[Title 40 CFR ]
[Code of Federal Regulations (annual edition) - July 1, 2003 Edition]
[From the U.S. Government Printing Office]



[[Page i]]

   

                    40


          Parts 50 to 51

                         Revised as of July 1, 2003

Protection of Environment





          Containing a codification of documents of general 
          applicability and future effect
          As of July 1, 2003
          With Ancillaries
          Published by
          Office of the Federal Register
          National Archives and Records
          Administration

A Special Edition of the Federal Register



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                            Table of Contents



                                                                    Page
  Explanation.................................................       v

  Title 40:
          Chapter I--Environmental Protection Agency                 3
  Finding Aids:
      Material Incorporated by Reference......................     515
      Table of CFR Titles and Chapters........................     517
      Alphabetical List of Agencies Appearing in the CFR......     535
      List of CFR Sections Affected...........................     545



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                     ----------------------------

                     Cite this Code:  CFR
                     To cite the regulations in 
                       this volume use title, 
                       part and section number. 
                       Thus, 40 CFR 50.1 refers 
                       to title 40, part 50, 
                       section 1.

                     ----------------------------

[[Page v]]



                               EXPLANATION

    The Code of Federal Regulations is a codification of the general and 
permanent rules published in the Federal Register by the Executive 
departments and agencies of the Federal Government. The Code is divided 
into 50 titles which represent broad areas subject to Federal 
regulation. Each title is divided into chapters which usually bear the 
name of the issuing agency. Each chapter is further subdivided into 
parts covering specific regulatory areas.
    Each volume of the Code is revised at least once each calendar year 
and issued on a quarterly basis approximately as follows:

Title 1 through Title 16.................................as of January 1
Title 17 through Title 27..................................as of April 1
Title 28 through Title 41...................................as of July 1
Title 42 through Title 50................................as of October 1

    The appropriate revision date is printed on the cover of each 
volume.

LEGAL STATUS

    The contents of the Federal Register are required to be judicially 
noticed (44 U.S.C. 1507). The Code of Federal Regulations is prima facie 
evidence of the text of the original documents (44 U.S.C. 1510).

HOW TO USE THE CODE OF FEDERAL REGULATIONS

    The Code of Federal Regulations is kept up to date by the individual 
issues of the Federal Register. These two publications must be used 
together to determine the latest version of any given rule.
    To determine whether a Code volume has been amended since its 
revision date (in this case, July 1, 2003), consult the ``List of CFR 
Sections Affected (LSA),'' which is issued monthly, and the ``Cumulative 
List of Parts Affected,'' which appears in the Reader Aids section of 
the daily Federal Register. These two lists will identify the Federal 
Register page number of the latest amendment of any given rule.

EFFECTIVE AND EXPIRATION DATES

    Each volume of the Code contains amendments published in the Federal 
Register since the last revision of that volume of the Code. Source 
citations for the regulations are referred to by volume number and page 
number of the Federal Register and date of publication. Publication 
dates and effective dates are usually not the same and care must be 
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Code a note has been inserted to reflect the future effective date. In 
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inserted following the text.

OMB CONTROL NUMBERS

    The Paperwork Reduction Act of 1980 (Pub. L. 96-511) requires 
Federal agencies to display an OMB control number with their information 
collection request.

[[Page vi]]

Many agencies have begun publishing numerous OMB control numbers as 
amendments to existing regulations in the CFR. These OMB numbers are 
placed as close as possible to the applicable recordkeeping or reporting 
requirements.

OBSOLETE PROVISIONS

    Provisions that become obsolete before the revision date stated on 
the cover of each volume are not carried. Code users may find the text 
of provisions in effect on a given date in the past by using the 
appropriate numerical list of sections affected. For the period before 
January 1, 2001, consult either the List of CFR Sections Affected, 1949-
1963, 1964-1972, 1973-1985, or 1986-2000, published in 11 separate 
volumes. For the period beginning January 1, 2001, a ``List of CFR 
Sections Affected'' is published at the end of each CFR volume.

INCORPORATION BY REFERENCE

    What is incorporation by reference? Incorporation by reference was 
established by statute and allows Federal agencies to meet the 
requirement to publish regulations in the Federal Register by referring 
to materials already published elsewhere. For an incorporation to be 
valid, the Director of the Federal Register must approve it. The legal 
effect of incorporation by reference is that the material is treated as 
if it were published in full in the Federal Register (5 U.S.C. 552(a)). 
This material, like any other properly issued regulation, has the force 
of law.
    What is a proper incorporation by reference? The Director of the 
Federal Register will approve an incorporation by reference only when 
the requirements of 1 CFR part 51 are met. Some of the elements on which 
approval is based are:
    (a) The incorporation will substantially reduce the volume of 
material published in the Federal Register.
    (b) The matter incorporated is in fact available to the extent 
necessary to afford fairness and uniformity in the administrative 
process.
    (c) The incorporating document is drafted and submitted for 
publication in accordance with 1 CFR part 51.
    Properly approved incorporations by reference in this volume are 
listed in the Finding Aids at the end of this volume.
    What if the material incorporated by reference cannot be found? If 
you have any problem locating or obtaining a copy of material listed in 
the Finding Aids of this volume as an approved incorporation by 
reference, please contact the agency that issued the regulation 
containing that incorporation. If, after contacting the agency, you find 
the material is not available, please notify the Director of the Federal 
Register, National Archives and Records Administration, Washington DC 
20408, or call (202) 741-6010.

CFR INDEXES AND TABULAR GUIDES

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separate volume, revised annually as of January 1, entitled CFR Index 
and Finding Aids. This volume contains the Parallel Table of Statutory 
Authorities and Agency Rules (Table I). A list of CFR titles, chapters, 
and parts and an alphabetical list of agencies publishing in the CFR are 
also included in this volume.
    An index to the text of ``Title 3--The President'' is carried within 
that volume.
    The Federal Register Index is issued monthly in cumulative form. 
This index is based on a consolidation of the ``Contents'' entries in 
the daily Federal Register.
    A List of CFR Sections Affected (LSA) is published monthly, keyed to 
the revision dates of the 50 CFR titles.

[[Page vii]]


REPUBLICATION OF MATERIAL

    There are no restrictions on the republication of material appearing 
in the Code of Federal Regulations.

INQUIRIES

    For a legal interpretation or explanation of any regulation in this 
volume, contact the issuing agency. The issuing agency's name appears at 
the top of odd-numbered pages.
    For inquiries concerning CFR reference assistance, call 202-741-6000 
or write to the Director, Office of the Federal Register, National 
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                              Raymond A. Mosley,
                                    Director,
                          Office of the Federal Register.

July 1, 2003.



[[Page ix]]



                               THIS TITLE

    Title 40--Protection of Environment is composed of twenty-nine 
volumes. The parts in these volumes are arranged in the following order: 
parts 1-49, parts 50-51, part 52 (52.01-52.1018), part 52 (52.1019-End), 
parts 53-59, part 60 (60.1-End), part 60 (Appendices), parts 61-62, part 
63 (63.1-63.599), part 63 (63.600-1-63.1199), part 63 (63.1200-63.1439), 
part 63 (63.1440-End) parts 64-71, parts 72-80, parts 81-85, part 86 
(86.1-86.599-99) part 86 (86.600-1-End), parts 87-99, parts 100-135, 
parts 136-149, parts 150-189, parts 190-259, parts 260-265, parts 266-
299, parts 300-399, parts 400-424, parts 425-699, parts 700-789, and 
part 790 to End. The contents of these volumes represent all current 
regulations codified under this title of the CFR as of July 1, 2003.

    Chapter I--Environmental Protection Agency appears in all twenty-
nine volumes. An alphabetical Listing of Pesticide Chemicals Index 
appears in parts 150-189. Regulations issued by the Council on 
Environmental Quality appear in the volume containing part 790 to End. 
The OMB control numbers for title 40 appear in Sec. 9.1 of this chapter.

[[Page x]]




[[Page 1]]



                   TITLE 40--PROTECTION OF ENVIRONMENT




                   (This book contains parts 50 to 51)

  --------------------------------------------------------------------
                                                                    Part

chapter i--Environmental Protection Agency (Continued)......          50

[[Page 3]]



         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)




  --------------------------------------------------------------------

                       SUBCHAPTER C--AIR PROGRAMS
Part                                                                Page
50              National primary and secondary ambient air 
                    quality standards.......................           5
51              Requirements for preparation, adoption, and 
                    submittal of implementation plans.......         129

[[Page 5]]



                       SUBCHAPTER C--AIR PROGRAMS





PART 50--NATIONAL PRIMARY AND SECONDARY AMBIENT AIR QUALITY STANDARDS--Table 
of Contents




Sec.
50.1  Definitions.
50.2  Scope.
50.3  Reference conditions.
50.4  National primary ambient air quality standards for sulfur oxides 
          (sulfur dioxide).
50.5  National secondary ambient air quality standard for sulfur oxides 
          (sulfur dioxide).
50.6  National primary and secondary ambient air quality standards for 
          PM10.
50.7  National primary and secondary ambient air quality standards for 
          particulate matter.
50.8  National primary ambient air quality standards for carbon 
          monoxide.
50.9  National 1-hour primary and secondary ambient air quality 
          standards for ozone.
50.10  National 8-hour primary and secondary ambient air quality 
          standards for ozone.
50.11  National primary and secondary ambient air quality standards for 
          nitrogen dioxide.
50.12  National primary and secondary ambient air quality standards for 
          lead.

Appendix A to Part 50--Reference Method for the Determination of Sulfur 
          Dioxide in the Atmosphere (Pararosaniline Method)
Appendix B to Part 50--Reference Method for the Determination of 
          Suspended Particulate Matter in the Atmosphere (High-Volume 
          Method)
Appendix C to Part 50--Measurement Principle and Calibration Procedure 
          for the Measurement of Carbon Monoxide in the Atmosphere (Non-
          Dispersive Infrared Photometry)
Appendix D to Part 50--Measurement Principle and Calibration Procedure 
          for the Measurement of Ozone in the Atmosphere
Appendix E to Part 50 [Reserved]
Appendix F to Part 50--Measurement Principle and Calibration Procedure 
          for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas 
          Phase Chemiluminescence)
Appendix G to Part 50--Reference Method for the Determination of Lead in 
          Suspended Particulate Matter Collected From Ambient Air
Appendix H to Part 50--Interpretation of the 1-Hour Primary and 
          Secondary National Ambient Air Quality Standards for Ozone
Appendix I to Part 50--Interpretation of the 8-Hour Primary and 
          Secondary National Ambient Air Quality Standards for Ozone
Appendix J to Part 50--Reference Method for the Determination of 
          Particulate Matter as PM10 in the Atmosphere
Appendix K to Part 50--Interpretation of the National Ambient Air 
          Quality Standards for Particulate Matter
Appendix L to Part 50--Reference Method for the Determination of Fine 
          Particulate Matter as PM2.5 in the Atmosphere
Appendix M to Part 50--Reference Method for the Determination of 
          Particulate Matter as PM10 in the Atmosphere
Appendix N to Part 50--Interpretation of the National Ambient Air 
          Quality Standards for Particulate Matter

    Authority: 42 U.S.C. 7401, et seq.

    Source: 36 FR 22384, Nov. 25, 1971, unless otherwise noted.



Sec. 50.1  Definitions.

    (a) As used in this part, all terms not defined herein shall have 
the meaning given them by the Act.
    (b) Act means the Clean Air Act, as amended (42 U.S.C. 1857-18571, 
as amended by Pub. L. 91-604).
    (c) Agency means the Environmental Protection Agency.
    (d) Administrator means the Administrator of the Environmental 
Protection Agency.
    (e) Ambient air means that portion of the atmosphere, external to 
buildings, to which the general public has access.
    (f) Reference method means a method of sampling and analyzing the 
ambient air for an air pollutant that is specified as a reference method 
in an appendix to this part, or a method that has been designated as a 
reference method in accordance with part 53 of this chapter; it does not 
include a method for which a reference method designation has been 
cancelled in accordance with Sec. 53.11 or Sec. 53.16 of this chapter.
    (g) Equivalent method means a method of sampling and analyzing the 
ambient air for an air pollutant that has been designated as an 
equivalent method in accordance with part 53 of this chapter; it does 
not include a method for which an equivalent method designation has

[[Page 6]]

been cancelled in accordance with Sec. 53.11 or Sec. 53.16 of this 
chapter.
    (h) Traceable means that a local standard has been compared and 
certified either directly or via not more than one intermediate 
standard, to a primary standard such as a National Bureau of Standards 
Standard Reference Material (NBS SRM), or a USEPA/NBS-approved Certified 
Reference Material (CRM).
    (i) Indian country is as defined in 18 U.S.C. 1151.

[36 FR 22384, Nov. 25, 1971, as amended at 41 FR 11253, Mar. 17, 1976; 
48 FR 2529, Jan. 20, 1983; 63 FR 7274, Feb. 12, 1998]



Sec. 50.2  Scope.

    (a) National primary and secondary ambient air quality standards 
under section 109 of the Act are set forth in this part.
    (b) National primary ambient air quality standards define levels of 
air quality which the Administrator judges are necessary, with an 
adequate margin of safety, to protect the public health. National 
secondary ambient air quality standards define levels of air quality 
which the Administrator judges necessary to protect the public welfare 
from any known or anticipated adverse effects of a pollutant. Such 
standards are subject to revision, and additional primary and secondary 
standards may be promulgated as the Administrator deems necessary to 
protect the public health and welfare.
    (c) The promulgation of national primary and secondary ambient air 
quality standards shall not be considered in any manner to allow 
significant deterioration of existing air quality in any portion of any 
State or Indian country.
    (d) The proposal, promulgation, or revision of national primary and 
secondary ambient air quality standards shall not prohibit any State or 
Indian country from establishing ambient air quality standards for that 
State or area under a tribal CAA program or any portion thereof which 
are more stringent than the national standards.

[36 FR 22384, Nov. 25, 1971, as amended at 63 FR 7274, Feb. 12, 1998]



Sec. 50.3   Reference conditions.

    All measurements of air quality that are expressed as mass per unit 
volume (e.g., micrograms per cubic meter) other than for the particulate 
matter (PM10 and PM2.5) standards contained in 
Sec. 50.7 shall be corrected to a reference temperature of 25  deg.C and 
a reference pressure of 760 millimeters of mercury (1,013.2 millibars). 
Measurements of PM10 and PM2.5 for purposes of 
comparison to the standards contained in Sec. 50.7 shall be reported 
based on actual ambient air volume measured at the actual ambient 
temperature and pressure at the monitoring site during the measurement 
period.

[62 FR 38711, July 18, 1997]



Sec. 50.4  National primary ambient air quality standards for sulfur oxides 
(sulfur dioxide).

    (a) The level of the annual standard is 0.030 parts per million 
(ppm), not to be exceeded in a calendar year. The annual arithmetic mean 
shall be rounded to three decimal places (fractional parts equal to or 
greater than 0.0005 ppm shall be rounded up).
    (b) The level of the 24-hour standard is 0.14 parts per million 
(ppm), not to be exceeded more than once per calendar year. The 24-hour 
averages shall be determined from successive nonoverlapping 24-hour 
blocks starting at midnight each calendar day and shall be rounded to 
two decimal places (fractional parts equal to or greater than 0.005 ppm 
shall be rounded up).
    (c) Sulfur oxides shall be measured in the ambient air as sulfur 
dioxide by the reference method described in appendix A to this part or 
by an equivalent method designated in accordance with part 53 of this 
chapter.
    (d) To demonstrate attainment, the annual arithmetic mean and the 
second-highest 24-hour averages must be based upon hourly data that are 
at least 75 percent complete in each calendar quarter. A 24-hour block 
average shall be considered valid if at least 75 percent of the hourly 
averages for the 24-hour period are available. In the event that only 
18, 19, 20, 21, 22, or 23 hourly averages are available, the 24-hour 
block average shall be computed as the sum of the available hourly

[[Page 7]]

averages using 18, 19, etc. as the divisor. If fewer than 18 hourly 
averages are available, but the 24-hour average would exceed the level 
of the standard when zeros are substituted for the missing values, 
subject to the rounding rule of paragraph (b) of this section, then this 
shall be considered a valid 24-hour average. In this case, the 24-hour 
block average shall be computed as the sum of the available hourly 
averages divided by 24.

[61 FR 25579, May 22, 1996]



Sec. 50.5  National secondary ambient air quality standard for sulfur oxides 
(sulfur dioxide).

    (a) The level of the 3-hour standard is 0.5 parts per million (ppm), 
not to be exceeded more than once per calendar year. The 3-hour averages 
shall be determined from successive nonoverlapping 3-hour blocks 
starting at midnight each calendar day and shall be rounded to 1 decimal 
place (fractional parts equal to or greater than 0.05 ppm shall be 
rounded up).
    (b) Sulfur oxides shall be measured in the ambient air as sulfur 
dioxide by the reference method described in appendix A of this part or 
by an equivalent method designated in accordance with part 53 of this 
chapter.
    (c) To demonstrate attainment, the second-highest 3-hour average 
must be based upon hourly data that are at least 75 percent complete in 
each calendar quarter. A 3-hour block average shall be considered valid 
only if all three hourly averages for the 3-hour period are available. 
If only one or two hourly averages are available, but the 3-hour average 
would exceed the level of the standard when zeros are substituted for 
the missing values, subject to the rounding rule of paragraph (a) of 
this section, then this shall be considered a valid 3-hour average. In 
all cases, the 3-hour block average shall be computed as the sum of the 
hourly averages divided by 3.

[61 FR 25580, May 22, 1996]



Sec. 50.6   National primary and secondary ambient air quality standards for 
PM10.

    (a) The level of the national primary and secondary 24-hour ambient 
air quality standards for particulate matter is 150 micrograms per cubic 
meter ([mu]g/m\3\), 24-hour average concentration. The standards are 
attained when the expected number of days per calendar year with a 24-
hour average concentration above 150 [mu]g/m\3\, as determined in 
accordance with appendix K to this part, is equal to or less than one.
    (b) The level of the national primary and secondary annual standards 
for particulate matter is 50 micrograms per cubic meter ([mu]g/m\3\), 
annual arithmetic mean. The standards are attained when the expected 
annual arithmetic mean concentration, as determined in accordance with 
appendix K to this part, is less than or equal to 50 [mu]g/m\3\.
    (c) For the purpose of determining attainment of the primary and 
secondary standards, particulate matter shall be measured in the ambient 
air as PM10 (particles with an aerodynamic diameter less than 
or equal to a nominal 10 micrometers) by:
    (1) A reference method based on appendix J and designated in 
accordance with part 53 of this chapter, or
    (2) An equivalent method designated in accordance with part 53 of 
this chapter.

[52 FR 24663, July 1, 1987, as amended at 62 FR 38711, July 18, 1997; 65 
FR 80779, Dec. 22, 2000]



Sec. 50.7   National primary and secondary ambient air quality standards 
for particulate matter.

    (a) The national primary and secondary ambient air quality standards 
for particulate matter are:
    (1) 15.0 micrograms per cubic meter ([mu]g/m\3\) annual arithmetic 
mean concentration, and 65 [mu]g/m\3\ 24-hour average concentration 
measured in the ambient air as PM2.5 (particles with an 
aerodynamic diameter less than or equal to a nominal 2.5 micrometers) by 
either:
    (i) A reference method based on appendix L of this part and 
designated in accordance with part 53 of this chapter; or
    (ii) An equivalent method designated in accordance with part 53 of 
this chapter.

[[Page 8]]

    (2) 50 micrograms per cubic meter ([mu]g/m\3\) annual arithmetic 
mean concentration, and 150 [mu]g/m\3\ 24-hour average concentration 
measured in the ambient air as PM10 (particles with an 
aerodynamic diameter less than or equal to a nominal 10 micrometers) by 
either:
    (i) A reference method based on appendix M of this part and 
designated in accordance with part 53 of this chapter; or
    (ii) An equivalent method designated in accordance with part 53 of 
this chapter.
    (b) The annual primary and secondary PM2.5 standards are 
met when the annual arithmetic mean concentration, as determined in 
accordance with appendix N of this part, is less than or equal to 15.0 
micrograms per cubic meter.
    (c) The 24-hour primary and secondary PM2.5 standards are 
met when the 98th percentile 24-hour concentration, as 
determined in accordance with appendix N of this part, is less than or 
equal to 65 micrograms per cubic meter.
    (d) The annual primary and secondary PM10 standards are 
met when the annual arithmetic mean concentration, as determined in 
accordance with appendix N of this part, is less than or equal to 50 
micrograms per cubic meter.
    (e) The 24-hour primary and secondary PM10 standards are 
met when the 99th percentile 24-hour concentration, as 
determined in accordance with appendix N of this part, is less than or 
equal to 150 micrograms per cubic meter.

[62 FR 38711, July 18, 1997]



Sec. 50.8  National primary ambient air quality standards for carbon monoxide.

    (a) The national primary ambient air quality standards for carbon 
monoxide are:
    (1) 9 parts per million (10 milligrams per cubic meter) for an 8-
hour average concentration not to be exceeded more than once per year 
and
    (2) 35 parts per million (40 milligrams per cubic meter) for a 1-
hour average concentration not to be exceeded more than once per year.
    (b) The levels of carbon monoxide in the ambient air shall be 
measured by:
    (1) A reference method based on appendix C and designated in 
accordance with part 53 of this chapter, or
    (2) An equivalent method designated in accordance with part 53 of 
this chapter.
    (c) An 8-hour average shall be considered valid if at least 75 
percent of the hourly average for the 8-hour period are available. In 
the event that only six (or seven) hourly averages are available, the 8-
hour average shall be computed on the basis of the hours available using 
six (or seven) as the divisor.
    (d) When summarizing data for comparision with the standards, 
averages shall be stated to one decimal place. Comparison of the data 
with the levels of the standards in parts per million shall be made in 
terms of integers with fractional parts of 0.5 or greater rounding up.

[50 FR 37501, Sept. 13, 1985]



Sec. 50.9   National 1-hour primary and secondary ambient air quality 
standards for ozone.

    (a) The level of the national 1-hour primary and secondary ambient 
air quality standards for ozone measured by a reference method based on 
appendix D to this part and designated in accordance with part 53 of 
this chapter, is 0.12 parts per million (235 [mu]g/m\3\). The standard 
is attained when the expected number of days per calendar year with 
maximum hourly average concentrations above 0.12 parts per million (235 
[mu]g/m\3\) is equal to or less than 1, as determined by appendix H to 
this part.
    (b) The 1-hour standards set forth in this section will remain 
applicable to all areas notwithstanding the promulgation of 8-hour ozone 
standards under Sec. 50.10. In addition, after the 8-hour standard has 
become fully enforceable under part D of title I of the CAA and subject 
to no further legal challenge, the 1-hour standards set forth in this 
section will no longer apply to an area once EPA determines that the 
area has

[[Page 9]]

air quality meeting the 1-hour standard. Area designations and 
classifications with respect to the 1-hour standards are codified in 40 
CFR part 81.

[62 FR 38894, July 18, 1997, as amended at 65 FR 45200, July 20, 2000]

    Effective Date Note: At 68 FR 38163, June 26, 2003, Sec. 50.9 was 
amended by adding paragraph (c), effective August 25, 2003. For the 
convenience of the user, the added text is set forth as follows.

Sec.  50.9  National 1-hour primary and secondary ambient air quality 
          standards for ozone.

                                * * * * *

    (c) EPA's authority under paragraph (b) of this section to determine 
that the 1-hour standard no longer applies to an area based on a 
determination that the area has attained the 1-hour standard is stayed 
until such time as EPA issues a final rule revising or reinstating such 
authority and considers and addresses in such rulemaking any comments 
concerning (1) which, if any, implementation activities for a revised 
ozone standard (including but not limited to designation and 
classification of areas) would need to occur before EPA would determine 
that the 1-hour ozone standard no longer applies to an area, and (2) the 
effect of revising the ozone NAAQS on the existing 1-hour ozone 
designations.



Sec. 50.10   National 8-hour primary and secondary ambient air quality 
standards for ozone.

    (a) The level of the national 8-hour primary and secondary ambient 
air quality standards for ozone, measured by a reference method based on 
appendix D to this part and designated in accordance with part 53 of 
this chapter, is 0.08 parts per million (ppm), daily maximum 8-hour 
average.
    (b) The 8-hour primary and secondary ozone ambient air quality 
standards are met at an ambient air quality monitoring site when the 
average of the annual fourth-highest daily maximum 8-hour average ozone 
concentration is less than or equal to 0.08 ppm, as determined in 
accordance with appendix I to this part.

[62 FR 38894, July 18, 1997]



Sec. 50.11  National primary and secondary ambient air quality standards for 
nitrogen dioxide.

    (a) The level of the national primary ambient air quality standard 
for nitrogen dioxide is 0.053 parts per million (100 micrograms per 
cubic meter), annual arithmetic mean concentration.
    (b) The level of national secondary ambient air quality standard for 
nitrogen dioxide is 0.053 parts per million (100 micrograms per cubic 
meter), annual arithmetic mean concentration.
    (c) The levels of the standards shall be measured by:
    (1) A reference method based on appendix F and designated in 
accordance with part 53 of this chapter, or
    (2) An equivalent method designated in accordance with part 53 of 
this chapter.
    (d) The standards are attained when the annual arithmetic mean 
concentration in a calendar year is less than or equal to 0.053 ppm, 
rounded to three decimal places (fractional parts equal to or greater 
than 0.0005 ppm must be rounded up). To demonstrate attainment, an 
annual mean must be based upon hourly data that are at least 75 percent 
complete or upon data derived from manual methods that are at least 75 
percent complete for the scheduled sampling days in each calendar 
quarter.

[50 FR 25544, June 19, 1985]



Sec. 50.12  National primary and secondary ambient air quality standards 
for lead.

    National primary and secondary ambient air quality standards for 
lead and its compounds, measured as elemental lead by a reference method 
based on appendix G to this part, or by an equivalent method, are: 1.5 
micrograms per cubic meter, maximum arithmetic mean averaged over a 
calendar quarter.

(Secs. 109, 301(a) Clean Air Act as amended (42 U.S.C. 7409, 7601(a)))

[43 FR 46258, Oct. 5, 1978]

Appendix A to Part 50--Reference Method for the Determination of Sulfur 
            Dioxide in the Atmosphere (Pararosaniline Method)

    1.0 Applicability.

[[Page 10]]

    1.1 This method provides a measurement of the concentration of 
sulfur dioxide (SO2) in ambient air for determining 
compliance with the primary and secondary national ambient air quality 
standards for sulfur oxides (sulfur dioxide) as specified in Sec. 50.4 
and Sec. 50.5 of this chapter. The method is applicable to the 
measurement of ambient SO2 concentrations using sampling 
periods ranging from 30 minutes to 24 hours. Additional quality 
assurance procedures and guidance are provided in part 58, appendixes A 
and B, of this chapter and in references 1 and 2.
    2.0 Principle.
    2.1 A measured volume of air is bubbled through a solution of 0.04 M 
potassium tetrachloromercurate (TCM). The SO2 present in the 
air stream reacts with the TCM solution to form a stable 
monochlorosulfonatomercurate(3) complex. Once formed, this complex 
resists air oxidation(4, 5) and is stable in the presence of strong 
oxidants such as ozone and oxides of nitrogen. During subsequent 
analysis, the complex is reacted with acid-bleached pararosaniline dye 
and formaldehyde to form an intensely colored pararosaniline methyl 
sulfonic acid.(6) The optical density of this species is determined 
spectrophotometrically at 548 nm and is directly related to the amount 
of SO2 collected. The total volume of air sampled, corrected 
to EPA reference conditions (25  deg.C, 760 mm Hg [101 kPa]), is 
determined from the measured flow rate and the sampling time. The 
concentration of SO2 in the ambient air is computed and 
expressed in micrograms per standard cubic meter ([mu]g/std m\3\).
    3.0 Range.
    3.1 The lower limit of detection of SO2 in 10 mL of TCM 
is 0.75 [mu]g (based on collaborative test results).(7) This represents 
a concentration of 25 [mu]g SO2/m\3\ (0.01 ppm) in an air 
sample of 30 standard liters (short-term sampling) and a concentration 
of 13 [mu]g SO2/m\3\ (0.005 ppm) in an air sample of 288 
standard liters (long-term sampling). Concentrations less than 25 [mu]g 
SO2/m\3\ can be measured by sampling larger volumes of 
ambient air; however, the collection efficiency falls off rapidly at low 
concentrations.(8, 9) Beer's law is adhered to up to 34 [mu]g of 
SO2 in 25 mL of final solution. This upper limit of the 
analysis range represents a concentration of 1,130 [mu]g SO2/
m\3\ (0.43 ppm) in an air sample of 30 standard liters and a 
concentration of 590 [mu]g SO2/m\3\ (0.23 ppm) in an air 
sample of 288 standard liters. Higher concentrations can be measured by 
collecting a smaller volume of air, by increasing the volume of 
absorbing solution, or by diluting a suitable portion of the collected 
sample with absorbing solution prior to analysis.
    4.0 Interferences.
    4.1 The effects of the principal potential interferences have been 
minimized or eliminated in the following manner: Nitrogen oxides by the 
addition of sulfamic acid,(10, 11) heavy metals by the addition of 
ethylenediamine tetracetic acid disodium salt (EDTA) and phosphoric 
acid,(10, 12) and ozone by time delay.(10) Up to 60 [mu]g Fe (III), 22 
[mu]g V (V), 10 [mu]g Cu (II), 10 [mu]g Mn (II), and 10 [mu]g Cr (III) 
in 10 mL absorbing reagent can be tolerated in the procedure.(10) No 
significant interference has been encountered with 2.3 [mu]g 
NH3.(13)
    5.0 Precision and Accuracy.
    5.1 The precision of the analysis is 4.6 percent (at the 95 percent 
confidence level) based on the analysis of standard sulfite samples.(10)
    5.2 Collaborative test results (14) based on the analysis of 
synthetic test atmospheres (SO2 in scrubbed air) using the 
24-hour sampling procedure and the sulfite-TCM calibration procedure 
show that:

 The replication error varies linearly with concentration from 
2.5 [mu]g/m\3\ at concentrations of 100 [mu]g/m\3\ to 
7 [mu]g/m\3\ at concentrations of 400 [mu]g/m\3\.
 The day-to-day variability within an individual laboratory 
(repeatability) varies linearly with concentration from 18.1 
[mu]g/m\3\ at levels of 100 [mu]g/m\3\ to 50.9 [mu]g/m\3\ at 
levels of 400 [mu]g/m\3\.
 The day-to-day variability between two or more laboratories 
(reproducibility) varies linearly with concentration from 
36.9 [mu]g/m\3\ at levels of 100 [mu]g/m\3\ to 
103.5 [mu] g/m\3\ at levels of 400 [mu]g/m\3\.
 The method has a concentration-dependent bias, which becomes 
significant at the 95 percent confidence level at the high concentration 
level. Observed values tend to be lower than the expected SO2 
concentration level.

    6.0 Stability.
    6.1 By sampling in a controlled temperature environment of 
15 deg.10  deg.C, greater than 98.9 percent of the 
SO2-TCM complex is retained at the completion of sampling. 
(15) If kept at 5  deg.C following the completion of sampling, the 
collected sample has been found to be stable for up to 30 days.(10) The 
presence of EDTA enhances the stability of SO2 in the TCM 
solution and the rate of decay is independent of the concentration of 
SO2.(16)
    7.0 Apparatus.
    7.1 Sampling.
    7.1.1 Sample probe: A sample probe meeting the requirements of 
section 7 of 40 CFR part 58, appendix E (Teflon[reg] or glass with 
residence time less than 20 sec.) is used to transport ambient air to 
the sampling train location. The end of the probe should be designed or 
oriented to preclude the sampling of precipitation, large particles, 
etc. A suitable probe can be constructed from Teflon[reg] tubing 
connected to an inverted funnel.
    7.1.2 Absorber--short-term sampling: An all glass midget impinger 
having a solution capacity of 30 mL and a stem clearance of 
41

[[Page 11]]

mm from the bottom of the vessel is used for sampling periods of 30 
minutes and 1 hour (or any period considerably less than 24 hours). Such 
an impinger is shown in Figure 1. These impingers are commercially 
available from distributors such as Ace Glass, Incorporated.
    7.1.3 Absorber--24-hour sampling: A polypropylene tube 32 mm in 
diameter and 164 mm long (available from Bel Art Products, Pequammock, 
NJ) is used as the absorber. The cap of the absorber must be a 
polypropylene cap with two ports (rubber stoppers are unacceptable 
because the absorbing reagent can react with the stopper to yield 
erroneously high SO2 concentrations). A glass impinger stem, 
6 mm in diameter and 158 mm long, is inserted into one port of the 
absorber cap. The tip of the stem is tapered to a small diameter orifice 
(0.40.1 mm) such that a No. 79 jeweler's drill bit will pass 
through the opening but a No. 78 drill bit will not. Clearance from the 
bottom of the absorber to the tip of the stem must be 62 mm. 
Glass stems can be fabricated by any reputable glass blower or can be 
obtained from a scientific supply firm. Upon receipt, the orifice test 
should be performed to verify the orifice size. The 50 mL volume level 
should be permanently marked on the absorber. The assembled absorber is 
shown in Figure 2.
    7.1.4 Moisture trap: A moisture trap constructed of a glass trap as 
shown in Figure 1 or a polypropylene tube as shown in Figure 2 is placed 
between the absorber tube and flow control device to prevent entrained 
liquid from reaching the flow control device. The tube is packed with 
indicating silica gel as shown in Figure 2. Glass wool may be 
substituted for silica gel when collecting short-term samples (1 hour or 
less) as shown in Figure 1, or for long term (24 hour) samples if flow 
changes are not routinely encountered.
    7.1.5 Cap seals: The absorber and moisture trap caps must seal 
securely to prevent leaks during use. Heat-shrink material as shown in 
Figure 2 can be used to retain the cap seals if there is any chance of 
the caps coming loose during sampling, shipment, or storage.

[[Page 12]]




[[Page 13]]





[[Page 14]]


    7.1.6 Flow control device: A calibrated rotameter and needle valve 
combination capable of maintaining and measuring air flow to within 
2 percent is suitable for short-term sampling but may not be 
used for long-term sampling. A critical orifice can be used for 
regulating flow rate for both long-term and short-term sampling. A 22-
gauge hypodermic needle 25 mm long may be used as a critical orifice to 
yield a flow rate of approximately 1 L/min for a 30-minute sampling 
period. When sampling for 1 hour, a 23-gauge hypodermic needle 16 mm in 
length will provide a flow rate of approximately 0.5 L/min. Flow control 
for a 24-hour sample may be provided by a 27-gauge hypodermic needle 
critical orifice that is 9.5 mm in length. The flow rate should be in 
the range of 0.18 to 0.22 L/min.
    7.1.7 Flow measurement device: Device calibrated as specified in 
9.4.1 and used to measure sample flow rate at the monitoring site.
    7.1.8 Membrane particle filter: A membrane filter of 0.8 to 2 [mu]m 
porosity is used to protect the flow controller from particles during 
long-term sampling. This item is optional for short-term sampling.
    7.1.9 Vacuum pump: A vacuum pump equipped with a vacuum gauge and 
capable of maintaining at least 70 kPa (0.7 atm) vacuum differential 
across the flow control device at the specified flow rate is required 
for sampling.
    7.1.10 Temperature control device: The temperature of the absorbing 
solution during sampling must be maintained at 15 deg. 10 
deg.C. As soon as possible following sampling and until analysis, the 
temperature of the collected sample must be maintained at 5 deg. 
5  deg.C. Where an extended period of time may elapse before 
the collected sample can be moved to the lower storage temperature, a 
collection temperature near the lower limit of the 15  10 
deg.C range should be used to minimize losses during this period. 
Thermoelectric coolers specifically designed for this temperature 
control are available commercially and normally operate in the range of 
5 deg. to 15  deg.C. Small refrigerators can be modified to provide the 
required temperature control; however, inlet lines must be insulated 
from the lower temperatures to prevent condensation when sampling under 
humid conditions. A small heating pad may be necessary when sampling at 
low temperatures (<7  deg.C) to prevent the absorbing solution from 
freezing.(17)
    7.1.11 Sampling train container: The absorbing solution must be 
shielded from light during and after sampling. Most commercially 
available sampler trains are enclosed in a light-proof box.
    7.1.12 Timer: A timer is recommended to initiate and to stop 
sampling for the 24-hour period. The timer is not a required piece of 
equipment; however, without the timer a technician would be required to 
start and stop the sampling manually. An elapsed time meter is also 
recommended to determine the duration of the sampling period.
    7.2 Shipping.
    7.2.1 Shipping container: A shipping container that can maintain a 
temperature of 5 deg. 5  deg.C is used for transporting the 
sample from the collection site to the analytical laboratory. Ice 
coolers or refrigerated shipping containers have been found to be 
satisfactory. The use of eutectic cold packs instead of ice will give a 
more stable temperature control. Such equipment is available from Cole-
Parmer Company, 7425 North Oak Park Avenue, Chicago, IL 60648.
    7.3 Analysis.
    7.3.1 Spectrophotometer: A spectrophotometer suitable for 
measurement of absorbances at 548 nm with an effective spectral 
bandwidth of less than 15 nm is required for analysis. If the 
spectrophotometer reads out in transmittance, convert to absorbance as 
follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.000

where:

A = absorbance, and
T = transmittance (0<[gE]T<1).

    A standard wavelength filter traceable to the National Bureau of 
Standards is used to verify the wavelength calibration according to the 
procedure enclosed with the filter. The wavelength calibration must be 
verified upon initial receipt of the instrument and after each 160 hours 
of normal use or every 6 months, whichever occurs first.
    7.3.2 Spectrophotometer cells: A set of 1-cm path length cells 
suitable for use in the visible region is used during analysis. If the 
cells are unmatched, a matching correction factor must be determined 
according to Section 10.1.
    7.3.3 Temperature control device: The color development step during 
analysis must be conducted in an environment that is in the range of 
20 deg. to 30  deg.C and controlled to 1  deg.C. Both 
calibration and sample analysis must be performed under identical 
conditions (within 1  deg.C). Adequate temperature control may be 
obtained by means of constant temperature baths, water baths with manual 
temperature control, or temperature controlled rooms.
    7.3.4 Glassware: Class A volumetric glassware of various capacities 
is required for preparing and standardizing reagents and standards and 
for dispensing solutions during analysis. These included pipets, 
volumetric flasks, and burets.
    7.3.5 TCM waste receptacle: A glass waste receptacle is required for 
the storage of spent TCM solution. This vessel should be stoppered and 
stored in a hood at all times.
    8.0 Reagents.
    8.1 Sampling.

[[Page 15]]

    8.1.1 Distilled water: Purity of distilled water must be verified by 
the following procedure:(18)
 Place 0.20 mL of potassium permanganate solution (0.316 g/L), 
500 mL of distilled water, and 1mL of concentrated sulfuric acid in a 
chemically resistant glass bottle, stopper the bottle, and allow to 
stand.
 If the permanganate color (pink) does not disappear completely 
after a period of 1 hour at room temperature, the water is suitable for 
use.
 If the permanganate color does disappear, the water can be 
purified by redistilling with one crystal each of barium hydroxide and 
potassium permanganate in an all glass still.

    8.1.2 Absorbing reagent (0.04 M potassium tetrachloromercurate 
[TCM]): Dissolve 10.86 g mercuric chloride, 0.066 g EDTA, and 6.0 g 
potassium chloride in distilled water and dilute to volume with 
distilled water in a 1,000-mL volumetric flask. (Caution: Mercuric 
chloride is highly poisonous. If spilled on skin, flush with water 
immediately.) The pH of this reagent should be between 3.0 and 5.0 (10) 
Check the pH of the absorbing solution by using pH indicating paper or a 
pH meter. If the pH of the solution is not between 3.0 and 5.0, dispose 
of the solution according to one of the disposal techniques described in 
Section 13.0. The absorbing reagent is normally stable for 6 months. If 
a precipitate forms, dispose of the reagent according to one of the 
procedures described in Section 13.0.
    8.2 Analysis.
    8.2.1 Sulfamic acid (0.6%): Dissolve 0.6 g sulfamic acid in 100 mL 
distilled water. Perpare fresh daily.
    8.2.2 Formaldehyde (0.2%): Dilute 5 mL formaldehyde solution (36 to 
38 percent) to 1,000 mL with distilled water. Prepare fresh daily.
    8.2.3 Stock iodine solution (0.1 N): Place 12.7 g resublimed iodine 
in a 250-mL beaker and add 40 g potassium iodide and 25 mL water. Stir 
until dissolved, transfer to a 1,000 mL volumetric flask and dilute to 
volume with distilled water.
    8.2.4 Iodine solution (0.01 N): Prepare approximately 0.01 N iodine 
solution by diluting 50 mL of stock iodine solution (Section 8.2.3) to 
500 mL with distilled water.
    8.2.5 Starch indicator solution: Triturate 0.4 g soluble starch and 
0.002 g mercuric iodide (preservative) with enough distilled water to 
form a paste. Add the paste slowly to 200 mL of boiling distilled water 
and continue boiling until clear. Cool and transfer the solution to a 
glass stopperd bottle.
    8.2.6 1 N hydrochloric acid: Slowly and while stirring, add 86 mL of 
concentrated hydrochloric acid to 500 mL of distilled water. Allow to 
cool and dilute to 1,000 mL with distilled water.
    8.2.7 Potassium iodate solution: Accurately weigh to the nearest 0.1 
mg, 1.5 g (record weight) of primary standard grade potassium iodate 
that has been previously dried at 180  deg.C for at least 3 hours and 
cooled in a dessicator. Dissolve, then dilute to volume in a 500-mL 
volumetric flask with distilled water.
    8.2.8 Stock sodium thiosulfate solution (0.1 N): Prepare a stock 
solution by dissolving 25 g sodium thiosulfate (Na2 
S2 O3/5H2 O) in 1,000 mL freshly 
boiled, cooled, distilled water and adding 0.1 g sodium carbonate to the 
solution. Allow the solution to stand at least 1 day before 
standardizing. To standardize, accurately pipet 50 mL of potassium 
iodate solution (Section 8.2.7) into a 500-mL iodine flask and add 2.0 g 
of potassium iodide and 10 mL of 1 N HCl. Stopper the flask and allow to 
stand for 5 minutes. Titrate the solution with stock sodium thiosulfate 
solution (Section 8.2.8) to a pale yellow color. Add 5 mL of starch 
solution (Section 8.2.5) and titrate until the blue color just 
disappears. Calculate the normality (Ns) of the stock sodium 
thiosulfate solution as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.001

where:

M = volume of thiosulfate required in mL, and
W = weight of potassium iodate in g (recorded weight in Section 8.2.7).
[GRAPHIC] [TIFF OMITTED] TC08NO91.002

    8.2.9  Working sodium thiosulfate titrant (0.01 N): Accurately pipet 
100 mL of stock sodium thiosulfate solution (Section 8.2.8) into a 
1,000-mL volumetric flask and dilute to volume with freshly boiled, 
cooled, distilled water. Calculate the normality of the working sodium 
thiosulfate titrant (NT) as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.003

    8.2.10 Standardized sulfite solution for the preparation of working 
sulfite-TCM solution: Dissolve 0.30 g sodium metabisulfite 
(Na2 S2 O5) or 0.40 g sodium sulfite 
(Na2 SO3) in 500 mL of recently boiled, cooled, 
distilled water. (Sulfite solution is unstable; it is therefore 
important to use water of the highest purity to minimize this 
instability.) This solution contains the equivalent of 320 to 400 [mu]g 
SO2/mL. The actual concentration of the solution is 
determined by adding excess iodine and back-titrating with standard 
sodium thiosulfate solution. To back-titrate, pipet 50 mL of the 0.01 N 
iodine solution (Section 8.2.4) into each of two 500-mL iodine flasks (A 
and B). To flask A (blank) add 25 mL distilled water, and to flask B 
(sample)

[[Page 16]]

pipet 25 mL sulfite solution. Stopper the flasks and allow to stand for 
5 minutes. Prepare the working sulfite-TCM solution (Section 8.2.11) 
immediately prior to adding the iodine solution to the flasks. Using a 
buret containing standardized 0.01 N thiosulfate titrant (Section 
8.2.9), titrate the solution in each flask to a pale yellow color. Then 
add 5 mL starch solution (Section 8.2.5) and continue the titration 
until the blue color just disappears.
    8.2.11 Working sulfite-TCM solution: Accurately pipet 5 mL of the 
standard sulfite solution (Section 8.2.10) into a 250-mL volumetric 
flask and dilute to volume with 0.04 M TCM. Calculate the concentration 
of sulfur dioxide in the working solution as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.004

where:

A = volume of thiosulfate titrant required for the blank, mL;
B = volume of thiosulfate titrant required for the sample, mL;
NT = normality of the thiosulfate titrant, from equation (3);
32,000 = milliequivalent weight of SO2, [mu]g;
25 = volume of standard sulfite solution, mL; and
0.02 = dilution factor.

    This solution is stable for 30 days if kept at 5  deg.C. (16) If not 
kept at 5  deg.C, prepare fresh daily.
    8.2.12 Purified pararosaniline (PRA) stock solution (0.2% nominal):
    8.2.12.1 Dye specifications--

 The dye must have a maximum absorbance at a wavelength of 540 
nm when assayed in a buffered solution of 0.1 M sodium acetate-acetic 
acid;
 The absorbance of the reagent blank, which is temperature 
sensitive (0.015 absorbance unit/  deg.C), must not exceed 0.170 at 22 
deg.C with a 1-cm optical path length when the blank is prepared 
according to the specified procedure;
 The calibration curve (Section 10.0) must have a slope equal to 
0.0300.002 absorbance unit/[mu]g SO2 with a 1-cm 
optical path length when the dye is pure and the sulfite solution is 
properly standardized.

    8.2.12.2 Preparation of stock PRA solution-- A specially purified 
(99 to 100 percent pure) solution of pararosaniline, which meets the 
above specifications, is commercially available in the required 0.20 
percent concentration (Harleco Co.). Alternatively, the dye may be 
purified, a stock solution prepared, and then assayed according to the 
procedure as described below.(10)
    8.2.12.3 Purification procedure for PRA--
    1. Place 100 mL each of 1-butanol and 1 N HCl in a large separatory 
funnel (250-mL) and allow to equilibrate. Note: Certain batches of 1-
butanol contain oxidants that create an SO2 demand. Before 
using, check by placing 20 mL of 1-butanol and 5 mL of 20 percent 
potassium iodide (KI) solution in a 50-mL separatory funnel and shake 
thoroughly. If a yellow color appears in the alcohol phase, redistill 
the 1-butanol from silver oxide and collect the middle fraction or 
purchase a new supply of 1-butanol.
    2. Weigh 100 mg of pararosaniline hydrochloride dye (PRA) in a small 
beaker. Add 50 mL of the equilibrated acid (drain in acid from the 
bottom of the separatory funnel in 1.) to the beaker and let stand for 
several minutes. Discard the remaining acid phase in the separatory 
funnel.
    3. To a 125-mL separatory funnel, add 50 mL of the equilibrated 1-
butanol (draw the 1-butanol from the top of the separatory funnel in 
1.). Transfer the acid solution (from 2.) containing the dye to the 
funnel and shake carefully to extract. The violet impurity will transfer 
to the organic phase.
    4. Transfer the lower aqueous phase into another separatory funnel, 
add 20 mL of equilibrated 1-butanol, and extract again.
    5. Repeat the extraction procedure with three more 10-mL portions of 
equilibrated 1-butanol.
    6. After the final extraction, filter the acid phase through a 
cotton plug into a 50-mL volumetric flask and bring to volume with 1 N 
HCl. This stock reagent will be a yellowish red.
    7. To check the purity of the PRA, perform the assay and adjustment 
of concentration (Section 8.2.12.4) and prepare a reagent blank (Section 
11.2); the absorbance of this reagent blank at 540 nm should be less 
than 0.170 at 22  deg.C. If the absorbance is greater than 0.170 under 
these conditions, further extractions should be performed.
    8.2.12.4 PRA assay procedure-- The concentration of pararosaniline 
hydrochloride (PRA) need be assayed only once after purification. It is 
also recommended that commercial solutions of pararosaniline be assayed 
when first purchased. The assay procedure is as follows:(10)
    1. Prepare 1 M acetate-acetic acid buffer stock solution with a pH 
of 4.79 by dissolving

[[Page 17]]

13.61 g of sodium acetate trihydrate in distilled water in a 100-mL 
volumetric flask. Add 5.70 mL of glacial acetic acid and dilute to 
volume with distilled water.
    2. Pipet 1 mL of the stock PRA solution obtained from the 
purification process or from a commercial source into a 100-mL 
volumetric flask and dilute to volume with distilled water.
    3. Transfer a 5-mL aliquot of the diluted PRA solution from 2. into 
a 50-mL volumetric flask. Add 5mL of 1 M acetate-acetic acid buffer 
solution from 1. and dilute the mixture to volume with distilled water. 
Let the mixture stand for 1 hour.
    4. Measure the absorbance of the above solution at 540 nm with a 
spectrophotometer against a distilled water reference. Compute the 
percentage of nominal concentration of PRA by
[GRAPHIC] [TIFF OMITTED] TC08NO91.005

where:

A = measured absorbance of the final mixture (absorbance units);
W = weight in grams of the PRA dye used in the assay to prepare 50 mL of 
stock solution (for example, 0.100 g of dye was used to prepare 50 mL of 
solution in the purification procedure; when obtained from commercial 
sources, use the stated concentration to compute W; for 98% PRA, W=.098 
g.); and
K = 21.3 for spectrophotometers having a spectral bandwidth of less than 
15 nm and a path length of 1 cm.

