth calendar year
following the date of designation of the area with the implementation
of control measures required under Sec. 51.1010(a), the state shall
submit quantitative milestones to be achieved no later than milestone
dates of 7.5 years, 10.5 years, and 13.5 years, respectively, from the
date of designation of the area.
(iii) The state shall select quantitative milestones that coincide
with the milestone due dates specified in paragraphs (a)(2)(i) and (ii)
of this section, as applicable, and that provide for objective
evaluation of emissions reductions and/or air quality improvements
representing progress toward attainment of the applicable
PM2.5 NAAQS in the area, including, at a minimum, a
milestone that all control measures identified and adopted as BACM and
BACT for the area will be fully implemented within 4 years of
reclassification of the area to Serious.
(3) Serious areas that fail to attain by the applicable Serious
area attainment date. For an attainment plan submittal for a Serious
area that failed to attain a particular PM2.5 NAAQS by the
applicable Serious area attainment date and is therefore subject to the
requirements of CAA section 189(d) and Sec. 51.1003(c), the state
shall submit
[[Page 15473]]
quantitative milestones to be achieved no later than a milestone date
of 13.5 years from the date of designation of the area and every 3
years thereafter until the projected attainment date for the area. The
state shall select quantitative milestones that coincide with the
milestone due dates for the area, and that provide for objective
evaluation of emissions reductions and/or air quality improvements
representing progress toward attainment of the applicable
PM2.5 NAAQS in the area.
(b) Not later than 90 days after the date on which a milestone
applicable to a PM2.5 nonattainment area occurs, each state
in which all or part of such area is located shall submit to the
Administrator a milestone report that contains all of the following:
(1) A certification by the Governor or Governor's designee that the
state's attainment plan control strategy, including the RFP plan, is
being implemented as described in the applicable attainment plan;
(2) A technical demonstration, including calculations, to document
completion statistics for appropriate milestones and to demonstrate
that the quantitative milestones have been satisfied and how the
emission reductions achieved to date compare to those required or
scheduled to meet RFP;
(3) An air quality screening analysis to determine if measured air
quality progress is consistent with the expected air quality
improvement target correlated with the RFP emissions reductions for the
previous 3-year period calculated in accordance with Sec. 51.1012;
(4) An evaluation of whether the area will attain the applicable
PM2.5 NAAQS by the projected attainment date for the area;
and,
(5) A description and schedule for any remedial actions the state
has taken or will take to address any failure to meet a quantitative
milestone, including the implementation status of contingency measures
required under Sec. 51.1014(a)(1)(i) for failing to meet RFP.
(c) In the event a state fails to submit a milestone report that
meets the requirements of paragraph (b) of this section by the due date
or the Administrator determines that the state failed to meet a
milestone by the milestone date, the state shall submit an attainment
plan revision within 9 months of the missed due date or the
Administrator's determination of the state's failure to meet a
milestone that assures that the state will achieve the next milestone
or attain the applicable NAAQS by the applicable date, whichever is
earlier.
Sec. 51.1014 Contingency measure requirements.
(a) The state must include as part of each attainment plan
submitted under this subpart for a PM2.5 nonattainment area
specific contingency measures that shall take effect with minimal
further action by the state or EPA within 60 days of the Administrator
making a determination that the area has failed to meet either of the
following conditions:
(1) The area failed to meet the RFP requirements of Sec. 51.1012
or to submit a milestone report due to EPA in accordance with Sec.
51.1013(b); or,
(2) The area failed to attain the applicable PM2.5 NAAQS
by the applicable attainment date.
(b) The contingency measures adopted as part of a PM2.5
attainment plan shall meet all of the following requirements:
(1) The contingency measures shall consist of control measures that
are not otherwise included in the control strategy for the area.
(2) The contingency measures shall provide for emissions reductions
approximately equivalent to 1 year's worth of reductions needed for
RFP, based on the overall level of reductions needed to demonstrate
attainment divided by the number of years from the base year to the
attainment year, or approximately equivalent to 1 year's worth of air
quality improvement or emissions reductions proportional to the overall
amount of air quality improvement or emissions reductions to be
achieved by the area's attainment plan.
(c) The attainment plan submission shall contain a description of
the specific trigger mechanisms for the contingency measures and
specify a schedule for implementation.
Sec. 51.1015 Clean data requirements.