    8.2.13 Pararosaniline reagent: To a 250-mL volumetric flask, add 20 
mL of stock PRA solution. Add an additional 0.2 mL of stock solution for 
each percentage that the stock assays below 100 percent. Then add 25 mL 
of 3 M phosphoric acid and dilute to volume with distilled water. The 
reagent is stable for at least 9 months. Store away from heat and light.
    9.0 Sampling Procedure.
    9.1 General Considerations. Procedures are described for short-term 
sampling (30-minute and 1-hour) and for long-term sampling (24-hour). 
Different combinations of absorbing reagent volume, sampling rate, and 
sampling time can be selected to meet special needs. For combinations 
other than those specifically described, the conditions must be adjusted 
so that linearity is maintained between absorbance and concentration 
over the dynamic range. Absorbing reagent volumes less than 10 mL are 
not recommended. The collection efficiency is above 98 percent for the 
conditions described; however, the efficiency may be substantially lower 
when sampling concentrations below 25[mu][gamma]SO2/
m\3\.(8,9)
    9.2 30-Minute and 1-Hour Sampling. Place 10 mL of TCM absorbing 
reagent in a midget impinger and seal the impinger with a thin film of 
silicon stopcock grease (around the ground glass joint). Insert the 
sealed impinger into the sampling train as shown in Figure 1, making 
sure that all connections between the various components are leak tight. 
Greaseless ball joint fittings, heat shrinkable Teflon[reg] 
tubing, or Teflon[reg] tube fittings may be used to attain 
leakfree conditions for portions of the sampling train that come into 
contact with air containing SO2. Shield the absorbing reagent 
from direct sunlight by covering the impinger with aluminum foil or by 
enclosing the sampling train in a light-proof box. Determine the flow 
rate according to Section 9.4.2. Collect the sample at 10.10 
L/min for 30-minute sampling or 0.5000.05 L/min for 1-hour 
sampling. Record the exact sampling time in minutes, as the sample 
volume will later be determined using the sampling flow rate and the 
sampling time. Record the atmospheric pressure and temperature.
    9.3 24-Hour Sampling. Place 50 mL of TCM absorbing solution in a 
large absorber, close the cap, and, if needed, apply the heat shrink 
material as shown in Figure 3. Verify that the reagent level is at the 
50 mL mark on the absorber. Insert the sealed absorber into the sampling 
train as shown in Figure 2. At this time verify that the absorber 
temperature is controlled to 1510  deg.C. During sampling, 
the absorber temperature must be controlled to prevent decomposition of 
the collected complex. From the onset of sampling until analysis, the 
absorbing solution must be protected from direct sunlight. Determine the 
flow rate according to Section 9.4.2. Collect the sample for 24 hours 
from midnight to midnight at a flow rate of 0.2000.020 L/
min. A start/stop timer is helpful for initiating and stopping sampling 
and an elapsed time meter will be useful for determining the sampling 
time.

[[Page 18]]



    9.4 Flow Measurement.
    9.4.1 Calibration: Flow measuring devices used for the on-site flow 
measurements required in 9.4.2 must be calibrated against a reliable 
flow or volume standard such as an NBS traceable bubble flowmeter or 
calibrated wet test meter. Rotameters or critical orifices used in the 
sampling train may be calibrated, if desired, as a quality control 
check, but such calibration shall not replace the on-site flow 
measurements required by 9.4.2. In-line rotameters, if they are to be 
calibrated, should be calibrated in situ, with the appropriate volume of 
solution in the absorber.
    9.4.2 Determination of flow rate at sampling site: For short-term 
samples, the standard flow rate is determined at the sampling site at 
the initiation and completion of sample collection with a calibrated 
flow measuring device connected to the inlet of the absorber. For 24-
hour samples, the standard flow rate is determined at the time the 
absorber is placed in the sampling train and again when the absorber is 
removed from the train for shipment to the analytical laboratory with a 
calibrated flow measuring device connected to the inlet of the sampling 
train. The flow rate determination must be made with all components of 
the sampling system in operation (e.g., the absorber temperature 
controller and any sample box heaters must also be operating). Equation 
6 may be used to determine the standard flow rate when a calibrated 
positive displacement meter is used as the flow measuring device. Other 
types of calibrated flow measuring devices may also be used to determine 
the flow rate at the sampling site provided that the user applies any 
appropriate corrections to devices for which output is dependent on 
temperature or pressure.

[[Page 19]]

[GRAPHIC] [TIFF OMITTED] TC08NO91.006

where:

Qstd = flow rate at standard conditions, std L/min (25  deg.C 
and 760 mm Hg);
Qact = flow rate at monitoring site conditions, L/min;
Pb = barometric pressure at monitoring site conditions, mm Hg 
or kPa;
RH = fractional relative humidity of the air being measured;
PH2O = vapor pressure of water at the temperature 
of the air in the flow or volume standard, in the same units as 
Pb, (for wet volume standards only, i.e., bubble flowmeter or 
wet test meter; for dry standards, i.e., dry test meter, 
PH2O=0);
Pstd = standard barometric pressure, in the same units as 
Pb (760 mm Hg or 101 kPa); and
Tmeter = temperature of the air in the flow or volume 
standard,  deg.C (e.g., bubble flowmeter).

    If a barometer is not available, the following equation may be used 
to determine the barometric pressure:
[GRAPHIC] [TIFF OMITTED] TC08NO91.007

where:

H = sampling site elevation above sea level in meters.

    If the initial flow rate (Qi) differs from the flow rate 
of the critical orifice or the flow rate indicated by the flowmeter in 
the sampling train (Qc) by more than 5 percent as determined 
by equation (8), check for leaks and redetermine Qi.
[GRAPHIC] [TIFF OMITTED] TC08NO91.008

    Invalidate the sample if the difference between the initial 
(Qi) and final (Qf) flow rates is more than 5 
percent as determined by equation (9):
[GRAPHIC] [TIFF OMITTED] TC08NO91.009

    9.5 Sample Storage and Shipment. Remove the impinger or absorber 
from the sampling train and stopper immediately. Verify that the 
temperature of the absorber is not above 25  deg.C. Mark the level of 
the solution with a temporary (e.g., grease pencil) mark. If the sample 
will not be analyzed within 12 hours of sampling, it must be stored at 
5 deg. 5  deg.C until analysis. Analysis must occur within 
30 days. If the sample is transported or shipped for a period exceeding 
12 hours, it is recommended that thermal coolers using eutectic ice 
packs, refrigerated shipping containers, etc., be used for periods up to 
48 hours. (17) Measure the temperature of the absorber solution when the 
shipment is received. Invalidate the sample if the temperature is above 
10  deg.C. Store the sample at 5 deg. 5  deg.C until it is 
analyzed.
    10.0 Analytical Calibration.
    10.1 Spectrophotometer Cell Matching. If unmatched spectrophotometer 
cells are used, an absorbance correction factor must be determined as 
follows:
    1. Fill all cells with distilled water and designate the one that 
has the lowest absorbance at 548 nm as the reference. (This reference 
cell should be marked as such and continually used for this purpose 
throughout all future analyses.)
    2. Zero the spectrophotometer with the reference cell.
    3. Determine the absorbance of the remaining cells (Ac) 
in relation to the reference cell and record these values for future 
use. Mark all cells in a manner that adequately identifies the 
correction.
    The corrected absorbance during future analyses using each cell is 
determining as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.010

where:

A = corrected absorbance,
Aobs = uncorrected absorbance, and
Ac = cell correction.

    10.2 Static Calibration Procedure (Option 1). Prepare a dilute 
working sulfite-TCM solution by diluting 10 mL of the working sulfite-
TCM solution (Section 8.2.11) to 100 mL with TCM absorbing reagent. 
Following the table below, accurately pipet the indicated volumes of the 
sulfite-TCM solutions into a series of 25-mL volumetric flasks. Add TCM 
absorbing reagent as indicated to bring the volume in each flask to 10 
mL.

[[Page 20]]



------------------------------------------------------------------------
                                         Volume of
                                          sulfite-  Volume of    Total
          Sulfite-TCM solution              TCM      TCM, mL   [mu]g SO2
                                          solution             (approx.*
------------------------------------------------------------------------
Working................................        4.0        6.0       28.8
Working................................        3.0        7.0       21.6
Working................................        2.0        8.0       14.4
Dilute working.........................       10.0        0.0        7.2
Dilute working.........................        5.0        5.0        3.6
                                               0.0       10.0        0.0
------------------------------------------------------------------------
*Based on working sulfite-TCM solution concentration of 7.2 [mu]g SO2/
  mL; the actual total [mu]g SO2 must be calculated using equation 11
  below.

    To each volumetric flask, add 1 mL 0.6% sulfamic acid (Section 
8.2.1), accurately pipet 2 mL 0.2% formaldehyde solution (Section 
8.2.2), then add 5 mL pararosaniline solution (Section 8.2.13). Start a 
laboratory timer that has been set for 30 minutes. Bring all flasks to 
volume with recently boiled and cooled distilled water and mix 
thoroughly. The color must be developed (during the 30-minute period) in 
a temperature environment in the range of 20 deg. to 30  deg.C, which is 
controlled to 1  deg.C. For increased precision, a constant 
temperature bath is recommended during the color development step. After 
30 minutes, determine the corrected absorbance of each standard at 548 
nm against a distilled water reference (Section 10.1). Denote this 
absorbance as (A). Distilled water is used in the reference cell rather 
than the reagant blank because of the temperature sensitivity of the 
reagent blank. Calculate the total micrograms SO2 in each 
solution:
[GRAPHIC] [TIFF OMITTED] TC08NO91.011

where:

VTCM/SO2 = volume of sulfite-TCM solution used, mL;
CTCM/SO2 = concentration of sulfur dioxide in the working 
sulfite-TCM, [mu]g SO2/mL (from equation 4); and
D = dilution factor (D = 1 for the working sulfite-TCM solution; D = 0.1 
for the diluted working sulfite-TCM solution).

    A calibration equation is determined using the method of linear 
least squares (Section 12.1). The total micrograms SO2 
contained in each solution is the x variable, and the corrected 
absorbance (eq. 10) associated with each solution is the y variable. For 
the calibration to be valid, the slope must be in the range of 0.030 
0.002 absorbance unit/[mu]g SO2, the intercept as 
determined by the least squares method must be equal to or less than 
0.170 absorbance unit when the color is developed at 22  deg.C (add 
0.015 to this 0.170 specification for each  deg.C above 22  deg.C) and 
the correlation coefficient must be greater than 0.998. If these 
criteria are not met, it may be the result of an impure dye and/or an 
improperly standardized sulfite-TCM solution. A calibration factor 
(Bs) is determined by calculating the reciprocal of the slope 
and is subsequently used for calculating the sample concentration 
(Section 12.3).
    10.3 Dynamic Calibration Procedures (Option 2). Atmospheres 
containing accurately known concentrations of sulfur dioxide are 
prepared using permeation devices. In the systems for generating these 
atmospheres, the permeation device emits gaseous SO2 at a 
known, low, constant rate, provided the temperature of the device is 
held constant (0.1  deg.C) and the device has been 
accurately calibrated at the temperature of use. The SO2 
permeating from the device is carried by a low flow of dry carrier gas 
to a mixing chamber where it is diluted with SO2-free air to 
the desired concentration and supplied to a vented manifold. A typical 
system is shown schematically in Figure 4 and this system and other 
similar systems have been described in detail by O'Keeffe and Ortman; 
(19) Scaringelli, Frey, and Saltzman, (20) and Scaringelli, O'Keeffe, 
Rosenberg, and Bell. (21) Permeation devices may be prepared or 
purchased and in both cases must be traceable either to a National 
Bureau of Standards (NBS) Standard Reference Material (SRM 1625, SRM 
1626, SRM 1627) or to an NBS/EPA-approved commercially available 
Certified Reference Material (CRM). CRM's are described in Reference 22, 
and a list of CRM sources is available from the address shown for 
Reference 22. A recommended protocol for certifying a permeation device 
to an NBS SRM or CRM is given in Section 2.0.7 of Reference 2. Device 
permeation rates of 0.2 to 0.4 [mu]g/min, inert gas flows of about 50 
mL/min, and dilution air flow rates from 1.1 to 15 L/min conveniently 
yield standard atmospheres in the range of 25 to 600 [mu]g 
SO2/m\3\ (0.010 to 0.230 ppm).
    10.3.1 Calibration Option 2A (30-minute and 1-hour samples): 
Generate a series of six standard atmospheres of SO2 (e.g., 
0, 50, 100, 200, 350, 500, 750 [mu]g/m\3\) by adjusting the dilution 
flow rates appropriately. The concentration of SO2 in each 
atmosphere is calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.014

where:


[[Page 21]]


Ca = concentration of SO2 at standard conditions, 
[mu]g/m\3\;
Pr = permeation rate, [mu]g/min;
Qd = flow rate of dilution air, std L/min; and
Qp = flow rate of carrier gas across permeation device, std 
L/min.



[[Page 22]]


    Be sure that the total flow rate of the standard exceeds the flow 
demand of the sample train, with the excess flow vented at atmospheric 
pressure. Sample each atmosphere using similar apparatus as shown in 
Figure 1 and under the same conditions as field sampling (i.e., use same 
absorbing reagent volume and sample same volume of air at an equivalent 
flow rate). Due to the length of the sampling periods required, this 
method is not recommended for 24-hour sampling. At the completion of 
sampling, quantitatively transfer the contents of each impinger to one 
of a series of 25-mL volumetric flasks (if 10 mL of absorbing solution 
was used) using small amounts of distilled water for rinse (<5mL). If 
10 mL of absorbing solution was used, bring the absorber 
solution in each impinger to orginal volume with distilled H2 
O and pipet 10-mL portions from each impinger into a series of 25-mL 
volumetric flasks. If the color development steps are not to be started 
within 12 hours of sampling, store the solutions at 5 deg.  
5  deg.C. Calculate the total micrograms SO2 in each solution 
as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.015

where:

Ca = concentration of SO2 in the standard 
atmosphere, [mu]g/m\3\ ;
Os = sampling flow rate, std L/min;
t=sampling time, min;
Va = volume of absorbing solution used for color development 
(10 mL); and
Vb = volume of absorbing solution used for sampling, mL.

    Add the remaining reagents for color development in the same manner 
as in Section 10.2 for static solutions. Calculate a calibration 
equation and a calibration factor (Bg) according to Section 
10.2, adhering to all the specified criteria.
    10.3.2 Calibration Option 2B (24-hour samples): Generate a standard 
atmosphere containing approximately 1,050 [mu]g SO2/m\3\ and 
calculate the exact concentration according to equation 12. Set up a 
series of six absorbers according to Figure 2 and connect to a common 
manifold for sampling the standard atmosphere. Be sure that the total 
flow rate of the standard exceeds the flow demand at the sample 
manifold, with the excess flow vented at atmospheric pressure. The 
absorbers are then allowed to sample the atmosphere for varying time 
periods to yield solutions containing 0, 0.2, 0.6, 1.0, 1.4, 1.8, and 
2.2 [mu]g SO2/mL solution. The sampling times required to 
attain these solution concentrations are calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.016

where:

t = sampling time, min;
Vb = volume of absorbing solution used for sampling (50 mL);
Cs = desired concentration of SO2 in the absorbing 
solution, [mu]g/mL;
Ca = concentration of the standard atmosphere calculated 
according to equation 12, [mu]g/m\3\ ; and
Qs = sampling flow rate, std L/min.

    At the completion of sampling, bring the absorber solutions to 
original volume with distilled water. Pipet a 10-mL portion from each 
absorber into one of a series of 25-mL volumetric flasks. If the color 
development steps are not to be started within 12 hours of sampling, 
store the solutions at 5 deg.  5  deg.C. Add the remaining 
reagents for color development in the same manner as in Section 10.2 for 
static solutions. Calculate the total [mu]g SO2 in each 
standard as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.017

where:

Va = volume of absorbing solution used for color development 
(10 mL).
All other parameters are defined in equation 14.

    Calculate a calibration equation and a calibration factor 
(Bt) according to Section 10.2 adhering to all the specified 
criteria.
    11.0 Sample Preparation and Analysis.
    11.1 Sample Preparation. Remove the samples from the shipping 
container. If the shipment period exceeded 12 hours from the completion 
of sampling, verify that the temperature is below 10  deg.C. Also, 
compare the solution level to the temporary level mark on the absorber. 
If either the temperature is above 10  deg.C or there was significant 
loss (more than 10 mL) of the sample during shipping, make an 
appropriate notation in the record and invalidate the sample. Prepare 
the samples for analysis as follows:
    1. For 30-minute or 1-hour samples: Quantitatively transfer the 
entire 10 mL amount of absorbing solution to a 25-mL volumetric flask 
and rinse with a small amount (<5 mL) of distilled water.
    2. For 24-hour samples: If the volume of the sample is less than the 
original 50-mL volume (permanent mark on the absorber), adjust the 
volume back to the original volume with distilled water to compensate 
for water lost to evaporation during sampling. If the final volume is 
greater than the original volume, the volume must be measured using a 
graduated cylinder. To analyze, pipet 10 mL

[[Page 23]]

of the solution into a 25-mL volumetric flask.
    11.2 Sample Analysis. For each set of determinations, prepare a 
reagent blank by adding 10 mL TCM absorbing solution to a 25-mL 
volumetric flask, and two control standards containing approximately 5 
and 15 [mu]g SO2, respectively. The control standards are 
prepared according to Section 10.2 or 10.3. The analysis is carried out 
as follows:
    1. Allow the sample to stand 20 minutes after the completion of 
sampling to allow any ozone to decompose (if applicable).
    2. To each 25-mL volumetric flask containing reagent blank, sample, 
or control standard, add 1 mL of 0.6% sulfamic acid (Section 8.2.1) and 
allow to react for 10 min.
    3. Accurately pipet 2 mL of 0.2% formaldehyde solution (Section 
8.2.2) and then 5 mL of pararosaniline solution (Section 8.2.13) into 
each flask. Start a laboratory timer set at 30 minutes.
    4. Bring each flask to volume with recently boiled and cooled 
distilled water and mix thoroughly.
    5. During the 30 minutes, the solutions must be in a temperature 
controlled environment in the range of 20 deg. to 30  deg.C maintained 
to 1  deg.C. This temperature must also be within 1  deg.C 
of that used during calibration.
    6. After 30 minutes and before 60 minutes, determine the corrected 
absorbances (equation 10) of each solution at 548 nm using 1-cm optical 
path length cells against a distilled water reference (Section 10.1). 
(Distilled water is used as a reference instead of the reagent blank 
because of the sensitivity of the reagent blank to temperature.)
    7. Do not allow the colored solution to stand in the cells because a 
film may be deposited. Clean the cells with isopropyl alcohol after use.
    8. The reagent blank must be within 0.03 absorbance units of the 
intercept of the calibration equation determined in Section 10.
    11.3 Absorbance range. If the absorbance of the sample solution 
ranges between 1.0 and 2.0, the sample can be diluted 1:1 with a portion 
of the reagent blank and the absorbance redetermined within 5 minutes. 
Solutions with higher absorbances can be diluted up to sixfold with the 
reagent blank in order to obtain scale readings of less than 1.0 
absorbance unit. However, it is recommended that a smaller portion (<10 
mL) of the original sample be reanalyzed (if possible) if the sample 
requires a dilution greater than 1:1.
    11.4 Reaqent disposal. All reagents containing mercury compounds 
must be stored and disposed of using one of the procedures contained in 
Section 13. Until disposal, the discarded solutions can be stored in 
closed glass containers and should be left in a fume hood.
    12.0 Calculations.
    12.1 Calibration Slope, Intercept, and Correlation Coefficient. The 
method of least squares is used to calculate a calibration equation in 
the form of:
[GRAPHIC] [TIFF OMITTED] TC08NO91.012

where:

y = corrected absorbance,
m = slope, absorbance unit/[mu]g SO2,
x = micrograms of SO2,
b = y intercept (absorbance units).

    The slope (m), intercept (b), and correlation coefficient (r) are 
calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.018

[GRAPHIC] [TIFF OMITTED] TR31AU93.019

[GRAPHIC] [TIFF OMITTED] TR31AU93.020

where n is the number of calibration points.
    A data form (Figure 5) is supplied for easily organizing calibration 
data when the slope, intercept, and correlation coefficient are 
calculated by hand.
    12.2 Total Sample Volume. Determine the sampling volume at standard 
conditions as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.021

where:

Vstd = sampling volume in std L,
Qi = standard flow rate determined at the initiation of 
sampling in std L/min,
Qf = standard flow rate determined at the completion of 
sampling is std L/min, and
t = total sampling time, min.

    12.3 Sulfur Dioxide Concentration. Calculate and report the 
concentration of each sample as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.022

where:

A = corrected absorbance of the sample solution, from equation (10);
Ao = corrected absorbance of the reagent blank, using 
equation (10);
Bx = calibration factor equal to Bs, 
Bg, or Bt depending on the calibration procedure 
used, the reciprocal of the slope of the calibration equation;
Va = volume of absorber solution analyzed, mL;
Vb = total volume of solution in absorber (see 11.1-2), mL; 
and
Vstd = standard air volume sampled, std L (from Section 
12.2).

[[Page 24]]



                                                    Data Form
                                             [For hand calculations]
----------------------------------------------------------------------------------------------------------------
                                                      Absor- bance
     Calibration point no.       Micro- grams So2        units
----------------------------------------------------------------------------------------------------------------
                                       (x)                (y)                 x2                xy           y2
1.............................  .................  .................  .................  ................  .....
2.............................  .................  .................  .................  ................  .....
3.............................  .................  .................  .................  ................  .....
4.............................  .................  .................  .................  ................  .....
5.............................  .................  .................  .................  ................  .....
6.............................  .................  .................  .................  ................  .....
----------------------------------------------------------------------------------------------------------------

[Sigma] x=------  [Sigma] y=------  [Sigma] x\2\=------  [Sigma]xy------  
[Sigma]y\2\------  
n=------ (number of pairs of coordinates.)
________________________________________________________________________

Figure 5. Data form for hand calculations.

    12.4 Control Standards. Calculate the analyzed micrograms of 
SO2 in each control standard as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.070

where:

Cq = analyzed [mu]g SO2 in each control standard,
A = corrected absorbance of the control standard, and
Ao = corrected absorbance of the reagent blank.

    The difference between the true and analyzed values of the control 
standards must not be greater than 1 [mu]g. If the difference is greater 
than 1 [mu]g, the source of the discrepancy must be identified and 
corrected.
    12.5 Conversion of [mu]g/m\3\ to ppm (v/v). If desired, the 
concentration of sulfur dioxide at reference conditions can be converted 
to ppm SO2 (v/v) as follows:
[GRAPHIC] [TIFF OMITTED] TR31AU93.023

    13.0 The TCM absorbing solution and any reagents containing mercury 
compounds must be treated and disposed of by one of the methods 
discussed below. Both methods remove greater than 99.99 percent of the 
mercury.
    13.1 Disposal of Mercury-Containing Solutions.
    13.2 Method for Forming an Amalgam.
    1. Place the waste solution in an uncapped vessel in a hood.
    2. For each liter of waste solution, add approximately 10 g of 
sodium carbonate until neutralization has occurred (NaOH may have to be 
used).
    3. Following neutralization, add 10 g of granular zinc or magnesium.
    4. Stir the solution in a hood for 24 hours. Caution must be 
exercised as hydrogen gas is evolved by this treatment process.
    5. After 24 hours, allow the solution to stand without stirring to 
allow the mercury amalgam (solid black material) to settle to the bottom 
of the waste receptacle.
    6. Upon settling, decant and discard the supernatant liquid.
    7. Quantitatively transfer the solid material to a container and 
allow to dry.
    8. The solid material can be sent to a mercury reclaiming plant. It 
must not be discarded.
    13.3 Method Using Aluminum Foil Strips.
    1. Place the waste solution in an uncapped vessel in a hood.
    2. For each liter of waste solution, add approximately 10 g of 
aluminum foil strips. If all the aluminum is consumed and no gas is 
evolved, add an additional 10 g of foil. Repeat until the foil is no 
longer consumed and allow the gas to evolve for 24 hours.
    3. Decant the supernatant liquid and discard.
    4. Transfer the elemental mercury that has settled to the bottom of 
the vessel to a storage container.
    5. The mercury can be sent to a mercury reclaiming plant. It must 
not be discarded.
    14.0 References for SO2 Method.
    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume I, Principles. EPA-600/9-76-005, U.S. Environmental Protection 
Agency, Research Triangle Park, NC 27711, 1976.
    2. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II, Ambient Air Specific Methods. EPA-600/4-77-027a, U.S. 
Environmental Protection Agency, Research Triangle Park, NC 27711, 1977.
    3. Dasqupta, P. K., and K. B. DeCesare. Stability of Sulfur Dioxide 
in Formaldehyde and Its Anomalous Behavior in Tetrachloromercurate (II). 
Submitted for publication in Atmospheric Environment, 1982.
    4. West, P. W., and G. C. Gaeke. Fixation of Sulfur Dioxide as 
Disulfitomercurate (II) and Subsequent Colorimetric Estimation. Anal. 
Chem., 28:1816, 1956.
    5. Ephraim, F. Inorganic Chemistry. P. C. L. Thorne and E. R. 
Roberts, Eds., 5th Edition, Interscience, 1948, p. 562.
    6. Lyles, G. R., F. B. Dowling, and V. J. Blanchard. Quantitative 
Determination of Formaldehyde in the Parts Per Hundred Million 
Concentration Level. J. Air. Poll. Cont. Assoc., Vol. 15(106), 1965.
    7. McKee, H. C., R. E. Childers, and O. Saenz, Jr. Collaborative 
Study of Reference Method for Determination of Sulfur Dioxide in the 
Atmosphere (Pararosaniline Method). EPA-APTD-0903, U.S. Environmental 
Protection Agency, Research Triangle Park, NC 27711, September 1971.
    8. Urone, P., J. B. Evans, and C. M. Noyes. Tracer Techniques in 
Sulfur--Air Pollution Studies Apparatus and Studies of Sulfur Dioxide 
Colorimetric and Conductometric Methods. Anal. Chem., 37: 1104, 1965.

[[Page 25]]

    9. Bostrom, C. E. The Absorption of Sulfur Dioxide at Low 
Concentrations (pphm) Studied by an Isotopic Tracer Method. Intern. J. 
Air Water Poll., 9:333, 1965.
    10. Scaringelli, F. P., B. E. Saltzman, and S. A. Frey. 
Spectrophotometric Determination of Atmospheric Sulfur Dioxide. Anal. 
Chem., 39: 1709, 1967.
    11. Pate, J. B., B. E. Ammons, G. A. Swanson, and J. P. Lodge, Jr. 
Nitrite Interference in Spectrophotometric Determination of Atmospheric 
Sulfur Dioxide. Anal. Chem., 37:942, 1965.
    12. Zurlo, N., and A. M. Griffini. Measurement of the Sulfur Dioxide 
Content of the Air in the Presence of Oxides of Nitrogen and Heavy 
Metals. Medicina Lavoro, 53:330, 1962.
    13. Rehme, K. A., and F. P. Scaringelli. Effect of Ammonia on the 
Spectrophotometric Determination of Atmospheric Concentrations of Sulfur 
Dioxide. Anal. Chem., 47:2474, 1975.
    14. McCoy, R. A., D. E. Camann, and H. C. McKee. Collaborative Study 
of Reference Method for Determination of Sulfur Dioxide in the 
Atmosphere (Pararosaniline Method) (24-Hour Sampling). EPA-650/4-74-027, 
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, 
December 1973.
    15. Fuerst, R. G. Improved Temperature Stability of Sulfur Dioxide 
Samples Collected by the Federal Reference Method. EPA-600/4-78-018, 
U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, 
April 1978.
    16. Scaringelli, F. P., L. Elfers, D. Norris, and S. Hochheiser. 
Enhanced Stability of Sulfur Dioxide in Solution. Anal. Chem., 42:1818, 
1970.
    17. Martin, B. E. Sulfur Dioxide Bubbler Temperature Study. EPA-600/
4-77-040, U.S. Environmental Protection Agency, Research Triangle Park, 
NC 27711, August 1977.
    18. American Society for Testing and Materials. ASTM Standards, 
Water; Atmospheric Analysis. Part 23. Philadelphia, PA, October 1968, p. 
226.
    19. O'Keeffe, A. E., and G. C. Ortman. Primary Standards for Trace 
Gas Analysis. Anal. Chem., 38:760, 1966.
    20. Scaringelli, F. P., S. A. Frey, and B. E. Saltzman. Evaluation 
of Teflon Permeation Tubes for Use with Sulfur Dioxide. Amer. Ind. 
Hygiene Assoc. J., 28:260, 1967.
    21. Scaringelli, F. P., A. E. O'Keeffe, E. Rosenberg, and J. P. 
Bell, Preparation of Known Concentrations of Gases and Vapors With 
Permeation Devices Calibrated Gravimetrically. Anal. Chem., 42:871, 
1970.
    22. A Procedure for Establishing Traceability of Gas Mixtures to 
Certain National Bureau of Standards Standard Reference Materials. EPA-
600/7-81-010, U.S. Environmental Protection Agency, Environmental 
Monitoring Systems Laboratory (MD-77), Research Triangle Park, NC 27711, 
January 1981.

[47 FR 54899, Dec. 6, 1982; 48 FR 17355, Apr. 22, 1983]

    Appendix B to Part 50--Reference Method for the Determination of 
   Suspended Particulate Matter in the Atmosphere (High-Volume Method)

    1.0 Applicability.
    1.1 This method provides a measurement of the mass concentration of 
total suspended particulate matter (TSP) in ambient air for determining 
compliance with the primary and secondary national ambient air quality 
standards for particulate matter as specified in Sec. 50.6 and Sec. 50.7 
of this chapter. The measurement process is nondestructive, and the size 
of the sample collected is usually adequate for subsequent chemical 
analysis. Quality assurance procedures and guidance are provided in part 
58, appendixes A and B, of this chapter and in References 1 and 2.
    2.0 Principle.
    2.1 An air sampler, properly located at the measurement site, draws 
a measured quantity of ambient air into a covered housing and through a 
filter during a 24-hr (nominal) sampling period. The sampler flow rate 
and the geometry of the shelter favor the collection of particles up to 
25-50 [mu]m (aerodynamic diameter), depending on wind speed and 
direction.(3) The filters used are specified to have a minimum 
collection efficiency of 99 percent for 0.3 [mu]m (DOP) particles (see 
Section 7.1.4).
    2.2 The filter is weighed (after moisture equilibration) before and 
after use to determine the net weight (mass) gain. The total volume of 
air sampled, corrected to EPA standard conditions (25  deg.C, 760 mm Hg 
[101 kPa]), is determined from the measured flow rate and the sampling 
time. The concentration of total suspended particulate matter in the 
ambient air is computed as the mass of collected particles divided by 
the volume of air sampled, corrected to standard conditions, and is 
expressed in micrograms per standard cubic meter ([mu]g/std m\3\). For 
samples collected at temperatures and pressures significantly different 
than standard conditions, these corrected concentrations may differ 
substantially from actual concentrations (micrograms per actual cubic 
meter), particularly at high elevations. The actual particulate matter 
concentration can be calculated from the corrected concentration using 
the actual temperature and pressure during the sampling period.
    3.0 Range.
    3.1 The approximate concentration range of the method is 2 to 750 
[mu]g/std m3. The upper limit is determined by the point at 
which the sampler can no longer maintain the specified

[[Page 26]]

flow rate due to the increased pressure drop of the loaded filter. This 
point is affected by particle size distribution, moisture content of the 
collected particles, and variability from filter to filter, among other 
things. The lower limit is determined by the sensitivity of the balance 
(see Section 7.10) and by inherent sources of error (see Section 6).
    3.2 At wind speeds between 1.3 and 4.5 m/sec (3 and 10 mph), the 
high-volume air sampler has been found to collect particles up to 25 to 
50 [mu]m, depending on wind speed and direction.(3) For the filter 
specified in Section 7.1, there is effectively no lower limit on the 
particle size collected.
    4.0 Precision.
    4.1 Based upon collaborative testing, the relative standard 
deviation (coefficient of variation) for single analyst precision 
(repeatability) of the method is 3.0 percent. The corresponding value 
for interlaboratory precision (reproducibility) is 3.7 percent.(4)
    5.0 Accuracy.
    5.1 The absolute accuracy of the method is undefined because of the 
complex nature of atmospheric particulate matter and the difficulty in 
determining the ``true'' particulate matter concentration. This method 
provides a measure of particulate matter concentration suitable for the 
purpose specified under Section 1.0, Applicability.
    6.0 Inherent Sources of Error.
    6.1 Airflow variation. The weight of material collected on the 
filter represents the (integrated) sum of the product of the 
instantaneous flow rate times the instantaneous particle concentration. 
Therefore, dividing this weight by the average flow rate over the 
sampling period yields the true particulate matter concentration only 
when the flow rate is constant over the period. The error resulting from 
a nonconstant flow rate depends on the magnitude of the instantaneous 
changes in the flow rate and in the particulate matter concentration. 
Normally, such errors are not large, but they can be greatly reduced by 
equipping the sampler with an automatic flow controlling mechanism that 
maintains constant flow during the sampling period. Use of a contant 
flow controller is recommended.*
---------------------------------------------------------------------------

    *At elevated altitudes, the effectiveness of automatic flow 
controllers may be reduced because of a reduction in the maximum sampler 
flow.
---------------------------------------------------------------------------

    6.2 Air volume measurement. If the flow rate changes substantially 
or nonuniformly during the sampling period, appreciable error in the 
estimated air volume may result from using the average of the 
presampling and postsampling flow rates. Greater air volume measurement 
accuracy may be achieved by (1) equipping the sampler with a flow 
controlling mechanism that maintains constant air flow during the 
sampling period,* (2) using a calibrated, continuous flow rate recording 
device to record the actual flow rate during the samping period and 
integrating the flow rate over the period, or (3) any other means that 
will accurately measure the total air volume sampled during the sampling 
period. Use of a continuous flow recorder is recommended, particularly 
if the sampler is not equipped with a constant flow controller.
    6.3 Loss of volatiles. Volatile particles collected on the filter 
may be lost during subsequent sampling or during shipment and/or storage 
of the filter prior to the postsampling weighing.(5) Although such 
losses are largely unavoidable, the filter should be reweighed as soon 
after sampling as practical.
    6.4 Artifact particulate matter. Artifact particulate matter can be 
formed on the surface of alkaline glass fiber filters by oxidation of 
acid gases in the sample air, resulting in a higher than true TSP 
determination.(6 7) This effect usually occurs early in the sample 
period and is a function of the filter pH and the presence of acid 
gases. It is generally believed to account for only a small percentage 
of the filter weight gain, but the effect may become more significant 
where relatively small particulate weights are collected.
    6.5 Humidity. Glass fiber filters are comparatively insensitive to 
changes in relative humidity, but collected particulate matter can be 
hygroscopic.(8) The moisture conditioning procedure minimizes but may 
not completely eliminate error due to moisture.
    6.6 Filter handling. Careful handling of the filter between the 
presampling and postsampling weighings is necessary to avoid errors due 
to loss of fibers or particles from the filter. A filter paper cartridge 
or cassette used to protect the filter can minimize handling errors. 
(See Reference 2, Section 2).
    6.7 Nonsampled particulate matter. Particulate matter may be 
deposited on the filter by wind during periods when the sampler is 
inoperative. (9) It is recommended that errors from this source be 
minimized by an automatic mechanical device that keeps the filter 
covered during nonsampling periods, or by timely installation and 
retrieval of filters to minimize the nonsampling periods prior to and 
following operation.
    6.8 Timing errors. Samplers are normally controlled by clock timers 
set to start and stop the sampler at midnight. Errors in the nominal 
1,440-min sampling period may result from a power interruption during 
the sampling period or from a discrepancy between the start or stop time 
recorded on the filter information record and the actual start or stop 
time of the sampler. Such discrepancies may be caused by (1) poor 
resolution of the timer set-points, (2) timer error due to power 
interruption, (3) missetting of

[[Page 27]]

the timer, or (4) timer malfunction. In general, digital electronic 
timers have much better set-point resolution than mechanical timers, but 
require a battery backup system to maintain continuity of operation 
after a power interruption. A continuous flow recorder or elapsed time 
meter provides an indication of the sampler run-time, as well as 
indication of any power interruption during the sampling period and is 
therefore recommended.
    6.9 Recirculation of sampler exhaust. Under stagnant wind 
conditions, sampler exhaust air can be resampled. This effect does not 
appear to affect the TSP measurement substantially, but may result in 
increased carbon and copper in the collected sample. (10) This problem 
can be reduced by ducting the exhaust air well away, preferably 
downwind, from the sampler.
    7.0 Apparatus.
    (See References 1 and 2 for quality assurance information.)
    Note: Samplers purchased prior to the effective date of this 
amendment are not subject to specifications preceded by ([dagger]).
    7.1 Filter. (Filters supplied by the Environmental Protection Agency 
can be assumed to meet the following criteria. Additional specifications 
are required if the sample is to be analyzed chemically.)
    7.1.1 Size: 20.3  0.2 x 25.4  0.2 cm 
(nominal 8 x 10 in).
    7.1.2 Nominal exposed area: 406.5 cm\2\ (63 in\2\).
    7.1.3. Material: Glass fiber or other relatively inert, 
nonhygroscopic material. (8)
    7.1.4 Collection efficiency: 99 percent minimum as measured by the 
DOP test (ASTM-2986) for particles of 0.3 [mu]m diameter.
    7.1.5 Recommended pressure drop range: 42-54 mm Hg (5.6-7.2 kPa) at 
a flow rate of 1.5 std m\3\/min through the nominal exposed area.
    7.1.6 pH: 6 to 10. (11)
    7.1.7 Integrity: 2.4 mg maximum weight loss. (11)
    7.1.8 Pinholes: None.
    7.1.9 Tear strength: 500 g minimum for 20 mm wide strip cut from 
filter in weakest dimension. (See ASTM Test D828-60).
    7.1.10 Brittleness: No cracks or material separations after single 
lengthwise crease.
    7.2 Sampler. The air sampler shall provide means for drawing the air 
sample, via reduced pressure, through the filter at a uniform face 
velocity.
    7.2.1 The sampler shall have suitable means to:
    a. Hold and seal the filter to the sampler housing.
    b. Allow the filter to be changed conveniently.
    c. Preclude leaks that would cause error in the measurement of the 
air volume passing through the filter.
    d. ([dagger]) Manually adjust the flow rate to accommodate 
variations in filter pressure drop and site line voltage and altitude. 
The adjustment may be accomplished by an automatic flow controller or by 
a manual flow adjustment device. Any manual adjustment device must be 
designed with positive detents or other means to avoid unintentional 
changes in the setting.
---------------------------------------------------------------------------

    ([dagger]) See note at beginning of Section 7 of this appendix.
---------------------------------------------------------------------------

    7.2.2 Minimum sample flow rate, heavily loaded filter: 1.1 m\3\/min 
(39 ft\3\/min).[Dagger]
---------------------------------------------------------------------------

    [Dagger] These specifications are in actual air volume units; to 
convert to EPA standard air volume units, multiply the specifications by 
(Pb/Pstd)(298/T) where Pb and T are the 
barometric pressure in mm Hg (or kPa) and the temperature in K at the 
sampler, and Pstd is 760 mm Hg (or 101 kPa).
---------------------------------------------------------------------------

    7.2.3 Maximum sample flow rate, clean filter: 1.7 m\3\/min (60 
ft\3\/min).[Dagger]
    7.2.4 Blower Motor: The motor must be capable of continuous 
operation for 24-hr periods.
    7.3 Sampler shelter.
    7.3.1 The sampler shelter shall:
    a. Maintain the filter in a horizontal position at least 1 m above 
the sampler supporting surface so that sample air is drawn downward 
through the filter.
    b. Be rectangular in shape with a gabled roof, similar to the design 
shown in Figure 1.
    c. Cover and protect the filter and sampler from precipitation and 
other weather.
    d. Discharge exhaust air at least 40 cm from the sample air inlet.
    e. Be designed to minimize the collection of dust from the 
supporting surface by incorporating a baffle between the exhaust outlet 
and the supporting surface.
    7.3.2 The sampler cover or roof shall overhang the sampler housing 
somewhat, as shown in Figure 1, and shall be mounted so as to form an 
air inlet gap between the cover and the sampler housing walls. 
[dagger] This sample air inlet should be approximately 
uniform on all sides of the sampler. [dagger] The area of the 
sample air inlet must be sized to provide an effective particle capture 
air velocity of between 20 and 35 cm/sec at the recommended operational 
flow rate. The capture velocity is the sample air flow rate divided by 
the inlet area measured in a horizontal plane at the lower edge of the 
cover. [dagger] Ideally, the inlet area and operational flow 
rate should be selected to obtain a capture air velocity of 25 
2 cm/sec.
    7.4 Flow rate measurement devices.
    7.4.1 The sampler shall incorporate a flow rate measurement device 
capable of indicating the total sampler flow rate. Two common types of 
flow indicators covered in the calibration procedure are (1) an 
electronic mass flowmeter and (2) an orifice or orifices

[[Page 28]]

located in the sample air stream together with a suitable pressure 
indicator such as a manometer, or aneroid pressure gauge. A pressure 
recorder may be used with an orifice to provide a continuous record of 
the flow. Other types of flow indicators (including rotameters) having 
comparable precision and accuracy are also acceptable.
    7.4.2 [dagger] The flow rate measurement device must be capable of 
being calibrated and read in units corresponding to a flow rate which is 
readable to the nearest 0.02 std m\3\/min over the range 1.0 to 1.8 std 
m\3\/min.
    7.5 Thermometer, to indicate the approximate air temperature at the 
flow rate measurement orifice, when temperature corrections are used.
    7.5.1 Range: -40 deg. to +50  deg.C (223-323 K).
    7.5.2 Resolution: 2  deg.C (2 K).
    7.6 Barometer, to indicate barometric pressure at the flow rate 
measurement orifice, when pressure corrections are used.
    7.6.1 Range: 500 to 800 mm Hg (66-106 kPa).
    7.6.2 Resolution: 5 mm Hg (0.67 kPa).
    7.7 Timing/control device.
    7.7.1 The timing device must be capable of starting and stopping the 
sampler to obtain an elapsed run-time of 24 hr 1 hr (1,440 
60 min).
    7.7.2 Accuracy of time setting: 30 min, or better. (See 
Section 6.8).
    7.8 Flow rate transfer standard, traceable to a primary standard. 
(See Section 9.2.)
    7.8.1 Approximate range: 1.0 to 1.8 m\3\/min.
    7.8.2 Resolution: 0.02 m\3\/min.
    7.8.3 Reproducibility: 2 percent (2 times coefficient of 
variation) over normal ranges of ambient temperature and pressure for 
the stated flow rate range. (See Reference 2, Section 2.)
    7.8.4 Maximum pressure drop at 1.7 std m\3\/min; 50 cm H2 O (5 kPa).
    7.8.5 The flow rate transfer standard must connect without leaks to 
the inlet of the sampler and measure the flow rate of the total air 
sample.
    7.8.6 The flow rate transfer standard must include a means to vary 
the sampler flow rate over the range of 1.0 to 1.8 m\3\/min (35-64 
ft\3\/min) by introducing various levels of flow resistance between the 
sampler and the transfer standard inlet.
    7.8.7 The conventional type of flow transfer standard consists of: 
An orifice unit with adapter that connects to the inlet of the sampler, 
a manometer or other device to measure orifice pressure drop, a means to 
vary the flow through the sampler unit, a thermometer to measure the 
ambient temperature, and a barometer to measure ambient pressure. Two 
such devices are shown in Figures 2a and 2b. Figure 2a shows multiple 
fixed resistance plates, which necessitate disassembly of the unit each 
time the flow resistance is changed. A preferable design, illustrated in 
Figure 2b, has a variable flow restriction that can be adjusted 
externally without disassembly of the unit. Use of a conventional, 
orifice-type transfer standard is assumed in the calibration procedure 
(Section 9). However, the use of other types of transfer standards 
meeting the above specifications, such as the one shown in Figure 2c, 
may be approved; see the note following Section 9.1.
    7.9 Filter conditioning environment
    7.9.1 Controlled temperature: between 15 deg. and 30  deg.C with 
less than 3  deg.C variation during equilibration period.
    7.9.2 Controlled humidity: Less than 50 percent relative humidity, 
constant within 5 percent.
    7.10 Analytical balance.
    7.10.1 Sensitivity: 0.1 mg.
    7.10.2 Weighing chamber designed to accept an unfolded 20.3x25.4 cm 
(8x10 in) filter.
    7.11 Area light source, similar to X-ray film viewer, to backlight 
filters for visual inspection.
    7.12 Numbering device, capable of printing identification numbers on 
the filters before they are placed in the filter conditioning 
environment, if not numbered by the supplier.
    8.0 Procedure.
    (See References 1 and 2 for quality assurance information.)
    8.1 Number each filter, if not already numbered, near its edge with 
a unique identification number.
    8.2 Backlight each filter and inspect for pinholes, particles, and 
other imperfections; filters with visible imperfections must not be 
used.
    8.3 Equilibrate each filter in the conditioning environment for at 
least 24-hr.
    8.4 Following equilibration, weigh each filter to the nearest 
milligram and record this tare weight (Wi) with the filter 
identification number.
    8.5 Do not bend or fold the filter before collection of the sample.
    8.6 Open the shelter and install a numbered, preweighed filter in 
the sampler, following the sampler manufacturer's instructions. During 
inclement weather, precautions must be taken while changing filters to 
prevent damage to the clean filter and loss of sample from or damage to 
the exposed filter. Filter cassettes that can be loaded and unloaded in 
the laboratory may be used to minimize this problem (See Section 6.6).
    8.7 Close the shelter and run the sampler for at least 5 min to 
establish run-temperature conditions.
    8.8 Record the flow indicator reading and, if needed, the barometric 
pressure (P 3) and the ambient temperature (T 3) 
see NOTE following step 8.12). Stop the sampler. Determine the sampler 
flow rate (see Section 10.1); if it is outside the acceptable range (1.1 
to 1.7 m\3\/min [39-60 ft\3\/min]), use a different filter, or adjust 
the sampler flow rate. Warning: Substantial flow adjustments may affect 
the

[[Page 29]]

calibration of the orifice-type flow indicators and may necessitate 
recalibration.
    8.9 Record the sampler identification information (filter number, 
site location or identification number, sample date, and starting time).
    8.10 Set the timer to start and stop the sampler such that the 
sampler runs 24-hrs, from midnight to midnight (local time).
    8.11 As soon as practical following the sampling period, run the 
sampler for at least 5 min to again establish run-temperature 
conditions.
    8.12 Record the flow indicator reading and, if needed, the 
barometric pressure (P 3) and the ambient temperature (T 
3).
    Note: No onsite pressure or temperature measurements are necessary 
if the sampler flow indicator does not require pressure or temperature 
corrections (e.g., a mass flowmeter) or if average barometric pressure 
and seasonal average temperature for the site are incorporated into the 
sampler calibration (see step 9.3.9). For individual pressure and 
temperature corrections, the ambient pressure and temperature can be 
obtained by onsite measurements or from a nearby weather station. 
Barometric pressure readings obtained from airports must be station 
pressure, not corrected to sea level, and may need to be corrected for 
differences in elevation between the sampler site and the airport. For 
samplers having flow recorders but not constant flow controllers, the 
average temperature and pressure at the site during the sampling period 
should be estimated from weather bureau or other available data.
    8.13 Stop the sampler and carefully remove the filter, following the 
sampler manufacturer's instructions. Touch only the outer edges of the 
filter. See the precautions in step 8.6.
    8.14 Fold the filter in half lengthwise so that only surfaces with 
collected particulate matter are in contact and place it in the filter 
holder (glassine envelope or manila folder).
    8.15 Record the ending time or elapsed time on the filter 
information record, either from the stop set-point time, from an elapsed 
time indicator, or from a continuous flow record. The sample period must 
be 1,440  60 min. for a valid sample.
    8.16 Record on the filter information record any other factors, such 
as meteorological conditions, construction activity, fires or dust 
storms, etc., that might be pertinent to the measurement. If the sample 
is known to be defective, void it at this time.
    8.17 Equilibrate the exposed filter in the conditioning environment 
for at least 24-hrs.
    8.18 Immediately after equilibration, reweigh the filter to the 
nearest milligram and record the gross weight with the filter 
identification number. See Section 10 for TSP concentration 
calculations.
    9.0 Calibration.
    9.1 Calibration of the high volume sampler's flow indicating or 
control device is necessary to establish traceability of the field 
measurement to a primary standard via a flow rate transfer standard. 
Figure 3a illustrates the certification of the flow rate transfer 
standard and Figure 3b illustrates its use in calibrating a sampler flow 
indicator. Determination of the corrected flow rate from the sampler 
flow indicator, illustrated in Figure 3c, is addressed in Section 10.1
    Note: The following calibration procedure applies to a conventional 
orifice-type flow transfer standard and an orifice-type flow indicator 
in the sampler (the most common types). For samplers using a pressure 
recorder having a square-root scale, 3 other acceptable calibration 
procedures are provided in Reference 12. Other types of transfer 
standards may be used if the manufacturer or user provides an 
appropriately modified calibration procedure that has been approved by 
EPA under Section 2.8 of appendix C to part 58 of this chapter.
    9.2 Certification of the flow rate transfer standard.
    9.2.1 Equipment required: Positive displacement standard volume 
meter traceable to the National Bureau of Standards (such as a Roots 
meter or equivalent), stop-watch, manometer, thermometer, and barometer.
    9.2.2 Connect the flow rate transfer standard to the inlet of the 
standard volume meter. Connect the manometer to measure the pressure at 
the inlet of the standard volume meter. Connect the orifice manometer to 
the pressure tap on the transfer standard. Connect a high-volume air 
pump (such as a high-volume sampler blower) to the outlet side of the 
standard volume meter. See Figure 3a.
    9.2.3 Check for leaks by temporarily clamping both manometer lines 
(to avoid fluid loss) and blocking the orifice with a large-diameter 
rubber stopper, wide cellophane tape, or other suitable means. Start the 
high-volume air pump and note any change in the standard volume meter 
reading. The reading should remain constant. If the reading changes, 
locate any leaks by listening for a whistling sound and/or retightening 
all connections, making sure that all gaskets are properly installed.
    9.2.4 After satisfactorily completing the leak check as described 
above, unclamp both manometer lines and zero both manometers.
    9.2.5 Achieve the appropriate flow rate through the system, either 
by means of the variable flow resistance in the transfer standard or by 
varying the voltage to the air pump. (Use of resistance plates as shown 
in Figure 1a is discouraged because the above leak check must be 
repeated each time a new resistance plate is installed.) At least five 
different but constant flow rates, evenly distributed, with at least 
three in the specified

[[Page 30]]

flow rate interval (1.1 to 1.7 m\3\/min [39-60 ft \3\/min]), are 
required.
    9.2.6 Measure and record the certification data on a form similar to 
the one illustrated in Figure 4 according to the following steps.
    9.2.7 Observe the barometric pressure and record as P1 
(item 8 in Figure 4).
    9.2.8 Read the ambient temperature in the vicinity of the standard 
volume meter and record it as T1 (item 9 in Figure 4).
    9.2.9 Start the blower motor, adjust the flow, and allow the system 
to run for at least 1 min for a constant motor speed to be attained.
    9.2.10 Observe the standard volume meter reading and simultaneously 
start a stopwatch. Record the initial meter reading (Vi) in 
column 1 of Figure 4.
    9.2.11 Maintain this constant flow rate until at least 3 m\3\ of air 
have passed through the standard volume meter. Record the standard 
volume meter inlet pressure manometer reading as [Delta]P (column 5 in 
Figure 4), and the orifice manometer reading as [Delta]H (column 7 in 
Figure 4). Be sure to indicate the correct units of measurement.
    9.2.12 After at least 3 m\3\ of air have passed through the system, 
observe the standard volume meter reading while simultaneously stopping 
the stopwatch. Record the final meter reading (Vf) in column 
2 and the elapsed time (t) in column 3 of Figure 4.
    9.2.13 Calculate the volume measured by the standard volume meter at 
meter conditions of temperature and pressures as 
Vm=Vf-Vi. Record in column 4 of Figure 
4.
    9.2.14 Correct this volume to standard volume (std m\3\) as follows:
    [GRAPHIC] [TIFF OMITTED] TR31AU93.024
    
where:

Vstd = standard volume, std m\3\;
Vm = actual volume measured by the standard volume meter;
P1 = barometric pressure during calibration, mm Hg or kPa;
[Delta]P = differential pressure at inlet to volume meter, mm Hg or kPa;
Pstd = 760 mm Hg or 101 kPa;
Tstd = 298 K;
T1 = ambient temperature during calibration, K.
Calculate the standard flow rate (std m\3\/min) as follows:
[GRAPHIC] [TIFF OMITTED] TC08NO91.013

where:

Qstd = standard volumetric flow rate, std m\3\/min
t = elapsed time, minutes.

    Record Qstd to the nearest 0.01 std m\3\/min in column 6 
of Figure 4.
    9.2.15 Repeat steps 9.2.9 through 9.2.14 for at least four 
additional constant flow rates, evenly spaced over the approximate range 
of 1.0 to 1.8 std m\3\/min (35-64 ft\3\/min).
    9.2.16 For each flow, compute

[radic][Delta][Delta]H (P1/Pstd)(298/
T1)

(column 7a of Figure 4) and plot these value against Qstd as 
shown in Figure 3a. Be sure to use consistent units (mm Hg or kPa) for 
barometric pressure. Draw the orifice transfer standard certification 
curve or calculate the linear least squares slope (m) and intercept (b) 
of the certification curve:

[radic][Delta][Delta]H (P1/Pstd)(298/
T1)

=mQstd+b. See Figures 3 and 4. A certification graph should 
be readable to 0.02 std m\3\/min.
    9.2.17 Recalibrate the transfer standard annually or as required by 
applicable quality control procedures. (See Reference 2.)
    9.3 Calibration of sampler flow indicator.

    Note: For samplers equipped with a flow controlling device, the flow 
controller must be disabled to allow flow changes during calibration of 
the sampler's flow indicator, or the alternate calibration of the flow 
controller given in 9.4 may be used. For samplers using an orifice-type 
flow indicator downstream of the motor, do not vary the flow rate by 
adjusting the voltage or power supplied to the sampler.

    9.3.1 A form similar to the one illustrated in Figure 5 should be 
used to record the calibration data.
    9.3.2 Connect the transfer standard to the inlet of the sampler. 
Connect the orifice manometer to the orifice pressure tap, as 
illustrated in Figure 3b. Make sure there are no leaks between the 
orifice unit and the sampler.
    9.3.3 Operate the sampler for at least 5 minutes to establish 
thermal equilibrium prior to the calibration.
    9.3.4 Measure and record the ambient temperature, T2, and 
the barometric pressure, P2, during calibration.
    9.3.5 Adjust the variable resistance or, if applicable, insert the 
appropriate resistance plate (or no plate) to achieve the desired flow 
rate.
    9.3.6 Let the sampler run for at least 2 min to re-establish the 
run-temperature conditions. Read and record the pressure drop across the 
orifice ([Delta]H) and the sampler flow rate indication (I) in the 
appropriate columns of Figure 5.
    9.3.7 Calculate [radic][Delta][Delta]H(P2/
Pstd)(298/T2) and determine the flow rate at 
standard conditions (Qstd) either graphically from the 
certification curve or by calculating Qstd from the least 
square slope and intercept of the transfer standard's transposed 
certification curve: Qstd=1/m [radic][Delta]H(P2/
Pstd)(298/T2)-b. Record the value of 
Qstd on Figure 5.

[[Page 31]]

    9.3.8 Repeat steps 9.3.5, 9.3.6, and 9.3.7 for several additional 
flow rates distributed over a range that includes 1.1 to 1.7 std m\3\/
min.
    9.3.9 Determine the calibration curve by plotting values of the 
appropriate expression involving I, selected from table 1, against 
Qstd. The choice of expression from table 1 depends on the 
flow rate measurement device used (see Section 7.4.1) and also on 
whether the calibration curve is to incorporate geographic average 
barometric pressure (Pa) and seasonal average temperature 
(Ta) for the site to approximate actual pressure and 
temperature. Where Pa and Ta can be determined for 
a site for a seasonal period such that the actual barometric pressure 
and temperature at the site do not vary by more than 60 mm 
Hg (8 kPa) from Pa or 15  deg.C from 
Ta, respectively, then using Pa and Ta 
avoids the need for subsequent pressure and temperature calculation when 
the sampler is used. The geographic average barometric pressure 
(Pa) may be estimated from an altitude-pressure table or by 
making an (approximate) elevation correction of -26 mm Hg (-3.46 kPa) 
for each 305 m (1,000 ft) above sea level (760 mm Hg or 101 kPa). The 
seasonal average temperature (Ta) may be estimated from 
weather station or other records. Be sure to use consistent units (mm Hg 
or kPa) for barometric pressure.
    9.3.10 Draw the sampler calibration curve or calculate the linear 
least squares slope (m), intercept (b), and correlation coefficient of 
the calibration curve: [Expression from table 1]= mQstd+b. 
See Figures 3 and 5. Calibration curves should be readable to 0.02 std 
m\3\/min.
    9.3.11 For a sampler equipped with a flow controller, the flow 
controlling mechanism should be re-enabled and set to a flow near the 
lower flow limit to allow maximum control range. The sample flow rate 
should be verified at this time with a clean filter installed. Then add 
two or more filters to the sampler to see if the flow controller 
maintains a constant flow; this is particularly important at high 
altitudes where the range of the flow controller may be reduced.
    9.4 Alternate calibration of flow-controlled samplers. A flow-
controlled sampler may be calibrated solely at its controlled flow rate, 
provided that previous operating history of the sampler demonstrates 
that the flow rate is stable and reliable. In this case, the flow 
indicator may remain uncalibrated but should be used to indicate any 
relative change between initial and final flows, and the sampler should 
be recalibrated more often to minimize potential loss of samples because 
of controller malfunction.
    9.4.1 Set the flow controller for a flow near the lower limit of the 
flow range to allow maximum control range.
    9.4.2 Install a clean filter in the sampler and carry out steps 
9.3.2, 9.3.3, 9.3.4, 9.3.6, and 9.3.7.
    9.4.3 Following calibration, add one or two additional clean filters 
to the sampler, reconnect the transfer standard, and operate the sampler 
to verify that the controller maintains the same calibrated flow rate; 
this is particularly important at high altitudes where the flow control 
range may be reduced.



[[Page 32]]




    10.0 Calculations of TSP Concentration.
    10.1 Determine the average sampler flow rate during the sampling 
period according to either 10.1.1 or 10.1.2 below.
    10.1.1 For a sampler without a continuous flow recorder, determine 
the appropriate expression to be used from table 2 corresponding to the 
one from table 1 used in step 9.3.9. Using this appropriate expression, 
determine Qstd for the initial flow rate from the sampler 
calibration curve, either graphically or from the transposed regression 
equation:

Qstd =
1/m ([Appropriate expression from table 2]-b)

Similarly, determine Qstd from the final flow reading, and 
calculate the average flow Qstd as one-half the sum of the 
initial and final flow rates.
    10.1.2 For a sampler with a continuous flow recorder, determine the 
average flow rate device reading, I, for the period. Determine the 
appropriate expression from table 2 corresponding to the one from table 
1 used in step 9.3.9. Then using this expression and the average flow 
rate reading, determine Qstd from the sampler calibration 
curve, either graphically or from the transposed regression equation:

Qstd =

1/m ([Appropriate expression from table 2]-b)
    If the trace shows substantial flow change during the sampling 
period, greater accuracy may be achieved by dividing the sampling period 
into intervals and calculating an average reading before determining 
Qstd.
    10.2 Calculate the total air volume sampled as:

V-Qstdx t

where:

V = total air volume sampled, in standard volume units, std m\3\/;
Qstd = average standard flow rate, std m\3\/min;
t = sampling time, min.

    10.3 Calculate and report the particulate matter concentration as:
    [GRAPHIC] [TIFF OMITTED] TR31AU93.025
    
where:

TSP = mass concentration of total suspended particulate matter, [mu]g/
std m\3\;
Wi = initial weight of clean filter, g;
Wf = final weight of exposed filter, g;
V = air volume sampled, converted to standard conditions, std m\3\,
10\6\ = conversion of g to [mu]g.

    10.4 If desired, the actual particulate matter concentration (see 
Section 2.2) can be calculated as follows:

(TSP)a=TSP (P3/Pstd)(298/T3)

where:

(TSP)a = actual concentration at field conditions, [mu]g/
m\3\;

[[Page 33]]

TSP = concentration at standard conditions, [mu]g/std m\3\;
P3 = average barometric pressure during sampling period, mm 
Hg;
Pstd = 760 mn Hg (or 101 kPa);
T3 = average ambient temperature during sampling period, K.

    11.0 References.
    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume I, Principles. EPA-600/9-76-005, U.S. Environmental Protection 
Agency, Research Triangle Park, NC 27711, 1976.
    2. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II, Ambient Air Specific Methods. EPA-600/4-77-027a, U.S. 
Environmental Protection Agency, Research Triangle Park, NC 27711, 1977.
    3. Wedding, J. B., A. R. McFarland, and J. E. Cernak. Large Particle 
Collection Characteristics of Ambient Aerosol Samplers. Environ. Sci. 
Technol. 11:387-390, 1977.
    4. McKee, H. C., et al. Collaborative Testing of Methods to Measure 
Air Pollutants, I. The High-Volume Method for Suspended Particulate 
Matter. J. Air Poll. Cont. Assoc., 22 (342), 1972.
    5. Clement, R. E., and F. W. Karasek. Sample Composition Changes in 
Sampling and Analysis of Organic Compounds in Aerosols. The Intern. J. 
Environ. Anal. Chem., 7:109, 1979.
    6. Lee, R. E., Jr., and J. Wagman. A Sampling Anomaly in the 
Determination of Atmospheric Sulfuric Concentration. Am. Ind. Hygiene 
Assoc. J., 27:266, 1966.
    7. Appel, B. R., et al. Interference Effects in Sampling Particulate 
Nitrate in Ambient Air. Atmospheric Environment, 13:319, 1979.
    8. Tierney, G. P., and W. D. Conner. Hygroscopic Effects on Weight 
Determinations of Particulates Collected on Glass-Fiber Filters. Am. 
Ind. Hygiene Assoc. J., 28:363, 1967.
    9. Chahal, H. S., and D. J. Romano. High-Volume Sampling Effect of 
Windborne Particulate Matter Deposited During Idle Periods. J. Air Poll. 
Cont. Assoc., Vol. 26 (885), 1976.
    10. Patterson, R. K. Aerosol Contamination from High-Volume Sampler 
Exhaust. J. Air Poll. Cont. Assoc., Vol. 30 (169), 1980.
    11. EPA Test Procedures for Determining pH and Integrity of High-
Volume Air Filters. QAD/M-80.01. Available from the Methods 
Standardization Branch, Quality Assurance Division, Environmental 
Monitoring Systems Laboratory (MD-77), U.S. Environmental Protection 
Agency, Research Triangle Park, NC 27711, 1980.
    12. Smith, F., P. S. Wohlschlegel, R. S. C. Rogers, and D. J. 
Mulligan. Investigation of Flow Rate Calibration Procedures Associated 
with the High-Volume Method for Determination of Suspended Particulates. 
EPA-600/4-78-047, U.S. Environmental Protection Agency, Research 
Triangle Park, NC, June 1978.



[[Page 34]]





[[Page 35]]





[[Page 36]]





[[Page 37]]





[47 FR 54912, Dec. 6, 1982; 48 FR 17355, Apr. 22, 1983]

 Appendix C to Part 50--Measurement Principle and Calibration Procedure 
for the Measurement of Carbon Monoxide in the Atmosphere (Non-Dispersive 
                          Infrared Photometry)

                          Measurement Principle

    1. Measurements are based on the absorption of infrared radiation by 
carbon monoxide (CO) in a non-dispersive photometer. Infrared energy 
from a source is passed through a cell containing the gas sample to be 
analyzed, and the quantitative absorption of energy by CO in the sample 
cell is measured by a suitable detector. The photometer is sensitized to 
CO by employing CO gas in either the detector or in a filter cell in the 
optical path, thereby limiting the measured absorption to one or more of 
the characteristic wavelengths at which CO strongly absorbs. Optical 
filters or other means may

[[Page 38]]

also be used to limit sensitivity of the photometer to a narrow band of 
interest. Various schemes may be used to provide a suitable zero 
reference for the photometer. The measured absorption is converted to an 
electrical output signal, which is related to the concentration of CO in 
the measurement cell.
    2. An analyzer based on this principle will be considered a 
reference method only if it has been designated as a reference method in 
accordance with part 53 of this chapter.
    3. Sampling considerations.
    The use of a particle filter on the sample inlet line of an NDIR CO 
analyzer is optional and left to the discretion of the user or the 
manufacturer. Use of filter should depend on the analyzer's 
susceptibility to interference, malfunction, or damage due to particles.

                          Calibration Procedure

    1. Principle. Either of two methods may be used for dynamic 
multipoint calibration of CO analyzers:
    (1) One method uses a single certified standard cylinder of CO, 
diluted as necessary with zero air, to obtain the various calibration 
concentrations needed.
    (2) The other method uses individual certified standard cylinders of 
CO for each concentration needed. Additional information on calibration 
may be found in Section 2.0.9 of Reference 1.
    2. Apparatus. The major components and typical configurations of the 
calibration systems for the two calibration methods are shown in Figures 
1 and 2.
    2.1 Flow controller(s). Device capable of adjusting and regulating 
flow rates. Flow rates for the dilution method (Figure 1) must be 
regulated to  1%.
    2.2 Flow meter(s). Calibrated flow meter capable of measuring and 
monitoring flow rates. Flow rates for the dilution method (Figure 1) 
must be measured with an accuracy of  2% of the measured 
value.
    2.3 Pressure regulator(s) for standard CO cylinder(s). Regulator 
must have nonreactive diaphragm and internal parts and a suitable 
delivery pressure.
    2.4 Mixing chamber. A chamber designed to provide thorough mixing of 
CO and diluent air for the dilution method.
    2.5 Output manifold. The output manifold should be of sufficient 
diameter to insure an insignificant pressure drop at the analyzer 
connection. The system must have a vent designed to insure atmospheric 
pressure at the manifold and to prevent ambient air from entering the 
manifold.
    3. Reagents.
    3.1 CO concentration standard(s). Cylinder(s) of CO in air 
containing appropriate concentrations(s) of CO suitable for the selected 
operating range of the analyzer under calibration; CO standards for the 
dilution method may be contained in a nitrogen matrix if the zero air 
dilution ratio is not less than 100:1. The assay of the cylinder(s) must 
be traceable either to a National Bureau of Standards (NBS) CO in air 
Standard Reference Material (SRM) or to an NBS/EPA-approved commercially 
available Certified Reference Material (CRM). CRM's are described in 
Reference 2, and a list of CRM sources is available from the address 
shown for Reference 2. A recommended protocol for certifying CO gas 
cylinders against either a CO SRM or a CRM is given in Reference 1. CO 
gas cylinders should be recertified on a regular basis as determined by 
the local quality control program.
    3.2 Dilution gas (zero air). Air, free of contaminants which will 
cause a detectable response on the CO analyzer. The zero air should 
contain <0.1 ppm CO. A procedure for generating zero air is given in 
Reference 1.
    4. Procedure Using Dynamic Dilution Method.
    4.1 Assemble a dynamic calibration system such as the one shown in 
Figure 1. All calibration gases including zero air must be introduced 
into the sample inlet of the analyzer system. For specific operating 
instructions refer to the manufacturer's manual.
    4.2 Insure that all flowmeters are properly calibrated, under the 
conditions of use, if appropriate, against an authoritative standard 
such as a soap-bubble meter or wet-test meter. All volumetric flowrates 
should be corrected to 25  deg.C and 760 mm Hg (101 kPa). A discussion 
on calibration of flowmeters is given in Reference 1.
    4.3 Select the operating range of the CO analyzer to be calibrated.
    4.4 Connect the signal output of the CO analyzer to the input of the 
strip chart recorder or other data collection device. All adjustments to 
the analyzer should be based on the appropriate strip chart or data 
device readings. References to analyzer responses in the procedure given 
below refer to recorder or data device responses.
    4.5 Adjust the calibration system to deliver zero air to the output 
manifold. The total air flow must exceed the total demand of the 
analyzer(s) connected to the output manifold to insure that no ambient 
air is pulled into the manifold vent. Allow the analyzer to sample zero 
air until a stable respose is obtained. After the response has 
stabilized, adjust the analyzer zero control. Offsetting the analyzer 
zero adjustments to +5 percent of scale is recommended to facilitate 
observing negative zero drift. Record the stable zero air response as 
ZCO.
    4.6 Adjust the zero air flow and the CO flow from the standard CO 
cylinder to provide a diluted CO concentration of approximately 80 
percent of the upper range limit (URL) of the operating range of the 
analyzer. The total air flow must exceed the total demand of the 
analyzer(s) connected to the output manifold to insure that no ambient 
air is

[[Page 39]]

pulled into the manifold vent. The exact CO concentration is calculated 
from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.026

where:

[CO]OUT = diluted CO concentration at the output manifold, 
ppm;
[CO]STD = concentration of the undiluted CO standard, ppm;
FCO = flow rate of the CO standard corrected to 25  deg.C and 
760 mm Hg, (101 kPa), L/min; and
FD = flow rate of the dilution air corrected to 25  deg.C and 
760 mm Hg, (101 kPa), L/min.

    Sample this CO concentration until a stable response is obtained. 
Adjust the analyzer span control to obtain a recorder response as 
indicated below:

Recorder response (percent scale) =

[GRAPHIC] [TIFF OMITTED] TR31AU93.027

where:

URL = nominal upper range limit of the analyzer's operating range, and
ZCO = analyzer response to zero air, % scale.

    If substantial adjustment of the analyzer span control is required, 
it may be necessary to recheck the zero and span adjustments by 
repeating Steps 4.5 and 4.6. Record the CO concentration and the 
analyzer's response. 4.7 Generate several additional concentrations (at 
least three evenly spaced points across the remaining scale are 
suggested to verify linearity) by decreasing FCO or 
increasing FD. Be sure the total flow exceeds the analyzer's 
total flow demand. For each concentration generated, calculate the exact 
CO concentration using Equation (1). Record the concentration and the 
analyzer's response for each concentration. Plot the analyzer responses 
versus the corresponding CO concentrations and draw or calculate the 
calibration curve.
    5. Procedure Using Multiple Cylinder Method. Use the procedure for 
the dynamic dilution method with the following changes:
    5.1 Use a multi-cylinder system such as the typical one shown in 
Figure 2.
    5.2 The flowmeter need not be accurately calibrated, provided the 
flow in the output manifold exceeds the analyzer's flow demand.
    5.3 The various CO calibration concentrations required in Steps 4.6 
and 4.7 are obtained without dilution by selecting the appropriate 
certified standard cylinder.

                               References

    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II--Ambient Air Specific Methods, EPA-600/4-77-027a, U.S. 
Environmental Protection Agency, Environmental Monitoring Systems 
Laboratory, Research Triangle Park, NC 27711, 1977.
    2. A procedure for Establishing Traceability of Gas Mixtures to 
Certain National Bureau of Standards Standard Reference Materials. EPA-
600/7-81-010, U.S. Environmental Protection Agency, Environmental 
Monitoring Systems Laboratory (MD-77), Research Triangle Park, NC 27711, 
January 1981.

[[Page 40]]




[[Page 41]]





[47 FR 54922, Dec. 6, 1982; 48 FR 17355, Apr. 22, 1983]

[[Page 42]]

 Appendix D to Part 50--Measurement Principle and Calibration Procedure 
             for the Measurement of Ozone in the Atmosphere

                          measurement principle

    1. Ambient air and ethylene are delivered simultaneously to a mixing 
zone where the ozone in the air reacts with the ethylene to emit light, 
which is detected by a photomultiplier tube. The resulting photocurrent 
is amplified and is either read directly or displayed on a recorder.
    2. An analyzer based on this principle will be considered a 
reference method only if it has been designated as a reference method in 
accordance with part 53 of this chapter and calibrated as follows:

                          calibration procedure

    1. Principle. The calibration procedure is based on the photometric 
assay of ozone (O3) concentrations in a dynamic flow system. 
The concentration of O3 in an absorption cell is determined 
from a measurement of the amount of 254 nm light absorbed by the sample. 
This determination requires knowledge of (1) the absorption coefficient 
([alpha]) of O3 at 254 nm, (2) the optical path length (l) 
through the sample, (3) the transmittance of the sample at a wavelength 
of 254 nm, and (4) the temperature (T) and pressure (P) of the sample. 
The transmittance is defined as the ratio I/I0, where I is 
the intensity of light which passes through the cell and is sensed by 
the detector when the cell contains an O3 sample, and 
I0 is the intensity of light which passes through the cell 
and is sensed by the detector when the cell contains zero air. It is 
assumed that all conditions of the system, except for the contents of 
the absorption cell, are identical during measurement of I and 
I0. The quantities defined above are related by the Beer-
Lambert absorption law,
[GRAPHIC] [TIFF OMITTED] TR31AU93.028

where:

[alpha] = absorption coefficient of O3 at 254 nm=308 
4 atm-1 cm-1 at 0  deg.C and 760 torr. 
(1, 2, 3, 4, 5, 6, 7)
c = O3 concentration in atmospheres
l = optical path length in cm

    In practice, a stable O3 generator is used to produce 
O3 concentrations over the required range. Each O3 
concentration is determined from the measurement of the transmittance 
(I/I0) of the sample at 254 nm with a photometer of path 
length l and calculated from the equation,
[GRAPHIC] [TIFF OMITTED] TR31AU93.029

The calculated O3 concentrations must be corrected for 
O3 losses which may occur in the photometer and for the 
temperature and pressure of the sample.
    2. Applicability. This procedure is applicable to the calibration of 
ambient air O3 analyzers, either directly or by means of a 
transfer standard certified by this procedure. Transfer standards must 
meet the requirements and specifications set forth in Reference 8.
    3. Apparatus. A complete UV calibration system consists of an ozone 
generator, an output port or manifold, a photometer, an appropriate 
source of zero air, and other components as necessary. The configuration 
must provide a stable ozone concentration at the system output and allow 
the photometer to accurately assay the output concentration to the 
precision specified for the photometer (3.1). Figure 1 shows a commonly 
used configuration and serves to illustrate the calibration procedure 
which follows. Other configurations may require appropriate variations 
in the procedural steps. All connections between components in the 
calibration system downstream of the O3 generator should be 
of glass, Teflon, or other relatively inert materials. Additional 
information regarding the assembly of a UV photometric calibration 
apparatus is given in Reference 9. For certification of transfer 
standards which provide their own source of O3, the transfer 
standard may replace the O3 generator and possibly other 
components shown in Figure 1; see Reference 8 for guidance.
    3.1 UV photometer. The photometer consists of a low-pressure mercury 
discharge lamp, (optional) collimation optics, an absorption cell, a 
detector, and signal-processing electronics, as illustrated in Figure 1. 
It must be capable of measuring the transmittance, I/I0, at a 
wavelength of 254 nm with sufficient precision such that the standard 
deviation of the concentration measurements does not exceed the greater 
of 0.005 ppm or 3% of the concentration. Because the low-pressure 
mercury lamp radiates at several wavelengths, the photometer must 
incorporate suitable means to assure that no O3 is generated 
in the cell by the lamp, and that at least 99.5% of the radiation sensed 
by the detector is 254 nm radiation. (This can be readily achieved by 
prudent selection of optical filter and detector response 
characteristics.) The length of the light path through the absorption 
cell must be known with an accuracy of at least 99.5%. In addition, the 
cell and associated plumbing must be designed to

[[Page 43]]

minimize loss of O3 from contact with cell walls and gas 
handling components. See Reference 9 for additional information.
    3.2 Air flow controllers. Devices capable of regulating air flows as 
necessary to meet the output stability and photometer precision 
requirements.
    3.3 Ozone generator. Device capable of generating stable levels of 
O3 over the required concentration range.
    3.4 Output manifold. The output manifold should be constructed of 
glass, Teflon, or other relatively inert material, and should be of 
sufficient diameter to insure a negligible pressure drop at the 
photometer connection and other output ports. The system must have a 
vent designed to insure atmospheric pressure in the manifold and to 
prevent ambient air from entering the manifold.
    3.5 Two-way valve. Manual or automatic valve, or other means to 
switch the photometer flow between zero air and the O3 
concentration.
    3.6 Temperature indicator. Accurate to 1  deg.C.
    3.7 Barometer or pressure indicator. Accurate to 2 torr.
    4. Reagents.
    4.1 Zero air. The zero air must be free of contaminants which would 
cause a detectable response from the O3 analyzer, and it 
should be free of NO, C2 H4, and other species 
which react with O3. A procedure for generating suitable zero 
air is given in Reference 9. As shown in Figure 1, the zero air supplied 
to the photometer cell for the I0 reference measurement must 
be derived from the same source as the zero air used for generation of 
the ozone concentration to be assayed (I measurement). When using the 
photometer to certify a transfer standard having its own source of 
ozone, see Reference 8 for guidance on meeting this requirement.
    5. Procedure.
    5.1 General operation. The calibration photometer must be dedicated 
exclusively to use as a calibration standard. It should always be used 
with clean, filtered calibration gases, and never used for ambient air 
sampling. Consideration should be given to locating the calibration 
photometer in a clean laboratory where it can be stationary, protected 
from physical shock, operated by a responsible analyst, and used as a 
common standard for all field calibrations via transfer standards.
    5.2 Preparation. Proper operation of the photometer is of critical 
importance to the accuracy of this procedure. The following steps will 
help to verify proper operation. The steps are not necessarily required 
prior to each use of the photometer. Upon initial operation of the 
photometer, these steps should be carried out frequently, with all 
quantitative results or indications recorded in a chronological record 
either in tabular form or plotted on a graphical chart. As the 
performance and stability record of the photometer is established, the 
frequency of these steps may be reduced consistent with the documented 
stability of the photometer.
    5.2.1 Instruction manual: Carry out all set up and adjustment 
procedures or checks as described in the operation or instruction manual 
associated with the photometer.
    5.2.2 System check: Check the photometer system for integrity, 
leaks, cleanliness, proper flowrates, etc. Service or replace filters 
and zero air scrubbers or other consumable materials, as necessary.
    5.2.3 Linearity: Verify that the photometer manufacturer has 
adequately established that the linearity error of the photometer is 
less than 3%, or test the linearity by dilution as follows: Generate and 
assay an O3 concentration near the upper range limit of the 
system (0.5 or 1.0 ppm), then accurately dilute that concentration with 
zero air and reassay it. Repeat at several different dilution ratios. 
Compare the assay of the original concentration with the assay of the 
diluted concentration divided by the dilution ratio, as follows
[GRAPHIC] [TIFF OMITTED] TR31AU93.030

where:

E = linearity error, percent
A1 = assay of the original concentration
A2 = assay of the diluted concentration
R = dilution ratio = flow of original concentration divided by the total 
flow

    The linearity error must be less than 5%. Since the accuracy of the 
measured flow-rates will affect the linearity error as measured this 
way, the test is not necessarily conclusive. Additional information on 
verifying linearity is contained in Reference 9.
    5.2.4 Intercomparison: When possible, the photometer should be 
occasionally intercompared, either directly or via transfer standards, 
with calibration photometers used by other agencies or laboratories.
    5.2.5 Ozone losses: Some portion of the O3 may be lost 
upon contact with the photometer cell walls and gas handling components. 
The magnitude of this loss must be determined and used to correct the 
calculated O3 concentration. This loss must not exceed 5%. 
Some guidelines for quantitatively determining this loss are discussed 
in Reference 9.
    5.3 Assay of O3 concentrations.
    5.3.1 Allow the photometer system to warm up and stabilizer.
    5.3.2 Verify that the flowrate through the photometer absorption 
cell, F allows the cell to be flushed in a reasonably short period of 
time (2 liter/min is a typical flow). The precision of the measurements 
is inversely related to the time required for flushing, since the 
photometer drift error increases with time.

[[Page 44]]

    5.3.3 Insure that the flowrate into the output manifold is at least 
1 liter/min greater than the total flowrate required by the photometer 
and any other flow demand connected to the manifold.
    5.3.4 Insure that the flowrate of zero air, Fz, is at 
least 1 liter/min greater than the flowrate required by the photometer.
    5.3.5 With zero air flowing in the output manifold, actuate the two-
way valve to allow the photometer to sample first the manifold zero air, 
then Fz. The two photometer readings must be equal 
(I=Io).
    Note: In some commercially available photometers, the operation of 
the two-way valve and various other operations in section 5.3 may be 
carried out automatically by the photometer.
    5.3.6 Adjust the O3 generator to produce an O3 
concentration as needed.
    5.3.7 Actuate the two-way valve to allow the photometer to sample 
zero air until the absorption cell is thoroughly flushed and record the 
stable measured value of Io.
    5.3.8 Actuate the two-way valve to allow the photometer to sample 
the ozone concentration until the absorption cell is thoroughly flushed 
and record the stable measured value of I.
    5.3.9 Record the temperature and pressure of the sample in the 
photometer absorption cell. (See Reference 9 for guidance.)
    5.3.10 Calculate the O3 concentration from equation 4. An 
average of several determinations will provide better precision.
[GRAPHIC] [TIFF OMITTED] TR31AU93.032

where:

[O3]OUT = O3 concentration, ppm
[alpha] = absorption coefficient of O3 at 254 nm=308 
atm-1 cm-1 at 0  deg.C and 760 torr
l = optical path length, cm
T = sample temperature, K
P = sample pressure, torr
L = correction factor for O3 losses from 5.2.5=(1-fraction 
O3 lost).

    Note: Some commercial photometers may automatically evaluate all or 
part of equation 4. It is the operator's responsibility to verify that 
all of the information required for equation 4 is obtained, either 
automatically by the photometer or manually. For ``automatic'' 
photometers which evaluate the first term of equation 4 based on a 
linear approximation, a manual correction may be required, particularly 
at higher O3 levels. See the photometer instruction manual 
and Reference 9 for guidance.
    5.3.11 Obtain additional O3 concentration standards as 
necessary by repeating steps 5.3.6 to 5.3.10 or by Option 1.
    5.4 Certification of transfer standards. A transfer standard is 
certified by relating the output of the transfer standard to one or more 
ozone standards as determined according to section 5.3. The exact 
procedure varies depending on the nature and design of the transfer 
standard. Consult Reference 8 for guidance.
    5.5 Calibration of ozone analyzers. Ozone analyzers are calibrated 
as follows, using ozone standards obtained directly according to section 
5.3 or by means of a certified transfer standard.
    5.5.1 Allow sufficient time for the O3 analyzer and the 
photometer or transfer standard to warmup and stabilize.
    5.5.2 Allow the O3 analyzer to sample zero air until a 
stable response is obtained and adjust the O3 analyzer's zero 
control. Offsetting the analyzer's zero adjustment to +5% of scale is 
recommended to facilitate observing negative zero drift. Record the 
stable zero air response as ``Z''.
    5.5.3 Generate an O3 concentration standard of 
approximately 80% of the desired upper range limit (URL) of the 
O3 analyzer. Allow the O3 analyzer to sample this 
O3 concentration standard until a stable response is 
obtained.
    5.5.4 Adjust the O3 analyzer's span control to obtain a 
convenient recorder response as indicated below:
    recorder response (%scale) =
    [GRAPHIC] [TIFF OMITTED] TR31AU93.033
    
where:

URL = upper range limit of the O3 analyzer, ppm
Z = recorder response with zero air, % scale

    Record the O3 concentration and the corresponding 
analyzer response. If substantial adjustment of the span control is 
necessary, recheck the zero and span adjustments by repeating steps 
5.5.2 to 5.5.4.
    5.5.5 Generate several other O3 concentration standards 
(at least 5 others are recommended) over the scale range of the 
O3 analyzer by adjusting the O3 source or by 
Option 1. For each O3 concentration standard, record the 
O3 and the corresponding analyzer response.
    5.5.6 Plot the O3 analyzer responses versus the 
corresponding O3 concentrations and draw the O3 
analyzer's calibration curve or calculate the appropriate response 
factor.
    5.5.7 Option 1: The various O3 concentrations required in 
steps 5.3.11 and 5.5.5 may be obtained by dilution of the O3 
concentration generated in steps 5.3.6 and 5.5.3. With this option, 
accurate flow measurements are required. The dynamic calibration system 
may be modified as shown in Figure 2 to allow for dilution air to be 
metered in downstream of the O3 generator. A mixing chamber 
between the O3 generator and the output manifold is also 
required. The flowrate through the O3 generator 
(Fo) and the dilution air flowrate

[[Page 45]]

(FD) are measured with a reliable flow or volume standard 
traceable to NBS. Each O3 concentration generated by dilution 
is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.031

where:

[O3]'OUT = diluted O3 concentration, 
ppm
F0 = flowrate through the O3 generator, liter/min
FD = diluent air flowrate, liter/min

                               References

    1. E.C.Y. Inn and Y. Tanaka, ``Absorption coefficient of Ozone in 
the Ultraviolet and Visible Regions'', J. Opt. Soc. Am., 43, 870 (1953).
    2. A. G. Hearn, ``Absorption of Ozone in the Ultraviolet and Visible 
Regions of the Spectrum'', Proc. Phys. Soc. (London), 78, 932 (1961).
    3. W. B. DeMore and O. Raper, ``Hartley Band Extinction Coefficients 
of Ozone in the Gas Phase and in Liquid Nitrogen, Carbon Monoxide, and 
Argon'', J. Phys. Chem., 68, 412 (1964).
    4. M. Griggs, ``Absorption Coefficients of Ozone in the Ultraviolet 
and Visible Regions'', J. Chem. Phys., 49, 857 (1968).
    5. K. H. Becker, U. Schurath, and H. Seitz, ``Ozone Olefin Reactions 
in the Gas Phase. 1. Rate Constants and Activation Energies'', Int'l 
Jour. of Chem. Kinetics, VI, 725 (1974).
    6. M. A. A. Clyne and J. A. Coxom, ``Kinetic Studies of Oxy-halogen 
Radical Systems'', Proc. Roy. Soc., A303, 207 (1968).
    7. J. W. Simons, R. J. Paur, H. A. Webster, and E. J. Bair, ``Ozone 
Ultraviolet Photolysis. VI. The Ultraviolet Spectrum'', J. Chem. Phys., 
59, 1203 (1973).
    8. Transfer Standards for Calibration of Ambient Air Monitoring 
Analyzers for Ozone, EPA publication number EPA-600/4-79-056, EPA, 
National Exposure Research Laboratory, Department E, (MD-77B), Research 
Triangle Park, NC 27711.
    9. Technical Assistance Document for the Calibration of Ambient 
Ozone Monitors, EPA publication number EPA-600/4-79-057, EPA, National 
Exposure Research Laboratory, Department E, (MD-77B), Research Triangle 
Park, NC 27711.

[[Page 46]]




[[Page 47]]



[44 FR 8224, Feb. 8, 1979, as amended at 62 FR 38895, July 18, 1997]

                    Appendix E to Part 50 [Reserved]

 Appendix F to Part 50--Measurement Principle and Calibration Procedure 
  for the Measurement of Nitrogen Dioxide in the Atmosphere (Gas Phase 
                           Chemiluminescence)

                       Principle and Applicability

    1. Atmospheric concentrations of nitrogen dioxide (NO2) 
are measured indirectly by photometrically measuring the light 
intensity, at wavelengths greater than 600 nanometers, resulting from 
the chemiluminescent reaction of nitric oxide (NO) with ozone 
(O3). (1,2,3) NO2 is first quantitatively reduced 
to NO(4,5,6) by means of a converter. NO, which commonly exists in 
ambient air together with NO2, passes through the converter 
unchanged causing a resultant total NOX concentration equal 
to NO+NO2. A sample of the input air is also measured without 
having passed through the converted. This latter NO measurement is 
subtracted from the former measurement (NO+NO2) to yield the 
final NO2 measurement. The NO and NO+NO2 
measurements may be made concurrently with dual systems, or cyclically 
with the same system provided the cycle time does not exceed 1 minute.
    2. Sampling considerations.
    2.1 Chemiluminescence NO/NOX/NO2 analyzers 
will respond to other nitrogen containing compounds, such as 
peroxyacetyl nitrate (PAN), which might be reduced to NO in the thermal 
converter. (7) Atmospheric concentrations of these potential 
interferences are generally low relative to NO2 and valid 
NO2 measurements may be obtained. In certain geographical 
areas, where the concentration of these potential interferences is known 
or suspected to be high relative to NO2, the use of an 
equivalent method for the measurement of NO2 is recommended.
    2.2 The use of integrating flasks on the sample inlet line of 
chemiluminescence NO/NOX/NO2 analyzers is optional 
and left to couraged. The sample residence time between the sampling 
point and the analyzer should be kept to a minimum to avoid erroneous 
NO2 measurements resulting from the reaction of ambient 
levels of NO and O3 in the sampling system.
    2.3 The use of particulate filters on the sample inlet line of 
chemiluminescence NO/NOX/NO2 analyzers is optional 
and left to the discretion of the user or the manufacturer.
Use of the filter should depend on the analyzer's susceptibility to 
interference, malfunction, or damage due to particulates. Users are 
cautioned that particulate matter concentrated on a filter may cause 
erroneous NO2 measurements and therefore filters should be 
changed frequently.
    3. An analyzer based on this principle will be considered a 
reference method only if it has been designated as a reference method in 
accordance with part 53 of this chapter.

                               Calibration

    1. Alternative A--Gas phase titration (GPT) of an NO standard with 
O3.
    Major equipment required: Stable O3 generator. 
Chemiluminescence NO/NOX/NO2 analyzer with strip 
chart recorder(s). NO concentration standard.
    1.1 Principle. This calibration technique is based upon the rapid 
gas phase reaction between NO and O3 to produce 
stoichiometric quantities of NO2 in accordance with the 
following equation: (8)
[GRAPHIC] [TIFF OMITTED] TC08NO91.075

The quantitative nature of this reaction is such that when the NO 
concentration is known, the concentration of NO2 can be 
determined. Ozone is added to excess NO in a dynamic calibration system, 
and the NO channel of the chemiluminescence NO/NOX/
NO2 analyzer is used as an indicator of changes in NO 
concentration. Upon the addition of O3, the decrease in NO 
concentration observed on the calibrated NO channel is equivalent to the 
concentration of NO2 produced. The amount of NO2 
generated may be varied by adding variable amounts of O3 from 
a stable uncalibrated O3 generator. (9)
    1.2 Apparatus. Figure 1, a schematic of a typical GPT apparatus, 
shows the suggested configuration of the components listed below. All 
connections between components in the calibration system downstream from 
the O3 generator should be of glass, Teflon[reg], 
or other non-reactive material.
    1.2.1 Air flow controllers. Devices capable of maintaining constant 
air flows within 2% of the required flowrate.
    1.2.2 NO flow controller. A device capable of maintaining constant 
NO flows within 2% of the required flowrate. Component parts 
in contact with the NO should be of a non-reactive material.
    1.2.3 Air flowmeters. Calibrated flowmeters capable of measuring and 
monitoring air flowrates with an accuracy of 2% of the 
measured flowrate.
    1.2.4 NO flowmeter. A calibrated flowmeter capable of measuring and 
monitoring NO flowrates with an accuracy of 2% of the 
measured flowrate. (Rotameters have been reported to operate unreliably 
when measuring low NO flows and are not recommended.)
    1.2.5 Pressure regulator for standard NO cylinder. This regulator 
must have a nonreactive diaphragm and internal parts and a suitable 
delivery pressure.