(a) Nonattainment areas initially classified as Moderate. Upon a
determination by EPA that a Moderate PM2.5 nonattainment
area has attained the PM2.5 NAAQS, the requirements for the
state to submit an attainment demonstration, provisions demonstrating
that reasonably available control measures, including reasonably
available control technology for stationary sources, shall be
implemented no later than 4 years following the date of designation of
the area, reasonable further progress plan, and contingency measures
for the area shall be suspended until such time as:
(1) The area is redesignated to attainment, after which such
requirements are permanently discharged; or,
(2) EPA determines that the area has re-violated the
PM2.5 NAAQS, at which time the state shall submit such
attainment plan elements for the Moderate nonattainment area by a
future date to be determined by EPA and announced through publication
in the Federal Register at the time EPA determines the area is
violating the PM2.5 NAAQS.
(b) Nonattainment areas reclassified as Serious. Upon a
determination by EPA that a Serious PM2.5 nonattainment area
has attained the PM2.5 NAAQS, the requirements for the state
to submit an attainment demonstration, reasonable further progress
plan, and contingency measures for the area shall be suspended until
such time as:
(1) The area is redesignated to attainment, after which such
requirements are permanently discharged; or,
(2) EPA determines that the area has re-violated the
PM2.5 NAAQS, at which time the state shall submit such
attainment plan elements for the Moderate nonattainment area by a
future date to be determined by EPA and announced through publication
in the Federal Register at the time EPA determines the area is
violating the PM2.5 NAAQS.
[ALTERNATIVE PROPOSED REGULATORY TEXT:
(b) Nonattainment areas reclassified as Serious. Upon a
determination by EPA that a Serious PM2.5 nonattainment area
has attained the PM2.5 NAAQS, the requirements for the state
to submit an attainment demonstration, provisions demonstrating that
best available control measures, including best available control
technology for stationary sources, shall be implemented no later than 4
years following the date of reclassification of the area to Serious,
reasonable further progress plan, and contingency measures for the area
shall be suspended until such time as:
(1) The area is redesignated to attainment, after which such
requirements are permanently discharged; or,
(2) EPA determines that the area has re-violated the
PM2.5 NAAQS, at which time the state shall submit such
attainment plan elements for the Serious nonattainment area by a future
date to be determined by EPA and announced through publication in the
Federal Register at the time EPA determines the area is violating the
PM2.5 NAAQS.]
[[Page 15474]]
PART 93--DETERMINING CONFORMITY OF FEDERAL ACTIONS TO STATE OR
FEDERAL IMPLEMENTATION PLANS
0
7. The authority citation for part 93 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
Subpart B--Determining Conformity of General Federal Actions to
State or Federal Implementation Plans
0
8. In Sec. 93.153, revise paragraphs (b)(1) and (2) to read as
follows:
Sec. 93.153 Applicability.
* * * * *
(b) * * *
(1) For purposes of paragraph (b) of this section the following
rates apply in nonattainment areas (NAA's):
------------------------------------------------------------------------
Tons/year
------------------------------------------------------------------------
Ozone (VOC's or NOX):
Serious NAA's..................................... 50
Severe NAA's...................................... 25
Extreme NAA's..................................... 10
Other ozone NAA's outside an ozone transport 100
region...........................................
Other ozone NAA's inside an ozone transport region:
VOC............................................... 50
NOX............................................... 100
Carbon Monoxide: All maintenance areas............ 100
SO2 or NO2: All NAA's............................. 100
PM10:
Moderate NAA's.................................... 100
Serious NAA's..................................... 70
PM2.5 (direct emissions, SO2, NOX, VOC, and ammonia):
Moderate NAA's.................................... 100
Serious NAA's..................................... 70
Pb: All NAA's..................................... 25
------------------------------------------------------------------------
(2) For purposes of paragraph (b) of this section the following
rates apply in maintenance areas:
------------------------------------------------------------------------
Tons/year
------------------------------------------------------------------------
Ozone (NOX, SO2 or NO2):
All maintenance areas............................. 100
Ozone (VOC's):
Maintenance areas inside an ozone transport region 50
Maintenance areas outside an ozone transport 100
region...........................................
Carbon monoxide: All maintenance areas............ 100
PM10: All maintenance areas....................... 100
PM2.5 (direct emissions, SO2, NOX, VOC, and 100
ammonia).........................................
All maintenance areas............................. 100
Pb: All maintenance areas......................... 25
------------------------------------------------------------------------
* * * * *
[FR Doc. 2015-06138 Filed 3-20-15; 8:45 am]
BILLING CODE 6560-50-P