[[Page 48]]

    1.2.6 Ozone generator. The generator must be capable of generating 
sufficient and stable levels of O3 for reaction with NO to 
generate NO2 concentrations in the range required. Ozone 
generators of the electric discharge type may produce NO and 
NO2 and are not recommended.
    1.2.7 Valve. A valve may be used as shown in Figure 1 to divert the 
NO flow when zero air is required at the manifold. The valve should be 
constructed of glass, Teflon[reg], or other nonreactive 
material.
    1.2.8 Reaction chamber. A chamber, constructed of glass, 
Teflon[reg], or other nonreactive material, for the 
quantitative reaction of O3 with excess NO. The chamber 
should be of sufficient volume (VRC) such that the residence 
time (tR) meets the requirements specified in 1.4. For 
practical reasons, tR should be less than 2 minutes.
    1.2.9 Mixing chamber. A chamber constructed of glass, 
Teflon[reg], or other nonreactive material and designed to 
provide thorough mixing of reaction products and diluent air. The 
residence time is not critical when the dynamic parameter specification 
given in 1.4 is met.
    1.2.10 Output manifold. The output manifold should be constructed of 
glass, Teflon[reg], or other non-reactive material and should 
be of sufficient diameter to insure an insignificant pressure drop at 
the analyzer connection. The system must have a vent designed to insure 
atmospheric pressure at the manifold and to prevent ambient air from 
entering the manifold.
    1.3 Reagents.
    1.3.1 NO concentration standard. Gas cylinder standard containing 50 
to 100 ppm NO in N2 with less than 1 ppm NO2. This 
standard must be traceable to a National Bureau of Standards (NBS) NO in 
N2 Standard Reference Material (SRM 1683 or SRM 1684), an NBS 
NO2 Standard Reference Material (SRM 1629), or an NBS/EPA-
approved commercially available Certified Reference Material (CRM). 
CRM's are described in Reference 14, and a list of CRM sources is 
available from the address shown for Reference 14. A recommended 
protocol for certifying NO gas cylinders against either an NO SRM or CRM 
is given in section 2.0.7 of Reference 15. Reference 13 gives procedures 
for certifying an NO gas cylinder against an NBS NO2 SRM and 
for determining the amount of NO2 impurity in an NO cylinder.
    1.3.2 Zero air. Air, free of contaminants which will cause a 
detectable response on the NO/NOX/NO2 analyzer or 
which might react with either NO, O3, or NO2 in 
the gas phase titration. A procedure for generating zero air is given in 
reference 13.
    1.4 Dynamic parameter specification.
    1.4.1 The O3 generator air flowrate (F0) and 
NO flowrate (FNO) (see Figure 1) must be adjusted such that 
the following relationship holds:
[GRAPHIC] [TIFF OMITTED] TC08NO91.076

[GRAPHIC] [TIFF OMITTED] TC08NO91.077

[GRAPHIC] [TIFF OMITTED] TC08NO91.078

where:

PR = dynamic parameter specification, determined empirically, 
to insure complete reaction of the available O3, ppm-minute
[NO]RC = NO concentration in the reaction chamber, ppm
R = residence time of the reactant gases in the reaction 
chamber, minute
[NO]STD = concentration of the undiluted NO standard, ppm
FNO = NO flowrate, scm 3/min
FO = O3 generator air flowrate, scm 3/
min
VRC = volume of the reaction chamber, scm 3

    1.4.2 The flow conditions to be used in the GPT system are 
determined by the following procedure:
    (a) Determine FT, the total flow required at the output 
manifold (FT=analyzer demand plus 10 to 50% excess).
    (b) Establish [NO]OUT as the highest NO concentration 
(ppm) which will be required at the output manifold. [NO]OUT 
should be approximately equivalent to 90% of the upper range limit (URL) 
of the NO2 concentration range to be covered.
    (c) Determine FNO as
    [GRAPHIC] [TIFF OMITTED] TC08NO91.079
    
    (d) Select a convenient or available reaction chamber volume. 
Initially, a trial VRC may be selected to be in the range of 
approximately 200 to 500 scm\3\.
    (e) Compute FO as
    
    
    (f) Compute tR as
    [GRAPHIC] [TIFF OMITTED] TC08NO91.080
    
Verify that tR < 2 minutes. If not, select a reaction chamber 
with a smaller VRC.
    (g) Compute the diluent air flowrate as
    [GRAPHIC] [TIFF OMITTED] TC08NO91.081
    
where:

FD = diluent air flowrate, scm 3/min


[[Page 49]]


    (h) If FO turns out to be impractical for the desired 
system, select a reaction chamber having a different VRC and 
recompute FO and FD.
    Note: A dynamic parameter lower than 2.75 ppm-minutes may be used if 
it can be determined empirically that quantitative reaction of 
O3 with NO occurs. A procedure for making this determination 
as well as a more detailed discussion of the above requirements and 
other related considerations is given in reference 13.
    1.5 Procedure.
    1.5.1 Assemble a dynamic calibration system such as the one shown in 
Figure 1.
    1.5.2 Insure that all flowmeters are calibrated under the conditions 
of use against a reliable standard such as a soap-bubble meter or wet-
test meter. All volumetric flowrates should be corrected to 25  deg.C 
and 760 mm Hg. A discussion on the calibration of flowmeters is given in 
reference 13.
    1.5.3 Precautions must be taken to remove O2 and other 
contaminants from the NO pressure regulator and delivery system prior to 
the start of calibration to avoid any conversion of the standard NO to 
NO2. Failure to do so can cause significant errors in 
calibration. This problem may be minimized by (1) carefully evacuating 
the regulator, when possible, after the regulator has been connected to 
the cylinder and before opening the cylinder valve; (2) thoroughly 
flushing the regulator and delivery system with NO after opening the 
cylinder valve; (3) not removing the regulator from the cylinder between 
calibrations unless absolutely necessary. Further discussion of these 
procedures is given in reference 13.
    1.5.4 Select the operating range of the NO/NOX/
NO2 analyzer to be calibrated. In order to obtain maximum 
precision and accuracy for NO2 calibration, all three 
channels of the analyzer should be set to the same range. If operation 
of the NO and NOX channels on higher ranges is desired, 
subsequent recalibration of the NO and NOX channels on the 
higher ranges is recommended.
    Note: Some analyzer designs may require identical ranges for NO, 
NOX, and NO2 during operation of the analyzer.
    1.5.5 Connect the recorder output cable(s) of the NO/NOX/
NO2 analyzer to the input terminals of the strip chart 
recorder(s). All adjustments to the analyzer should be performed based 
on the appropriate strip chart readings. References to analyzer 
responses in the procedures given below refer to recorder responses.
    1.5.6 Determine the GPT flow conditions required to meet the dynamic 
parameter specification as indicated in 1.4.
    1.5.7 Adjust the diluent air and O3 generator air flows 
to obtain the flows determined in section 1.4.2. The total air flow must 
exceed the total demand of the analyzer(s) connected to the output 
manifold to insure that no ambient air is pulled into the manifold vent. 
Allow the analyzer to sample zero air until stable NO, NOX, 
and NO2 responses are obtained. After the responses have 
stabilized, adjust the analyzer zero control(s).
    Note: Some analyzers may have separate zero controls for NO, 
NOX, and NO2. Other analyzers may have separate 
zero controls only for NO and NOX, while still others may 
have only one zero control common to all three channels.
    Offsetting the analyzer zero adjustments to +5 percent of scale is 
recommended to facilitate observing negative zero drift. Record the 
stable zero air responses as ZNO, Znox, and Zno2.
    1.5.8 Preparation of NO and NOX calibration curves.
    1.5.8.1 Adjustment of NO span control. Adjust the NO flow from the 
standard NO cylinder to generate an NO concentration of approximately 80 
percent of the upper range limit (URL) of the NO range. This exact NO 
concentration is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.044

where:

[NO]OUT = diluted NO concentration at the output manifold, 
ppm

Sample this NO concentration until the NO and NOX responses 
have stabilized. Adjust the NO span control to obtain a recorder 
response as indicated below:

recorder response (percent scale) =
[GRAPHIC] [TIFF OMITTED] TR31AU93.045

where:

URL = nominal upper range limit of the NO channel, ppm
    Note: Some analyzers may have separate span controls for NO, 
NOX, and NO2. Other analyzers may have separate 
span controls only for NO and NOX, while still others may 
have only one span control common to all three channels. When only one 
span control is available, the span adjustment is made on the NO channel 
of the analyzer.
If substantial adjustment of the NO span control is necessary, it may be 
necessary to recheck the zero and span adjustments by repeating steps 
1.5.7 and 1.5.8.1. Record the NO concentration and the analyzer's NO 
response.
    1.5.8.2 Adjustment of NOX span control. When adjusting 
the analyzer's NOX span control, the presence of any 
NO2 impurity in the standard NO cylinder must be taken into 
account. Procedures for determining the amount of NO2 
impurity in the standard NO

[[Page 50]]

cylinder are given in reference 13. The exact NOX 
concentration is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.046

where:

[NOX]OUT = diluted NOX concentration at 
the output manifold, ppm
[NO2]IMP = concentration of NO2 
impurity in the standard NO cylinder, ppm

Adjust the NOX span control to obtain a recorder response as 
indicated below:

recorder response (% scale) =
[GRAPHIC] [TIFF OMITTED] TR31AU93.047

    Note: If the analyzer has only one span control, the span adjustment 
is made on the NO channel and no further adjustment is made here for 
NOx.
If substantial adjustment of the NOX span control is 
necessary, it may be necessary to recheck the zero and span adjustments 
by repeating steps 1.5.7 and 1.5.8.2. Record the NOX 
concentration and the analyzer's NOX response.
    1.5.8.3 Generate several additional concentrations (at least five 
evenly spaced points across the remaining scale are suggested to verify 
linearity) by decreasing FNO or increasing FD. For 
each concentration generated, calculate the exact NO and NOX 
concentrations using equations (9) and (11) respectively. Record the 
analyzer's NO and NOX responses for each concentration. Plot 
the analyzer responses versus the respective calculated NO and 
NOX concentrations and draw or calculate the NO and 
NOX calibration curves. For subsequent calibrations where 
linearity can be assumed, these curves may be checked with a two-point 
calibration consisting of a zero air point and NO and NOX 
concentrations of approximately 80% of the URL.
    1.5.9 Preparation of NO2 calibration curve.
    1.5.9.1 Assuming the NO2 zero has been properly adjusted 
while sampling zero air in step 1.5.7, adjust FO and 
FD as determined in section 1.4.2. Adjust FNO to 
generate an NO concentration near 90% of the URL of the NO range. Sample 
this NO concentration until the NO and NOX responses have 
stabilized. Using the NO calibration curve obtained in section 1.5.8, 
measure and record the NO concentration as [NO]orig. Using 
the NOX calibration curve obtained in section 1.5.8, measure 
and record the NOX concentration as 
[NOX]orig.
    1.5.9.2 Adjust the O3 generator to generate sufficient 
O3 to produce a decrease in the NO concentration equivalent 
to approximately 80% of the URL of the NO2 range. The 
decrease must not exceed 90% of the NO concentration determined in step 
1.5.9.1. After the analyzer responses have stabilized, record the 
resultant NO and NOX concentrations as [NO]rem and 
[NOX]rem.
    1.5.9.3 Calculate the resulting NO2 concentration from:
    [GRAPHIC] [TIFF OMITTED] TC08NO91.082
    
where:

[NO2]OUT = diluted NO2 concentration at 
the output manifold, ppm
[NO]orig = original NO concentration, prior to addition of 
O3, ppm
[NO]rem = NO concentration remaining after addition of 
O3, ppm

Adjust the NO2 span control to obtain a recorder response as 
indicated below:

recorder response (% scale) =
[GRAPHIC] [TIFF OMITTED] TR31AU93.048

    Note: If the analyzer has only one or two span controls, the span 
adjustments are made on the NO channel or NO and NOX channels 
and no further adjustment is made here for NO2.
If substantial adjustment of the NO2 span control is 
necessary, it may be necessary to recheck the zero and span adjustments 
by repeating steps 1.5.7 and 1.5.9.3. Record the NO2 
concentration and the corresponding analyzer NO2 and 
NOX responses.
    1.5.9.4 Maintaining the same FNO, FO, and 
FD as in section 1.5.9.1, adjust the ozone generator to 
obtain several other concentrations of NO2 over the 
NO2 range (at least five evenly spaced points across the 
remaining scale are suggested). Calculate each NO2 
concentration using equation (13) and record the corresponding analyzer 
NO2 and NOX responses. Plot the analyzer's 
NO2 responses versus the corresponding calculated 
NO2 concentrations and draw or calculate the NO2 
calibration curve.
    1.5.10 Determination of converter efficiency.

[[Page 51]]

    1.5.10.1 For each NO2 concentration generated during the 
preparation of the NO2 calibration curve (see section 1.5.9) 
calculate the concentration of NO2 converted from:
[GRAPHIC] [TIFF OMITTED] TC08NO91.083

where:

[NO2]CONV = concentration of NO2 
converted, ppm
[NOX]orig = original NOX concentration 
prior to addition of O3, ppm
[NOX]rem = NOX concentration remaining 
after addition of O3, ppm

    Note: Supplemental information on calibration and other procedures 
in this method are given in reference 13.
Plot [NO2]CONV (y-axis) versus 
[NO2]OUT (x-axis) and draw or calculate the 
converter efficiency curve. The slope of the curve times 100 is the 
average converter efficiency, EC. The average converter 
efficiency must be greater than 96%; if it is less than 96%, replace or 
service the converter.
    2. Alternative B--NO2 permeation device.
    Major equipment required:
    Stable O3 generator.
    Chemiluminescence NO/NOX/NO2 analyzer with 
strip chart recorder(s).
    NO concentration standard.
    NO2 concentration standard.
    2.1 Principle. Atmospheres containing accurately known 
concentrations of nitrogen dioxide are generated by means of a 
permeation device. (10) The permeation device emits NO2 at a 
known constant rate provided the temperature of the device is held 
constant (0.1  deg.C) and the device has been accurately 
calibrated at the temperature of use. The NO2 emitted from 
the device is diluted with zero air to produce NO2 
concentrations suitable for calibration of the NO2 channel of 
the NO/NOX/NO2 analyzer. An NO concentration 
standard is used for calibration of the NO and NOX channels 
of the analyzer.
    2.2 Apparatus. A typical system suitable for generating the required 
NO and NO2 concentrations is shown in Figure 2. All 
connections between components downstream from the permeation device 
should be of glass, Teflon[reg], or other non-reactive 
material.
    2.2.1 Air flow controllers. Devices capable of maintaining constant 
air flows within 2% of the required flowrate.
    2.2.2 NO flow controller. A device capable of maintaining constant 
NO flows within 2% of the required flowrate. Component parts 
in contact with the NO must be of a non-reactive material.
    2.2.3 Air flowmeters. Calibrated flowmeters capable of measuring and 
monitoring air flowrates with an accuracy of 2% of the 
measured flowrate.
    2.2.4 NO flowmeter. A calibrated flowmeter capable of measuring and 
monitoring NO flowrates with an accuracy of 2% of the 
measured flowrate. (Rotameters have been reported to operate unreliably 
when measuring low NO flows and are not recommended.)
    2.2.5 Pressure regulator for standard NO cylinder. This regulator 
must have a non-reactive diaphragm and internal parts and a suitable 
delivery pressure.
    2.2.6 Drier. Scrubber to remove moisture from the permeation device 
air system. The use of the drier is optional with NO2 
permeation devices not sensitive to moisture. (Refer to the supplier's 
instructions for use of the permeation device.)
    2.2.7 Constant temperature chamber. Chamber capable of housing the 
NO2 permeation device and maintaining its temperature to 
within 0.1  deg.C.
    2.2.8 Temperature measuring device. Device capable of measuring and 
monitoring the temperature of the NO2 permeation device with 
an accuracy of 0.05  deg.C.
    2.2.9 Valves. A valve may be used as shown in Figure 2 to divert the 
NO2 from the permeation device when zero air or NO is 
required at the manifold. A second valve may be used to divert the NO 
flow when zero air or NO2 is required at the manifold.
    The valves should be constructed of glass, Teflon[reg], 
or other nonreactive material.
    2.2.10 Mixing chamber. A chamber constructed of glass, 
Teflon[reg], or other nonreactive material and designed to 
provide thorough mixing of pollutant gas streams and diluent air.
    2.2.11 Output manifold. The output manifold should be constructed of 
glass, Teflon[reg], or other non-reactive material and should 
be of sufficient diameter to insure an insignificant pressure drop at 
the analyzer connection. The system must have a vent designed to insure 
atmospheric pressure at the manifold and to prevent ambient air from 
entering the manifold.
    2.3 Reagents.
    2.3.1 Calibration standards. Calibration standards are required for 
both NO and NO2. The reference standard for the calibration 
may be either an NO or NO2 standard, and must be traceable to 
a National Bureau of Standards (NBS) NO in N2 Standard 
Reference Material (SRM 1683 or SRM 1684), and NBS NO2 
Standard Reference Material (SRM 1629), or an NBS/EPA-approved 
commercially

[[Page 52]]

available Certified Reference Material (CRM). CRM's are described in 
Reference 14, and a list of CRM sources is available from the address 
shown for Reference 14. Reference 15 gives recommended procedures for 
certifying an NO gas cylinder against an NO SRM or CRM and for 
certifying an NO2 permeation device against an NO2 
SRM. Reference 13 contains procedures for certifying an NO gas cylinder 
against an NO2 SRM and for certifying an NO2 
permeation device against an NO SRM or CRM. A procedure for determining 
the amount of NO2 impurity in an NO cylinder is also 
contained in Reference 13. The NO or NO2 standard selected as 
the reference standard must be used to certify the other standard to 
ensure consistency between the two standards.
    2.3.1.1 NO2 Concentration standard. A permeation device 
suitable for generating NO2 concentrations at the required 
flow-rates over the required concentration range. If the permeation 
device is used as the reference standard, it must be traceable to an SRM 
or CRM as specified in 2.3.1. If an NO cylinder is used as the reference 
standard, the NO2 permeation device must be certified against 
the NO standard according to the procedure given in Reference 13. The 
use of the permeation device should be in strict accordance with the 
instructions supplied with the device. Additional information regarding 
the use of permeation devices is given by Scaringelli et al. (11) and 
Rook et al. (12).
    2.3.1.2 NO Concentration standard. Gas cylinder containing 50 to 100 
ppm NO in N2 with less than 1 ppm NO2. If this 
cylinder is used as the reference standard, the cylinder must be 
traceable to an SRM or CRM as specified in 2.3.1. If an NO2 
permeation device is used as the reference standard, the NO cylinder 
must be certified against the NO2 standard according to the 
procedure given in Reference 13. The cylinder should be recertified on a 
regular basis as determined by the local quality control program.
    2.3.3 Zero air. Air, free of contaminants which might react with NO 
or NO2 or cause a detectable response on the NO/
NOX/NO2 analyzer. When using permeation devices 
that are sensitive to moisture, the zero air passing across the 
permeation device must be dry to avoid surface reactions on the device. 
(Refer to the supplier's instructions for use of the permeation device.) 
A procedure for generating zero air is given in reference 13.
    2.4 Procedure.
    2.4.1 Assemble the calibration apparatus such as the typical one 
shown in Figure 2.
    2.4.2 Insure that all flowmeters are calibrated under the conditions 
of use against a reliable standard such as a soap bubble meter or wet-
test meter. All volumetric flowrates should be corrected to 25  deg.C 
and 760 mm Hg. A discussion on the calibration of flowmeters is given in 
reference 13.
    2.4.3 Install the permeation device in the constant temperature 
chamber. Provide a small fixed air flow (200-400 scm 3/min) 
across the device. The permeation device should always have a continuous 
air flow across it to prevent large buildup of NO2 in the 
system and a consequent restabilization period. Record the flowrate as 
FP. Allow the device to stabilize at the calibration temperature for at 
least 24 hours. The temperature must be adjusted and controlled to 
within 0.1  deg.C or less of the calibration temperature as 
monitored with the temperature measuring device.
    2.4.4 Precautions must be taken to remove O2 and other 
contaminants from the NO pressure regulator and delivery system prior to 
the start of calibration to avoid any conversion of the standard NO to 
NO2. Failure to do so can cause significant errors in 
calibration. This problem may be minimized by
    (1) Carefully evacuating the regulator, when possible, after the 
regulator has been connected to the cylinder and before opening the 
cylinder valve;
    (2) Thoroughly flushing the regulator and delivery system with NO 
after opening the cylinder valve;
    (3) Not removing the regulator from the cylinder between 
calibrations unless absolutely necessary. Further discussion of these 
procedures is given in reference 13.
    2.4.5 Select the operating range of the NO/NOX 
NO2 analyzer to be calibrated. In order to obtain maximum 
precision and accuracy for NO2 calibration, all three 
channels of the analyzer should be set to the same range. If operation 
of the NO and NOX channels on higher ranges is desired, 
subsequent recalibration of the NO and NOX channels on the 
higher ranges is recommended.
    Note: Some analyzer designs may require identical ranges for NO, 
NOX, and NO2 during operation of the analyzer.
    2.4.6 Connect the recorder output cable(s) of the NO/NOX/
NO2 analyzer to the input terminals of the strip chart 
recorder(s). All adjustments to the analyzer should be performed based 
on the appropriate strip chart readings. References to analyzer 
responses in the procedures given below refer to recorder responses.
    2.4.7 Switch the valve to vent the flow from the permeation device 
and adjust the diluent air flowrate, FD, to provide zero air 
at the output manifold. The total air flow must exceed the total demand 
of the analyzer(s) connected to the output manifold to insure that no 
ambient air is pulled into the manifold vent. Allow the analyzer to 
sample zero air until stable NO, NOX, and NO2 
responses are obtained. After the responses have stabilized, adjust the 
analyzer zero control(s).
    Note: Some analyzers may have separate zero controls for NO, 
NOX, and NO2. Other analyzers may have separate 
zero controls only for NO and NOX, while still others may

[[Page 53]]

have only one zero common control to all three channels.
Offsetting the analyzer zero adjustments to +5% of scale is recommended 
to facilitate observing negative zero drift. Record the stable zero air 
responses as ZNO, ZNOX, and 
ZNO2.
    2.4.8 Preparation of NO and NOX calibration curves.
    2.4.8.1 Adjustment of NO span control. Adjust the NO flow from the 
standard NO cylinder to generate an NO concentration of approximately 
80% of the upper range limit (URL) of the NO range. The exact NO 
concentration is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.049

where:

[NO]OUT = diluted NO concentration at the output manifold, 
ppm
FNO = NO flowrate, scm\3\/min
[NO]STD=concentration of the undiluted NO standard, ppm
FD = diluent air flowrate, scm 3/min

Sample this NO concentration until the NO and NOX responses 
have stabilized. Adjust the NO span control to obtain a recorder 
response as indicated below:

recorder response (% scale) =
[GRAPHIC] [TIFF OMITTED] TR31AU93.050

[GRAPHIC] [TIFF OMITTED] TR31AU93.051

where:

URL = nominal upper range limit of the NO channel, ppm
    Note: Some analyzers may have separate span controls for NO, 
NOX, and NO2. Other analyzers may have separate 
span controls only for NO and NOX, while still others may 
have only one span control common to all three channels. When only one 
span control is available, the span adjustment is made on the NO channel 
of the analyzer.
If substantial adjustment of the NO span control is necessary, it may be 
necessary to recheck the zero and span adjustments by repeating steps 
2.4.7 and 2.4.8.1. Record the NO concentration and the analyzer's NO 
response.
    2.4.8.2 Adjustment of NOX span control. When adjusting 
the analyzer's NOX span control, the presence of any 
NO2 impurity in the standard NO cylinder must be taken into 
account. Procedures for determining the amount of NO2 
impurity in the standard NO cylinder are given in reference 13. The 
exact NOX concentration is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.052

where:

[NOX]OUT = diluted NOX cencentration at 
the output manifold, ppm
[NO2]IMP = concentration of NO2 
impurity in the standard NO cylinder, ppm

Adjust the NOX span control to obtain a convenient recorder 
response as indicated below:

recorder response (% scale)
[GRAPHIC] [TIFF OMITTED] TR31AU93.053

    Note: If the analyzer has only one span control, the span adjustment 
is made on the NO channel and no further adjustment is made here for 
NOX.
If substantial adjustment of the NOX span control is 
necessary, it may be necessary to recheck the zero and span adjustments 
by repeating steps 2.4.7 and 2.4.8.2. Record the NOX 
concentration and the analyzer's NOX response.
    2.4.8.3 Generate several additional concentrations (at least five 
evenly spaced points across the remaining scale are suggested to verify 
linearity) by decreasing FNO or increasing FD. For 
each concentration generated, calculate the exact NO and NOX 
concentrations using equations (16) and (18) respectively. Record the 
analyzer's NO and NOX responses for each concentration. Plot 
the analyzer responses versus the respective calculated NO and 
NOX concentrations and draw or calculate the NO and 
NOX calibration curves. For subsequent calibrations where 
linearity can be assumed, these curves may be checked with a two-point 
calibration consisting of a zero point and NO and NOX 
concentrations of approximately 80 percent of the URL.
    2.4.9 Preparation of NO2 calibration curve.
    2.4.9.1 Remove the NO flow. Assuming the NO2 zero has 
been properly adjusted while sampling zero air in step 2.4.7, switch the 
valve to provide NO2 at the output manifold.
    2.4.9.2 Adjust FD to generate an NO2 
concentration of approximately 80 percent of the URL of the 
NO2 range. The total air flow must exceed the demand of the 
analyzer(s) under calibration. The actual concentration of 
NO2 is calculated from:
[GRAPHIC] [TIFF OMITTED] TR31AU93.054

where:

[NO2]OUT = diluted NO2 concentration at 
the output manifold, ppm
R = permeation rate, [mu]g/min

[[Page 54]]

K = 0.532[mu]l NO2/[mu]g NO2 (at 25  deg.C and 760 
mm Hg)
Fp = air flowrate across permeation device, scm\3\/min
FD = diluent air flowrate, scm\3\/min

Sample this NO2 concentration until the NOX and 
NO2 responses have stabilized. Adjust the NO2 span 
control to obtain a recorder response as indicated below:

recorder response (% scale)
[GRAPHIC] [TIFF OMITTED] TR31AU93.055

    Note: If the analyzer has only one or two span controls, the span 
adjustments are made on the NO channel or NO and NOX channels 
and no further adjustment is made here for NO2.

If substantial adjustment of the NO2 span control is 
necessary it may be necessary to recheck the zero and span adjustments 
by repeating steps 2.4.7 and 2.4.9.2. Record the NO2 
concentration and the analyzer's NO2 response. Using the 
NOX calibration curve obtained in step 2.4.8, measure and 
record the NOX concentration as [NOX]M.
    2.4.9.3 Adjust FD to obtain several other concentrations 
of NO2 over the NO2 range (at least five evenly 
spaced points across the remaining scale are suggested). Calculate each 
NO2 concentration using equation (20) and record the 
corresponding analyzer NO2 and NOX responses. Plot 
the analyzer's NO2 responses versus the corresponding 
calculated NO2 concentrations and draw or calculate the 
NO2 calibration curve.
    2.4.10 Determination of converter efficiency.
    2.4.10.1 Plot [NOX]M (y-axis) versus 
[NO2]OUT (x-axis) and draw or calculate the 
converter efficiency curve. The slope of the curve times 100 is the 
average converter efficiency, EC. The average converter 
efficiency must be greater than 96 percent; if it is less than 96 
percent, replace or service the converter.
    Note: Supplemental information on calibration and other procedures 
in this method are given in reference 13.
    3. Frequency of calibration. The frequency of calibration, as well 
as the number of points necessary to establish the calibration curve and 
the frequency of other performance checks, will vary from one analyzer 
to another. The user's quality control program should provide guidelines 
for initial establishment of these variables and for subsequent 
alteration as operational experience is accumulated. Manufacturers of 
analyzers should include in their instruction/operation manuals 
information and guidance as to these variables and on other matters of 
operation, calibration, and quality control.

                               References

    1. A. Fontijn, A. J. Sabadell, and R. J. Ronco, ``Homogeneous 
Chemiluminescent Measurement of Nitric Oxide with Ozone,'' Anal. Chem., 
42, 575 (1970).
    2. D. H. Stedman, E. E. Daby, F. Stuhl, and H. Niki, ``Analysis of 
Ozone and Nitric Oxide by a Chemiluminiscent Method in Laboratory and 
Atmospheric Studies of Photochemical Smog,'' J. Air Poll. Control 
Assoc., 22, 260 (1972).
    3. B. E. Martin, J. A. Hodgeson, and R. K. Stevens, ``Detection of 
Nitric Oxide Chemiluminescence at Atmospheric Pressure,'' Presented at 
164th National ACS Meeting, New York City, August 1972.
    4. J. A. Hodgeson, K. A. Rehme, B. E. Martin, and R. K. Stevens, 
``Measurements for Atmospheric Oxides of Nitrogen and Ammonia by 
Chemiluminescence,'' Presented at 1972 APCA Meeting, Miami, FL, June 
1972.
    5. R. K. Stevens and J. A. Hodgeson, ``Applications of 
Chemiluminescence Reactions to the Measurement of Air Pollutants,'' 
Anal. Chem., 45, 443A (1973).
    6. L. P. Breitenbach and M. Shelef, ``Development of a Method for 
the Analysis of NO2 and NH3 by NO-Measuring 
Instruments,'' J. Air Poll. Control Assoc., 23, 128 (1973).
    7. A. M. Winer, J. W. Peters, J. P. Smith, and J. N. Pitts, Jr., 
``Response of Commercial Chemiluminescent NO-NO2 Analyzers to 
Other Nitrogen-Containing Compounds,'' Environ. Sci. Technol., 8, 1118 
(1974).
    8. K. A. Rehme, B. E. Martin, and J. A. Hodgeson, Tentative Method 
for the Calibration of Nitric Oxide, Nitrogen Dioxide, and Ozone 
Analyzers by Gas Phase Titration,'' EPA-R2-73-246, March 1974.
    9. J. A. Hodgeson, R. K. Stevens, and B. E. Martin, ``A Stable Ozone 
Source Applicable as a Secondary Standard for Calibration of Atmospheric 
Monitors,'' ISA Transactions, 11, 161 (1972).
    10. A. E. O'Keeffe and G. C. Ortman, ``Primary Standards for Trace 
Gas Analysis,'' Anal. Chem., 38, 760 (1966).
    11. F. P. Scaringelli, A. E. O'Keeffe, E. Rosenberg, and J. P. Bell, 
``Preparation of Known Concentrations of Gases and Vapors with 
Permeation Devices Calibrated Gravimetrically,'' Anal. Chem., 42, 871 
(1970).
    12. H. L. Rook, E. E. Hughes, R. S. Fuerst, and J. H. Margeson, 
``Operation Characteristics of NO2 Permeation Devices,'' 
Presented at 167th National ACS Meeting, Los Angeles, CA, April 1974.
    13. E. C. Ellis, ``Technical Assistance Document for the 
Chemiluminescence Measurement of Nitrogen Dioxide,'' EPA-E600/4-75-003 
(Available in draft form from the United States Environmental Protection 
Agency, Department E (MD-76), Environmental Monitoring and Support 
Laboratory, Research Triangle Park, NC 27711).

[[Page 55]]

    14. A Procedure for Establishing Traceability of Gas Mixtures to 
Certain National Bureau of Standards Standard Reference Materials. EPA-
600/7-81-010, Joint publication by NBS and EPA. Available from the U.S. 
Environmental Protection Agency, Environmental Monitoring Systems 
Laboratory (MD-77), Research Triangle Park, NC 27711, May 1981.
    15. Quality Assurance Handbook for Air Pollution Measurement 
Systems, Volume II, Ambient Air Specific Methods. The U.S. Environmental 
Protection Agency, Environmental Monitoring Systems Laboratory, Research 
Triangle Park, NC 27711. Publication No. EAP-600/4-77-027a.



[[Page 56]]





[41 FR 52688, Dec. 1, 1976, as amended at 48 FR 2529, Jan 20, 1983]

Appendix G to Part 50--Reference Method for the Determination of Lead in 
         Suspended Particulate Matter Collected From Ambient Air

    1. Principle and applicability.
    1.1 Ambient air suspended particulate matter is collected on a 
glass-fiber filter for 24 hours using a high volume air sampler. The 
analysis of the 24-hour samples may be performed for either individual 
samples or composites of the samples collected over a calendar month or 
quarter, provided that the compositing procedure has been approved in 
accordance with section 2.8 of appendix C to part 58 of this chapter--
Modifications of methods by users. (Guidance or assistance in requesting 
approval under Section 2.8 can be obtained from the address given in 
section 2.7 of appendix C to part 58 of this chapter.)
    1.2 Lead in the particulate matter is solubilized by extraction with 
nitric acid (HNO3), facilitated by heat or by a mixture of 
HNO3 and hydrochloric acid (HCl) facilitated by 
ultrasonication.
    1.3 The lead content of the sample is analyzed by atomic absorption 
spectrometry using an air-acetylene flame, the 283.3 or 217.0 nm lead 
absorption line, and the optimum instrumental conditions recommended by 
the manufacturer.
    1.4 The ultrasonication extraction with HNO3/HCl will 
extract metals other than lead from ambient particulate matter.
    2. Range, sensitivity, and lower detectable limit. The values given 
below are typical of the methods capabilities. Absolute values will vary 
for individual situations depending on the type of instrument used, the 
lead line, and operating conditions.
    2.1 Range. The typical range of the method is 0.07 to 7.5 [mu]g Pb/
m\3\ assuming an upper linear range of analysis of 15 [mu]g/ml and an 
air volume of 2,400 m\3\.
    2.2 Sensitivity. Typical sensitivities for a 1 percent change in 
absorption (0.0044 absorbance units) are 0.2 and 0.5 [mu]g Pb/ml for the 
217.0 and 283.3 nm lines, respectively.
    2.3 Lower detectable limit (LDL). A typical LDL is 0.07 [mu]g Pb/
m\3\. The above value was calculated by doubling the between-laboratory 
standard deviation obtained for the lowest measurable lead concentration 
in a collaborative test of the method.(15) An air volume of 2,400 m\3\ 
was assumed.
    3. Interferences. Two types of interferences are possible: chemical 
and light scattering.
    3.1 Chemical. Reports on the absence (1, 2, 3, 4, 5) of chemical 
interferences far outweigh those reporting their presence, (6) 
therefore, no correction for chemical interferences is given here. If 
the analyst suspects that the sample matrix is causing a chemical 
interference, the interference can be verified and corrected for by 
carrying out the analysis

[[Page 57]]

with and without the method of standard additions.(7)
    3.2 Light scattering. Nonatomic absorption or light scattering, 
produced by high concentrations of dissolved solids in the sample, can 
produce a significant interference, especially at low lead 
concentrations. (2) The interference is greater at the 217.0 nm line 
than at the 283.3 nm line. No interference was observed using the 283.3 
nm line with a similar method.(1)
    Light scattering interferences can, however, be corrected for 
instrumentally. Since the dissolved solids can vary depending on the 
origin of the sample, the correction may be necessary, especially when 
using the 217.0 nm line. Dual beam instruments with a continuum source 
give the most accurate correction. A less accurate correction can be 
obtained by using a nonabsorbing lead line that is near the lead 
analytical line. Information on use of these correction techniques can 
be obtained from instrument manufacturers' manuals.
    If instrumental correction is not feasible, the interference can be 
eliminated by use of the ammonium pyrrolidinecarbodithioate-
methylisobutyl ketone, chelation-solvent extraction technique of sample 
preparation.(8)
    4. Precision and bias.
    4.1 The high-volume sampling procedure used to collect ambient air 
particulate matter has a between-laboratory relative standard deviation 
of 3.7 percent over the range 80 to 125 [mu]g/m\3\.(9) The combined 
extraction-analysis procedure has an average within-laboratory relative 
standard deviation of 5 to 6 percent over the range 1.5 to 15 [mu]g Pb/
ml, and an average between laboratory relative standard deviation of 7 
to 9 percent over the same range. These values include use of either 
extraction procedure.
    4.2 Single laboratory experiments and collaborative testing indicate 
that there is no significant difference in lead recovery between the hot 
and ultrasonic extraction procedures.(15)
    5. Apparatus.
    5.1 Sampling.
    5.1.1 High-Volume Sampler. Use and calibrate the sampler as 
described in appendix B to this part.
    5.2 Analysis.
    5.2.1 Atomic absorption spectrophotometer. Equipped with lead hollow 
cathode or electrodeless discharge lamp.
    5.2.1.1 Acetylene. The grade recommended by the instrument 
manufacturer should be used. Change cylinder when pressure drops below 
50-100 psig.
    5.2.1.2 Air. Filtered to remove particulate, oil, and water.
    5.2.2 Glassware. Class A borosilicate glassware should be used 
throughout the analysis.
    5.2.2.1 Beakers. 30 and 150 ml. graduated, Pyrex.
    5.2.2.2 Volumetric flasks. 100-ml.
    5.2.2.3 Pipettes. To deliver 50, 30, 15, 8, 4, 2, 1 ml.
    5.2.2.4 Cleaning. All glassware should be scrupulously cleaned. The 
following procedure is suggested. Wash with laboratory detergent, rinse, 
soak for 4 hours in 20 percent (w/w) HNO3, rinse 3 times with 
distilled-deionized water, and dry in a dust free manner.
    5.2.3 Hot plate.
    5.2.4. Ultrasonication water bath, unheated. Commercially available 
laboratory ultrasonic cleaning baths of 450 watts or higher ``cleaning 
power,'' i.e., actual ultrasonic power output to the bath have been 
found satisfactory.
    5.2.5 Template. To aid in sectioning the glass-fiber filter. See 
figure 1 for dimensions.
    5.2.6 Pizza cutter. Thin wheel. Thickness 1mm.
    5.2.7 Watch glass.
    5.2.8 Polyethylene bottles. For storage of samples. Linear 
polyethylene gives better storage stability than other polyethylenes and 
is preferred.
    5.2.9 Parafilm ``M''.\1\ American Can Co., Marathon Products, 
Neenah, Wis., or equivalent.
---------------------------------------------------------------------------

    \1\ Mention of commercial products does not imply endorsement by the 
U.S. Environmental Protection Agency.
---------------------------------------------------------------------------

    6. Reagents.
    6.1 Sampling.
    6.1.1 Glass fiber filters. The specifications given below are 
intended to aid the user in obtaining high quality filters with 
reproducible properties. These specifications have been met by EPA 
contractors.
    6.1.1.1 Lead content. The absolute lead content of filters is not 
critical, but low values are, of course, desirable. EPA typically 
obtains filters with a lead content of 75 [mu]g/filter.
    It is important that the variation in lead content from filter to 
filter, within a given batch, be small.
    6.1.1.2 Testing.
    6.1.1.2.1 For large batches of filters (500 filters) 
select at random 20 to 30 filters from a given batch. For small batches 
(500 filters) a lesser number of filters may be taken. Cut 
one \3/4\[dprime]x8[dprime] strip from each filter anywhere in the 
filter. Analyze all strips, separately, according to the directions in 
sections 7 and 8.
    6.1.1.2.2 Calculate the total lead in each filter as
    [GRAPHIC] [TIFF OMITTED] TC08NO91.084
    
where:

Fb = Amount of lead per 72 square inches of filter, [mu]g.

    6.1.1.2.3 Calculate the mean, Fb, of the values and the 
relative standard deviation

[[Page 58]]

(standard deviation/mean x 100). If the relative standard deviation is 
high enough so that, in the analysts opinion, subtraction of 
Fb, (section 10.3) may result in a significant error in the 
[mu]g Pb/m\3,\ the batch should be rejected.
    6.1.1.2.4 For acceptable batches, use the value of Fb to 
correct all lead analyses (section 10.3) of particulate matter collected 
using that batch of filters. If the analyses are below the LDL (section 
2.3) no correction is necessary.
    6.2 Analysis.
    6.2.1 Concentrated (15.6 M) HNO3. ACS reagent grade 
HNO3 and commercially available redistilled HNO3 
has found to have sufficiently low lead concentrations.
    6.2.2 Concentrated (11.7 M) HCl. ACS reagent grade.
    6.2.3 Distilled-deionized water. (D.I. water).
    6.2.4 3 M HNO3. This solution is used in the hot 
extraction procedure. To prepare, add 192 ml of concentrated 
HNO3 to D.I. water in a 1 l volumetric flask. Shake well, 
cool, and dilute to volume with D.I. water. Caution: Nitric acid fumes 
are toxic. Prepare in a well ventilated fume hood.
    6.2.5 0.45 M HNO3. This solution is used as the matrix 
for calibration standards when using the hot extraction procedure. To 
prepare, add 29 ml of concentrated HNO3 to D.I. water in a 1 
l volumetric flask. Shake well, cool, and dilute to volume with D.I. 
water.
    6.2.6 2.6 M HNO3+0 to 0.9 M HCl. This solution is used in 
the ultrasonic extraction procedure. The concentration of HCl can be 
varied from 0 to 0.9 M. Directions are given for preparation of a 2.6 M 
HNO3+0.9 M HCl solution. Place 167 ml of concentrated 
HNO3 into a 1 l volumetric flask and add 77 ml of 
concentrated HCl. Stir 4 to 6 hours, dilute to nearly 1 l with D.I. 
water, cool to room temperature, and dilute to 1 l.
    6.2.7 0.40 M HNO3 + X M HCl. This solution is used as the 
matrix for calibration standards when using the ultrasonic extraction 
procedure. To prepare, add 26 ml of concentrated HNO3, plus 
the ml of HCl required, to a 1 l volumetric flask. Dilute to nearly 1 l 
with D.I. water, cool to room temperature, and dilute to 1 l. The amount 
of HCl required can be determined from the following equation:
[GRAPHIC] [TIFF OMITTED] TC08NO91.085

where:

y = ml of concentrated HCl required.
x = molarity of HCl in 6.2.6.
0.15 = dilution factor in 7.2.2.

    6.2.8 Lead nitrate, Pb(NO3)2. ACS reagent 
grade, purity 99.0 percent. Heat for 4 hours at 120  deg.C and cool in a 
desiccator.
    6.3 Calibration standards.
    6.3.1 Master standard, 1000 [mu]g Pb/ml in HNO3. Dissolve 
1.598 g of Pb(NO3)2 in 0.45 M HNO3 
contained in a 1 l volumetric flask and dilute to volume with 0.45 M 
HNO3.
    6.3.2 Master standard, 1000 [mu]g Pb/ml in HNO3/HCl. 
Prepare as in section 6.3.1 except use the HNO3/HCl solution 
in section 6.2.7.
    Store standards in a polyethylene bottle. Commercially available 
certified lead standard solutions may also be used.
    7. Procedure.
    7.1 Sampling. Collect samples for 24 hours using the procedure 
described in reference 10 with glass-fiber filters meeting the 
specifications in section 6.1.1. Transport collected samples to the 
laboratory taking care to minimize contamination and loss of sample. 
(16).
    7.2 Sample preparation.
    7.2.1 Hot extraction procedure.
    7.2.1.1 Cut a \3/4\[dprime]x8[dprime] strip from the exposed filter 
using a template and a pizza cutter as described in Figures 1 and 2. 
Other cutting procedures may be used.
    Lead in ambient particulate matter collected on glass fiber filters 
has been shown to be uniformly distributed across the 
filter.1, 3, 11 Another study \12\ has shown that when 
sampling near a roadway, strip position contributes significantly to the 
overall variability associated with lead analyses. Therefore, when 
sampling near a roadway, additional strips should be analyzed to 
minimize this variability.
    7.2.1.2 Fold the strip in half twice and place in a 150-ml beaker. 
Add 15 ml of 3 M HNO3 to cover the sample. The acid should 
completely cover the sample. Cover the beaker with a watch glass.
    7.2.1.3 Place beaker on the hot-plate, contained in a fume hood, and 
boil gently for 30 min. Do not let the sample evaporate to dryness. 
Caution: Nitric acid fumes are toxic.
    7.2.1.4 Remove beaker from hot plate and cool to near room 
temperature.
    7.2.1.5 Quantitatively transfer the sample as follows:
    7.2.1.5.1 Rinse watch glass and sides of beaker with D.I. water.
    7.2.1.5.2 Decant extract and rinsings into a 100-ml volumetric 
flask.
    7.2.1.5.3 Add D.I. water to 40 ml mark on beaker, cover with watch 
glass, and set aside for a minimum of 30 minutes. This is a critical 
step and cannot be omitted since it allows the HNO3 trapped 
in the filter to diffuse into the rinse water.
    7.2.1.5.4 Decant the water from the filter into the volumetric 
flask.
    7.2.1.5.5 Rinse filter and beaker twice with D.I. water and add 
rinsings to volumetric flask until total volume is 80 to 85 ml.
    7.2.1.5.6 Stopper flask and shake vigorously. Set aside for 
approximately 5 minutes or until foam has dissipated.
    7.2.1.5.7 Bring solution to volume with D.I. water. Mix thoroughly.

[[Page 59]]

    7.2.1.5.8 Allow solution to settle for one hour before proceeding 
with analysis.
    7.2.1.5.9 If sample is to be stored for subsequent analysis, 
transfer to a linear polyethylene bottle.
    7.2.2 Ultrasonic extraction procedure.
    7.2.2.1 Cut a \3/4\[dprime]x8[dprime] strip from the exposed filter 
as described in section 7.2.1.1.
    7.2.2.2 Fold the strip in half twice and place in a 30 ml beaker. 
Add 15 ml of the HNO3/HCl solution in section 6.2.6. The acid 
should completely cover the sample. Cover the beaker with parafilm.
    The parafilm should be placed over the beaker such that none of the 
parafilm is in contact with water in the ultrasonic bath. Otherwise, 
rinsing of the parafilm (section 7.2.2.4.1) may contaminate the sample.
    7.2.2.3 Place the beaker in the ultrasonication bath and operate for 
30 minutes.
    7.2.2.4 Quantitatively transfer the sample as follows:
    7.2.2.4.1 Rinse parafilm and sides of beaker with D.I. water.
    7.2.2.4.2 Decant extract and rinsings into a 100 ml volumetric 
flask.
    7.2.2.4.3 Add 20 ml D.I. water to cover the filter strip, cover with 
parafilm, and set aside for a minimum of 30 minutes. This is a critical 
step and cannot be omitted. The sample is then processed as in sections 
7.2.1.5.4 through 7.2.1.5.9.
    Note: Samples prepared by the hot extraction procedure are now in 
0.45 M HNO3. Samples prepared by the ultrasonication 
procedure are in 0.40 M HNO3 + X M HCl.
    8. Analysis.
    8.1 Set the wavelength of the monochromator at 283.3 or 217.0 nm. 
Set or align other instrumental operating conditions as recommended by 
the manufacturer.
    8.2 The sample can be analyzed directly from the volumetric flask, 
or an appropriate amount of sample decanted into a sample analysis tube. 
In either case, care should be taken not to disturb the settled solids.
    8.3 Aspirate samples, calibration standards and blanks (section 9.2) 
into the flame and record the equilibrium absorbance.
    8.4 Determine the lead concentration in [mu]g Pb/ml, from the 
calibration curve, section 9.3.
    8.5 Samples that exceed the linear calibration range should be 
diluted with acid of the same concentration as the calibration standards 
and reanalyzed.
    9. Calibration.
    9.1 Working standard, 20 [mu]g Pb/ml. Prepared by diluting 2.0 ml of 
the master standard (section 6.3.1 if the hot acid extraction was used 
or section 6.3.2 if the ultrasonic extraction procedure was used) to 100 
ml with acid of the same concentration as used in preparing the master 
standard.
    9.2 Calibration standards. Prepare daily by diluting the working 
standard, with the same acid matrix, as indicated below. Other lead 
concentrations may be used.

------------------------------------------------------------------------
                                                  Final    Concentration
  Volume of 20 [mu]g/ml working standard, ml   volume, ml   [mu]g Pb/ml
------------------------------------------------------------------------
0............................................         100             0
1.0..........................................         200           0.1
2.0..........................................         200           0.2
2.0..........................................         100           0.4
4.0..........................................         100           0.8
8.0..........................................         100           1.6
15.0.........................................         100           3.0
30.0.........................................         100           6.0
50.0.........................................         100          10.0
100.0........................................         100          20.0
------------------------------------------------------------------------

    9.3 Preparation of calibration curve. Since the working range of 
analysis will vary depending on which lead line is used and the type of 
instrument, no one set of instructions for preparation of a calibration 
curve can be given. Select standards (plus the reagent blank), in the 
same acid concentration as the samples, to cover the linear absorption 
range indicated by the instrument manufacturer. Measure the absorbance 
of the blank and standards as in section 8.0. Repeat until good 
agreement is obtained between replicates. Plot absorbance (y-axis) 
versus concentration in [mu]g Pb/ml (x-axis). Draw (or compute) a 
straight line through the linear portion of the curve. Do not force the 
calibration curve through zero. Other calibration procedures may be 
used.
    To determine stability of the calibration curve, remeasure--
alternately--one of the following calibration standards for every 10th 
sample analyzed: Concentration [le] 1[mu]g Pb/ml; 
concentration [le] 10 [mu]g Pb/ml. If either standard 
deviates by more than 5 percent from the value predicted by the 
calibration curve, recalibrate and repeat the previous 10 analyses.
    10. Calculation.
    10.1 Measured air volume. Calculate the measured air volume at 
Standard Temperature and Pressure as described in Reference 10.
    10.2 Lead concentration. Calculate lead concentration in the air 
sample.

[[Page 60]]



where:

C = Concentration, [mu]g Pb/sm\3\.
[mu]g Pb/ml = Lead concentration determined from section 8.
100 ml/strip = Total sample volume.
12 strips = Total useable filter area, 8[dprime]x9[dprime]. Exposed area 
of one strip, \3/4\[dprime]x7[dprime].
Filter = Total area of one strip, \3/4\[dprime]x8[dprime].
Fb = Lead concentration of blank filter, [mu]g, from section 
6.1.1.2.3.
VSTP = Air volume from section 10.2.

    11. Quality control.
    \3/4\[dprime]x8[dprime] glass fiber filter strips containing 80 to 
2000 [mu]g Pb/strip (as lead salts) and blank strips with zero Pb 
content should be used to determine if the method--as being used--has 
any bias. Quality control charts should be established to monitor 
differences between measured and true values. The frequency of such 
checks will depend on the local quality control program.
    To minimize the possibility of generating unreliable data, the user 
should follow practices established for assuring the quality of air 
pollution data, (13) and take part in EPA's semiannual audit program for 
lead analyses.
    12. Trouble shooting.
    1. During extraction of lead by the hot extraction procedure, it is 
important to keep the sample covered so that corrosion products--formed 
on fume hood surfaces which may contain lead--are not deposited in the 
extract.
    2. The sample acid concentration should minimize corrosion of the 
nebulizer. However, different nebulizers may require lower acid 
concentrations. Lower concentrations can be used provided samples and 
standards have the same acid concentration.
    3. Ashing of particulate samples has been found, by EPA and 
contractor laboratories, to be unnecessary in lead analyses by atomic 
absorption. Therefore, this step was omitted from the method.
    4. Filtration of extracted samples, to remove particulate matter, 
was specifically excluded from sample preparation, because some analysts 
have observed losses of lead due to filtration.
    5. If suspended solids should clog the nebulizer during analysis of 
samples, centrifuge the sample to remove the solids.
    13. Authority.
    (Secs. 109 and 301(a), Clean Air Act, as amended (42 U.S.C. 7409, 
7601(a)))
    14. References.
    1. Scott, D. R. et al. ``Atomic Absorption and Optical Emission 
Analysis of NASN Atmospheric Particulate Samples for Lead.'' Envir. Sci. 
and Tech., 10, 877-880 (1976).
    2. Skogerboe, R. K. et al. ``Monitoring for Lead in the 
Environment.'' pp. 57-66, Department of Chemistry, Colorado State 
University, Fort Collins, CO 80523. Submitted to National Science 
Foundation for publications, 1976.
    3. Zdrojewski, A. et al. ``The Accurate Measurement of Lead in 
Airborne Particulates.'' Inter. J. Environ. Anal. Chem., 2, 63-77 
(1972).
    4. Slavin, W., ``Atomic Absorption Spectroscopy.'' Published by 
Interscience Company, New York, NY (1968).
    5. Kirkbright, G. F., and Sargent, M., ``Atomic Absorption and 
Fluorescence Spectroscopy.'' Published by Academic Press, New York, NY 
1974.
    6. Burnham, C. D. et al., ``Determination of Lead in Airborne 
Particulates in Chicago and Cook County, IL, by Atomic Absorption 
Spectroscopy.'' Envir. Sci. and Tech., 3, 472-475 (1969).
    7. ``Proposed Recommended Practices for Atomic Absorption 
Spectrometry.'' ASTM Book of Standards, part 30, pp. 1596-1608 (July 
1973).
    8. Koirttyohann, S. R. and Wen, J. W., ``Critical Study of the APCD-
MIBK Extraction System for Atomic Absorption.'' Anal. Chem., 45, 1986-
1989 (1973).
    9. Collaborative Study of Reference Method for the Determination of 
Suspended Particulates in the Atmosphere (High Volume Method). 
Obtainable from National Technical Information Service, Department of 
Commerce, Port Royal Road, Springfield, VA 22151, as PB-205-891.
    10. [Reserved]
    11. Dubois, L., et al., ``The Metal Content of Urban Air.'' JAPCA, 
16, 77-78 (1966).
    12. EPA Report No. 600/4-77-034, June 1977, ``Los Angeles Catalyst 
Study Symposium.'' Page 223.
    13. Quality Assurance Handbook for Air Pollution Measurement System. 
Volume 1--Principles. EPA-600/9-76-005, March 1976.
    14. Thompson, R. J. et al., ``Analysis of Selected Elements in 
Atmospheric Particulate Matter by Atomic Absorption.'' Atomic Absorption 
Newsletter, 9, No. 3, May-June 1970.
    15. To be published. EPA, QAB, EMSL, RTP, N.C. 27711

[[Page 61]]

    16. Quality Assurance Handbook for Air Pollution Measurement 
Systems. Volume II--Ambient Air Specific Methods. EPA-600/4-77/027a, May 
1977.



[[Page 62]]





(Secs. 109, 301(a) of the Clean Air Act, as amended (42 U.S.C. 7409, 
7601(a)); secs. 110, 301(a) and 319 of the Clean Air Act (42 U.S.C. 
7410, 7601(a), 7619))

[43 FR 46258, Oct. 5, 1978; 44 FR 37915, June 29, 1979, as amended at 46 
FR 44163, Sept. 3, 1981; 52 FR 24664, July 1, 1987]

    Appendix H to Part 50--Interpretation of the 1-Hour Primary and 
       Secondary National Ambient Air Quality Standards for Ozone

                               1. General

    This appendix explains how to determine when the expected number of 
days per calendar year with maximum hourly average concentrations above 
0.12 ppm (235 [mu]g/m\3\) is equal to or less than 1. An expanded 
discussion of these procedures and associated examples are contained in 
the ``Guideline for Interpretation of Ozone Air Quality Standards.'' For 
purposes of clarity in the following discussion, it is convenient to use 
the term ``exceedance'' to describe a daily maximum hourly average ozone 
measurement that is greater than the level of the standard. Therefore, 
the phrase ``expected number of days with maximum hourly average ozone 
concentrations above the level of the standard'' may be simply stated as 
the ``expected number of exceedances.''

[[Page 63]]

    The basic principle in making this determination is relatively 
straightforward. Most of the complications that arise in determining the 
expected number of annual exceedances relate to accounting for 
incomplete sampling. In general, the average number of exceedances per 
calendar year must be less than or equal to 1. In its simplest form, the 
number of exceedances at a monitoring site would be recorded for each 
calendar year and then averaged over the past 3 calendar years to 
determine if this average is less than or equal to 1.

                2. Interpretation of Expected Exceedances

    The ozone standard states that the expected number of exceedances 
per year must be less than or equal to 1. The statistical term 
``expected number'' is basically an arithmetic average. The following 
example explains what it would mean for an area to be in compliance with 
this type of standard. Suppose a monitoring station records a valid 
daily maximum hourly average ozone value for every day of the year 
during the past 3 years. At the end of each year, the number of days 
with maximum hourly concentrations above 0.12 ppm is determined and this 
number is averaged with the results of previous years. As long as this 
average remains ``less than or equal to 1,'' the area is in compliance.

           3. Estimating the Number of Exceedances for a Year

    In general, a valid daily maximum hourly average value may not be 
available for each day of the year, and it will be necessary to account 
for these missing values when estimating the number of exceedances for a 
particular calendar year. The purpose of these computations is to 
determine if the expected number of exceedances per year is less than or 
equal to 1. Thus, if a site has two or more observed exceedances each 
year, the standard is not met and it is not necessary to use the 
procedures of this section to account for incomplete sampling.
    The term ``missing value'' is used here in the general sense to 
describe all days that do not have an associated ozone measurement. In 
some cases, a measurement might actually have been missed but in other 
cases no measurement may have been scheduled for that day. A daily 
maximum ozone value is defined to be the highest hourly ozone value 
recorded for the day. This daily maximum value is considered to be valid 
if 75 percent of the hours from 9:01 a.m. to 9:00 p.m. (LST) were 
measured or if the highest hour is greater than the level of the 
standard.
    In some areas, the seasonal pattern of ozone is so pronounced that 
entire months need not be sampled because it is extremely unlikely that 
the standard would be exceeded. Any such waiver of the ozone monitoring 
requirement would be handled under provisions of 40 CFR, part 58. Some 
allowance should also be made for days for which valid daily maximum 
hourly values were not obtained but which would quite likely have been 
below the standard. Such an allowance introduces a complication in that 
it becomes necessary to define under what conditions a missing value may 
be assumed to have been less than the level of the standard. The 
following criterion may be used for ozone:
    A missing daily maximum ozone value may be assumed to be less than 
the level of the standard if the valid daily maxima on both the 
preceding day and the following day do not exceed 75 percent of the 
level of the standard.
    Let z denote the number of missing daily maximum values that may be 
assumed to be less than the standard. Then the following formula shall 
be used to estimate the expected number of exceedances for the year:
[GRAPHIC] [TIFF OMITTED] TC08NO91.086

    (*Indicates multiplication.)

where:

e = the estimated number of exceedances for the year,
N = the number of required monitoring days in the year,
n = the number of valid daily maxima,
v = the number of daily values above the level of the standard, and
z = the number of days assumed to be less than the standard level.

    This estimated number of exceedances shall be rounded to one decimal 
place (fractional parts equal to 0.05 round up).
    It should be noted that N will be the total number of days in the 
year unless the appropriate Regional Administrator has granted a waiver 
under the provisions of 40 CFR part 58.
    The above equation may be interpreted intuitively in the following 
manner. The estimated number of exceedances is equal to the observed 
number of exceedances (v) plus an increment that accounts for incomplete 
sampling. There were (N-n) missing values for the year but a certain 
number of these, namely z, were assumed to be less than the standard. 
Therefore, (N-n-z) missing values are considered to include possible 
exceedances. The fraction of measured values that are above the level of 
the standard is v/n. It is assumed that this same fraction applies to 
the (N-n-z) missing values and that (v/n)*(N-n-z) of these values would 
also have exceeded the level of the standard.

[44 FR 8220, Feb. 8, 1979, as amended at 62 FR 38895, July 18, 1997]

[[Page 64]]

    Appendix I to Part 50--Interpretation of the 8-Hour Primary and 
       Secondary National Ambient Air Quality Standards for Ozone

    1. General.
    This appendix explains the data handling conventions and 
computations necessary for determining whether the national 8-hour 
primary and secondary ambient air quality standards for ozone specified 
in Sec. 50.10 are met at an ambient ozone air quality monitoring site. 
Ozone is measured in the ambient air by a reference method based on 
appendix D of this part. Data reporting, data handling, and computation 
procedures to be used in making comparisons between reported ozone 
concentrations and the level of the ozone standard are specified in the 
following sections. Whether to exclude, retain, or make adjustments to 
the data affected by stratospheric ozone intrusion or other natural 
events is subject to the approval of the appropriate Regional 
Administrator.
    2. Primary and Secondary Ambient Air Quality Standards for Ozone.
    2.1  Data Reporting and Handling Conventions.
    2.1.1 Computing 8-hour averages. Hourly average concentrations shall 
be reported in parts per million (ppm) to the third decimal place, with 
additional digits to the right being truncated. Running 8-hour averages 
shall be computed from the hourly ozone concentration data for each hour 
of the year and the result shall be stored in the first, or start, hour 
of the 8-hour period. An 8-hour average shall be considered valid if at 
least 75% of the hourly averages for the 8-hour period are available. In 
the event that only 6 (or 7) hourly averages are available, the 8-hour 
average shall be computed on the basis of the hours available using 6 
(or 7) as the divisor. (8-hour periods with three or more missing hours 
shall not be ignored if, after substituting one-half the minimum 
detectable limit for the missing hourly concentrations, the 8-hour 
average concentration is greater than the level of the standard.) The 
computed 8-hour average ozone concentrations shall be reported to three 
decimal places (the insignificant digits to the right of the third 
decimal place are truncated, consistent with the data handling 
procedures for the reported data.)
    2.1.2  Daily maximum 8-hour average concentrations. (a) There are 24 
possible running 8-hour average ozone concentrations for each calendar 
day during the ozone monitoring season. (Ozone monitoring seasons vary 
by geographic location as designated in part 58, appendix D to this 
chapter.) The daily maximum 8-hour concentration for a given calendar 
day is the highest of the 24 possible 8-hour average concentrations 
computed for that day. This process is repeated, yielding a daily 
maximum 8-hour average ozone concentration for each calendar day with 
ambient ozone monitoring data. Because the 8-hour averages are recorded 
in the start hour, the daily maximum 8-hour concentrations from two 
consecutive days may have some hourly concentrations in common. 
Generally, overlapping daily maximum 8-hour averages are not likely, 
except in those non-urban monitoring locations with less pronounced 
diurnal variation in hourly concentrations.
    (b) An ozone monitoring day shall be counted as a valid day if valid 
8-hour averages are available for at least 75% of possible hours in the 
day (i.e., at least 18 of the 24 averages). In the event that less than 
75% of the 8-hour averages are available, a day shall also be counted as 
a valid day if the daily maximum 8-hour average concentration for that 
day is greater than the level of the ambient standard.
    2.2  Primary and Secondary Standard-related Summary Statistic. The 
standard-related summary statistic is the annual fourth-highest daily 
maximum 8-hour ozone concentration, expressed in parts per million, 
averaged over three years. The 3-year average shall be computed using 
the three most recent, consecutive calendar years of monitoring data 
meeting the data completeness requirements described in this appendix. 
The computed 3-year average of the annual fourth-highest daily maximum 
8-hour average ozone concentrations shall be expressed to three decimal 
places (the remaining digits to the right are truncated.)
    2.3 Comparisons with the Primary and Secondary Ozone Standards. (a) 
The primary and secondary ozone ambient air quality standards are met at 
an ambient air quality monitoring site when the 3-year average of the 
annual fourth-highest daily maximum 8-hour average ozone concentration 
is less than or equal to 0.08 ppm. The number of significant figures in 
the level of the standard dictates the rounding convention for comparing 
the computed 3-year average annual fourth-highest daily maximum 8-hour 
average ozone concentration with the level of the standard. The third 
decimal place of the computed value is rounded, with values equal to or 
greater than 5 rounding up. Thus, a computed 3-year average ozone 
concentration of 0.085 ppm is the smallest value that is greater than 
0.08 ppm.
    (b) This comparison shall be based on three consecutive, complete 
calendar years of air quality monitoring data. This requirement is met 
for the three year period at a monitoring site if daily maximum 8-hour 
average concentrations are available for at least 90%, on average, of 
the days during the designated ozone monitoring season, with a minimum 
data completeness in any one year of at least 75% of the designated 
sampling days. When

[[Page 65]]

computing whether the minimum data completeness requirements have been 
met, meteorological or ambient data may be sufficient to demonstrate 
that meteorological conditions on missing days were not conducive to 
concentrations above the level of the standard. Missing days assumed 
less than the level of the standard are counted for the purpose of 
meeting the data completeness requirement, subject to the approval of 
the appropriate Regional Administrator.
    (c) Years with concentrations greater than the level of the standard 
shall not be ignored on the ground that they have less than complete 
data. Thus, in computing the 3-year average fourth maximum 
concentration, calendar years with less than 75% data completeness shall 
be included in the computation if the average annual fourth maximum 8-
hour concentration is greater than the level of the standard.
    (d) Comparisons with the primary and secondary ozone standards are 
demonstrated by examples 1 and 2 in paragraphs (d)(1) and (d) (2) 
respectively as follows:
    (1) As shown in example 1, the primary and secondary standards are 
met at this monitoring site because the 3-year average of the annual 
fourth-highest daily maximum 8-hour average ozone concentrations (i.e., 
0.084 ppm) is less than or equal to 0.08 ppm. The data completeness 
requirement is also met because the average percent of days with valid 
ambient monitoring data is greater than 90%, and no single year has less 
than 75% data completeness.

             Example 1. Ambient monitoring site attaining the primary and secondary ozone standards
----------------------------------------------------------------------------------------------------------------
                                                 1st Highest  2nd Highest  3rd Highest  4th Highest  5th Highest
                                      Percent    Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8-
               Year                  Valid Days   hour Conc.   hour Conc.   hour Conc.   hour Conc.   hour Conc.
                                                    (ppm)        (ppm)        (ppm)        (ppm)        (ppm)
----------------------------------------------------------------------------------------------------------------
1993..............................         100%        0.092        0.091        0.090        0.088        0.085
----------------------------------------------------------------------------------------------------------------
1994..............................          96%        0.090        0.089        0.086        0.084        0.080
----------------------------------------------------------------------------------------------------------------
1995..............................          98%        0.087        0.085        0.083        0.080        0.075
================================================================================================================
    Average.......................          98%
----------------------------------------------------------------------------------------------------------------

    (2) As shown in example 2, the primary and secondary standards are 
not met at this monitoring site because the 3-year average of the 
fourth-highest daily maximum 8-hour average ozone concentrations (i.e., 
0.093 ppm) is greater than 0.08 ppm. Note that the ozone concentration 
data for 1994 is used in these computations, even though the data 
capture is less than 75%, because the average fourth-highest daily 
maximum 8-hour average concentration is greater than 0.08 ppm.

          Example 2. Ambient Monitoring Site Failing to Meet the Primary and Secondary Ozone Standards
----------------------------------------------------------------------------------------------------------------
                                                 1st Highest  2nd Highest  3rd Highest  4th Highest  5th Highest
                                      Percent    Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8- Daily Max 8-
               Year                  Valid Days   hour Conc.   hour Conc.   hour Conc.   hour Conc.   hour Conc.
                                                    (ppm)        (ppm)        (ppm)        (ppm)        (ppm)
----------------------------------------------------------------------------------------------------------------
1993..............................          96%        0.105        0.103        0.103        0.102        0.102
----------------------------------------------------------------------------------------------------------------
1994..............................          74%        0.090        0.085        0.082        0.080        0.078
----------------------------------------------------------------------------------------------------------------
1995..............................          98%        0.103        0.101        0.101        0.097        0.095
================================================================================================================
    Average.......................          89%
----------------------------------------------------------------------------------------------------------------

    3. Design Values for Primary and Secondary Ambient Air Quality 
Standards for Ozone. The air quality design value at a monitoring site 
is defined as that concentration that when reduced to the level of the 
standard ensures that the site meets the standard. For a concentration-
based standard, the air quality design value is simply the standard-
related test statistic. Thus, for the primary and secondary ozone 
standards, the 3-year average annual fourth-highest daily maximum 8-hour 
average ozone concentration is also the air quality design value for the 
site.

[62 FR 38895, July 18, 1997]

    Appendix J to Part 50--Reference Method for the Determination of 
         Particulate Matter as PM10 in the Atmosphere

    1.0 Applicability.

[[Page 66]]

    1.1 This method provides for the measurement of the mass 
concentration of particulate matter with an aerodynamic diameter less 
than or equal to a nominal 10 micrometers (PM1O) in ambient 
air over a 24-hour period for purposes of determining attainment and 
maintenance of the primary and secondary national ambient air quality 
standards for particulate matter specified in Sec. 50.6 of this chapter. 
The measurement process is nondestructive, and the PM10 
sample can be subjected to subsequent physical or chemical analyses. 
Quality assurance procedures and guidance are provided in part 58, 
appendices A and B, of this chapter and in References 1 and 2.
    2.0 Principle.
    2.1 An air sampler draws ambient air at a constant flow rate into a 
specially shaped inlet where the suspended particulate matter is 
inertially separated into one or more size fractions within the 
PM10 size range. Each size fraction in the PM1O 
size range is then collected on a separate filter over the specified 
sampling period. The particle size discrimination characteristics 
(sampling effectiveness and 50 percent cutpoint) of the sampler inlet 
are prescribed as performance specifications in part 53 of this chapter.
    2.2 Each filter is weighed (after moisture equilibration) before and 
after use to determine the net weight (mass) gain due to collected 
PM10. The total volume of air sampled, corrected to EPA 
reference conditions (25 C, 101.3 kPa), is determined from the measured 
flow rate and the sampling time. The mass concentration of 
PM10 in the ambient air is computed as the total mass of 
collected particles in the PM10 size range divided by the 
volume of air sampled, and is expressed in micrograms per standard cubic 
meter ([mu]g/std m\3\). For PM10 samples collected at 
temperatures and pressures significantly different from EPA reference 
conditions, these corrected concentrations sometimes differ 
substantially from actual concentrations (in micrograms per actual cubic 
meter), particularly at high elevations. Although not required, the 
actual PM10 concentration can be calculated from the 
corrected concentration, using the average ambient temperature and 
barometric pressure during the sampling period.
    2.3 A method based on this principle will be considered a reference 
method only if (a) the associated sampler meets the requirements 
specified in this appendix and the requirements in part 53 of this 
chapter, and (b) the method has been designated as a reference method in 
accordance with part 53 of this chapter.
    3.0 Range.
    3.1 The lower limit of the mass concentration range is determined by 
the repeatability of filter tare weights, assuming the nominal air 
sample volume for the sampler. For samplers having an automatic filter-
changing mechanism, there may be no upper limit. For samplers that do 
not have an automatic filter-changing mechanism, the upper limit is 
determined by the filter mass loading beyond which the sampler no longer 
maintains the operating flow rate within specified limits due to 
increased pressure drop across the loaded filter. This upper limit 
cannot be specified precisely because it is a complex function of the 
ambient particle size distribution and type, humidity, filter type, and 
perhaps other factors. Nevertheless, all samplers should be capable of 
measuring 24-hour PM10 mass concentrations of at least 300 
[mu]g/std m\3\ while maintaining the operating flow rate within the 
specified limits.
    4.0 Precision.
    4.1 The precision of PM10 samplers must be 5 [mu]g/m\3\ 
for PM10 concentrations below 80 [mu]g/m\3\ and 7 percent for 
PM10 concentrations above 80 [mu]g/m\3\, as required by part 
53 of this chapter, which prescribes a test procedure that determines 
the variation in the PM10 concentration measurements of 
identical samplers under typical sampling conditions. Continual 
assessment of precision via collocated samplers is required by part 58 
of this chapter for PM10 samplers used in certain monitoring 
networks.
    5.0 Accuracy.
    5.1 Because the size of the particles making up ambient particulate 
matter varies over a wide range and the concentration of particles 
varies with particle size, it is difficult to define the absolute 
accuracy of PM10 samplers. Part 53 of this chapter provides a 
specification for the sampling effectiveness of PM10 
samplers. This specification requires that the expected mass 
concentration calculated for a candidate PM10 sampler, when 
sampling a specified particle size distribution, be within 
10 percent of that calculated for an ideal sampler whose 
sampling effectiveness is explicitly specified. Also, the particle size 
for 50 percent sampling effectivensss is required to be 
100.5 micrometers. Other specifications related to accuracy 
apply to flow measurement and calibration, filter media, analytical 
(weighing) procedures, and artifact. The flow rate accuracy of 
PM10 samplers used in certain monitoring networks is required 
by part 58 of this chapter to be assessed periodically via flow rate 
audits.
    6.0 Potential Sources of Error.
    6.1 Volatile Particles. Volatile particles collected on filters are 
often lost during shipment and/or storage of the filters prior to the 
post-sampling weighing \3\. Although shipment or storage of loaded 
filters is sometimes unavoidable, filters should be reweighed as soon as 
practical to minimize these losses.
    6.2 Artifacts. Positive errors in PM10 concentration 
measurements may result from retention of gaseous species on filters 
4, 5. Such errors include the retention of sulfur

[[Page 67]]

dioxide and nitric acid. Retention of sulfur dioxide on filters, 
followed by oxidation to sulfate, is referred to as artifact sulfate 
formation, a phenomenon which increases with increasing filter 
alkalinity \6\. Little or no artifact sulfate formation should occur 
using filters that meet the alkalinity specification in section 7.2.4. 
Artifact nitrate formation, resulting primarily from retention of nitric 
acid, occurs to varying degrees on many filter types, including glass 
fiber, cellulose ester, and many quartz fiber filters 
5, 7, 8, 9, 10. Loss of true atmospheric particulate nitrate 
during or following sampling may also occur due to dissociation or 
chemical reaction. This phenomenon has been observed on 
Teflon[reg] filters \8\ and inferred for quartz fiber filters 
11, 12. The magnitude of nitrate artifact errors in 
PM10 mass concentration measurements will vary with location 
and ambient temperature; however, for most sampling locations, these 
errors are expected to be small.
    6.3 Humidity. The effects of ambient humidity on the sample are 
unavoidable. The filter equilibration procedure in section 9.0 is 
designed to minimize the effects of moisture on the filter medium.
    6.4 Filter Handling. Careful handling of filters between presampling 
and postsampling weighings is necessary to avoid errors due to damaged 
filters or loss of collected particles from the filters. Use of a filter 
cartridge or cassette may reduce the magnitude of these errors. Filters 
must also meet the integrity specification in section 7.2.3.
    6.5 Flow Rate Variation. Variations in the sampler's operating flow 
rate may alter the particle size discrimination characteristics of the 
sampler inlet. The magnitude of this error will depend on the 
sensitivity of the inlet to variations in flow rate and on the particle 
distribution in the atmosphere during the sampling period. The use of a 
flow control device (section 7.1.3) is required to minimize this error.
    6.6 Air Volume Determination. Errors in the air volume determination 
may result from errors in the flow rate and/or sampling time 
measurements. The flow control device serves to minimize errors in the 
flow rate determination, and an elapsed time meter (section 7.1.5) is 
required to minimize the error in the sampling time measurement.
    7.0 Apparatus.
    7.1 PM10 Sampler.
    7.1.1 The sampler shall be designed to:
    a. Draw the air sample into the sampler inlet and through the 
particle collection filter at a uniform face velocity.
    b. Hold and seal the filter in a horizontal position so that sample 
air is drawn downward through the filter.
    c. Allow the filter to be installed and removed conveniently.
    d. Protect the filter and sampler from precipitation and prevent 
insects and other debris from being sampled.
    e. Minimize air leaks that would cause error in the measurement of 
the air volume passing through the filter.
    f. Discharge exhaust air at a sufficient distance from the sampler 
inlet to minimize the sampling of exhaust air.
    g. Minimize the collection of dust from the supporting surface.
    7.1.2 The sampler shall have a sample air inlet system that, when 
operated within a specified flow rate range, provides particle size 
discrimination characteristics meeting all of the applicable performance 
specifications prescribed in part 53 of this chapter. The sampler inlet 
shall show no significant wind direction dependence. The latter 
requirement can generally be satisfied by an inlet shape that is 
circularly symmetrical about a vertical axis.
    7.1.3 The sampler shall have a flow control device capable of 
maintaining the sampler's operating flow rate within the flow rate 
limits specified for the sampler inlet over normal variations in line 
voltage and filter pressure drop.
    7.1.4 The sampler shall provide a means to measure the total flow 
rate during the sampling period. A continuous flow recorder is 
recommended but not required. The flow measurement device shall be 
accurate to 2 percent.
    7.1.5 A timing/control device capable of starting and stopping the 
sampler shall be used to obtain a sample collection period of 24 
1 hr (1,440 60 min). An elapsed time meter, 
accurate to within 15 minutes, shall be used to measure 
sampling time. This meter is optional for samplers with continuous flow 
recorders if the sampling time measurement obtained by means of the 
recorder meets the 15 minute accuracy specification.
    7.1.6 The sampler shall have an associated operation or instruction 
manual as required by part 53 of this chapter which includes detailed 
instructions on the calibration, operation, and maintenance of the 
sampler.
    7.2 Filters.
    7.2.1 Filter Medium. No commercially available filter medium is 
ideal in all respects for all samplers. The user's goals in sampling 
determine the relative importance of various filter characteristics 
(e.g., cost, ease of handling, physical and chemical characteristics, 
etc.) and, consequently, determine the choice among acceptable filters. 
Furthermore, certain types of filters may not be suitable for use with 
some samplers, particularly under heavy loading conditions (high mass 
concentrations), because of high or rapid increase in the filter flow 
resistance that would exceed the capability of the sampler's flow 
control device. However, samplers equipped with automatic filter-
changing

[[Page 68]]

mechanisms may allow use of these types of filters. The specifications 
given below are minimum requirements to ensure acceptability of the 
filter medium for measurement of PM10 mass concentrations. 
Other filter evaluation criteria should be considered to meet individual 
sampling and analysis objectives.
    7.2.2 Collection Efficiency. [gE]99 percent, as measured by the DOP 
test (ASTM-2986) with 0.3 [mu]m particles at the sampler's operating 
face velocity.
    7.2.3 Integrity. 5 [mu]g/m\3\ (assuming sampler's 
nominal 24-hour air sample volume). Integrity is measured as the 
PM10 concentration equivalent corresponding to the average 
difference between the initial and the final weights of a random sample 
of test filters that are weighed and handled under actual or simulated 
sampling conditions, but have no air sample passed through them (i.e., 
filter blanks). As a minimum, the test procedure must include initial 
equilibration and weighing, installation on an inoperative sampler, 
removal from the sampler, and final equilibration and weighing.
    7.2.4 Alkalinity. <25 microequivalents/gram of filter, as measured 
by the procedure given in Reference 13 following at least two months 
storage in a clean environment (free from contamination by acidic gases) 
at room temperature and humidity.
    7.3 Flow Rate Transfer Standard. The flow rate transfer standard 
must be suitable for the sampler's operating flow rate and must be 
calibrated against a primary flow or volume standard that is traceable 
to the National Bureau of Standards (NBS). The flow rate transfer 
standard must be capable of measuring the sampler's operating flow rate 
with an accuracy of 2 percent.
    7.4 Filter Conditioning Environment.
    7.4.1 Temperature range: 15 to 30 C.
    7.4.2 Temperature control: 3 C.
    7.4.3 Humidity range: 20% to 45% RH.
    7.4.4 Humidity control: 5% RH.
    7.5 Analytical Balance. The analytical balance must be suitable for 
weighing the type and size of filters required by the sampler. The range 
and sensitivity required will depend on the filter tare weights and mass 
loadings. Typically, an analytical balance with a sensitivity of 0.1 mg 
is required for high volume samplers (flow rates 0.5 m\3\/
min). Lower volume samplers (flow rates <0.5 m\3\/min) will require a 
more sensitive balance.
    8.0 Calibration.
    8.1 General Requirements.
    8.1.1 Calibration of the sampler's flow measurement device is 
required to establish traceability of subsequent flow measurements to a 
primary standard. A flow rate transfer standard calibrated against a 
primary flow or volume standard shall be used to calibrate or verify the 
accuracy of the sampler's flow measurement device.
    8.1.2 Particle size discrimination by inertial separation requires 
that specific air velocities be maintained in the sampler's air inlet 
system. Therefore, the flow rate through the sampler's inlet must be 
maintained throughout the sampling period within the design flow rate 
range specified by the manufacturer. Design flow rates are specified as 
actual volumetric flow rates, measured at existing conditions of 
temperature and pressure (Qa). In contrast, mass 
concentrations of PM10 are computed using flow rates 
corrected to EPA reference conditions of temperature and pressure 
(Qstd).
    8.2 Flow Rate Calibration Procedure.
    8.2.1 PM10 samplers employ various types of flow control 
and flow measurement devices. The specific procedure used for flow rate 
calibration or verification will vary depending on the type of flow 
controller and flow indicator employed. Calibration in terms of actual 
volumetric flow rates (Qa) is generally recommended, but 
other measures of flow rate (e.g., Qstd) may be used provided 
the requirements of section 8.1 are met. The general procedure given 
here is based on actual volumetric flow units (Qa) and serves 
to illustrate the steps involved in the calibration of a PM10 
sampler. Consult the sampler manufacturer's instruction manual and 
Reference 2 for specific guidance on calibration. Reference 14 provides 
additional information on the use of the commonly used measures of flow 
rate and their interrelationships.
    8.2.2 Calibrate the flow rate transfer standard against a primary 
flow or volume standard traceable to NBS. Establish a calibration 
relationship (e.g., an equation or family of curves) such that 
traceability to the primary standard is accurate to within 2 percent 
over the expected range of ambient conditions (i.e., temperatures and 
pressures) under which the transfer standard will be used. Recalibrate 
the transfer standard periodically.
    8.2.3 Following the sampler manufacturer's instruction manual, 
remove the sampler inlet and connect the flow rate transfer standard to 
the sampler such that the transfer standard accurately measures the 
sampler's flow rate. Make sure there are no leaks between the transfer 
standard and the sampler.
    8.2.4 Choose a minimum of three flow rates (actual m\3\/min), spaced 
over the acceptable flow rate range specified for the inlet (see 7.1.2) 
that can be obtained by suitable adjustment of the sampler flow rate. In 
accordance with the sampler manufacturer's instruction manual, obtain or 
verify the calibration relationship between the flow rate (actual m\3\/
min) as indicated by the transfer standard and the sampler's flow 
indicator response. Record the ambient temperature and barometric 
pressure. Temperature and pressure corrections to subsequent flow 
indicator readings may be required for certain types of

[[Page 69]]

flow measurement devices. When such corrections are necessary, 
correction on an individual or daily basis is preferable. However, 
seasonal average temperature and average barometric pressure for the 
sampling site may be incorporated into the sampler calibration to avoid 
daily corrections. Consult the sampler manufacturer's instruction manual 
and Reference 2 for additional guidance.
    8.2.5 Following calibration, verify that the sampler is operating at 
its design flow rate (actual m\3\/min) with a clean filter in place.
    8.2.6 Replace the sampler inlet.
    9.0 Procedure.
    9.1 The sampler shall be operated in accordance with the specific 
guidance provided in the sampler manufacturer's instruction manual and 
in Reference 2. The general procedure given here assumes that the 
sampler's flow rate calibration is based on flow rates at ambient 
conditions (Qa) and serves to illustrate the steps involved 
in the operation of a PM10 sampler.
    9.2 Inspect each filter for pinholes, particles, and other 
imperfections. Establish a filter information record and assign an 
identification number to each filter.
    9.3 Equilibrate each filter in the conditioning environment (see 
7.4) for at least 24 hours.
    9.4 Following equilibration, weigh each filter and record the 
presampling weight with the filter identification number.
    9.5 Install a preweighed filter in the sampler following the 
instructions provided in the sampler manufacturer's instruction manual.
    9.6 Turn on the sampler and allow it to establish run-temperature 
conditions. Record the flow indicator reading and, if needed, the 
ambient temperature and barometric pressure. Determine the sampler flow 
rate (actual m\3\/min) in accordance with the instructions provided in 
the sampler manufacturer's instruction manual. NOTE.--No onsite 
temperature or pressure measurements are necessary if the sampler's flow 
indicator does not require temperature or pressure corrections or if 
seasonal average temperature and average barometric pressure for the 
sampling site are incorporated into the sampler calibration (see step 
8.2.4). If individual or daily temperature and pressure corrections are 
required, ambient temperature and barometric pressure can be obtained by 
on-site measurements or from a nearby weather station. Barometric 
pressure readings obtained from airports must be station pressure, not 
corrected to sea level, and may need to be corrected for differences in 
elevation between the sampling site and the airport.
    9.7 If the flow rate is outside the acceptable range specified by 
the manufacturer, check for leaks, and if necessary, adjust the flow 
rate to the specified setpoint. Stop the sampler.
    9.8 Set the timer to start and stop the sampler at appropriate 
times. Set the elapsed time meter to zero or record the initial meter 
reading.
    9.9 Record the sample information (site location or identification 
number, sample date, filter identification number, and sampler model and 
serial number).
    9.10 Sample for 241 hours.
    9.11 Determine and record the average flow rate (Qa) in 
actual m\3\/min for the sampling period in accordance with the 
instructions provided in the sampler manufacturer's instruction manual. 
Record the elapsed time meter final reading and, if needed, the average 
ambient temperature and barometric pressure for the sampling period (see 
note following step 9.6).
    9.12 Carefully remove the filter from the sampler, following the 
sampler manufacturer's instruction manual. Touch only the outer edges of 
the filter.
    9.13 Place the filter in a protective holder or container (e.g., 
petri dish, glassine envelope, or manila folder).
    9.14 Record any factors such as meteorological conditions, 
construction activity, fires or dust storms, etc., that might be 
pertinent to the measurement on the filter information record.
    9.15 Transport the exposed sample filter to the filter conditioning 
environment as soon as possible for equilibration and subsequent 
weighing.
    9.16 Equilibrate the exposed filter in the conditioning environment 
for at least 24 hours under the same temperature and humidity conditions 
used for presampling filter equilibration (see 9.3).
    9.17 Immediately after equilibration, reweigh the filter and record 
the postsampling weight with the filter identification number.
    10.0 Sampler Maintenance.
    10.1 The PM10 sampler shall be maintained in strict 
accordance with the maintenance procedures specified in the sampler 
manufacturer's instruction manual.
    11.0 Calculations.
    11.1 Calculate the average flow rate over the sampling period 
corrected to EPA reference conditions as Qstd. When the 
sampler's flow indicator is calibrated in actual volumetric units 
(Qa), Qstd is calculated as:

Qstd=Qax(Pav/
Tav)(Tstd/Pstd)

where

Qstd = average flow rate at EPA reference conditions, std 
m\3\/min;
Qa = average flow rate at ambient conditions, m\3\/min;
Pav = average barometric pressure during the sampling period 
or average barometric pressure for the sampling site, kPa (or mm Hg);
Tav = average ambient temperature during the sampling period 
or seasonal average

[[Page 70]]

ambient temperature for the sampling site, K;
Tstd = standard temperature, defined as 298 K;
Pstd = standard pressure, defined as 101.3 kPa (or 760 mm 
Hg).

    11.2 Calculate the total volume of air sampled as:

Vstd = Qstdxt

where

Vstd = total air sampled in standard volume units, std m\3\;
t = sampling time, min.

    11.3 Calculate the PM10 concentration as:

PM10 = (Wf-Wi)x10\6\/Vstd

where

PM10 = mass concentration of PM10, [mu]g/std m\3\;
Wf, Wi = final and initial weights of filter 
collecting PM1O particles, g;
10\6\ = conversion of g to [mu]g.

    Note: If more than one size fraction in the PM10 size 
range is collected by the sampler, the sum of the net weight gain by 
each collection filter [[Sigma](Wf-Wi)] is used to 
calculate the PM10 mass concentration.
    12.0 References.
    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume I, Principles. EPA-600/9-76-005, March 1976. Available from CERI, 
ORD Publications, U.S. Environmental Protection Agency, 26 West St. 
Clair Street, Cincinnati, OH 45268.
    2. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II, Ambient Air Specific Methods. EPA-600/4-77-027a, May 1977. 
Available from CERI, ORD Publications, U.S. Environmental Protection 
Agency, 26 West St. Clair Street, Cincinnati, OH 45268.
    3. Clement, R.E., and F.W. Karasek. Sample Composition Changes in 
Sampling and Analysis of Organic Compounds in Aerosols. Int. J. Environ. 
Analyt. Chem., 7:109, 1979.
    4. Lee, R.E., Jr., and J. Wagman. A Sampling Anomaly in the 
Determination of Atmospheric Sulfate Concentration. Amer. Ind. Hyg. 
Assoc. J., 27:266, 1966.
    5. Appel, B.R., S.M. Wall, Y. Tokiwa, and M. Haik. Interference 
Effects in Sampling Particulate Nitrate in Ambient Air. Atmos. Environ., 
13:319, 1979.
    6. Coutant, R.W. Effect of Environmental Variables on Collection of 
Atmospheric Sulfate. Environ. Sci. Technol., 11:873, 1977.
    7. Spicer, C.W., and P. Schumacher. Interference in Sampling 
Atmospheric Particulate Nitrate. Atmos. Environ., 11:873, 1977.
    8. Appel, B.R., Y. Tokiwa, and M. Haik. Sampling of Nitrates in 
Ambient Air. Atmos. Environ., 15:283, 1981.
    9. Spicer, C.W., and P.M. Schumacher. Particulate Nitrate: 
Laboratory and Field Studies of Major Sampling Interferences. Atmos. 
Environ., 13:543, 1979.
    10. Appel, B.R. Letter to Larry Purdue, U.S. EPA, Environmental 
Monitoring and Support Laboratory. March 18, 1982, Docket No. A-82-37, 
II-I-1.
    11. Pierson, W.R., W.W. Brachaczek, T.J. Korniski, T.J. Truex, and 
J.W. Butler. Artifact Formation of Sulfate, Nitrate, and Hydrogen Ion on 
Backup Filters: Allegheny Mountain Experiment. J. Air Pollut. Control 
Assoc., 30:30, 1980.
    12. Dunwoody, C.L. Rapid Nitrate Loss From PM10 Filters. 
J. Air Pollut. Control Assoc., 36:817, 1986.
    13. Harrell, R.M. Measuring the Alkalinity of Hi-Vol Air Filters. 
EMSL/RTP-SOP-QAD-534, October 1985. Available from the U.S. 
Environmental Protection Agency, EMSL/QAD, Research Triangle Park, NC 
27711.
    14. Smith, F., P.S. Wohlschlegel, R.S.C. Rogers, and D.J. Mulligan. 
Investigation of Flow Rate Calibration Procedures Associated With the 
High Volume Method for Determination of Suspended Particulates. EPA-600/
4-78-047, U.S. Environmental Protection Agency, Research Triangle Park, 
NC 27711, 1978.

[52 FR 24664, July 1, 1987; 52 FR 29467, Aug. 7, 1987]

   Appendix K to Part 50--Interpretation of the National Ambient Air 
                Quality Standards for Particulate Matter

    1.0  General.
    (a) This appendix explains the computations necessary for analyzing 
particulate matter data to determine attainment of the 24-hour and 
annual standards specified in 40 CFR 50.6. For the primary and secondary 
standards, particulate matter is measured in the ambient air as 
PM10 (particles with an aerodynamic diameter less than or 
equal to a nominal 10 micrometers) by a reference method based on 
appendix J of this part and designated in accordance with part 53 of 
this chapter, or by an equivalent method designated in accordance with 
part 53 of this chapter. The required frequency of measurements is 
specified in part 58 of this chapter.
    (b) The terms used in this appendix are defined as follows:
    Average refers to an arithmetic mean. All particulate matter 
standards are expressed in terms of expected annual values: Expected 
number of exceedances per year for the 24-hour standards and expected 
annual arithmetic mean for the annual standards.
    Daily value for PM10 refers to the 24-hour average 
concentration of PM10 calculated or measured from midnight to 
midnight (local time).
    Exceedance means a daily value that is above the level of the 24-
hour standard after

[[Page 71]]

rounding to the nearest 10 [mu]g/m\3\ (i.e., values ending in 5 or 
greater are to be rounded up).
    Expected annual value is the number approached when the annual 
values from an increasing number of years are averaged, in the absence 
of long-term trends in emissions or meteorological conditions.
    Year refers to a calendar year.
    (c) Although the discussion in this appendix focuses on monitored 
data, the same principles apply to modeling data, subject to EPA 
modeling guidelines.
    2.0  Attainment Determinations.
    2.1  24-Hour Primary and Secondary Standards.
    (a) Under 40 CFR 50.6(a) the 24-hour primary and secondary standards 
are attained when the expected number of exceedances per year at each 
monitoring site is less than or equal to one. In the simplest case, the 
number of expected exceedances at a site is determined by recording the 
number of exceedances in each calendar year and then averaging them over 
the past 3 calendar years. Situations in which 3 years of data are not 
available and possible adjustments for unusual events or trends are 
discussed in sections 2.3 and 2.4 of this appendix. Further, when data 
for a year are incomplete, it is necessary to compute an estimated 
number of exceedances for that year by adjusting the observed number of 
exceedances. This procedure, performed by calendar quarter, is described 
in section 3.0 of this appendix. The expected number of exceedances is 
then estimated by averaging the individual annual estimates for the past 
3 years.
    (b) The comparison with the allowable expected exceedance rate of 
one per year is made in terms of a number rounded to the nearest tenth 
(fractional values equal to or greater than 0.05 are to be rounded up; 
e.g., an exceedance rate of 1.05 would be rounded to 1.1, which is the 
lowest rate for nonattainment).
    2.2  Annual Primary and Secondary Standards. Under 40 CFR 50.6(b), 
the annual primary and secondary standards are attained when the 
expected annual arithmetic mean PM10 concentration is less 
than or equal to the level of the standard. In the simplest case, the 
expected annual arithmetic mean is determined by averaging the annual 
arithmetic mean PM10 concentrations for the past 3 calendar 
years. Because of the potential for incomplete data and the possible 
seasonality in PM10 concentrations, the annual mean shall be 
calculated by averaging the four quarterly means of PM10 
concentrations within the calendar year. The equations for calculating 
the annual arithmetic mean are given in section 4.0 of this appendix. 
Situations in which 3 years of data are not available and possible 
adjustments for unusual events or trends are discussed in sections 2.3 
and 2.4 of this appendix. The expected annual arithmetic mean is rounded 
to the nearest 1 [mu]g/m\3\ before comparison with the annual standards 
(fractional values equal to or greater than 0.5 are to be rounded up).
    2.3  Data Requirements.
    (a) 40 CFR 58.13 specifies the required minimum frequency of 
sampling for PM10. For the purposes of making comparisons 
with the particulate matter standards, all data produced by National Air 
Monitoring Stations (NAMS), State and Local Air Monitoring Stations 
(SLAMS) and other sites submitted to EPA in accordance with the part 58 
requirements must be used, and a minimum of 75 percent of the scheduled 
PM10 samples per quarter are required.
    (b) To demonstrate attainment of either the annual or 24-hour 
standards at a monitoring site, the monitor must provide sufficient data 
to perform the required calculations of sections 3.0 and 4.0 of this 
appendix. The amount of data required varies with the sampling 
frequency, data capture rate and the number of years of record. In all 
cases, 3 years of representative monitoring data that meet the 75 
percent criterion of the previous paragraph should be utilized, if 
available, and would suffice. More than 3 years may be considered, if 
all additional representative years of data meeting the 75 percent 
criterion are utilized. Data not meeting these criteria may also suffice 
to show attainment; however, such exceptions will have to be approved by 
the appropriate Regional Administrator in accordance with EPA guidance.
    (c) There are less stringent data requirements for showing that a 
monitor has failed an attainment test and thus has recorded a violation 
of the particulate matter standards. Although it is generally necessary 
to meet the minimum 75 percent data capture requirement per quarter to 
use the computational equations described in sections 3.0 and 4.0 of 
this appendix, this criterion does not apply when less data is 
sufficient to unambiguously establish nonattainment. The following 
examples illustrate how nonattainment can be demonstrated when a site 
fails to meet the completeness criteria. Nonattainment of the 24-hour 
primary standards can be established by the observed annual number of 
exceedances (e.g., four observed exceedances in a single year), or by 
the estimated number of exceedances derived from the observed number of 
exceedances and the required number of scheduled samples (e.g., two 
observed exceedances with every other day sampling). Nonattainment of 
the annual standards can be demonstrated on the basis of quarterly mean 
concentrations developed from observed data combined with one-half the 
minimum detectable concentration substituted for missing values. In both 
cases, expected annual values must exceed the levels allowed by the 
standards.
    2.4  Adjustment for Exceptional Events and Trends.

[[Page 72]]

    (a) An exceptional event is an uncontrollable event caused by 
natural sources of particulate matter or an event that is not expected 
to recur at a given location. Inclusion of such a value in the 
computation of exceedances or averages could result in inappropriate 
estimates of their respective expected annual values. To reduce the 
effect of unusual events, more than 3 years of representative data may 
be used. Alternatively, other techniques, such as the use of statistical 
models or the use of historical data could be considered so that the 
event may be discounted or weighted according to the likelihood that it 
will recur. The use of such techniques is subject to the approval of the 
appropriate Regional Administrator in accordance with EPA guidance.
    (b) In cases where long-term trends in emissions and air quality are 
evident, mathematical techniques should be applied to account for the 
trends to ensure that the expected annual values are not inappropriately 
biased by unrepresentative data. In the simplest case, if 3 years of 
data are available under stable emission conditions, this data should be 
used. In the event of a trend or shift in emission patterns, either the 
most recent representative year(s) could be used or statistical 
techniques or models could be used in conjunction with previous years of 
data to adjust for trends. The use of less than 3 years of data, and any 
adjustments are subject to the approval of the appropriate Regional 
Administrator in accordance with EPA guidance.
    3.0  Computational Equations for the 24-hour Standards.
    3.1  Estimating Exceedances for a Year.
    (a) If PM10 sampling is scheduled less frequently than 
every day, or if some scheduled samples are missed, a PM10 
value will not be available for each day of the year. To account for the 
possible effect of incomplete data, an adjustment must be made to the 
data collected at each monitoring location to estimate the number of 
exceedances in a calendar year. In this adjustment, the assumption is 
made that the fraction of missing values that would have exceeded the 
standard level is identical to the fraction of measured values above 
this level. This computation is to be made for all sites that are 
scheduled to monitor throughout the entire year and meet the minimum 
data requirements of section 2.3 of this appendix. Because of possible 
seasonal imbalance, this adjustment shall be applied on a quarterly 
basis. The estimate of the expected number of exceedances for the 
quarter is equal to the observed number of exceedances plus an increment 
associated with the missing data. The following equation must be used 
for these computations:

                               Equation 1
[GRAPHIC] [TIFF OMITTED] TR18JY97.180

where:

eq = the estimated number of exceedances for calendar quarter 
q;
vq = the observed number of exceedances for calendar quarter 
q;
Nq = the number of days in calendar quarter q;
nq = the number of days in calendar quarter q with 
PM10 data; and
q = the index for calendar quarter, q=1, 2, 3 or 4.

    (b) The estimated number of exceedances for a calendar quarter must 
be rounded to the nearest hundredth (fractional values equal to or 
greater than 0.005 must be rounded up).
    (c) The estimated number of exceedances for the year, e, is the sum 
of the estimates for each calendar quarter.

                               Equation 2
[GRAPHIC] [TIFF OMITTED] TR18JY97.181

    (d) The estimated number of exceedances for a single year must be 
rounded to one decimal place (fractional values equal to or greater than 
0.05 are to be rounded up). The expected number of exceedances is then 
estimated by averaging the individual annual estimates for the most 
recent 3 or more representative years of data. The expected number of 
exceedances must be rounded to one decimal place (fractional values 
equal to or greater than 0.05 are to be rounded up).
    (e) The adjustment for incomplete data will not be necessary for 
monitoring or modeling data which constitutes a complete record, i.e., 
365 days per year.
    (f) To reduce the potential for overestimating the number of 
expected exceedances, the correction for missing data will not be 
required for a calendar quarter in which the first observed exceedance 
has occurred if:
    (1) There was only one exceedance in the calendar quarter;
    (2) Everyday sampling is subsequently initiated and maintained for 4 
calendar quarters in accordance with 40 CFR 58.13; and
    (3) Data capture of 75 percent is achieved during the required 
period of everyday sampling. In addition, if the first exceedance is 
observed in a calendar quarter in which the monitor is already sampling 
every day, no adjustment for missing data will be made to the first 
exceedance if a 75 percent data capture rate was achieved in the quarter 
in which it was observed.

[[Page 73]]

                                Example 1

    a. During a particular calendar quarter, 39 out of a possible 92 
samples were recorded, with one observed exceedance of the 24-hour 
standard. Using Equation 1, the estimated number of exceedances for the 
quarter is:

eq=1x92/39=2.359 or 2.36.

    b. If the estimated exceedances for the other 3 calendar quarters in 
the year were 2.30, 0.0 and 0.0, then, using Equation 2, the estimated 
number of exceedances for the year is 2.36=2.30=0.0=0.0 which equals 
4.66 or 4.7. If no exceedances were observed for the 2 previous years, 
then the expected number of exceedances is estimated by: (1/
3)x(4.7=0=0)=1.57 or 1.6. Since 1.6 exceeds the allowable number of 
expected exceedances, this monitoring site would fail the attainment 
test.

                                Example 2

    In this example, everyday sampling was initiated following the first 
observed exceedance as required by 40 CFR 58.13. Accordingly, the first 
observed exceedance would not be adjusted for incomplete sampling. 
During the next three quarters, 1.2 exceedances were estimated. In this 
case, the estimated exceedances for the year would be 1.0=1.2=0.0=0.0 
which equals 2.2. If, as before, no exceedances were observed for the 
two previous years, then the estimated exceedances for the 3-year period 
would then be (1/3)x(2.2=0.0=0.0)=0.7, and the monitoring site would not 
fail the attainment test.
    3.2 Adjustments for Non-Scheduled Sampling Days.
    (a) If a systematic sampling schedule is used and sampling is 
performed on days in addition to the days specified by the systematic 
sampling schedule, e.g., during episodes of high pollution, then an 
adjustment must be made in the eqution for the estimation of 
exceedances. Such an adjustment is needed to eliminate the bias in the 
estimate of the quarterly and annual number of exceedances that would 
occur if the chance of an exceedance is different for scheduled than for 
non-scheduled days, as would be the case with episode sampling.
    (b) The required adjustment treats the systematic sampling schedule 
as a stratified sampling plan. If the period from one scheduled sample 
until the day preceding the next scheduled sample is defined as a 
sampling stratum, then there is one stratum for each scheduled sampling 
day. An average number of observed exceedances is computed for each of 
these sampling strata. With nonscheduled sampling days, the estimated 
number of exceedances is defined as:

                               Equation 3
[GRAPHIC] [TIFF OMITTED] TR18JY97.182

where:

eq = the estimated number of exceedances for the quarter;
Nq = the number of days in the quarter;
mq = the number of strata with samples during the quarter;
vj = the number of observed exceedances in stratum j; and
kj = the number of actual samples in stratum j.

    (c) Note that if only one sample value is recorded in each stratum, 
then Equation 3 reduces to Equation 1.

                                Example 3

    A monitoring site samples according to a systematic sampling 
schedule of one sample every 6 days, for a total of 15 scheduled samples 
in a quarter out of a total of 92 possible samples. During one 6-day 
period, potential episode levels of PM10 were suspected, so 5 
additional samples were taken. One of the regular scheduled samples was 
missed, so a total of 19 samples in 14 sampling strata were measured. 
The one 6-day sampling stratum with 6 samples recorded 2 exceedances. 
The remainder of the quarter with one sample per stratum recorded zero 
exceedances. Using Equation 3, the estimated number of exceedances for 
the quarter is:

eq=(92/14)x(2/6=0=. . .=0)=2.19.

    4.0 Computational Equations for Annual Standards.
    4.1 Calculation of the Annual Arithmetic Mean. (a) An annual 
arithmetic mean value for PM10 is determined by averaging the 
quarterly means for the 4 calendar quarters of the year. The following 
equation is to be used for calculation of the mean for a calendar 
quarter:

                               Equation 4
[GRAPHIC] [TIFF OMITTED] TR18JY97.183

where:

xq = the quarterly mean concentration for quarter q, q=1, 2, 
3, or 4,
nq = the number of samples in the quarter, and
xi = the ith concentration value recorded in the quarter.

    (b) The quarterly mean, expressed in [mu]g/m\3\, must be rounded to 
the nearest tenth (fractional values of 0.05 should be rounded up).

[[Page 74]]

    (c) The annual mean is calculated by using the following equation:

                               Equation 5
[GRAPHIC] [TIFF OMITTED] TR18JY97.184

where:

x = the annual mean; and
xq = the mean for calendar quarter q.

    (d) The average of quarterly means must be rounded to the nearest 
tenth (fractional values of 0.05 should be rounded up).
    (e) The use of quarterly averages to compute the annual average will 
not be necessary for monitoring or modeling data which results in a 
complete record, i.e., 365 days per year.
    (f) The expected annual mean is estimated as the average of three or 
more annual means. This multi-year estimate, expressed in [mu]g/m\3\, 
shall be rounded to the nearest integer for comparison with the annual 
standard (fractional values of 0.5 should be rounded up).

                                Example 4

    Using Equation 4, the quarterly means are calculated for each 
calendar quarter. If the quarterly means are 52.4, 75.3, 82.1, and 63.2 
[mu]g/m \3\, then the annual mean is:

x = (1/4)x(52.4=75.3=82.1=63.2) = 68.25 or 68.3.

    4.2 Adjustments for Non-scheduled Sampling Days. (a) An adjustment 
in the calculation of the annual mean is needed if sampling is performed 
on days in addition to the days specified by the systematic sampling 
schedule. For the same reasons given in the discussion of estimated 
exceedances, under section 3.2 of this appendix, the quarterly averages 
would be calculated by using the following equation:

                               Equation 6
[GRAPHIC] [TIFF OMITTED] TR18JY97.185

where:

xq = the quarterly mean concentration for quarter q, q=1, 2, 
3, or 4;
xij = the ith concentration value recorded in stratum j;
kj = the number of actual samples in stratum j; and
mq = the number of strata with data in the quarter.

    (b) If one sample value is recorded in each stratum, Equation 6 
reduces to a simple arithmetic average of the observed values as 
described by Equation 4.

                                Example 5

    a. During one calendar quarter, 9 observations were recorded. These 
samples were distributed among 7 sampling strata, with 3 observations in 
one stratum. The concentrations of the 3 observations in the single 
stratum were 202, 242, and 180 [mu]g/m\3\. The remaining 6 observed 
concentrations were 55, 68, 73, 92, 120, and 155 [mu]g/m\3\. Applying 
the weighting factors specified in Equation 6, the quarterly mean is:

xq = (1/7) x [(1/3) x (202 = 242 = 180) = 155 = 68 = 73 = 92 
= 120 = 155] = 110.1

    b. Although 24-hour measurements are rounded to the nearest 10 
[mu]g/m\3\ for determinations of exceedances of the 24-hour standard, 
note that these values are rounded to the nearest 1 [mu]g/m\3\ for the 
calculation of means.

[62 FR 38712, July 18, 1997]

 Appendix L to Part 50--Reference Method for the Determination of Fine 
        Particulate Matter as PM2.5 in the Atmosphere

    1.0 Applicability.
    1.1 This method provides for the measurement of the mass 
concentration of fine particulate matter having an aerodynamic diameter 
less than or equal to a nominal 2.5 micrometers (PM2.5) in 
ambient air over a 24-hour period for purposes of determining whether 
the primary and secondary national ambient air quality standards for 
fine particulate matter specified in Sec. 50.7 of this part are met. The 
measurement process is considered to be nondestructive, and the 
PM2.5 sample obtained can be subjected to subsequent physical 
or chemical analyses. Quality assessment procedures are provided in part 
58, appendix A of this chapter, and quality assurance guidance are 
provided in references 1, 2, and 3 in section 13.0 of this appendix.
    1.2 This method will be considered a reference method for purposes 
of part 58 of this chapter only if:
    (a) The associated sampler meets the requirements specified in this 
appendix and the applicable requirements in part 53 of this chapter, and
    (b) The method and associated sampler have been designated as a 
reference method in accordance with part 53 of this chapter.
    1.3 PM2.5 samplers that meet nearly all specifications 
set forth in this method but have minor deviations and/or modifications 
of the reference method sampler will be designated as ``Class I'' 
equivalent methods for PM2.5 in accordance with part 53 of 
this chapter.
    2.0 Principle.
    2.1 An electrically powered air sampler draws ambient air at a 
constant volumetric flow rate into a specially shaped inlet and

[[Page 75]]

through an inertial particle size separator (impactor) where the 
suspended particulate matter in the PM2.5 size range is 
separated for collection on a polytetrafluoroethylene (PTFE) filter over 
the specified sampling period. The air sampler and other aspects of this 
reference method are specified either explicitly in this appendix or 
generally with reference to other applicable regulations or quality 
assurance guidance.
    2.2 Each filter is weighed (after moisture and temperature 
conditioning) before and after sample collection to determine the net 
gain due to collected PM2.5. The total volume of air sampled 
is determined by the sampler from the measured flow rate at actual 
ambient temperature and pressure and the sampling time. The mass 
concentration of PM2.5 in the ambient air is computed as the 
total mass of collected particles in the PM2.5 size range 
divided by the actual volume of air sampled, and is expressed in 
micrograms per cubic meter of air ([mu]g/m\3\).
    3.0 PM2.5 Measurement Range.
    3.1 Lower concentration limit. The lower detection limit of the mass 
concentration measurement range is estimated to be approximately 2 
[mu]g/m\3\, based on noted mass changes in field blanks in conjunction 
with the 24 m\3\ nominal total air sample volume specified for the 24-
hour sample.
    3.2 Upper concentration limit. The upper limit of the mass 
concentration range is determined by the filter mass loading beyond 
which the sampler can no longer maintain the operating flow rate within 
specified limits due to increased pressure drop across the loaded 
filter. This upper limit cannot be specified precisely because it is a 
complex function of the ambient particle size distribution and type, 
humidity, the individual filter used, the capacity of the sampler flow 
rate control system, and perhaps other factors. Nevertheless, all 
samplers are estimated to be capable of measuring 24-hour 
PM2.5 mass concentrations of at least 200 [mu]g/m\3\ while 
maintaining the operating flow rate within the specified limits.
    3.3 Sample period. The required sample period for PM2.5 
concentration measurements by this method shall be 1,380 to 1500 minutes 
(23 to 25 hours). However, when a sample period is less than 1,380 
minutes, the measured concentration (as determined by the collected 
PM2.5 mass divided by the actual sampled air volume), 
multiplied by the actual number of minutes in the sample period and 
divided by 1,440, may be used as if it were a valid concentration 
measurement for the specific purpose of determining a violation of the 
NAAQS. This value assumes that the PM2.5 concentration is 
zero for the remaining portion of the sample period and therefore 
represents the minimum concentration that could have been measured for 
the full 24-hour sample period. Accordingly, if the value thus 
calculated is high enough to be an exceedance, such an exceedance would 
be a valid exceedance for the sample period. When reported to AIRS, this 
data value should receive a special code to identify it as not to be 
commingled with normal concentration measurements or used for other 
purposes.
    4.0 Accuracy.
    4.1 Because the size and volatility of the particles making up 
ambient particulate matter vary over a wide range and the mass 
concentration of particles varies with particle size, it is difficult to 
define the accuracy of PM2.5 measurements in an absolute 
sense. The accuracy of PM2.5 measurements is therefore 
defined in a relative sense, referenced to measurements provided by this 
reference method. Accordingly, accuracy shall be defined as the degree 
of agreement between a subject field PM2.5 sampler and a 
collocated PM2.5 reference method audit sampler operating 
simultaneously at the monitoring site location of the subject sampler 
and includes both random (precision) and systematic (bias) errors. The 
requirements for this field sampler audit procedure are set forth in 
part 58, appendix A of this chapter.
    4.2 Measurement system bias. Results of collocated measurements 
where the duplicate sampler is a reference method sampler are used to 
assess a portion of the measurement system bias according to the 
schedule and procedure specified in part 58, appendix A of this chapter.
    4.3 Audits with reference method samplers to determine system 
accuracy and bias. According to the schedule and procedure specified in 
part 58, appendix A of this chapter, a reference method sampler is 
required to be located at each of selected PM2.5 SLAMS sites 
as a duplicate sampler. The results from the primary sampler and the 
duplicate reference method sampler are used to calculate accuracy of the 
primary sampler on a quarterly basis, bias of the primary sampler on an 
annual basis, and bias of a single reporting organization on an annual 
basis. Reference 2 in section 13.0 of this appendix provides additional 
information and guidance on these reference method audits.
    4.4 Flow rate accuracy and bias. Part 58, appendix A of this chapter 
requires that the flow rate accuracy and bias of individual 
PM2.5 samplers used in SLAMS monitoring networks be assessed 
periodically via audits of each sampler's operational flow rate. In 
addition, part 58, appendix A of this chapter requires that flow rate 
bias for each reference and equivalent method operated by each reporting 
organization be assessed quarterly and annually. Reference 2 in section 
13.0 of this appendix provides additional information and guidance on 
flow rate accuracy audits and calculations for accuracy and bias.
    5.0 Precision. A data quality objective of 10 percent coefficient of 
variation or better has

[[Page 76]]

been established for the operational precision of PM2.5 
monitoring data.
    5.1 Tests to establish initial operational precision for each 
reference method sampler are specified as a part of the requirements for 
designation as a reference method under Sec. 53.58 of this chapter.
    5.2 Measurement System Precision. Collocated sampler results, where 
the duplicate sampler is not a reference method sampler but is a sampler 
of the same designated method as the primary sampler, are used to assess 
measurement system precision according to the schedule and procedure 
specified in part 58, appendix A of this chapter. Part 58, appendix A of 
this chapter requires that these collocated sampler measurements be used 
to calculate quarterly and annual precision estimates for each primary 
sampler and for each designated method employed by each reporting 
organization. Reference 2 in section 13.0 of this appendix provides 
additional information and guidance on this requirement.
    6.0 Filter for PM2.5 Sample Collection. Any filter 
manufacturer or vendor who sells or offers to sell filters specifically 
identified for use with this PM2.5 reference method shall 
certify that the required number of filters from each lot of filters 
offered for sale as such have been tested as specified in this section 
6.0 and meet all of the following design and performance specifications.
    6.1 Size. Circular, 46.2 mm diameter 0.25 mm.
    6.2 Medium. Polytetrafluoroethylene (PTFE Teflon), with integral 
support ring.
    6.3 Support ring. Polymethylpentene (PMP) or equivalent inert 
material, 0.38 0.04 mm thick, outer diameter 46.2 mm 
0.25 mm, and width of 3.68 mm ( 0.00, -0.51 mm).
    6.4 Pore size. 2 [mu]m as measured by ASTM F 316-94.
    6.5 Filter thickness. 30 to 50 [mu]m.
    6.6 Maximum pressure drop (clean filter). 30 cm H2O 
column @ 16.67 L/min clean air flow.
    6.7 Maximum moisture pickup. Not more than 10 [mu]g weight increase 
after 24-hour exposure to air of 40 percent relative humidity, relative 
to weight after 24-hour exposure to air of 35 percent relative humidity.
    6.8 Collection efficiency. Greater than 99.7 percent, as measured by 
the DOP test (ASTM D 2986-91) with 0.3 [mu]m particles at the sampler's 
operating face velocity.
    6.9 Filter weight stability. Filter weight loss shall be less than 
20 [mu]g, as measured in each of the following two tests specified in 
sections 6.9.1 and 6.9.2 of this appendix. The following conditions 
apply to both of these tests: Filter weight loss shall be the average 
difference between the initial and the final filter weights of a random 
sample of test filters selected from each lot prior to sale. The number 
of filters tested shall be not less than 0.1 percent of the filters of 
each manufacturing lot, or 10 filters, whichever is greater. The filters 
shall be weighed under laboratory conditions and shall have had no air 
sample passed through them, i.e., filter blanks. Each test procedure 
must include initial conditioning and weighing, the test, and final 
conditioning and weighing. Conditioning and weighing shall be in 
accordance with sections 8.0 through 8.2 of this appendix and general 
guidance provided in reference 2 of section 13.0 of this appendix.
    6.9.1 Test for loose, surface particle contamination. After the 
initial weighing, install each test filter, in turn, in a filter 
cassette (Figures L-27, L-28, and L-29 of this appendix) and drop the 
cassette from a height of 25 cm to a flat hard surface, such as a 
particle-free wood bench. Repeat two times, for a total of three drop 
tests for each test filter. Remove the test filter from the cassette and 
weigh the filter. The average change in weight must be less than 20 
[mu]g.
    6.9.2 Test for temperature stability. After weighing each filter, 
place the test filters in a drying oven set at 40  deg.C 2 
deg.C for not less than 48 hours. Remove, condition, and reweigh each 
test filter. The average change in weight must be less than 20 [mu]g.
    6.10 Alkalinity. Less than 25 microequivalents/gram of filter, as 
measured by the guidance given in reference 2 in section 13.0 of this 
appendix.
    6.11 Supplemental requirements. Although not required for 
determination of PM2.5 mass concentration under this 
reference method, additional specifications for the filter must be 
developed by users who intend to subject PM2.5 filter samples 
to subsequent chemical analysis. These supplemental specifications 
include background chemical contamination of the filter and any other 
filter parameters that may be required by the method of chemical 
analysis. All such supplemental filter specifications must be compatible 
with and secondary to the primary filter specifications given in this 
section 6.0 of this appendix.
    7.0 PM2.5 Sampler.
    7.1 Configuration. The sampler shall consist of a sample air inlet, 
downtube, particle size separator (impactor), filter holder assembly, 
air pump and flow rate control system, flow rate measurement device, 
ambient and filter temperature monitoring system, barometric pressure 
measurement system, timer, outdoor environmental enclosure, and suitable 
mechanical, electrical, or electronic control capability to meet or 
exceed the design and functional performance as specified in this 
section 7.0 of this appendix. The performance specifications require 
that the sampler:
    (a) Provide automatic control of sample volumetric flow rate and 
other operational parameters.
    (b) Monitor these operational parameters as well as ambient 
temperature and pressure.
    (c) Provide this information to the sampler operator at the end of 
each sample period in

[[Page 77]]

digital form, as specified in table L-1 of section 7.4.19 of this 
appendix.
    7.2 Nature of specifications. The PM2.5 sampler is 
specified by a combination of design and performance requirements. The 
sample inlet, downtube, particle size discriminator, filter cassette, 
and the internal configuration of the filter holder assembly are 
specified explicitly by design figures and associated mechanical 
dimensions, tolerances, materials, surface finishes, assembly 
instructions, and other necessary specifications. All other aspects of 
the sampler are specified by required operational function and 
performance, and the design of these other aspects (including the design 
of the lower portion of the filter holder assembly) is optional, subject 
to acceptable operational performance. Test procedures to demonstrate 
compliance with both the design and performance requirements are set 
forth in subpart E of part 53 of this chapter.
    7.3 Design specifications. Except as indicated in this section 7.3 
of this appendix, these components must be manufactured or reproduced 
exactly as specified, in an ISO 9001-registered facility, with 
registration initially approved and subsequently maintained during the 
period of manufacture. See Sec. 53.1(t) of this chapter for the 
definition of an ISO-registered facility. Minor modifications or 
variances to one or more components that clearly would not affect the 
aerodynamic performance of the inlet, downtube, impactor, or filter 
cassette will be considered for specific approval. Any such proposed 
modifications shall be described and submitted to the EPA for specific 
individual acceptability either as part of a reference or equivalent 
method application under part 53 of this chapter or in writing in 
advance of such an intended application under part 53 of this chapter.
    7.3.1 Sample inlet assembly. The sample inlet assembly, consisting 
of the inlet, downtube, and impactor shall be configured and assembled 
as indicated in Figure L-1 of this appendix and shall meet all 
associated requirements. A portion of this assembly shall also be 
subject to the maximum overall sampler leak rate specification under 
section 7.4.6 of this appendix.
    7.3.2 Inlet. The sample inlet shall be fabricated as indicated in 
Figures L-2 through L-18 of this appendix and shall meet all associated 
requirements.
    7.3.3 Downtube. The downtube shall be fabricated as indicated in 
Figure L-19 of this appendix and shall meet all associated requirements.
    7.3.4 Impactor.
    7.3.4.1 The impactor (particle size separator) shall be fabricated 
as indicated in Figures L-20 through L-24 of this appendix and shall 
meet all associated requirements. Following the manufacture and 
finishing of each upper impactor housing (Figure L-21 of this appendix), 
the dimension of the impaction jet must be verified by the manufacturer 
using Class ZZ go/no-go plug gauges that are traceable to NIST.
    7.3.4.2 Impactor filter specifications:
    (a) Size. Circular, 35 to 37 mm diameter.
    (b) Medium. Borosilicate glass fiber, without binder.
    (c) Pore size. 1 to 1.5 micrometer, as measured by ASTM F 316-80.
    (d) Thickness. 300 to 500 micrometers.
    7.3.4.3 Impactor oil specifications:
    (a) Composition. Tetramethyltetraphenyltrisiloxane, single-compound 
diffusion oil.
    (b) Vapor pressure. Maximum 2x10-8 mm Hg at 25  deg.C.
    (c) Viscosity. 36 to 40 centistokes at 25  deg.C.
    (d) Density. 1.06 to 1.07 g/cm\3\ at 25  deg.C.
    (e) Quantity. 1 mL 0.1 mL.
    7.3.5 Filter holder assembly. The sampler shall have a sample filter 
holder assembly to adapt and seal to the down tube and to hold and seal 
the specified filter, under section 6.0 of this appendix, in the sample 
air stream in a horizontal position below the downtube such that the 
sample air passes downward through the filter at a uniform face 
velocity. The upper portion of this assembly shall be fabricated as 
indicated in Figures L-25 and L-26 of this appendix and shall accept and 
seal with the filter cassette, which shall be fabricated as indicated in 
Figures L-27 through L-29 of this appendix.
    (a) The lower portion of the filter holder assembly shall be of a 
design and construction that:
    (1) Mates with the upper portion of the assembly to complete the 
filter holder assembly,
    (2) Completes both the external air seal and the internal filter 
cassette seal such that all seals are reliable over repeated filter 
changings, and
    (3) Facilitates repeated changing of the filter cassette by the 
sampler operator.
    (b) Leak-test performance requirements for the filter holder 
assembly are included in section 7.4.6 of this appendix.
    (c) If additional or multiple filters are stored in the sampler as 
part of an automatic sequential sample capability, all such filters, 
unless they are currently and directly installed in a sampling channel 
or sampling configuration (either active or inactive), shall be covered 
or (preferably) sealed in such a way as to:
    (1) Preclude significant exposure of the filter to possible 
contamination or accumulation of dust, insects, or other material that 
may be present in the ambient air, sampler, or sampler ventilation air 
during storage periods either before or after sampling; and
    (2) To minimize loss of volatile or semi-volatile PM sample 
components during storage of the filter following the sample period.
    7.3.6 Flow rate measurement adapter. A flow rate measurement adapter 
as specified in

[[Page 78]]

Figure L-30 of this appendix shall be furnished with each sampler.
    7.3.7 Surface finish. All internal surfaces exposed to sample air 
prior to the filter shall be treated electrolytically in a sulfuric acid 
bath to produce a clear, uniform anodized surface finish of not less 
than 1000 mg/ft2 (1.08 mg/cm2) in accordance with 
military standard specification (mil. spec.) 8625F, Type II, Class 1 in 
reference 4 of section 13.0 of this appendix. This anodic surface 
coating shall not be dyed or pigmented. Following anodization, the 
surfaces shall be sealed by immersion in boiling deionized water for not 
less than 15 minutes. Section 53.51(d)(2) of this chapter should also be 
consulted.
    7.3.8 Sampling height. The sampler shall be equipped with legs, a 
stand, or other means to maintain the sampler in a stable, upright 
position and such that the center of the sample air entrance to the 
inlet, during sample collection, is maintained in a horizontal plane and 
is 2.0 0.2 meters above the floor or other horizontal 
supporting surface. Suitable bolt holes, brackets, tie-downs, or other 
means should be provided to facilitate mechanically securing the sample 
to the supporting surface to prevent toppling of the sampler due to 
wind.
    7.4 Performance specifications.
    7.4.1 Sample flow rate. Proper operation of the impactor requires 
that specific air velocities be maintained through the device. 
Therefore, the design sample air flow rate through the inlet shall be 
16.67 L/min (1.000 m\3\/hour) measured as actual volumetric flow rate at 
the temperature and pressure of the sample air entering the inlet.
    7.4.2 Sample air flow rate control system. The sampler shall have a 
sample air flow rate control system which shall be capable of providing 
a sample air volumetric flow rate within the specified range, under 
section 7.4.1 of this appendix, for the specified filter, under section 
6.0 of this appendix, at any atmospheric conditions specified, under 
section 7.4.7 of this appendix, at a filter pressure drop equal to that 
of a clean filter plus up to 75 cm water column (55 mm Hg), and over the 
specified range of supply line voltage, under section 7.4.15.1 of this 
appendix. This flow control system shall allow for operator adjustment 
of the operational flow rate of the sampler over a range of at least 
15 percent of the flow rate specified in section 7.4.1 of 
this appendix.
    7.4.3 Sample flow rate regulation. The sample flow rate shall be 
regulated such that for the specified filter, under section 6.0 of this 
appendix, at any atmospheric conditions specified, under section 7.4.7 
of this appendix, at a filter pressure drop equal to that of a clean 
filter plus up to 75 cm water column (55 mm Hg), and over the specified 
range of supply line voltage, under section 7.4.15.1 of this appendix, 
the flow rate is regulated as follows:
    7.4.3.1 The volumetric flow rate, measured or averaged over 
intervals of not more than 5 minutes over a 24-hour period, shall not 
vary more than 5 percent from the specified 16.67 L/min flow 
rate over the entire sample period.
    7.4.3.2 The coefficient of variation (sample standard deviation 
divided by the mean) of the flow rate, measured over a 24-hour period, 
shall not be greater than 2 percent.
    7.4.3.3 The amplitude of short-term flow rate pulsations, such as 
may originate from some types of vacuum pumps, shall be attenuated such 
that they do not cause significant flow measurement error or affect the 
collection of particles on the particle collection filter.
    7.4.4 Flow rate cut off. The sampler's sample air flow rate control 
system shall terminate sample collection and stop all sample flow for 
the remainder of the sample period in the event that the sample flow 
rate deviates by more than 10 percent from the sampler design flow rate 
specified in section 7.4.1 of this appendix for more than 60 seconds. 
However, this sampler cut-off provision shall not apply during periods 
when the sampler is inoperative due to a temporary power interruption, 
and the elapsed time of the inoperative period shall not be included in 
the total sample time measured and reported by the sampler, under 
section 7.4.13 of this appendix.
    7.4.5 Flow rate measurement.
    7.4.5.1 The sampler shall provide a means to measure and indicate 
the instantaneous sample air flow rate, which shall be measured as 
volumetric flow rate at the temperature and pressure of the sample air 
entering the inlet, with an accuracy of 2 percent. The 
measured flow rate shall be available for display to the sampler 
operator at any time in either sampling or standby modes, and the 
measurement shall be updated at least every 30 seconds. The sampler 
shall also provide a simple means by which the sampler operator can 
manually start the sample flow temporarily during non-sampling modes of 
operation, for the purpose of checking the sample flow rate or the flow 
rate measurement system.
    7.4.5.2 During each sample period, the sampler's flow rate 
measurement system shall automatically monitor the sample volumetric 
flow rate, obtaining flow rate measurements at intervals of not greater 
than 30 seconds.
    (a) Using these interval flow rate measurements, the sampler shall 
determine or calculate the following flow-related parameters, scaled in 
the specified engineering units:
    (1) The instantaneous or interval-average flow rate, in L/min.
    (2) The value of the average sample flow rate for the sample period, 
in L/min.
    (3) The value of the coefficient of variation (sample standard 
deviation divided by the

[[Page 79]]

average) of the sample flow rate for the sample period, in percent.
    (4) The occurrence of any time interval during the sample period in 
which the measured sample flow rate exceeds a range of 5 
percent of the average flow rate for the sample period for more than 5 
minutes, in which case a warning flag indicator shall be set.
    (5) The value of the integrated total sample volume for the sample 
period, in m\3\.
    (b) Determination or calculation of these values shall properly 
exclude periods when the sampler is inoperative due to temporary 
interruption of electrical power, under section 7.4.13 of this appendix, 
or flow rate cut off, under section 7.4.4 of this appendix.
    (c) These parameters shall be accessible to the sampler operator as 
specified in table L-1 of section 7.4.19 of this appendix. In addition, 
it is strongly encouraged that the flow rate for each 5-minute interval 
during the sample period be available to the operator following the end 
of the sample period.
    7.4.6 Leak test capability.
    7.4.6.1 External leakage. The sampler shall include an external air 
leak-test capability consisting of components, accessory hardware, 
operator interface controls, a written procedure in the associated 
Operation/Instruction Manual, under section 7.4.18 of this appendix, and 
all other necessary functional capability to permit and facilitate the 
sampler operator to conveniently carry out a leak test of the sampler at 
a field monitoring site without additional equipment. The sampler 
components to be subjected to this leak test include all components and 
their interconnections in which external air leakage would or could 
cause an error in the sampler's measurement of the total volume of 
sample air that passes through the sample filter.
    (a) The suggested technique for the operator to use for this leak 
test is as follows:
    (1) Remove the sampler inlet and installs the flow rate measurement 
adapter supplied with the sampler, under section 7.3.6 of this appendix.
    (2) Close the valve on the flow rate measurement adapter and use the 
sampler air pump to draw a partial vacuum in the sampler, including (at 
least) the impactor, filter holder assembly (filter in place), flow 
measurement device, and interconnections between these devices, of at 
least 55 mm Hg (75 cm water column), measured at a location downstream 
of the filter holder assembly.
    (3) Plug the flow system downstream of these components to isolate 
the components under vacuum from the pump, such as with a built-in 
valve.
    (4) Stop the pump.
    (5) Measure the trapped vacuum in the sampler with a built-in 
pressure measuring device.
    (6) (i) Measure the vacuum in the sampler with the built-in pressure 
measuring device again at a later time at least 10 minutes after the 
first pressure measurement.
    (ii) Caution: Following completion of the test, the adaptor valve 
should be opened slowly to limit the flow rate of air into the sampler. 
Excessive air flow rate may blow oil out of the impactor.
    (7) Upon completion of the test, open the adaptor valve, remove the 
adaptor and plugs, and restore the sampler to the normal operating 
configuration.
    (b) The associated leak test procedure shall require that for 
successful passage of this test, the difference between the two pressure 
measurements shall not be greater than the number of mm of Hg specified 
for the sampler by the manufacturer, based on the actual internal volume 
of the sampler, that indicates a leak of less than 80 mL/min.
    (c) Variations of the suggested technique or an alternative external 
leak test technique may be required for samplers whose design or 
configuration would make the suggested technique impossible or 
impractical. The specific proposed external leak test procedure, or 
particularly an alternative leak test technique, proposed for a 
particular candidate sampler may be described and submitted to the EPA 
for specific individual acceptability either as part of a reference or 
equivalent method application under part 53 of this chapter or in 
writing in advance of such an intended application under part 53 of this 
chapter.
    7.4.6.2 Internal, filter bypass leakage. The sampler shall include 
an internal, filter bypass leak-check capability consisting of 
components, accessory hardware, operator interface controls, a written 
procedure in the Operation/Instruction Manual, and all other necessary 
functional capability to permit and facilitate the sampler operator to 
conveniently carry out a test for internal filter bypass leakage in the 
sampler at a field monitoring site without additional equipment. The 
purpose of the test is to determine that any portion of the sample flow 
rate that leaks past the sample filter without passing through the 
filter is insignificant relative to the design flow rate for the 
sampler.
    (a) The suggested technique for the operator to use for this leak 
test is as follows:
    (1) Carry out an external leak test as provided under section 
7.4.6.1 of this appendix which indicates successful passage of the 
prescribed external leak test.
    (2) Install a flow-impervious membrane material in the filter 
cassette, either with or without a filter, as appropriate, which 
effectively prevents air flow through the filter.
    (3) Use the sampler air pump to draw a partial vacuum in the 
sampler, downstream of the filter holder assembly, of at least 55 mm Hg 
(75 cm water column).
    (4) Plug the flow system downstream of the filter holder to isolate 
the components under

[[Page 80]]

vacuum from the pump, such as with a built-in valve.
    (5) Stop the pump.
    (6) Measure the trapped vacuum in the sampler with a built-in 
pressure measuring device.
    (7) Measure the vacuum in the sampler with the built-in pressure 
measuring device again at a later time at least 10 minutes after the 
first pressure measurement.
    (8) Remove the flow plug and membrane and restore the sampler to the 
normal operating configuration.
    (b) The associated leak test procedure shall require that for 
successful passage of this test, the difference between the two pressure 
measurements shall not be greater than the number of mm of Hg specified 
for the sampler by the manufacturer, based on the actual internal volume 
of the portion of the sampler under vacuum, that indicates a leak of 
less than 80 mL/min.
    (c) Variations of the suggested technique or an alternative 
internal, filter bypass leak test technique may be required for samplers 
whose design or configuration would make the suggested technique 
impossible or impractical. The specific proposed internal leak test 
procedure, or particularly an alternative internal leak test technique 
proposed for a particular candidate sampler may be described and 
submitted to the EPA for specific individual acceptability either as 
part of a reference or equivalent method application under part 53 of 
this chapter or in writing in advance of such intended application under 
part 53 of this chapter.
    7.4.7 Range of operational conditions. The sampler is required to 
operate properly and meet all requirements specified in this appendix 
over the following operational ranges.
    7.4.7.1 Ambient temperature. -30 to =45  deg.C (Note: Although for 
practical reasons, the temperature range over which samplers are 
required to be tested under part 53 of this chapter is -20 to =40 
deg.C, the sampler shall be designed to operate properly over this wider 
temperature range.).
    7.4.7.2 Ambient relative humidity. 0 to 100 percent.
    7.4.7.3 Barometric pressure range. 600 to 800 mm Hg.
    7.4.8 Ambient temperature sensor. The sampler shall have capability 
to measure the temperature of the ambient air surrounding the sampler 
over the range of -30 to =45  deg.C, with a resolution of 0.1  deg.C and 
accuracy of 2.0  deg.C, referenced as described in reference 
3 in section 13.0 of this appendix, with and without maximum solar 
insolation.
    7.4.8.1 The ambient temperature sensor shall be mounted external to 
the sampler enclosure and shall have a passive, naturally ventilated sun 
shield. The sensor shall be located such that the entire sun shield is 
at least 5 cm above the horizontal plane of the sampler case or 
enclosure (disregarding the inlet and downtube) and external to the 
vertical plane of the nearest side or protuberance of the sampler case 
or enclosure. The maximum temperature measurement error of the ambient 
temperature measurement system shall be less than 1.6  deg.C at 1 m/s 
wind speed and 1000 W/m2 solar radiation intensity.
    7.4.8.2 The ambient temperature sensor shall be of such a design and 
mounted in such a way as to facilitate its convenient dismounting and 
immersion in a liquid for calibration and comparison to the filter 
temperature sensor, under section 7.4.11 of this appendix.
    7.4.8.3 This ambient temperature measurement shall be updated at 
least every 30 seconds during both sampling and standby (non-sampling) 
modes of operation. A visual indication of the current (most recent) 
value of the ambient temperature measurement, updated at least every 30 
seconds, shall be available to the sampler operator during both sampling 
and standby (non-sampling) modes of operation, as specified in table L-1 
of section 7.4.19 of this appendix.
    7.4.8.4 This ambient temperature measurement shall be used for the 
purpose of monitoring filter temperature deviation from ambient 
temperature, as required by section 7.4.11 of this appendix, and may be 
used for purposes of effecting filter temperature control, under section 
7.4.10 of this appendix, or computation of volumetric flow rate, under 
sections 7.4.1 to 7.4.5 of this appendix, if appropriate.
    7.4.8.5 Following the end of each sample period, the sampler shall 
report the maximum, minimum, and average temperature for the sample 
period, as specified in table L-1 of section 7.4.19 of this appendix.
    7.4.9 Ambient barometric sensor. The sampler shall have capability 
to measure the barometric pressure of the air surrounding the sampler 
over a range of 600 to 800 mm Hg referenced as described in reference 3 
in section 13.0 of this appendix; also see part 53, subpart E of this 
chapter. This barometric pressure measurement shall have a resolution of 
5 mm Hg and an accuracy of 10 mm Hg and shall be updated at 
least every 30 seconds. A visual indication of the value of the current 
(most recent) barometric pressure measurement, updated at least every 30 
seconds, shall be available to the sampler operator during both sampling 
and standby (non-sampling) modes of operation, as specified in table L-1 
of section 7.4.19 of this appendix. This barometric pressure measurement 
may be used for purposes of computation of volumetric flow rate, under 
sections 7.4.1 to 7.4.5 of this appendix, if appropriate. Following the 
end of a sample period, the sampler shall report the maximum, minimum, 
and mean barometric pressures for the sample period, as specified in 
table L-1 of section 7.4.19 of this appendix.

[[Page 81]]

    7.4.10 Filter temperature control (sampling and post-sampling). The 
sampler shall provide a means to limit the temperature rise of the 
sample filter (all sample filters for sequential samplers), from 
insolation and other sources, to no more 5  deg.C above the temperature 
of the ambient air surrounding the sampler, during both sampling and 
post-sampling periods of operation. The post-sampling period is the non-
sampling period between the end of the active sampling period and the 
time of retrieval of the sample filter by the sampler operator.
    7.4.11 Filter temperature sensor(s).
    7.4.11.1 The sampler shall have the capability to monitor the 
temperature of the sample filter (all sample filters for sequential 
samplers) over the range of -30 to =45  deg.C during both sampling and 
non-sampling periods. While the exact location of this temperature 
sensor is not explicitly specified, the filter temperature measurement 
system must demonstrate agreement, within 1  deg.C, with a test 
temperature sensor located within 1 cm of the center of the filter 
downstream of the filter during both sampling and non-sampling modes, as 
specified in the filter temperature measurement test described in part 
53, subpart E of this chapter. This filter temperature measurement shall 
have a resolution of 0.1  deg.C and accuracy of 1.0  deg.C, 
referenced as described in reference 3 in section 13.0 of this appendix. 
This temperature sensor shall be of such a design and mounted in such a 
way as to facilitate its reasonably convenient dismounting and immersion 
in a liquid for calibration and comparison to the ambient temperature 
sensor under section 7.4.8 of this appendix.
    7.4.11.2 The filter temperature measurement shall be updated at 
least every 30 seconds during both sampling and standby (non-sampling) 
modes of operation. A visual indication of the current (most recent) 
value of the filter temperature measurement, updated at least every 30 
seconds, shall be available to the sampler operator during both sampling 
and standby (non-sampling) modes of operation, as specified in table L-1 
of section 7.4.19 of this appendix.
    7.4.11.3 For sequential samplers, the temperature of each filter 
shall be measured individually unless it can be shown, as specified in 
the filter temperature measurement test described in Sec. 53.57 of this 
chapter, that the temperature of each filter can be represented by fewer 
temperature sensors.
    7.4.11.4 The sampler shall also provide a warning flag indicator 
following any occurrence in which the filter temperature (any filter 
temperature for sequential samplers) exceeds the ambient temperature by 
more than 5  deg.C for more than 30 consecutive minutes during either 
the sampling or post-sampling periods of operation, as specified in 
table L-1 of section 7.4.19 of this appendix, under section 10.12 of 
this appendix, regarding sample validity when a warning flag occurs. It 
is further recommended (not required) that the sampler be capable of 
recording the maximum differential between the measured filter 
temperature and the ambient temperature and its time and date of 
occurrence during both sampling and post-sampling (non-sampling) modes 
of operation and providing for those data to be accessible to the 
sampler operator following the end of the sample period, as suggested in 
table L-1 of section 7.4.19 of this appendix.
    7.4.12 Clock/timer system.
    (a) The sampler shall have a programmable real-time clock timing/
control system that:
    (1) Is capable of maintaining local time and date, including year, 
month, day-of-month, hour, minute, and second to an accuracy of 
1.0 minute per month.
    (2) Provides a visual indication of the current system time, 
including year, month, day-of-month, hour, and minute, updated at least 
each minute, for operator verification.
    (3) Provides appropriate operator controls for setting the correct 
local time and date.
    (4) Is capable of starting the sample collection period and sample 
air flow at a specific, operator-settable time and date, and stopping 
the sample air flow and terminating the sampler collection period 24 
hours (1440 minutes) later, or at a specific, operator-settable time and 
date.
    (b) These start and stop times shall be readily settable by the 
sampler operator to within 1.0 minute. The system shall 
provide a visual indication of the current start and stop time settings, 
readable to 1.0 minute, for verification by the operator, 
and the start and stop times shall also be available via the data output 
port, as specified in table L-1 of section 7.4.19 of this appendix. Upon 
execution of a programmed sample period start, the sampler shall 
automatically reset all sample period information and warning flag 
indications pertaining to a previous sample period. Refer also to 
section 7.4.15.4 of this appendix regarding retention of current date 
and time and programmed start and stop times during a temporary 
electrical power interruption.
    7.4.13 Sample time determination. The sampler shall be capable of 
determining the elapsed sample collection time for each PM2.5 
sample, accurate to within 1.0 minute, measured as the time 
between the start of the sampling period, under section 7.4.12 of this 
appendix and the termination of the sample period, under section 7.4.12 
of this appendix or section 7.4.4 of this appendix. This elapsed sample 
time shall not include periods when the sampler is inoperative due to a 
temporary interruption of electrical power, under section 7.4.15.4 of 
this appendix. In the event that the elapsed sample time determined for 
the sample period is not within the

[[Page 82]]

range specified for the required sample period in section 3.3 of this 
appendix, the sampler shall set a warning flag indicator. The date and 
time of the start of the sample period, the value of the elapsed sample 
time for the sample period, and the flag indicator status shall be 
available to the sampler operator following the end of the sample 
period, as specified in table L-1 of section 7.4.19 of this appendix.
    7.4.14 Outdoor environmental enclosure. The sampler shall have an 
outdoor enclosure (or enclosures) suitable to protect the filter and 
other non-weatherproof components of the sampler from precipitation, 
wind, dust, extremes of temperature and humidity; to help maintain 
temperature control of the filter (or filters, for sequential samplers); 
and to provide reasonable security for sampler components and settings.
    7.4.15 Electrical power supply.
    7.4.15.1 The sampler shall be operable and function as specified 
herein when operated on an electrical power supply voltage of 105 to 125 
volts AC (RMS) at a frequency of 59 to 61 Hz. Optional operation as 
specified at additional power supply voltages and/or frequencies shall 
not be precluded by this requirement.
    7.4.15.2 The design and construction of the sampler shall comply 
with all applicable National Electrical Code and Underwriters 
Laboratories electrical safety requirements.
    7.4.15.3 The design of all electrical and electronic controls shall 
be such as to provide reasonable resistance to interference or 
malfunction from ordinary or typical levels of stray electromagnetic 
fields (EMF) as may be found at various monitoring sites and from 
typical levels of electrical transients or electronic noise as may often 
or occasionally be present on various electrical power lines.
    7.4.15.4 In the event of temporary loss of electrical supply power 
to the sampler, the sampler shall not be required to sample or provide 
other specified functions during such loss of power, except that the 
internal clock/timer system shall maintain its local time and date 
setting within 1 minute per week, and the sampler shall 
retain all other time and programmable settings and all data required to 
be available to the sampler operator following each sample period for at 
least 7 days without electrical supply power. When electrical power is 
absent at the operator-set time for starting a sample period or is 
interrupted during a sample period, the sampler shall automatically 
start or resume sampling when electrical power is restored, if such 
restoration of power occurs before the operator-set stop time for the 
sample period.
    7.4.15.5 The sampler shall have the capability to record and retain 
a record of the year, month, day-of-month, hour, and minute of the start 
of each power interruption of more than 1 minute duration, up to 10 such 
power interruptions per sample period. (More than 10 such power 
interruptions shall invalidate the sample, except where an exceedance is 
measured, under section 3.3 of this appendix.) The sampler shall provide 
for these power interruption data to be available to the sampler 
operator following the end of the sample period, as specified in table 
L-1 of section 7.4.19 of this appendix.
    7.4.16 Control devices and operator interface. The sampler shall 
have mechanical, electrical, or electronic controls, control devices, 
electrical or electronic circuits as necessary to provide the timing, 
flow rate measurement and control, temperature control, data storage and 
computation, operator interface, and other functions specified. 
Operator-accessible controls, data displays, and interface devices shall 
be designed to be simple, straightforward, reliable, and easy to learn, 
read, and operate under field conditions. The sampler shall have 
provision for operator input and storage of up to 64 characters of 
numeric (or alphanumeric) data for purposes of site, sampler, and sample 
identification. This information shall be available to the sampler 
operator for verification and change and for output via the data output 
port along with other data following the end of a sample period, as 
specified in table L-1 of section 7.4.19 of this appendix. All data 
required to be available to the operator following a sample collection 
period or obtained during standby mode in a post-sampling period shall 
be retained by the sampler until reset, either manually by the operator 
or automatically by the sampler upon initiation of a new sample 
collection period.
    7.4.17 Data output port requirement. The sampler shall have a 
standard RS-232C data output connection through which digital data may 
be exported to an external data storage or transmission device. All 
information which is required to be available at the end of each sample 
period shall be accessible through this data output connection. The 
information that shall be accessible though this output port is 
summarized in table L-1 of section 7.4.19 of this appendix. Since no 
specific format for the output data is provided, the sampler 
manufacturer or vendor shall make available to sampler purchasers 
appropriate computer software capable of receiving exported sampler data 
and correctly translating the data into a standard spreadsheet format 
and optionally any other formats as may be useful to sampler users. This 
requirement shall not preclude the sampler from offering other types of 
output connections in addition to the required RS-232C port.
    7.4.18 Operation/instruction manual. The sampler shall include an 
associated comprehensive operation or instruction manual, as required by 
part 53 of this chapter, which includes detailed operating instructions 
on

[[Page 83]]

the setup, operation, calibration, and maintenance of the sampler. This 
manual shall provide complete and detailed descriptions of the 
operational and calibration procedures prescribed for field use of the 
sampler and all instruments utilized as part of this reference method. 
The manual shall include adequate warning of potential safety hazards 
that may result from normal use or malfunction of the method and a 
description of necessary safety precautions. The manual shall also 
include a clear description of all procedures pertaining to 
installation, operation, periodic and corrective maintenance, and 
troubleshooting, and shall include parts identification diagrams.
    7.4.19 Data reporting requirements. The various information that the 
sampler is required to provide and how it is to be provided is 
summarized in the following table L-1.

                                             Table L-1--Summary of Information To Be Provided By the Sampler
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Availability                                        Format
                                    Appendix L section -------------------------------------------------------------------------------------------------
    Information to be provided          reference                        End of        Visual
                                                          Anytime1       period2     display\3\   Data output4    Digital reading5          Units
--------------------------------------------------------------------------------------------------------------------------------------------------------
Flow rate, 30-second maximum       7.4.5.1............     [bcheck]   ............     [bcheck]             *   XX.X...............  L/min
 interval.
Flow rate, average for the sample  7.4.5.2............            *      [bcheck]             *      [bcheck]   XX.X...............  L/min
 period.
Flow rate, CV, for sample period.  7.4.5.2............            *      [bcheck]             *   [bcheck][msh  XX.X...............  %
                                                                                                         box]
Flow rate, 5-min. average out of   7.4.5.2............     [bcheck]      [bcheck]      [bcheck]   [bcheck][msh  On/Off.............  ...................
 spec. (FLAG6).                                                                                          box]
Sample volume, total.............  7.4.5.2............            *      [bcheck]      [bcheck]   [bcheck][msh  XX.X...............  m\3\
                                                                                                         box]
Temperature, ambient, 30-second    7.4.8..............     [bcheck]   ............     [bcheck]   ............  XX.X...............    deg.C
 interval.
Temperature, ambient, min., max.,  7.4.8..............            *      [bcheck]      [bcheck]   [bcheck][msh  XX.X...............    deg.C
 average for the sample period.                                                                          box]
Baro pressure, ambient, 30-second  7.4.9..............     [bcheck]   ............     [bcheck]   ............  XXX................  mm Hg
 interval.
Baro pressure, ambient, min.,      7.4.9..............            *      [bcheck]      [bcheck]   [bcheck][msh  XXX................  mm Hg
 max., average for the sample                                                                            box]
 period.
Filter temperature, 30-second      7.4.11.............     [bcheck]   ............     [bcheck]   ............  XX.X...............    deg.C
 interval.
Filter temperature differential,   7.4.11.............            *      [bcheck]      [bcheck]   [bcheck][msh  On/Off.............  ...................
 30-second interval, out of spec.                                                                        box]
 (FLAG6).
Filter temperature, maximum        7.4.11.............            *             *             *             *   X.X, YY/MM/DD HH:mm    deg.C, Yr./Mon./
 differential from ambient, date,                                                                                                     Day Hrs. min
 time of occurrence.
Date and time....................  7.4.12.............     [bcheck]   ............     [bcheck]   ............  YY/MM/DD HH:mm.....  Yr./Mon./Day Hrs.
                                                                                                                                      min
Sample start and stop time         7.4.12.............     [bcheck]      [bcheck]      [bcheck]      [bcheck]   YY/MM/DD HH:mm.....  Yr./Mon./Day Hrs.
 settings.                                                                                                                            min
Sample period start time.........  7.4.12.............  ............     [bcheck]      [bcheck]   [bcheck][msh  YYYY/MM/DD HH:mm...  Yr./Mon./Day Hrs.
                                                                                                         box]                         min
Elapsed sample time..............  7.4.13.............            *      [bcheck]      [bcheck]   [bcheck][msh  HH:mm..............  Hrs. min
                                                                                                         box]

[[Page 84]]

 
Elapsed sample time, out of spec.  7.4.13.............  ............     [bcheck]      [bcheck]   [bcheck][msh  On/Off.............  ...................
 (FLAG6).                                                                                                box]
Power interruptions [lE]1 min.,    7.4.15.5...........            *      [bcheck]             *      [bcheck]   1HH:mm, 2HH:mm, etc  Hrs. min
 start time of first 10.                                                                                         ....
User-entered information, such as  7.4.16.............     [bcheck]      [bcheck]      [bcheck]   [bcheck][msh  As entered.........  ...................
 sampler and site identification.                                                                        box]
--------------------------------------------------------------------------------------------------------------------------------------------------------
[bcheck] Provision of this information is required.
*Provision of this information is optional. If information related to the entire sample period is optionally provided prior to the end of the sample
  period, the value provided should be the value calculated for the portion of the sampler period completed up to the time the information is provided.
[mshbox] Indicates that this information is also required to be provided to the AIRS data bank; see Sec.  Sec.  58.26 and 58.35 of this chapter.
 
1 Information is required to be available to the operator at any time the sampler is operating, whether sampling or not.
2 Information relates to the entire sampler period and must be provided following the end of the sample period until reset manually by the operator or
  automatically by the sampler upon the start of a new sample period.
\3\ Information shall be available to the operator visually.
4 Information is to be available as digital data at the sampler's data output port specified in section 7.4.16 of this appendix following the end of the
  sample period until reset manually by the operator or automatically by the sampler upon the start of a new sample period.
5 Digital readings, both visual and data output, shall have not less than the number of significant digits and resolution specified.
6 Flag warnings may be displayed to the operator by a single-flag indicator or each flag may be displayed individually. Only a set (on) flag warning
  must be indicated; an off (unset) flag may be indicated by the absence of a flag warning. Sampler users should refer to section 10.12 of this appendix
  regarding the validity of samples for which the sampler provided an associated flag warning.

    8.0 Filter Weighing. See reference 2 in section 13.0 of this 
appendix, for additional, more detailed guidance.
    8.1 Analytical balance. The analytical balance used to weigh filters 
must be suitable for weighing the type and size of filters specified, 
under section 6.0 of this appendix, and have a readability of 
1 [mu]g. The balance shall be calibrated as specified by the 
manufacturer at installation and recalibrated immediately prior to each 
weighing session. See reference 2 in section 13.0 of this appendix for 
additional guidance.
    8.2 Filter conditioning. All sample filters used shall be 
conditioned immediately before both the pre- and post-sampling weighings 
as specified below. See reference 2 in section 13.0 of this appendix for 
additional guidance.
    8.2.1 Mean temperature. 20 - 23  deg.C.
    8.2.2 Temperature control. 2  deg.C over 24 hours.
    8.2.3 Mean humidity. Generally, 30-40 percent relative humidity; 
however, where it can be shown that the mean ambient relative humidity 
during sampling is less than 30 percent, conditioning is permissible at 
a mean relative humidity within 5 relative humidity percent 
of the mean ambient relative humidity during sampling, but not less than 
20 percent.
    8.2.4 Humidity control. 5 relative humidity percent over 
24 hours.
    8.2.5 Conditioning time. Not less than 24 hours.
    8.3 Weighing procedure.
    8.3.1 New filters should be placed in the conditioning environment 
immediately upon arrival and stored there until the pre-sampling 
weighing. See reference 2 in section 13.0 of this appendix for 
additional guidance.
    8.3.2 The analytical balance shall be located in the same controlled 
environment in which the filters are conditioned. The filters shall be 
weighed immediately following the conditioning period without 
intermediate or transient exposure to other conditions or environments.
    8.3.3 Filters must be conditioned at the same conditions (humidity 
within 5 relative humidity percent) before both the pre- and 
post-sampling weighings.
    8.3.4 Both the pre- and post-sampling weighings should be carried 
out on the same analytical balance, using an effective technique to 
neutralize static charges on the filter, under reference 2 in section 
13.0 of this appendix. If possible, both weighings should be carried out 
by the same analyst.
    8.3.5 The pre-sampling (tare) weighing shall be within 30 days of 
the sampling period.
    8.3.6 The post-sampling conditioning and weighing shall be completed 
within 240 hours (10 days) after the end of the sample period, unless 
the filter sample is maintained at 4  deg.C

[[Page 85]]

or less during the entire time between retrieval from the sampler and 
the start of the conditioning, in which case the period shall not exceed 
30 days. Reference 2 in section 13.0 of this appendix has additional 
guidance on transport of cooled filters.
    8.3.7 Filter blanks.
    8.3.7.1 New field blank filters shall be weighed along with the pre-
sampling (tare) weighing of each lot of PM2.5 filters. These 
blank filters shall be transported to the sampling site, installed in 
the sampler, retrieved from the sampler without sampling, and reweighed 
as a quality control check.
    8.3.7.2 New laboratory blank filters shall be weighed along with the 
pre-sampling (tare) weighing of each set of PM2.5 filters. 
These laboratory blank filters should remain in the laboratory in 
protective containers during the field sampling and should be reweighed 
as a quality control check.
    8.3.8 Additional guidance for proper filter weighing and related 
quality assurance activities is provided in reference 2 in section 13.0 
of this appendix.
    9.0 Calibration. Reference 2 in section 13.0 of this appendix 
contains additional guidance.
    9.1 General requirements.
    9.1.1 Multipoint calibration and single-point verification of the 
sampler's flow rate measurement device must be performed periodically to 
establish and maintain traceability of subsequent flow measurements to a 
flow rate standard.
    9.1.2 An authoritative flow rate standard shall be used for 
calibrating or verifying the sampler's flow rate measurement device with 
an accuracy of 2 percent. The flow rate standard shall be a 
separate, stand-alone device designed to connect to the flow rate 
measurement adapter, Figure L-30 of this appendix. This flow rate 
standard must have its own certification and be traceable to a National 
Institute of Standards and Technology (NIST) primary standard for volume 
or flow rate. If adjustments to the sampler's flow rate measurement 
system calibration are to be made in conjunction with an audit of the 
sampler's flow measurement system, such adjustments shall be made 
following the audit. Reference 2 in section 13.0 of this appendix 
contains additional guidance.
    9.1.3 The sampler's flow rate measurement device shall be re-
calibrated after electromechanical maintenance or transport of the 
sampler.
    9.2 Flow rate calibration/verification procedure.
    9.2.1 PM2.5 samplers may employ various types of flow 
control and flow measurement devices. The specific procedure used for 
calibration or verification of the flow rate measurement device will 
vary depending on the type of flow rate controller and flow rate 
measurement employed. Calibration shall be in terms of actual ambient 
volumetric flow rates (Qa), measured at the sampler's inlet 
downtube. The generic procedure given here serves to illustrate the 
general steps involved in the calibration of a PM2.5 sampler. 
The sampler operation/instruction manual required under section 7.4.18 
of this appendix and the Quality Assurance Handbook in reference 2 in 
section 13.0 of this appendix provide more specific and detailed 
guidance for calibration.
    9.2.2 The flow rate standard used for flow rate calibration shall 
have its own certification and be traceable to a NIST primary standard 
for volume or flow rate. A calibration relationship for the flow rate 
standard, e.g., an equation, curve, or family of curves relating actual 
flow rate (Qa) to the flow rate indicator reading, shall be 
established that is accurate to within 2 percent over the expected range 
of ambient temperatures and pressures at which the flow rate standard 
may be used. The flow rate standard must be re-calibrated or re-verified 
at least annually.
    9.2.3 The sampler flow rate measurement device shall be calibrated 
or verified by removing the sampler inlet and connecting the flow rate 
standard to the sampler's downtube in accordance with the operation/
instruction manual, such that the flow rate standard accurately measures 
the sampler's flow rate. The sampler operator shall first carry out a 
sampler leak check and confirm that the sampler passes the leak test and 
then verify that no leaks exist between the flow rate standard and the 
sampler.
    9.2.4 The calibration relationship between the flow rate (in actual 
L/min) indicated by the flow rate standard and by the sampler's flow 
rate measurement device shall be established or verified in accordance 
with the sampler operation/instruction manual. Temperature and pressure 
corrections to the flow rate indicated by the flow rate standard may be 
required for certain types of flow rate standards. Calibration of the 
sampler's flow rate measurement device shall consist of at least three 
separate flow rate measurements (multipoint calibration) evenly spaced 
within the range of -10 percent to =10 percent of the sampler's 
operational flow rate, section 7.4.1 of this appendix. Verification of 
the sampler's flow rate shall consist of one flow rate measurement at 
the sampler's operational flow rate. The sampler operation/instruction 
manual and reference 2 in section 13.0 of this appendix provide 
additional guidance.
    9.2.5 If during a flow rate verification the reading of the 
sampler's flow rate indicator or measurement device differs by 
 4 percent or more from the flow rate measured by the flow 
rate standard, a new multipoint calibration shall be performed and the 
flow rate verification must then be repeated.
    9.2.6 Following the calibration or verification, the flow rate 
standard shall be removed from the sampler and the sampler inlet shall 
be reinstalled. Then the sampler's

[[Page 86]]

normal operating flow rate (in L/min) shall be determined with a clean 
filter in place. If the flow rate indicated by the sampler differs by 
2 percent or more from the required sampler flow rate, the 
sampler flow rate must be adjusted to the required flow rate, under 
section 7.4.1 of this appendix.
    9.3 Periodic calibration or verification of the calibration of the 
sampler's ambient temperature, filter temperature, and barometric 
pressure measurement systems is also required. Reference 3 of section 
13.0 of this appendix contains additional guidance.
    10.0 PM2.5 Measurement Procedure. The detailed procedure 
for obtaining valid PM2.5 measurements with each specific 
sampler designated as part of a reference method for PM2.5 
under part 53 of this chapter shall be provided in the sampler-specific 
operation or instruction manual required by section 7.4.18 of this 
appendix. Supplemental guidance is provided in section 2.12 of the 
Quality Assurance Handbook listed in reference 2 in section 13.0 of this 
appendix. The generic procedure given here serves to illustrate the 
general steps involved in the PM2.5 sample collection and 
measurement, using a PM2.5 reference method sampler.
    10.1 The sampler shall be set up, calibrated, and operated in 
accordance with the specific, detailed guidance provided in the specific 
sampler's operation or instruction manual and in accordance with a 
specific quality assurance program developed and established by the 
user, based on applicable supplementary guidance provided in reference 2 
in section 13.0 of this appendix.
    10.2 Each new sample filter shall be inspected for correct type and 
size and for pinholes, particles, and other imperfections. Unacceptable 
filters should be discarded. A unique identification number shall be 
assigned to each filter, and an information record shall be established 
for each filter. If the filter identification number is not or cannot be 
marked directly on the filter, alternative means, such as a number-
identified storage container, must be established to maintain positive 
filter identification.
    10.3 Each filter shall be conditioned in the conditioning 
environment in accordance with the requirements specified in section 8.2 
of this appendix.
    10.4 Following conditioning, each filter shall be weighed in 
accordance with the requirements specified in section 8.0 of this 
appendix and the presampling weight recorded with the filter 
identification number.
    10.5 A numbered and preweighed filter shall be installed in the 
sampler following the instructions provided in the sampler operation or 
instruction manual.
    10.6 The sampler shall be checked and prepared for sample collection 
in accordance with instructions provided in the sampler operation or 
instruction manual and with the specific quality assurance program 
established for the sampler by the user.
    10.7 The sampler's timer shall be set to start the sample collection 
at the beginning of the desired sample period and stop the sample 
collection 24 hours later.
    10.8 Information related to the sample collection (site location or 
identification number, sample date, filter identification number, and 
sampler model and serial number) shall be recorded and, if appropriate, 
entered into the sampler.
    10.9 The sampler shall be allowed to collect the PM2.5 
sample during the set 24-hour time period.
    10.10 Within 96 hours of the end of the sample collection period, 
the filter, while still contained in the filter cassette, shall be 
carefully removed from the sampler, following the procedure provided in 
the sampler operation or instruction manual and the quality assurance 
program, and placed in a protective container. The protective container 
shall contain no loose material that could be transferred to the filter. 
The protective container shall hold the filter cassette securely such 
that the cover shall not come in contact with the filter's surfaces. 
Reference 2 in section 13.0 of this appendix contains additional 
information.
    10.11 The total sample volume in actual m\3\ for the sampling period 
and the elapsed sample time shall be obtained from the sampler and 
recorded in accordance with the instructions provided in the sampler 
operation or instruction manual. All sampler warning flag indications 
and other information required by the local quality assurance program 
shall also be recorded.
    10.12 All factors related to the validity or representativeness of 
the sample, such as sampler tampering or malfunctions, unusual 
meteorological conditions, construction activity, fires or dust storms, 
etc. shall be recorded as required by the local quality assurance 
program. The occurrence of a flag warning during a sample period shall 
not necessarily indicate an invalid sample but rather shall indicate the 
need for specific review of the QC data by a quality assurance officer 
to determine sample validity.
    10.13 After retrieval from the sampler, the exposed filter 
containing the PM2.5 sample should be transported to the 
filter conditioning environment as soon as possible ideally to arrive at 
the conditioning environment within 24 hours for conditioning and 
subsequent weighing. During the period between filter retrieval from the 
sampler and the start of the conditioning, the filter shall be 
maintained as cool as practical and continuously protected from exposure 
to temperatures over 25  deg.C. See section 8.3.6 of this appendix 
regarding time limits for completing the post-sampling weighing. See 
reference 2 in section 13.0 of this appendix for additional guidance on 
transporting filter

[[Page 87]]

samplers to the conditioning and weighing laboratory.
    10.14. The exposed filter containing the PM2.5 sample 
shall be re-conditioned in the conditioning environment in accordance 
with the requirements specified in section 8.2 of this appendix.
    10.15. The filter shall be reweighed immediately after conditioning 
in accordance with the requirements specified in section 8.0 of this 
appendix, and the postsampling weight shall be recorded with the filter 
identification number.
    10.16 The PM2.5 concentration shall be calculated as 
specified in section 12.0 of this appendix.
    11.0 Sampler Maintenance. The sampler shall be maintained as 
described by the sampler's manufacturer in the sampler-specific 
operation or instruction manual required under section 7.4.18 of this 
appendix and in accordance with the specific quality assurance program 
developed and established by the user based on applicable supplementary 
guidance provided in reference 2 in section 13.0 of this appendix.
    12.0 Calculations
    12.1 (a) The PM2.5 concentration is calculated as:

PM2.5 = (Wf - Wi)/Va

where:

PM2.5 = mass concentration of PM2.5, [mu]g/m\3\;
Wf, Wi = final and initial weights, respectively, 
of the filter used to collect the PM2.5 particle sample, 
[mu]g;
Va = total air volume sampled in actual volume units, as 
provided by the sampler, m\3\.

    Note: Total sample time must be between 1,380 and 1,500 minutes (23 
and 25 hrs) for a fully valid PM2.5 sample; however, see also 
section 3.3 of this appendix.
    13.0 References.
    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume I, Principles. EPA/600/R-94/038a, April 1994. Available from 
CERI, ORD Publications, U.S. Environmental Protection Agency, 26 West 
Martin Luther King Drive, Cincinnati, Ohio 45268.
    2. Copies of section 2.12 of the Quality Assurance Handbook for Air 
Pollution Measurement Systems, Volume II, Ambient Air Specific Methods, 
EPA/600/R-94/038b, are available from Department E (MD-77B), U.S. EPA, 
Research Triangle Park, NC 27711.
    3. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume IV: Meteorological Measurements, (Revised Edition) EPA/600/R-94/
038d, March, 1995. Available from CERI, ORD Publications, U.S. 
Environmental Protection Agency, 26 West Martin Luther King Drive, 
Cincinnati, Ohio 45268.
    4. Military standard specification (mil. spec.) 8625F, Type II, 
Class 1 as listed in Department of Defense Index of Specifications and 
Standards (DODISS), available from DODSSP-Customer Service, 
Standardization Documents Order Desk, 700 Robbins Avenue, Building 4D, 
Philadelphia, PA 1911-5094.
    14.0 Figures L-1 through L-30 to Appendix L.

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[62 FR 38714, July 18, 1997, as amended at 64 FR 19719, Apr. 22, 1999]

    Appendix M to Part 50--Reference Method for the Determination of 
         Particulate Matter as PM10 in the Atmosphere

    1.0 Applicability.
    1.1 This method provides for the measurement of the mass 
concentration of particulate matter with an aerodynamic diameter less 
than or equal to a nominal 10 micrometers (PM1O) in ambient 
air over a 24-hour period for purposes of determining attainment and 
maintenance of the primary and secondary national ambient air quality 
standards for particulate matter specified in Sec. 50.6 of this chapter. 
The measurement process is nondestructive, and the PM10 
sample can be subjected to subsequent physical or chemical analyses. 
Quality assurance procedures and guidance are provided in part 58, 
Appendices A and B of this chapter and in references 1 and 2 of section 
12.0 of this appendix.
    2.0 Principle.
    2.1 An air sampler draws ambient air at a constant flow rate into a 
specially shaped inlet where the suspended particulate matter is 
inertially separated into one or more size fractions within the 
PM10 size range. Each size fraction in the PM1O 
size range is then collected on a separate filter over the specified 
sampling period. The particle size discrimination characteristics 
(sampling effectiveness and 50 percent cutpoint) of the sampler inlet 
are prescribed as performance specifications in part 53 of this chapter.
    2.2 Each filter is weighed (after moisture equilibration) before and 
after use to determine the net weight (mass) gain due to collected 
PM10. The total volume of air sampled, measured at the actual 
ambient temperature and pressure, is determined from the measured flow 
rate and the sampling time. The mass concentration of PM10 in 
the ambient air is computed as the total mass of collected particles in 
the PM10 size range divided by the volume of air sampled, and 
is expressed in micrograms per actual cubic meter ([mu]g/m\3\).
    2.3 A method based on this principle will be considered a reference 
method only if the associated sampler meets the requirements specified 
in this appendix and the requirements in part 53 of this chapter, and 
the method has been designated as a reference method in accordance with 
part 53 of this chapter.
    3.0 Range.
    3.1 The lower limit of the mass concentration range is determined by 
the repeatability of filter tare weights, assuming the nominal air 
sample volume for the sampler. For samplers having an automatic filter-
changing mechanism, there may be no upper limit. For samplers that do 
not have an automatic filter-changing mechanism, the upper limit is 
determined by the filter mass loading beyond which the sampler no longer 
maintains the operating flow rate within specified limits due to 
increased pressure drop across the loaded filter. This upper limit 
cannot be specified precisely because it is a complex function of the 
ambient particle size distribution and type, humidity, filter type, and 
perhaps other factors. Nevertheless, all samplers should be capable of 
measuring 24-hour PM10 mass concentrations of at least 300 
[mu]g/m\3\ while maintaining the operating flow rate within the 
specified limits.
    4.0 Precision.
    4.1 The precision of PM10 samplers must be 5 [mu]g/m\3\ 
for PM10 concentrations below 80 [mu]g/m\3\ and 7 percent for 
PM10 concentrations above 80 [mu]g/m\3\, as required by part 
53 of this chapter, which prescribes a test procedure that determines 
the variation in the PM10 concentration measurements of 
identical samplers under typical sampling conditions. Continual 
assessment of precision via collocated samplers is required by part 58 
of this chapter for PM10 samplers used in certain monitoring 
networks.
    5.0 Accuracy.
    5.1 Because the size of the particles making up ambient particulate 
matter varies over a wide range and the concentration of particles 
varies with particle size, it is difficult to define the absolute 
accuracy of PM10 samplers. Part 53 of this chapter provides a 
specification for the sampling effectiveness of PM10 
samplers. This specification requires that the expected mass 
concentration calculated for a candidate PM10 sampler, when 
sampling a specified particle size distribution, be within 
10 percent of that calculated for an ideal sampler whose 
sampling effectiveness is explicitly specified. Also, the particle size 
for 50 percent sampling effectiveness is required to be 
100.5 micrometers. Other specifications related to accuracy 
apply to flow measurement and calibration, filter media, analytical 
(weighing) procedures, and artifact. The flow rate accuracy of 
PM10 samplers used in certain monitoring networks is required 
by part 58 of this chapter to be assessed periodically via flow rate 
audits.
    6.0 Potential Sources of Error.
    6.1 Volatile Particles. Volatile particles collected on filters are 
often lost during shipment and/or storage of the filters prior to the 
post-sampling weighing \3\. Although shipment or storage of loaded 
filters is sometimes unavoidable, filters should be reweighed as soon as 
practical to minimize these losses.
    6.2 Artifacts. Positive errors in PM10 concentration 
measurements may result from retention of gaseous species on filters 
4, 5. Such errors include the retention of sulfur dioxide and 
nitric acid. Retention of sulfur

[[Page 119]]

dioxide on filters, followed by oxidation to sulfate, is referred to as 
artifact sulfate formation, a phenomenon which increases with increasing 
filter alkalinity \6\. Little or no artifact sulfate formation should 
occur using filters that meet the alkalinity specification in section 
7.2.4 of this appendix, Artifact nitrate formation, resulting primarily 
from retention of nitric acid, occurs to varying degrees on many filter 
types, including glass fiber, cellulose ester, and many quartz fiber 
filters 5, 7, 8, 9, 10. Loss of true atmospheric particulate 
nitrate during or following sampling may also occur due to dissociation 
or chemical reaction. This phenomenon has been observed on 
Teflon[reg]filters \8\ and inferred for quartz fiber filters 
11, 12. The magnitude of nitrate artifact errors in 
PM10 mass concentration measurements will vary with location 
and ambient temperature; however, for most sampling locations, these 
errors are expected to be small.
    6.3 Humidity. The effects of ambient humidity on the sample are 
unavoidable. The filter equilibration procedure in section 9.0 of this 
appendix is designed to minimize the effects of moisture on the filter 
medium.
    6.4 Filter Handling. Careful handling of filters between presampling 
and postsampling weighings is necessary to avoid errors due to damaged 
filters or loss of collected particles from the filters. Use of a filter 
cartridge or cassette may reduce the magnitude of these errors. Filters 
must also meet the integrity specification in section 7.2.3 of this 
appendix.
    6.5 Flow Rate Variation. Variations in the sampler's operating flow 
rate may alter the particle size discrimination characteristics of the 
sampler inlet. The magnitude of this error will depend on the 
sensitivity of the inlet to variations in flow rate and on the particle 
distribution in the atmosphere during the sampling period. The use of a 
flow control device, under section 7.1.3 of this appendix, is required 
to minimize this error.
    6.6 Air Volume Determination. Errors in the air volume determination 
may result from errors in the flow rate and/or sampling time 
measurements. The flow control device serves to minimize errors in the 
flow rate determination, and an elapsed time meter, under section 7.1.5 
of this appendix, is required to minimize the error in the sampling time 
measurement.
    7.0 Apparatus.
    7.1 PM10 Sampler.
    7.1.1 The sampler shall be designed to:
    (a) Draw the air sample into the sampler inlet and through the 
particle collection filter at a uniform face velocity.
    (b) Hold and seal the filter in a horizontal position so that sample 
air is drawn downward through the filter.
    (c) Allow the filter to be installed and removed conveniently.
    (d) Protect the filter and sampler from precipitation and prevent 
insects and other debris from being sampled.
    (e) Minimize air leaks that would cause error in the measurement of 
the air volume passing through the filter.
    (f) Discharge exhaust air at a sufficient distance from the sampler 
inlet to minimize the sampling of exhaust air.
    (g) Minimize the collection of dust from the supporting surface.
    7.1.2 The sampler shall have a sample air inlet system that, when 
operated within a specified flow rate range, provides particle size 
discrimination characteristics meeting all of the applicable performance 
specifications prescribed in part 53 of this chapter. The sampler inlet 
shall show no significant wind direction dependence. The latter 
requirement can generally be satisfied by an inlet shape that is 
circularly symmetrical about a vertical axis.
    7.1.3 The sampler shall have a flow control device capable of 
maintaining the sampler's operating flow rate within the flow rate 
limits specified for the sampler inlet over normal variations in line 
voltage and filter pressure drop.
    7.1.4 The sampler shall provide a means to measure the total flow 
rate during the sampling period. A continuous flow recorder is 
recommended but not required. The flow measurement device shall be 
accurate to 2 percent.
    7.1.5 A timing/control device capable of starting and stopping the 
sampler shall be used to obtain a sample collection period of 24 
1 hr (1,440 60 min). An elapsed time meter, 
accurate to within 15 minutes, shall be used to measure 
sampling time. This meter is optional for samplers with continuous flow 
recorders if the sampling time measurement obtained by means of the 
recorder meets the 15 minute accuracy specification.
    7.1.6 The sampler shall have an associated operation or instruction 
manual as required by part 53 of this chapter which includes detailed 
instructions on the calibration, operation, and maintenance of the 
sampler.
    7.2 Filters.
    7.2.1 Filter Medium. No commercially available filter medium is 
ideal in all respects for all samplers. The user's goals in sampling 
determine the relative importance of various filter characteristics, 
e.g., cost, ease of handling, physical and chemical characteristics, 
etc., and, consequently, determine the choice among acceptable filters. 
Furthermore, certain types of filters may not be suitable for use with 
some samplers, particularly under heavy loading conditions (high mass 
concentrations), because of high or rapid increase in the filter flow 
resistance that would exceed the capability of the sampler's flow 
control device. However, samplers equipped with automatic filter-
changing

[[Page 120]]

mechanisms may allow use of these types of filters. The specifications 
given below are minimum requirements to ensure acceptability of the 
filter medium for measurement of PM10 mass concentrations. 
Other filter evaluation criteria should be considered to meet individual 
sampling and analysis objectives.
    7.2.2 Collection Efficiency. [lE]99 percent, as measured by the DOP 
test (ASTM-2986) with 0.3 [mu]m particles at the sampler's operating 
face velocity.
    7.2.3 Integrity. 5 [mu]g/m\3\ (assuming sampler's 
nominal 24-hour air sample volume). Integrity is measured as the 
PM10 concentration equivalent corresponding to the average 
difference between the initial and the final weights of a random sample 
of test filters that are weighed and handled under actual or simulated 
sampling conditions, but have no air sample passed through them, i.e., 
filter blanks. As a minimum, the test procedure must include initial 
equilibration and weighing, installation on an inoperative sampler, 
removal from the sampler, and final equilibration and weighing.
    7.2.4 Alkalinity. <25 microequivalents/gram of filter, as measured 
by the procedure given in reference 13 of section 12.0 of this appendix 
following at least two months storage in a clean environment (free from 
contamination by acidic gases) at room temperature and humidity.
    7.3 Flow Rate Transfer Standard. The flow rate transfer standard 
must be suitable for the sampler's operating flow rate and must be 
calibrated against a primary flow or volume standard that is traceable 
to the National Institute of Standard and Technology (NIST). The flow 
rate transfer standard must be capable of measuring the sampler's 
operating flow rate with an accuracy of 2 percent.
    7.4 Filter Conditioning Environment.
    7.4.1 Temperature range. 15 to 30 C.
    7.4.2 Temperature control. 3 C.
    7.4.3 Humidity range. 20% to 45% RH.
    7.4.4 Humidity control. 5% RH.
    7.5 Analytical Balance. The analytical balance must be suitable for 
weighing the type and size of filters required by the sampler. The range 
and sensitivity required will depend on the filter tare weights and mass 
loadings. Typically, an analytical balance with a sensitivity of 0.1 mg 
is required for high volume samplers (flow rates 0.5 m\3\/
min). Lower volume samplers (flow rates <0.5 m\3\/min) will require a 
more sensitive balance.
    8.0 Calibration.
    8.1 General Requirements.
    8.1.1 Calibration of the sampler's flow measurement device is 
required to establish traceability of subsequent flow measurements to a 
primary standard. A flow rate transfer standard calibrated against a 
primary flow or volume standard shall be used to calibrate or verify the 
accuracy of the sampler's flow measurement device.
    8.1.2 Particle size discrimination by inertial separation requires 
that specific air velocities be maintained in the sampler's air inlet 
system. Therefore, the flow rate through the sampler's inlet must be 
maintained throughout the sampling period within the design flow rate 
range specified by the manufacturer. Design flow rates are specified as 
actual volumetric flow rates, measured at existing conditions of 
temperature and pressure (Qa).
    8.2 Flow Rate Calibration Procedure.
    8.2.1 PM10 samplers employ various types of flow control 
and flow measurement devices. The specific procedure used for flow rate 
calibration or verification will vary depending on the type of flow 
controller and flow rate indicator employed. Calibration is in terms of 
actual volumetric flow rates (Qa) to meet the requirements of 
section 8.1 of this appendix. The general procedure given here serves to 
illustrate the steps involved in the calibration. Consult the sampler 
manufacturer's instruction manual and reference 2 of section 12.0 of 
this appendix for specific guidance on calibration. Reference 14 of 
section 12.0 of this appendix provides additional information on various 
other measures of flow rate and their interrelationships.
    8.2.2 Calibrate the flow rate transfer standard against a primary 
flow or volume standard traceable to NIST. Establish a calibration 
relationship, e.g., an equation or family of curves, such that 
traceability to the primary standard is accurate to within 2 percent 
over the expected range of ambient conditions, i.e., temperatures and 
pressures, under which the transfer standard will be used. Recalibrate 
the transfer standard periodically.
    8.2.3 Following the sampler manufacturer's instruction manual, 
remove the sampler inlet and connect the flow rate transfer standard to 
the sampler such that the transfer standard accurately measures the 
sampler's flow rate. Make sure there are no leaks between the transfer 
standard and the sampler.
    8.2.4 Choose a minimum of three flow rates (actual m\3\/min), spaced 
over the acceptable flow rate range specified for the inlet, under 
section 7.1.2 of the appendix, that can be obtained by suitable 
adjustment of the sampler flow rate. In accordance with the sampler 
manufacturer's instruction manual, obtain or verify the calibration 
relationship between the flow rate (actual m\3\/min) as indicated by the 
transfer standard and the sampler's flow indicator response. Record the 
ambient temperature and barometric pressure. Temperature and pressure 
corrections to subsequent flow indicator readings may be required for 
certain types of flow measurement devices. When such corrections are 
necessary, correction on an individual or

[[Page 121]]

daily basis is preferable. However, seasonal average temperature and 
average barometric pressure for the sampling site may be incorporated 
into the sampler calibration to avoid daily corrections. Consult the 
sampler manufacturer's instruction manual and reference 2 in section 
12.0 of this appendix for additional guidance.
    8.2.5 Following calibration, verify that the sampler is operating at 
its design flow rate (actual m\3\/min) with a clean filter in place.
    8.2.6 Replace the sampler inlet.
    9.0 Procedure.
    9.1 The sampler shall be operated in accordance with the specific 
guidance provided in the sampler manufacturer's instruction manual and 
in reference 2 in section 12.0 of this appendix. The general procedure 
given here assumes that the sampler's flow rate calibration is based on 
flow rates at ambient conditions (Qa) and serves to 
illustrate the steps involved in the operation of a PM10 
sampler.
    9.2 Inspect each filter for pinholes, particles, and other 
imperfections. Establish a filter information record and assign an 
identification number to each filter.
    9.3 Equilibrate each filter in the conditioning environment (see 
7.4) for at least 24 hours.
    9.4 Following equilibration, weigh each filter and record the 
presampling weight with the filter identification number.
    9.5 Install a preweighed filter in the sampler following the 
instructions provided in the sampler manufacturer's instruction manual.
    9.6 (a) Turn on the sampler and allow it to establish run-
temperature conditions. Record the flow indicator reading and, if 
needed, the ambient temperature and barometric pressure. Determine the 
sampler flow rate (actual m\3\/min) in accordance with the instructions 
provided in the sampler manufacturer's instruction manual.
    (b) Note: No onsite temperature or pressure measurements are 
necessary if the sampler's flow indicator does not require temperature 
or pressure corrections or if seasonal average temperature and average 
barometric pressure for the sampling site are incorporated into the 
sampler calibration, under section 8.2.4 of this appendix. If individual 
or daily temperature and pressure corrections are required, ambient 
temperature and barometric pressure can be obtained by on-site 
measurements or from a nearby weather station. Barometric pressure 
readings obtained from airports must be station pressure, not corrected 
to sea level, and may need to be corrected for differences in elevation 
between the sampling site and the airport.
    9.7 If the flow rate is outside the acceptable range specified by 
the manufacturer, check for leaks, and if necessary, adjust the flow 
rate to the specified setpoint. Stop the sampler.
    9.8 Set the timer to start and stop the sampler at appropriate 
times. Set the elapsed time meter to zero or record the initial meter 
reading.
    9.9 Record the sample information (site location or identification 
number, sample date, filter identification number, and sampler model and 
serial number).
    9.10 Sample for 241 hours.
    9.11 Determine and record the average flow rate (Qa) in 
actual m\3\/min for the sampling period in accordance with the 
instructions provided in the sampler manufacturer's instruction manual. 
Record the elapsed time meter final reading and, if needed, the average 
ambient temperature and barometric pressure for the sampling period, in 
note following section 9.6 of this appendix.
    9.12 Carefully remove the filter from the sampler, following the 
sampler manufacturer's instruction manual. Touch only the outer edges of 
the filter.
    9.13 Place the filter in a protective holder or container, e.g., 
petri dish, glassine envelope, or manila folder.
    9.14 Record any factors such as meteorological conditions, 
construction activity, fires or dust storms, etc., that might be 
pertinent to the measurement on the filter information record.
    9.15 Transport the exposed sample filter to the filter conditioning 
environment as soon as possible for equilibration and subsequent 
weighing.
    9.16 Equilibrate the exposed filter in the conditioning environment 
for at least 24 hours under the same temperature and humidity conditions 
used for presampling filter equilibration (see section 9.3 of this 
appendix).
    9.17 Immediately after equilibration, reweigh the filter and record 
the postsampling weight with the filter identification number.
    10.0 Sampler Maintenance.
    10.1 The PM10 sampler shall be maintained in strict 
accordance with the maintenance procedures specified in the sampler 
manufacturer's instruction manual.
    11.0 Calculations.
    11.1 Calculate the total volume of air sampled as:

V = Qat

where:

V = total air sampled, at ambient temperature and pressure,m\3\;
Qa = average sample flow rate at ambient temperature and 
pressure, m\3\/min; and
t = sampling time, min.
    11.2 (a) Calculate the PM10 concentration as:

PM10 = (Wf-Wi)x10\6\/V

where:


[[Page 122]]


PM10 = mass concentration of PM10, [mu]g/m\3\;
Wf, Wi = final and initial weights of filter 
collecting PM1O particles, g; and
10\6\ = conversion of g to [mu]g.

    (b) Note: If more than one size fraction in the PM10 size 
range is collected by the sampler, the sum of the net weight gain by 
each collection filter [[Sigma](Wf-Wi)] is used to 
calculate the PM10 mass concentration.
    12.0 References.
    1. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume I, Principles. EPA-600/9-76-005, March 1976. Available from CERI, 
ORD Publications, U.S. Environmental Protection Agency, 26 West St. 
Clair Street, Cincinnati, OH 45268.
    2. Quality Assurance Handbook for Air Pollution Measurement Systems, 
Volume II, Ambient Air Specific Methods. EPA-600/4-77-027a, May 1977. 
Available from CERI, ORD Publications, U.S. Environmental Protection 
Agency, 26 West St. Clair Street, Cincinnati, OH 45268.
    3. Clement, R.E., and F.W. Karasek. Sample Composition Changes in 
Sampling and Analysis of Organic Compounds in Aerosols. Int. J. Environ. 
Analyt. Chem., 7:109, 1979.
    4. Lee, R.E., Jr., and J. Wagman. A Sampling Anomaly in the 
Determination of Atmospheric Sulfate Concentration. Amer. Ind. Hyg. 
Assoc. J., 27:266, 1966.
    5. Appel, B.R., S.M. Wall, Y. Tokiwa, and M. Haik. Interference 
Effects in Sampling Particulate Nitrate in Ambient Air. Atmos. Environ., 
13:319, 1979.
    6. Coutant, R.W. Effect of Environmental Variables on Collection of 
Atmospheric Sulfate. Environ. Sci. Technol., 11:873, 1977.Spicer, C.W., 
and P. Schumacher. Interference in Sampling Atmospheric Particulate 
Nitrate. Atmos. Environ., 11:873, 1977.
    8. Appel, B.R., Y. Tokiwa, and M. Haik. Sampling of Nitrates in 
Ambient Air. Atmos. Environ., 15:283, 1981.
    9. Spicer, C.W., and P.M. Schumacher. Particulate Nitrate: 
Laboratory and Field Studies of Major Sampling Interferences. Atmos. 
Environ., 13:543, 1979.
    10. Appel, B.R. Letter to Larry Purdue, U.S. EPA, Environmental 
Monitoring and Support Laboratory. March 18, 1982, Docket No. A-82-37, 
II-I-1.
    11. Pierson, W.R., W.W. Brachaczek, T.J. Korniski, T.J. Truex, and 
J.W. Butler. Artifact Formation of Sulfate, Nitrate, and Hydrogen Ion on 
Backup Filters: Allegheny Mountain Experiment. J. Air Pollut. Control 
Assoc., 30:30, 1980.
    12. Dunwoody, C.L. Rapid Nitrate Loss From PM10 Filters. 
J. Air Pollut. Control Assoc., 36:817, 1986.
    13. Harrell, R.M. Measuring the Alkalinity of Hi-Vol Air Filters. 
EMSL/RTP-SOP-QAD-534, October 1985. Available from the U.S. 
Environmental Protection Agency, EMSL/QAD, Research Triangle Park, NC 
27711.
    14. Smith, F., P.S. Wohlschlegel, R.S.C. Rogers, and D.J. Mulligan. 
Investigation of Flow Rate Calibration Procedures Associated With the 
High Volume Method for Determination of Suspended Particulates. EPA-600/
4-78-047, U.S. Environmental Protection Agency, Research Triangle Park, 
NC 27711, 1978.

[62 FR 38753, July 18, 1997]

   Appendix N to Part 50--Interpretation of the National Ambient Air 
                Quality Standards for Particulate Matter

    1.0 General.
    (a) This appendix explains the data handling conventions and 
computations necessary for determining when the annual and 24-hour 
primary and secondary national ambient air quality standards for PM 
specified in Sec. 50.7 of this chapter are met. Particulate matter is 
measured in the ambient air as PM10 and PM2.5 
(particles with an aerodynamic diameter less than or equal to a nominal 
10 and 2.5 micrometers, respectively) by a reference method based on 
appendix M of this part for PM10 and on appendix L of this 
part for PM2.5, as applicable, and designated in accordance 
with part 53 of this chapter, or by an equivalent method designated in 
accordance with part 53 of this chapter. Data handling and computation 
procedures to be used in making comparisons between reported 
PM10 and PM2.5 concentrations and the levels of 
the PM standards are specified in the following sections.
    (b) Data resulting from uncontrollable or natural events, for 
example structural fires or high winds, may require special 
consideration. In some cases, it may be appropriate to exclude these 
data because they could result in inappropriate values to compare with 
the levels of the PM standards. In other cases, it may be more 
appropriate to retain the data for comparison with the level of the PM 
standards and then allow the EPA to formulate the appropriate regulatory 
response. Whether to exclude, retain, or make adjustments to the data 
affected by uncontrollable or natural events is subject to the approval 
of the appropriate Regional Administrator.
    (c) The terms used in this appendix are defined as follows:
    Average and mean refer to an arithmetic mean.
    Daily value for PM refers to the 24-hour average concentration of PM 
calculated or measured from midnight to midnight (local time) for 
PM10 or PM2.5.
    Designated monitors are those monitoring sites designated in a State 
PM Monitoring Network Description for spatial averaging in areas opting 
for spatial averaging in accordance with part 58 of this chapter.

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    98th percentile (used for PM2.5) means the 
daily value out of a year of monitoring data below which 98 percent of 
all values in the group fall.
    99th percentile (used for PM10) means the 
daily value out of a year of monitoring data below which 99 percent of 
all values in the group fall.
    Year refers to a calendar year.
    (d) Sections 2.1 and 2.5 of this appendix contain data handling 
instructions for the option of using a spatially averaged network of 
monitors for the annual standard. If spatial averaging is not considered 
for an area, then the spatial average is equivalent to the annual 
average of a single site and is treated accordingly in subsequent 
calculations. For example, paragraph (a)(3) of section 2.1 of this 
appendix could be eliminated since the spatial average would be 
equivalent to the annual average.
    2.0 Comparisons with the PM2.5 Standards.
    2.1 Annual PM2.5 Standard.
    (a) The annual PM2.5 standard is met when the 3-year 
average of the spatially averaged annual means is less than or equal to 
15.0 [mu]g/m\3\. The 3-year average of the spatially averaged annual 
means is determined by averaging quarterly means at each monitor to 
obtain the annual mean PM2.5 concentrations at each monitor, 
then averaging across all designated monitors, and finally averaging for 
3 consecutive years. The steps can be summarized as follows:
    (1) Average 24-hour measurements to obtain quarterly means at each 
monitor.
    (2) Average quarterly means to obtain annual means at each monitor.
    (3) Average across designated monitoring sites to obtain an annual 
spatial mean for an area (this can be one site in which case the spatial 
mean is equal to the annual mean).
    (4) Average 3 years of annual spatial means to obtain a 3-year 
average of spatially averaged annual means.
    (b) In the case of spatial averaging, 3 years of spatial averages 
are required to demonstrate that the standard has been met. Designated 
sites with less than 3 years of data shall be included in spatial 
averages for those years that data completeness requirements are met. 
For the annual PM2.5 standard, a year meets data completeness 
requirements when at least 75 percent of the scheduled sampling days for 
each quarter have valid data. However, years with high concentrations 
and more than a minimal amount of data (at least 11 samples in each 
quarter) shall not be ignored just because they are comprised of 
quarters with less than complete data. Thus, in computing annual 
spatially averaged means, years containing quarters with at least 11 
samples but less than 75 percent data completeness shall be included in 
the computation if the resulting spatially averaged annual mean 
concentration (rounded according to the conventions of section 2.3 of 
this appendix) is greater than the level of the standard.
    (c) Situations may arise in which there are compelling reasons to 
retain years containing quarters which do not meet the data completeness 
requirement of 75 percent or the minimum number of 11 samples. The use 
of less than complete data is subject to the approval of the appropriate 
Regional Administrator.
    (d) The equations for calculating the 3-year average annual mean of 
the PM2.5 standard are given in section 2.5 of this appendix.
    2.2 24-Hour PM2.5 Standard.
    (a) The 24-hour PM2.5 standard is met when the 3-year 
average of the 98th percentile values at each monitoring site 
is less than or equal to 65 [mu]g/m\3\. This comparison shall be based 
on 3 consecutive, complete years of air quality data. A year meets data 
completeness requirements when at least 75 percent of the scheduled 
sampling days for each quarter have valid data. However, years with high 
concentrations shall not be ignored just because they are comprised of 
quarters with less than complete data. Thus, in computing the 3-year 
average 98th percentile value, years containing quarters with 
less than 75 percent data completeness shall be included in the 
computation if the annual 98th percentile value (rounded 
according to the conventions of section 2.3 of this appendix) is greater 
than the level of the standard.
    (b) Situations may arise in which there are compelling reasons to 
retain years containing quarters which do not meet the data completeness 
requirement. The use of less than complete data is subject to the 
approval of the appropriate Regional Administrator.
    (c) The equations for calculating the 3-year average of the annual 
98th percentile values is given in section 2.6 of this 
appendix.
    2.3 Rounding Conventions. For the purposes of comparing calculated 
values to the applicable level of the standard, it is necessary to round 
the final results of the calculations described in sections 2.5 and 2.6 
of this appendix. For the annual PM2.5 standard, the 3-year 
average of the spatially averaged annual means shall be rounded to the 
nearest 0.1 [mu]g/m\3\ (decimals 0.05 and greater are rounded up to the 
next 0.1, and any decimal lower than 0.05 is rounded down to the nearest 
0.1). For the 24-hour PM2.5 standard, the 3-year average of 
the annual 98th percentile values shall be rounded to the 
nearest 1 [mu]g/m\3\ (decimals 0.5 and greater are rounded up to nearest 
whole number, and any decimal lower than 0.5 is rounded down to the 
nearest whole number).
    2.4 Monitoring Considerations.
    (a) Section 58.13 of this chapter specifies the required minimum 
frequency of sampling

[[Page 124]]

for PM2.5. Exceptions to the specified sampling frequencies, 
such as a reduced frequency during a season of expected low 
concentrations, are subject to the approval of the appropriate Regional 
Administrator. Section 58.14 of 40 CFR part 58 and section 2.8 of 
appendix D of 40 CFR part 58, specify which monitors are eligible for 
making comparisons with the PM standards. In determining a spatial mean 
using two or more monitoring sites operating in a given year, the annual 
mean for an individual site may be included in the spatial mean if and 
only if the mean for that site meets the criterion specified in Sec. 2.8 
of appendix D of 40 CFR part 58. In the event data from an otherwise 
eligible site is excluded from being averaged with data from other sites 
on the basis of this criterion, then the 3-year mean from that site 
shall be compared directly to the annual standard.
    (b) For the annual PM2.5 standard, when designated 
monitors are located at the same site and are reporting PM2.5 
values for the same time periods, and when spatial averaging has been 
chosen, their concentrations shall be averaged before an area-wide 
spatial average is calculated. Such monitors will then be considered as 
one monitor.
    2.5 Equations for the Annual PM2.5 Standard.
    (a) An annual mean value for PM2.5 is determined by first 
averaging the daily values of a calendar quarter:

                               Equation 1
[GRAPHIC] [TIFF OMITTED] TR18JY97.000

where:

xq,y,s = the mean for quarter q of year y for site s;
nq = the number of monitored values in the quarter; and
xi,q,y,s = the ith value in quarter q for year y 
for site s.

    (b) The following equation is then to be used for calculation of the 
annual mean:

                               Equation 2
[GRAPHIC] [TIFF OMITTED] TR18JY97.001

where:

xy,s = the annual mean concentration for year y (y = 1, 2, or 
3) and for site s; and
xq,y,s = the mean for quarter q of year y for site s.

    (c)(1) The spatially averaged annual mean for year y is computed by 
first calculating the annual mean for each site designated to be 
included in a spatial average, xy,s, and then computing the 
average of these values across sites:

                               Equation 3
[GRAPHIC] [TIFF OMITTED] TR18JY97.002

where:

xy = the spatially averaged mean for year y;
xy,s = the annual mean for year y and site s; and
ns = the number of sites designated to be averaged.

    (2) In the event that an area designated for spatial averaging has 
two or more sites at the same location producing data for the same time 
periods, the sites are averaged together before using Equation 3 by:

                               Equation 4
[GRAPHIC] [TIFF OMITTED] TR18JY97.003

where:

xy,s* = the annual mean for year y for the sites at the same 
location (which will now be considered one site);
nc = the number of sites at the same location designated to 
be included in the spatial average; and
xy,s = the annual mean for year y and site s.

    (d) The 3-year average of the spatially averaged annual means is 
calculated by using the following equation:

                               Equation 5
[GRAPHIC] [TIFF OMITTED] TR18JY97.004

where:

x = the 3-year average of the spatially averaged annual means; and
xy = the spatially averaged annual mean for year y.

Example 1--Area Designated for Spatial Averaging That Meets the Primary 
                    Annual PM2.5 Standard.

    a. In an area designated for spatial averaging, four designated 
monitors recorded data in at least 1 year of a particular 3-year period. 
Using Equations 1 and 2, the annual means for PM2.5 at each 
site are calculated for each year. The following table can be created 
from the results. Data completeness percentages for the quarter with the 
fewest number of samples are also shown.

[[Page 125]]



                                                         Table 1--Results from Equations 1 and 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Site          Site          Site          Site
                                                                                      [bottom]1     [bottom]2     [bottom]3     [bottom]4   Spatial mean
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1.........................................  Annual mean ([mu]g/m\3\).........          12.7  ............  ............  ............         12.7
                                                 % data completeness..............          80             0             0             0    ............
Year 2.........................................  Annual mean ([mu]g/m\3\).........          12.6          17.5          15.2  ............         15.05
                                                 % data completeness..............          90            63            38             0    ............
Year 3.........................................  Annual mean ([mu]g/m\3\).........          12.5          18.5          14.1          16.9         15.50
                                                 % data completeness..............          90            80            85            50    ............
3-year mean....................................  .................................  ............  ............  ............  ............         14.42
--------------------------------------------------------------------------------------------------------------------------------------------------------

    b. The data from these sites are averaged in the order described in 
section 2.1 of this appendix. Note that the annual mean from site 
3 in year 2 and the annual mean from site 4 in year 3 
do not meet the 75 percent data completeness criteria. Assuming the 38 
percent data completeness represents a quarter with fewer than 11 
samples, site 3 in year 2 does not meet the minimum data 
completeness requirement of 11 samples in each quarter. The site is 
therefore excluded from the calculation of the spatial mean for year 2. 
However, since the spatial mean for year 3 is above the level of the 
standard and the minimum data requirement of 11 samples in each quarter 
has been met, the annual mean from site 4 in year 3 is included 
in the calculation of the spatial mean for year 3 and in the calculation 
of the 3-year average. The 3-year average is rounded to 14.4 [mu]g/m\3\, 
indicating that this area meets the annual PM2.5 standard.

 Example 2--Area With Two Monitors at the Same Location That Meets the 
                Primary Annual PM2.5 Standard.

    a. In an area designated for spatial averaging, six designated 
monitors, with two monitors at the same location (5 and 
6), recorded data in a particular 3-year period. Using 
Equations 1 and 2, the annual means for PM2.5 are calculated 
for each year. The following table can be created from the results.

                                                         Table 2--Results From Equations 1 and 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                  Average of
                                                        Site         Site         Site         Site         Site         Site      [bottom]5    Spatial
             Annual mean ([mu]g/m\3\)                [bottom]1    [bottom]2    [bottom]3    [bottom]4    [bottom]5    [bottom]6       and        mean
                                                                                                                                   [bottom]6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 1............................................         12.9          9.9         12.6         11.1         14.5         14.6       14.55       12.21
Year 2............................................         14.5         13.3         12.2         10.9         16.1         16.0       16.05       13.39
Year 3............................................         14.4         12.4         11.5          9.7         12.3         12.1       12.20       12.04
3-Year mean.......................................  ...........  ...........  ...........  ...........  ...........  ...........  ..........       12.55
--------------------------------------------------------------------------------------------------------------------------------------------------------

    b. The annual means for sites 5 and 6 are averaged 
together using Equation 4 before the spatial average is calculated using 
Equation 3 since they are in the same location. The 3-year mean is 
rounded to 12.6 [mu]g/m\3\, indicating that this area meets the annual 
PM2.5 standard.

  Example 3--Area With a Single Monitor That Meets the Primary Annual 
                       PM2.5 Standard.

    a. Given data from a single monitor in an area, the calculations are 
as follows. Using Equations 1 and 2, the annual means for 
PM2.5 are calculated for each year. If the annual means are 
10.28, 17.38, and 12.25 [mu]g/m\3\, then the 3-year mean is:
[GRAPHIC] [TIFF OMITTED] TR18JY97.005

    b. This value is rounded to 13.3, indicating that this area meets 
the annual PM2.5 standard.
    2.6 Equations for the 24-Hour PM2.5 Standard.
    (a) When the data for a particular site and year meet the data 
completeness requirements in section 2.2 of this appendix, calculation 
of the 98th percentile is accomplished by the following 
steps. All the daily values from a particular site and year comprise a 
series of values (x1, x2, x3, ..., 
xn), that can be sorted into a series where each number is 
equal to or larger than the preceding number (x[1], 
x[2], x[3], ..., x[n]). In this case, 
x[1] is the smallest number and x[n] is the 
largest value. The 98th percentile is found from the

[[Page 126]]

sorted series of daily values which is ordered from the lowest to the 
highest number. Compute (0.98) x (n) as the number ``i.d'', where ``i'' 
is the integer part of the result and ``d'' is the decimal part of the 
result. The 98th percentile value for year y, 
P0.98, y, is given by Equation 6:

                               Equation 6
[GRAPHIC] [TIFF OMITTED] TR18JY97.006

where:

P0.98,y = 98th percentile for year y;
x[i=1] = the (i=1)th number in the ordered series 
of numbers; and
i = the integer part of the product of 0.98 and n.

    (b) The 3-year average 98th percentile is then calculated 
by averaging the annual 98th percentiles:

                               Equation 7
[GRAPHIC] [TIFF OMITTED] TR18JY97.007

    (c) The 3-year average 98th percentile is rounded 
according to the conventions in section 2.3 of this appendix before a 
comparison with the standard is made.

 Example 4--Ambient Monitoring Site With Every-Day Sampling That Meets 
             the Primary 24-Hour PM2.5 Standard.

    a. In each year of a particular 3 year period, varying numbers of 
daily PM2.5 values (e.g., 281, 304, and 296) out of a 
possible 365 values were recorded at a particular site with the 
following ranked values (in [mu]g/m\3\):

                                  Table 3--Ordered Monitoring Data For 3 Years
----------------------------------------------------------------------------------------------------------------
               Year 1                                Year 2                                Year 3
----------------------------------------------------------------------------------------------------------------
      j rank            Xj value            j rank            Xj value            j rank            Xj value
----------------------------------------------------------------------------------------------------------------
           275               57.9                296               54.3                290               66.0
           276               59.0                297               57.1                291               68.4
           277               62.2                298               63.0                292               69.8
----------------------------------------------------------------------------------------------------------------

    b. Using Equation 6, the 98th percentile values for each 
year are calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR18JY97.008

[GRAPHIC] [TIFF OMITTED] TR18JY97.009

[GRAPHIC] [TIFF OMITTED] TR18JY97.010

    c.1. Using Equation 7, the 3-year average 98th percentile 
is calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR18JY97.011

    2. Therefore, this site meets the 24-hour PM2.5 standard.
    3.0 Comparisons with the PM10 Standards.
    3.1 Annual PM10 Standard.
    (a) The annual PM10 standard is met when the 3-year 
average of the annual mean PM10 concentrations at each 
monitoring site is less than or equal to 50 [mu]g/m\3\. The 3-year 
average of the annual means is determined by averaging quarterly means 
to obtain annual mean PM10 concentrations for 3 consecutive, 
complete years at each monitoring site. The steps can be summarized as 
follows:
    (1) Average 24-hour measurements to obtain a quarterly mean.

[[Page 127]]

    (2) Average quarterly means to obtain an annual mean.
    (3) Average annual means to obtain a 3-year mean.
    (b) For the annual PM10 standard, a year meets data 
completeness requirements when at least 75 percent of the scheduled 
sampling days for each quarter have valid data. However, years with high 
concentrations and more than a minimal amount of data (at least 11 
samples in each quarter) shall not be ignored just because they are 
comprised of quarters with less than complete data. Thus, in computing 
the 3-year average annual mean concentration, years containing quarters 
with at least 11 samples but less than 75 percent data completeness 
shall be included in the computation if the annual mean concentration 
(rounded according to the conventions of section 2.3 of this appendix) 
is greater than the level of the standard.
    (c) Situations may arise in which there are compelling reasons to 
retain years containing quarters which do not meet the data completeness 
requirement of 75 percent or the minimum number of 11 samples. The use 
of less than complete data is subject to the approval of the appropriate 
Regional Administrator.
    (d) The equations for calculating the 3-year average annual mean of 
the PM10 standard are given in section 3.5 of this appendix.
    3.2 24-Hour PM10 Standard.
    (a) The 24-hour PM10 standard is met when the 3-year 
average of the annual 99th percentile values at each 
monitoring site is less than or equal to 150 [mu]g/m\3\. This comparison 
shall be based on 3 consecutive, complete years of air quality data. A 
year meets data completeness requirements when at least 75 percent of 
the scheduled sampling days for each quarter have valid data. However, 
years with high concentrations shall not be ignored just because they 
are comprised of quarters with less than complete data. Thus, in 
computing the 3-year average of the annual 99th percentile 
values, years containing quarters with less than 75 percent data 
completeness shall be included in the computation if the annual 
99th percentile value (rounded according to the conventions 
of section 2.3 of this appendix) is greater than the level of the 
standard.
    (b) Situations may arise in which there are compelling reasons to 
retain years containing quarters which do not meet the data completeness 
requirement. The use of less than complete data is subject to the 
approval of the appropriate Regional Administrator.
    (c) The equation for calculating the 3-year average of the annual 
99th percentile values is given in section 2.6 of this 
appendix.
    3.3 Rounding Conventions. For the annual PM10 standard, 
the 3-year average of the annual PM10 means shall be rounded 
to the nearest 1 [mu]g/m\3\ (decimals 0.5 and greater are rounded up to 
the next whole number, and any decimal less than 0.5 is rounded down to 
the nearest whole number). For the 24-hour PM10 standard, the 
3-year average of the annual 99th percentile values of 
PM10 shall be rounded to the nearest 10 [mu]g/m\3\ (155 
[mu]g/m\3\ and greater would be rounded to 160 [mu]g/m\3\ and 154 [mu]g/
m\3\ and less would be rounded to 150 [mu]g/m\3\).
    3.4 Monitoring Considerations. Section 58.13 of this chapter 
specifies the required minimum frequency of sampling for 
PM10. Exceptions to the specified sampling frequencies, such 
as a reduced frequency during a season of expected low concentrations, 
are subject to the approval of the appropriate Regional Administrator. 
For making comparisons with the PM10 NAAQS, all sites meeting 
applicable requirements in part 58 of this chapter would be used.
    3.5 Equations for the Annual PM10 Standard.
    (a) An annual arithmetic mean value for PM10 is 
determined by first averaging the 24-hour values of a calendar quarter 
using the following equation:

                               Equation 8
[GRAPHIC] [TIFF OMITTED] TR18JY97.012

where:

xq,y = the mean for quarter q of year y;
nq = the number of monitored values in the quarter; and
xi,q,y = the ith value in quarter q for year y.

    (b) The following equation is then to be used for calculation of the 
annual mean:

                               Equation 9
[GRAPHIC] [TIFF OMITTED] TR18JY97.013

where:

xy = the annual mean concentration for year y, (y=1, 2, or 
3); and
xq,y = the mean for a quarter q of year y.

    (c) The 3-year average of the annual means is calculated by using 
the following equation:

                               Equation 10
[GRAPHIC] [TIFF OMITTED] TR18JY97.014

where:

x = the 3-year average of the annual means; and

xy = the annual mean for calendar year y.


[[Page 128]]



    Example 5--Ambient Monitoring Site That Does Not Meet the Annual 
                        PM10 Standard.

    a. Given data from a PM10 monitor and using Equations 8 
and 9, the annual means for PM10 are calculated for each 
year. If the annual means are 52.42, 82.17, and 63.23 [mu]g/m\3\, then 
the 3-year average annual mean is:
[GRAPHIC] [TIFF OMITTED] TR18JY97.015

    b. Therefore, this site does not meet the annual PM10 
standard.
    3.6 Equation for the 24-Hour PM10 Standard.
    (a) When the data for a particular site and year meet the data 
completeness requirements in section 3.2 of this appendix, calculation 
of the 99th percentile is accomplished by the following 
steps. All the daily values from a particular site and year comprise a 
series of values (x1, x2, x3, ..., 
xn) that can be sorted into a series where each number is 
equal to or larger than the preceding number (x[1], 
x[2], x[3], ..., x[n]). In this case, 
x[1] is the smallest number and x[n] is the largest value. 
The 99th percentile is found from the sorted series of daily 
values which is ordered from the lowest to the highest number. Compute 
(0.99) x (n) as the number ``i.d'', where ``i'' is the integer part of 
the result and ``d'' is the decimal part of the result. The 
99th percentile value for year y, P0.99,y, is 
given by Equation 11:

                               Equation 11
[GRAPHIC] [TIFF OMITTED] TR18JY97.016

where:

P0.99,y = the 99th percentile for year y;

x[i=1] = the (i=1)th number in the ordered series 
of numbers; and

i = the integer part of the product of 0.99 and n.

    (b) The 3-year average 99th percentile value is then 
calculated by averaging the annual 99th percentiles:

                               Equation 12
[GRAPHIC] [TIFF OMITTED] TR18JY97.017

    (c) The 3-year average 99th percentile is rounded 
according to the conventions in section 3.3 of this appendix before a 
comparison with the standard is made.

 Example 6--Ambient Monitoring Site With Sampling Every Sixth Day That 
           Meets the Primary 24-Hour PM10 Standard.

    a. In each year of a particular 3 year period, varying numbers of 
PM10 daily values (e.g., 110, 98, and 100) out of a possible 
121 daily values were recorded at a particular site with the following 
ranked values (in [mu]g/m\3\):

                                  Table 4--Ordered Monitoring Data For 3 Years
----------------------------------------------------------------------------------------------------------------
               Year 1                                Year 2                                Year 3
----------------------------------------------------------------------------------------------------------------
      j rank            Xj value            j rank            Xj value            j rank            Xj value
----------------------------------------------------------------------------------------------------------------
           108                120                 96                143                 98                140
           109                128                 97                148                 99                144
           110                130                 98                150                100                147
----------------------------------------------------------------------------------------------------------------

    b. Using Equation 11, the 99th percentile values for each 
year are calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR18JY97.018

[GRAPHIC] [TIFF OMITTED] TR18JY97.019


[[Page 129]]


[GRAPHIC] [TIFF OMITTED] TR18JY97.020

    c. 1. Using Equation 12, the 3-year average 99th 
percentile is calculated as follows:
[GRAPHIC] [TIFF OMITTED] TR18JY97.021

    2. Therefore, this site meets the 24-hour PM10 standard.

[62 FR 38755, July 18, 1997]



PART 51--REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF 
IMPLEMENTATION PLANS--Table of Contents




Sec.

          Subpart A--Emission Inventory Reporting Requirements

               General Information for Inventory Preparers

51.1  Who is responsible for actions described in this subpart?
51.5  What tools are available to help prepare and report emissions 
          data?
51.10  How does my State report emissions that are required by the 
          NOX SIP Call?

                     Specific Reporting Requirements

51.15  What data does my State need to report to EPA?
51.20  What are the emission thresholds that separate point and area 
          sources?
51.25  What geographic area must my State's inventory cover?
51.30  When does my State report the data to EPA?
51.35  How can my State equalize the effort for annual reporting?
51.40  In what form should my State report the data to EPA?
51.45  Where should my State report the data?

Appendix A to Subpart A of Part 51--Tables and Glossary
Appendix B to Subpart A of Part 51 [Reserved]

Subparts B--E [Reserved]

                   Subpart F--Procedural Requirements

51.100  Definitions.
51.101  Stipulations.
51.102  Public hearings.
51.103  Submission of plans, preliminary review of plans.
51.104  Revisions.
51.105  Approval of plans.

                       Subpart G--Control Strategy

51.110  Attainment and maintenance of national standards.
51.111  Description of control measures.
51.112  Demonstration of adequacy.
51.113  [Reserved]
51.114  Emissions data and projections.
51.115  Air quality data and projections.
51.116  Data availability.
51.117  Additional provisions for lead.
51.118  Stack height provisions.
51.119  Intermittent control systems.
51.120  Requirements for State Implementation Plan revisions relating to 
          new motor vehicles.
51.121  Findings and requirements for submission of State implementation 
          plan revisions relating to emissions of oxides of nitrogen.
51.122  Emissions reporting requirements for SIP revisions relating to 
          budgets for NOX emissions.

        Subpart H--Prevention of Air Pollution Emergency Episodes

51.150  Classification of regions for episode plans.
51.151  Significant harm levels.
51.152  Contingency plans.
51.153  Reevaluation of episode plans.

           Subpart I--Review of New Sources and Modifications

51.160  Legally enforceable procedures.
51.161  Public availability of information.
51.162  Identification of responsible agency.
51.163  Administrative procedures.
51.164  Stack height procedures.
51.165  Permit requirements.
51.166  Prevention of significant deterioration of air quality.

[[Page 130]]

               Subpart J--Ambient Air Quality Surveillance

51.190  Ambient air quality monitoring requirements.

                     Subpart K--Source Survelliance

51.210  General.
51.211  Emission reports and recordkeeping.
51.212  Testing, inspection, enforcement, and complaints.
51.213  Transportation control measures.
51.214  Continuous emission monitoring.

                       Subpart L--Legal Authority

51.230  Requirements for all plans.
51.231  Identification of legal authority.
51.232  Assignment of legal authority to local agencies.

                Subpart M--Intergovernmental Consultation

                           Agency Designation

51.240  General plan requirements.
51.241  Nonattainment areas for carbon monoxide and ozone.
51.242  [Reserved]

                     Subpart N--Compliance Schedules

51.260  Legally enforceable compliance schedules.
51.261  Final compliance schedules.
51.262  Extension beyond one year.

           Subpart O--Miscellaneous Plan Content Requirements

51.280  Resources.
51.281  Copies of rules and regulations.
51.285  Public notification.

                   Subpart P--Protection of Visibility

51.300  Purpose and applicability.
51.301  Definitions.
51.302  Implementation control strategies for reasonably attributable 
          visibility impairment.
51.303  Exemptions from control.
51.304  Identification of integral vistas.
51.305  Monitoring for reasonably attributable visibility impairment.
51.306  Long-term strategy requirements for reasonably attributable 
          visibility impairment.
51.307  New source review.
51.308  Regional haze program requirements.
51.309  Requirements related to the Grand Canyon Visibility Transport 
          Commission.

                           Subpart Q--Reports

                       Air Quality Data Reporting

51.320  Annual air quality data report.

               Source Emissions and State Action Reporting

51.321  Annual source emissions and State action report.
51.322  Sources subject to emissions reporting.
51.323  Reportable emissions data and information.
51.324  Progress in plan enforcement.
51.326  Reportable revisions.
51.327  Enforcement orders and other State actions.
51.328  [Reserved]

                          Subpart R--Extensions

51.341  Request for 18-month extension.

         Subpart S--Inspection/Maintenance Program Requirements

51.350  Applicability.
51.351  Enhanced I/M performance standard.
51.352  Basic I/M performance standard.
51.353  Network type and program evaluation.
51.354  Adequate tools and resources.
51.355  Test frequency and convenience.
51.356  Vehicle coverage.
51.357  Test procedures and standards.
51.358  Test equipment.
51.359  Quality control.
51.360  Waivers and compliance via diagnostic inspection.
51.361  Motorist compliance enforcement.
51.362  Motorist compliance enforcement program oversight.
51.363  Quality assurance.
51.364  Enforcement against contractors, stations and inspectors.
51.365  Data collection.
51.366  Data analysis and reporting.
51.367  Inspector training and licensing or certification.
51.368  Public information and consumer protection.
51.369  Improving repair effectiveness.
51.370  Compliance with recall notices.
51.371  On-road testing.
51.372  State Implementation Plan submissions.
51.373  Implementation deadlines.

Appendix A to Subpart S--Calibrations, Adjustments and Quality Control
Appendix B to Subpart S--Test Procedures
Appendix C to Subpart S--Steady-State Short Test Standards
Appendix D to Subpart S--Steady-State Short Test Equipment

[[Page 131]]

Appendix E to Subpart S--Transient Test Driving Cycle

   Subpart T--Conformity to State or Federal Implementation Plans of 
   Transportation Plans, Programs, and Projects Developed, Funded or 
       Approved Under Title 23 U.S.C. or the Federal Transit Laws

51.390  Implementation plan revision.

                 Subpart U--Economic Incentive Programs

51.490  Applicability.
51.491  Definitions.
51.492  State program election and submittal.
51.493  State program requirements.
51.494  Use of program revenues.

Subpart W--Determining Conformity of General Federal Actions to State or 
                      Federal Implementation Plans

51.850  Prohibition.
51.851  State Implementation Plan (SIP) revision.
51.852  Definitions.
51.853  Applicability.
51.854  Conformity analysis.
51.855  Reporting requirements.
51.856  Public participation.
51.857  Frequency of conformity determinations.
51.858  Criteria for determining conformity of general Federal actions.
51.859  Procedures for conformity determinations of general Federal 
          actions.
51.860  Mitigation of air quality impacts.

Appendixes A-K [Reserved]
Appendix L to Part 51--Example Regulations for Prevention of Air 
          Pollution Emergency Episodes
Appendix M to Part 51--Recommended Test Methods for State Implementation 
          Plans
Appendixes N-O [Reserved]
Appendix P to Part 51--Minimum Emission Monitoring Requirements
Appendixes Q-R [Reserved]
Appendix S to Part 51--Emission Offset Interpretative Ruling
Appendixes T-U [Reserved]
Appendix V to Part 51--Criteria for Determining the Completeness of Plan 
          Submissions
Appendix W to Part 51--Guideline on Air Quality Models
Appendix X to Part 51--Examples of Economic Incentive Programs

    Authority: 23 U.S.C. 101; 42 U.S.C. 7401-7671q.

    Source: 36 FR 22398, Nov. 25, 1971, unless otherwise noted.



          Subpart A--Emission Inventory Reporting Requirements

    Source: 67 FR 39611, June 10, 2002, unless otherwise noted.

               General Information for Inventory Preparers



Sec. 51.1  Who is responsible for actions described in this subpart?

    State agencies whose geographic coverage include any point, area, 
mobile, or biogenic sources must inventory these sources and report this 
information to EPA.



Sec. 51.5  What tools are available to help prepare and report emissions data?

    We urge your State to use estimation procedures described in 
documents from the Emission Inventory Improvement Program (EIIP). These 
procedures are standardized and ranked according to relative uncertainty 
for each emission estimating technique. Using this guidance will enable 
others to use your State's data and evaluate its quality and consistency 
with other data.



Sec. 51.10  How does my State report emissions that are required by the 
NOX SIP Call?

    The States and the District of Columbia that are subject to the 
NOX SIP Call (Sec. 51.121) should report their emissions 
under the provisions of Sec. 51.122. To avoid confusion, these 
requirements are not repeated here.

                     Specific Reporting Requirements



Sec. 51.15  What data does my State need to report to EPA?

    (a) Pollutants. Report actual emissions of the following (see 
Glossary to Appendix A to this subpart for precise definitions as 
required):
    (1) Required Pollutants:
    (i) Sulfur oxides.
    (ii) VOC.
    (iii) Nitrogen oxides.
    (iv) Carbon monoxide.
    (v) Lead and lead compounds.
    (vi) Primary PM2.5.
    (vii) Primary PM10.
    (viii) NH3.
    (2) Optional Pollutant:

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    (i) Primary PM.
    (ii) [Reserved]
    (b) Sources. Emissions should be reported from the following 
sources:
    (1) Point.
    (2) Area.
    (3) Onroad mobile.
    (4) Nonroad mobile.
    (5) Biogenic.
    (c) Supporting information. Report the data elements in Tables 2a 
through 2d of Appendix A to this subpart. Depending on the format you 
choose to report your State data, additional information not listed in 
Tables 2a through 2d will be required. We may ask you for other data on 
a voluntary basis to meet special purposes.
    (d) Confidential data. We don't consider the data in Tables 2a 
through 2d of Appendix A to this subpart confidential, but some States 
limit release of this type of data. Any data that you submit to EPA 
under this rule will be considered in the public domain and cannot be 
treated as confidential. If Federal and State requirements are 
inconsistent, consult your EPA Regional Office for a final 
reconciliation.



Sec. 51.20  What are the emission thresholds that separate point and area 
sources?

    (a) All anthropogenic stationary sources must be included in your 
inventory as either point or area sources.
    (b) See Table 1 of Appendix A to this subpart for minimum reporting 
thresholds on point sources.
    (c) Your State has two alternatives to the point source reporting 
thresholds in paragraph (b) of this section:
    (1) You may choose to define point sources by the definition of a 
major source used under CAA Title V, see 40 CFR 70.2.
    (2) If your State has lower emission reporting thresholds for point 
sources than paragraph (b) of this section, then you may use these in 
reporting your emissions to EPA.
    (d) All stationary sources that have actual emissions lower than the 
thresholds specified in paragraphs (b) and (c) of this section, should 
be reported as area sources.



Sec. 51.25  What geographic area must my State's inventory cover?

    Because of the regional nature of these pollutants, your State's 
inventory must be statewide, regardless of an area's attainment status.



Sec. 51.30  When does my State report the data to EPA?

    Your State is required to report two basic types of emission 
inventories to us: Annual Cycle Inventory; and Three-year Cycle 
Inventory.
    (a) Annual cycle. You are required to report annually data from Type 
A (large) point sources. Except as provided in paragraph (e) of this 
section, the first annual cycle inventory will be for the year 2001 and 
must be submitted to us within 17 months, i.e., by June 1, 2003. 
Subsequent annual cycle inventories will be due 17 months following the 
end of the reporting year. See Table 2a of Appendix A to this subpart 
for the specific data elements to report annually.
    (b) Three-year cycle. You are required to report triennially, data 
for Type B (all) point sources, area sources and mobile sources. Except 
as provided in paragraph (e) of this section, the first three-year cycle 
inventory will be for the year 2002 and must be submitted to us within 
17 months, i.e., by June 1, 2004. Subsequent three-year cycle 
inventories will be due 17 months following the end of the reporting 
year. See Tables 2a, 2b and 2c of Appendix A to this subpart for the 
specific data elements that must be reported triennially.
    (c) NOX SIP call. There are specific annual and three-
year reporting requirements for States subject to the NOX SIP 
call. See Sec. 51.122 for these requirements.
    (d) Biogenic emissions. Biogenic emissions are part of your 3-year 
cycle inventory. Your State must establish an initial baseline for 
biogenic emissions that is due as specified under paragraph (b) of this 
section. Your State need not submit more biogenic data unless land use 
characteristics or the methods for estimating emissions change 
substantially. If either of these changes, your State must report the 
biogenic emission data elements shown

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in Table 2d of Appendix A to this subpart. Report these data elements 17 
months after the end of the reporting year.
    (e) Point Sources. States must commence reporting point source 
emissions of PM2.5 and NH3 on June 1, 2004 unless 
that date is less than 60 days after EPA publishes an approved 
Information Collection Request (ICR) addressing this section of the 
rule. If EPA fails to publish an approved ICR 60 days in advance of June 
1, 2004, States must commence reporting point source emissions of 
PM2.5 and NH3 on the next annual or triennial 
reporting date (as appropriate) that is at least 60 days after EPA 
publishes an approved ICR addressing this section.



Sec. 51.35  How can my State equalize the effort for annual reporting?

    (a) Compiling a 3-year cycle inventory means much more effort every 
three years. As an option, your State may ease this workload spike by 
using the following approach:
    (1) Annually collect and report data for all Type A (large) point 
sources (This is required for all Type A point sources).
    (2) Annually collect data for one-third of your smaller point 
sources (Type B point sources minus Type A (large) point sources). 
Collect data for a different third of these sources each year so that 
data has been collected for all of the smaller point sources by the end 
of each three-year cycle. You may report these data to EPA annually, or 
as an option you may save three years of data and then report all of the 
smaller point sources on the three-year cycle due date.
    (3) Annually collect data for one-third of the area, nonroad mobile, 
onroad mobile and, if required, biogenic sources. You may report these 
data to EPA annually, or as an option you may save three years of data 
and then report all of these data on the three-year cycle due date.
    (b) For the sources described in paragraph (a) of this section, your 
State will therefore have data from three successive years at any given 
time, rather than from the single year in which it is compiled.
    (c) If your State chooses the method of inventorying one-third of 
your smaller point sources and 3-year cycle area, nonroad mobile, onroad 
mobile sources each year, your State must compile each year of the 
three-year period identically. For example, if a process hasn't changed 
for a source category or individual plant, your State must use the same 
emission factors to calculate emissions for each year of the three-year 
period. If your State has revised emission factors during the three 
years for a process that hasn't changed, resubmit previous year's data 
using the revised factor. If your State uses models to estimate 
emissions, you must make sure that the model is the same for all three 
years.
    (d) If your State chooses the method of inventorying one-third of 
your smaller point sources and 3-year cycle area, nonroad mobile, onroad 
mobile sources each year and reporting them on the 3-year cycle due 
date, the first required date for you to report on all such sources will 
be June 1, 2004 as specified in Sec. 51.25. You can satisfy the 2004 
reporting requirement by either: Starting to inventory one third of your 
sources in 2000; or doing a one-time complete 3-year cycle inventory for 
2002, then changing to the option of inventorying one third of your 
sources for subsequent years.
    (e) If your State needs a new reference year emission inventory for 
a selected pollutant, your State can't use these optional reporting 
frequencies for the new reference year.
    (f) If your State is a NOX SIP call State, you can't use 
these optional reporting frequencies for NOX SIP call 
reporting.



Sec. 51.40  In what form should my State report the data to EPA?

    You must report your emission inventory data to us in electronic 
form. We support specific electronic data reporting formats and you are 
required to report your data in a format consistent with these. Because 
electronic reporting technology continually changes, contact the 
Emission Factor and Inventory Group (EFIG) for the latest specific 
formats. You can find information on the current formats at the 
following Internet address: http://

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www.epa.gov/ttn/chief. You may also call our Info CHIEF help desk at 
(919) 541-1000 or email to info.chief@epa.gov.



Sec. 51.45  Where should my State report the data?

    (a) Your State submits or reports data by providing it directly to 
EPA.
    (b) The latest information on data reporting procedures is available 
at the following Internet address: http://www.epa.gov/ttn/chief.
    You may also call our Info CHIEF help desk at (919)541-1000 or email 
to info.chief@epa.gov.

         Appendix A to Subpart A of Part 51--Tables and Glossary

                    Table 1--Minimum Point Source Reporting Thresholds by Pollutant(tpy \1\)
----------------------------------------------------------------------------------------------------------------
                                                                             Three-year cycle
             Pollutant                  Annual cycle    --------------------------------------------------------
                                      (type A sources)   Type B sources \2\                NAA \3\
----------------------------------------------------------------------------------------------------------------
1. SOx.............................            [ge]2500             [ge]100  [ge]100
2. VOC.............................             [ge]250             [ge]100  03 (moderate)[ge]100
3. VOC.............................  ..................  ..................  O3 (serious)[ge]50
4. VOC.............................  ..................  ..................  O3 (severe)[ge]25
5. VOC.............................  ..................  ..................  O3 (extreme)[ge]10
6. NOX.............................            [ge]2500             [ge]100  [ge]100
7. CO..............................            [ge]2500            [ge]1000  O3 (all areas)[ge]100
8. CO..............................  ..................  ..................  CO (all areas)[ge]100
9. Pb..............................  ..................               [ge]5  [ge]5
10. PM10...........................             [ge]250             [ge]100  PM1010 (moderate)[ge]100
11. PM10...........................  ..................  ..................  PM10 (serious)[ge]70
12. PM2.5..........................             [ge]250             [ge]100  [ge]100
13. NH3............................             [ge]250             [ge]100  [ge]100
----------------------------------------------------------------------------------------------------------------
\1\ tpy = tons per year of actual emissions.
\2\ Type A sources are a subset of the Type B sources and are the larger emitting sources by pollutant.
\3\ NAA = Nonattainment Area. Special point source reporting thresholds apply for certain pollutants by type of
  nonattainment area. The pollutants by nonattainment area are: Ozone: VOC, NOX, CO; CO: CO; PM10: PM10.


    Table 2a--Data Elements That States Must Report for Point Sources
------------------------------------------------------------------------
                                                         Every 3 years
          Data elements             Annual (Type A      (Type B sources
                                       sources)            and NAAs)
------------------------------------------------------------------------
1. Inventory year...............           [bcheck]            [bcheck]
2. Inventory start date.........           [bcheck]            [bcheck]
3. Inventory end date...........           [bcheck]            [bcheck]
4. Inventory type...............           [bcheck]            [bcheck]
5. State FIPS code..............           [bcheck]            [bcheck]
6. County FIPS code.............           [bcheck]            [bcheck]
7. Facility ID code.............           [bcheck]            [bcheck]
8. Point ID code................           [bcheck]            [bcheck]
9. Process ID code..............           [bcheck]            [bcheck]
10. Stack ID code...............           [bcheck]            [bcheck]
11. Site name...................           [bcheck]            [bcheck]
12. Physical address............           [bcheck]            [bcheck]
13. SCC or PCC..................           [bcheck]            [bcheck]
14. Heat content (fuel) (annual            [bcheck]            [bcheck]
 average).......................
15. Ash content (fuel) (annual             [bcheck]            [bcheck]
 average).......................
16. Sulfur content (fuel)                  [bcheck]            [bcheck]
 (annual average)...............
17. Pollutant code..............           [bcheck]            [bcheck]
18. Activity/throughput (annual)           [bcheck]            [bcheck]
19. Activity/throughput (daily).           [bcheck]            [bcheck]
20. Work weekday emissions......           [bcheck]            [bcheck]
21. Annual emissions............           [bcheck]            [bcheck]
22. Emission factor.............           [bcheck]            [bcheck]
23. Winter throughput (%).......           [bcheck]            [bcheck]
24. Spring throughput (%).......           [bcheck]            [bcheck]
25. Summer throughput (%).......           [bcheck]            [bcheck]
26. Fall throughput (%).........           [bcheck]            [bcheck]
27. Hr/day in operation.........           [bcheck]            [bcheck]
28. Start time (hour)...........           [bcheck]            [bcheck]
29. Day/wk in operation.........           [bcheck]            [bcheck]
30. Wk/yr in operation..........           [bcheck]            [bcheck]
31. X stack coordinate            ..................           [bcheck]
 (latitude).....................
32. Y stack coordinate            ..................           [bcheck]
 (longitude)....................
33. Stack Height................  ..................           [bcheck]

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34. Stack diameter..............  ..................           [bcheck]
35. Exit gas temperature........  ..................           [bcheck]
36. Exit gas velocity...........  ..................           [bcheck]
37. Exit gas flow rate..........  ..................           [bcheck]
38. SIC/NAICS...................  ..................           [bcheck]
39. Design capacity.............  ..................           [bcheck]
40. Maximum namemplate capacity.  ..................           [bcheck]
41. Primary control eff (%).....  ..................           [bcheck]
42. Secondary control eff (%)...  ..................           [bcheck]
43. Control device type.........  ..................           [bcheck]
44. Rule effectiveness (%)......  ..................           [bcheck]
------------------------------------------------------------------------


  Table 2b--Data Elements that States Must Report for Area and Nonroad
                             Mobile Sources
------------------------------------------------------------------------
                                                               Every 3
                       Data elements                            years
------------------------------------------------------------------------
1. Inventory year.........................................     [bcheck]
2. Inventory start date...................................     [bcheck]
3. Inventory end date.....................................     [bcheck]
4. Inventory type.........................................     [bcheck]
5. State FIPS code........................................     [bcheck]
6. County FIPS code.......................................     [bcheck]
7. SCC or PCC.............................................     [bcheck]
8. Emission factor........................................     [bcheck]
9. Activity/throughput level (annual).....................     [bcheck]
10. Total capture/control efficiency (%)..................     [bcheck]
11. Rule effectiveness (%)................................     [bcheck]
12. Rule penetration (%)..................................     [bcheck]
13. Pollutant code........................................     [bcheck]
14. Summer/winter work weekday emissions..................     [bcheck]
15. Annual emissions......................................     [bcheck]
16. Winter throughput (%).................................     [bcheck]
17. Spring throughput (%).................................     [bcheck]
18. Summer throughput (%).................................     [bcheck]
19. Fall throughput (%)...................................     [bcheck]
20. Hrs/day in operation..................................     [bcheck]
21. Days/wk in operation..................................     [bcheck]
22. Wks/yr in operation...................................     [bcheck]
------------------------------------------------------------------------


    Table 2c--Data Elements that States Must Report for Onroad Mobile
                                 Sources
------------------------------------------------------------------------
                                                               Every 3
                       Data elements                            years
------------------------------------------------------------------------
1. Inventory year.........................................     [bcheck]
2. Inventory start date...................................     [bcheck]
3. Inventory end date.....................................     [bcheck]
4. Inventory type.........................................     [bcheck]
5. State FIPS code........................................     [bcheck]
6. County FIPS code.......................................     [bcheck]
7. SCC or PCC.............................................     [bcheck]
8. Emission factor........................................     [bcheck]
9. Activity (VMT by Roadway Class)........................     [bcheck]
10. Pollutant code........................................     [bcheck]
11. Summer/winter work weekday emissions..................     [bcheck]
12. Annual emissions......................................     [bcheck]
------------------------------------------------------------------------


  Table 2d--Data Elements that States Must Report for Biogenic Sources
------------------------------------------------------------------------
                                                               Every 3
                       Data elements                            years
------------------------------------------------------------------------
1. Inventory year.........................................     [bcheck]
2. Inventory start date...................................     [bcheck]
3. Inventory end date.....................................     [bcheck]
4. Inventory type.........................................     [bcheck]
5. State FIPS code........................................     [bcheck]
6. County FIPS code.......................................     [bcheck]
7. SCC or PCC.............................................     [bcheck]
8. Pollutant code.........................................     [bcheck]
9. Summer/winter work weekday emissions...................     [bcheck]
10. Annual emissions......................................     [bcheck]
------------------------------------------------------------------------

                                Glossary

    Activity rate/throughput (annual)--A measurable factor or parameter 
that relates directly or indirectly to the emissions of an air pollution 
source. Depending on the type of source category, activity information 
may refer to the amount of fuel combusted, raw material processed, 
product manufactured, or material handled or processed. It may also 
refer to population, employment, number of units, or miles traveled. 
Activity information is typically the value that is multiplied against 
an emission factor to generate an emissions estimate.
    Activity rate/throughput (daily)--The beginning and ending dates and 
times that define the emissions period used to estimate the daily 
activity rate/throughput.
    Annual emissions--Actual emissions for a plant, point, or process--
measured or calculated that represent a calendar year.
    Area sources--Area sources collectively represent individual sources 
that have not been inventoried as specific point, mobile, or biogenic 
sources. These individual sources treated collectively as area sources 
are typically too small, numerous, or difficult to inventory using the 
methods for the other classes of sources.
    Ash content--Inert residual portion of a fuel.
    Biogenic sources--Biogenic emissions are all pollutants emitted from 
non-anthropogenic sources. Example sources include trees

[[Page 136]]

and vegetation, oil and gas seeps, and microbial activity.
    Control device type--The name of the type of control device (e.g., 
wet scrubber, flaring, or process change).
    County FIPS Code--Federal Information Placement System (FIPS) is the 
system of unique numeric codes the government developed to identify 
States, counties and parishes for the entire United States, Puerto Rico, 
and Guam.
    Day/wk in operations--Days per week that the emitting process 
operates--average over the inventory period.
    Design capacity--A measure of the size of a point source, based on 
the reported maximum continuous capacity of the unit.
    Emission factor--Ratio relating emissions of a specific pollutant to 
an activity or material throughput level.
    Exit gas flow rate--Numeric value of stack gas's flow rate.
    Exit gas temperature--Numeric value of an exit gas stream's 
temperature.
    Exit gas velocity--Numeric value of an exit gas stream's velocity.
    Facility ID code--Unique code for a plant or facility, containing 
one or more pollutant-emitting sources. This is the data element in 
Appendix A, Table 2a, that is defined elsewhere in this glossary as a 
``point source''.
    Fall throughput(%)--Part of the throughput for the three Fall months 
(September, October, November). This expresses part of the annual 
activity information based on four seasons--typically spring, summer, 
fall, and winter. It can be a percentage of the annual activity (e.g., 
production in summer is 40% of the year's production) or units of the 
activity (e.g., out of 600 units produced, spring = 150 units, summer = 
250 units, fall = 150 units, and winter = 50 units).
    Heat content--The amount of thermal heat energy in a solid, liquid, 
or gaseous fuel. Fuel heat content is typically expressed in units of 
Btu/lb of fuel, Btu/gal of fuel, joules/kg of fuel, etc.
    Hr/day in operations--Hours per day that the emitting process 
operates--average over the inventory period.
    Inventory end date--Last day of the inventory period.
    Inventory start date--First day of the inventory period.
    Inventory type--Type of inventory represented by data (i.e., point, 
3-year cycle, daily).
    Inventory year--The calendar year for which you calculated emissions 
estimates.
    Lead (Pb)--As defined in 40 CFR 50.12, lead should be reported as 
elemental lead and its compounds.
    Maximum nameplate capacity--A measure of a unit's size that the 
manufacturer puts on the unit's nameplate.
    Mobile source--A motor vehicle, nonroad engine or nonroad vehicle.
     A ``motor vehicle'' is any self-propelled vehicle used to 
carry people or property on a street or highway.
     A ``nonroad engine'' is an internal combustion engine 
(including fuel system) that is not used in a motor vehicle or vehicle 
only used for competition, or that is not affected by sections 111 or 
202 of the CAA.
     A ``nonroad vehicle'' is a vehicle that is run by a nonroad 
engine and that is not a motor vehicle or a vehicle only used for 
competition.
    PM (Particulate Matter)--Particulate matter is a criteria air 
pollutant. For the purpose of this subpart, the following definitions 
apply:
    (1) Primary PM: Particles that enter the atmosphere as a direct 
emission from a stack or an open source. It is comprised of two 
components: Filterable PM and Condensible PM. (As specified in 
Sec. 51.15 (a)(2), these two PM components are the components measured 
by a stack sampling train such as EPA Method 5 and have no upper 
particle size limit.)
    (2) Filterable PM: Particles that are directly emitted by a source 
as a solid or liquid at stack or release conditions and captured on the 
filter of a stack test train.
    (3) Condensible PM: Material that is vapor phase at stack 
conditions, but which condenses and/or reacts upon cooling and dilution 
in the ambient air to form solid or liquid PM immediately after 
discharge from the stack.
    (4) Secondary PM: Particles that form through chemical reactions in 
the ambient air well after dilution and condensation have occurred. 
Secondary PM is usually formed at some distance downwind from the 
source. Secondary PM should NOT be reported in the emission inventory 
and is NOT covered by this subpart.
    (5) Primary PM2.5: Also PM2.5 (or Filterable 
PM2.5 and Condensible PM individually. Note that all 
Condensible PM is assumed to be in the PM2.5 size fraction)--
Particulate matter with an aerodynamic diameter equal to or less than 
2.5 micrometers.
    (6) Primary PM10: Also PM10 (or Filterable 
PM10 and Condensible PM individually)--Particulate matter 
with an aerodynamic diameter equal to or less than 10 micrometers.
    PCC--Process classification code. A process-level code that 
describes the equipment or operation which is emitting pollutants. This 
code is being considered as a replacement for the SCC.
    Physical address--Street address of a facility. This is the address 
of the location where the emissions occur; not, for example, the 
corporate headquarters.
    Point ID code--Unique code for the point of generation of emissions, 
typically a physical piece of equipment.

[[Page 137]]

    Point source--Point sources are large, stationary (non-mobile), 
identifiable sources of emissions that release pollutants into the 
atmosphere. As used in this rule, a point source is defined as a 
facility that annually emits more than a ``threshold'' value as defined 
under Sec. 51.20.
    Pollutant code--A unique code for each reported pollutant assigned 
in the Emission Inventory Improvement Program (EIIP) Data Model. The 
EIIP model was developed to promote consistency in organizations sharing 
emissions data. The model uses character names for criteria pollutants 
and Chemical Abstracts Service (CAS) numbers for all other pollutants. 
You may be using SAROAD codes for pollutants, but you should be able to 
map them to the pollutant codes in the EIIP Data Model.
    Process ID code--Unique code for the process generating the 
emissions, typically a description of a process.
    Roadway class--A classification system developed by the Federal 
Highway Administration that defines all public roadways as to type. 
Currently there are four roadway types: (1) Freeway, (2) freeway ramp, 
(3) arterial/collector and (4) local.
    Rule effectiveness (RE)--How well a regulatory program achieves all 
possible emission reductions. This rating reflects the assumption that 
controls typically aren't 100 percent effective because of equipment 
downtime, upsets, decreases in control efficiencies, and other 
deficiencies in emission estimates. RE adjusts the control efficiency.
    Rule penetration--The percentage of an area source category covered 
by an applicable regulation.
    SCC--Source classification code. A process-level code that describes 
the equipment and/or operation which is emitting pollutants.
    Seasonal activity rate/throughput--A measurable factor or parameter 
that relates directly or indirectly to the pollutant season emissions of 
an air pollution source. Depending on the type of source category, 
activity information may refer to the amount of fuel combusted, raw 
material processed, product manufactured, or material handled or 
processed. It may also refer to population, employment, number of units, 
or miles traveled. Activity information is typically the value that is 
multiplied against an emission factor to generate an emissions estimate.
    Seasonal fuel heat content--The amount of thermal heat energy in a 
solid, liquid, or gaseous fuel used during the pollutant season. Fuel 
heat content is typically expressed in units of Btu/lb of fuel, Btu/gal 
of fuel, joules/kg of fuel, etc.
    Secondary control eff (%)--The emission reduction efficiency of a 
secondary control device. Control efficiency is usually expressed as a 
percentage or in tenths.
    SIC/NAICS--Standard Industrial Classification code. NAICS (North 
American Industry Classification System) codes will replace SIC codes. 
U.S. Department of Commerce's code for businesses by products or 
services.
    Site name--The name of the facility.
    Spring throughput (%)--Part of throughput or activity for the three 
spring months (March, April, May). See the definition of Fall 
Throughput.
    Stack diameter--A stack's inner physical diameter.
    Stack height--A stack's physical height above the surrounding 
terrain.
    Stack ID code--Unique code for the point where emissions from one or 
more processes release into the atmosphere.
    Start time (hour)--Start time (if available) that you used to 
calculate the emissions estimates.
    State FIPS Code--Federal Information Placement System (FIPS) is the 
system of unique numeric codes the government developed to identify 
States, counties and parishes for the entire United States, Puerto Rico, 
and Guam.
    Sulfur content--Sulfur content of a fuel, usually expressed as 
percent by weight.
    Summer throughput(%)--Part of throughput or activity for the three 
summer months (June, July, August). See the definition of Fall 
Throughput.
    Summer/winter work weekday emissions--Average day's emissions for a 
typical day. Ozone daily emissions = summer work weekday; CO and PM 
daily emissions = winter work weekday.
    Total capture/control efficiency--The emission reduction efficiency 
of a primary control device, which shows the amount controls or material 
changes reduce a particular pollutant from a process' emissions. Control 
efficiency is usually expressed as a percentage or in tenths.
    Type A source--Large point sources with actual annual emissions 
greater than or equal to any of the emission thresholds listed in Table 
1 for Type A sources.
    Type B source--Point sources with actual annual emissions during any 
year of the three year cycle greater than or equal to any of the 
emission thresholds listed in Table 1 for Type B sources. Type B sources 
include all Type A sources.
    VMT by Roadway Class--Vehicle miles traveled (VMT) expresses vehicle 
activity and is used with emission factors. The emission factors are 
usually expressed in terms of grams per mile of travel. Because VMT 
doesn't correlate directly to emissions that occur while the vehicle 
isn't moving, these nonmoving emissions are incorporated into the 
emission factors in EPA's MOBILE Model.
    VOC--Volatile Organic Compounds. The EPA's regulatory definition of 
VOC is in 40 CFR 51.100.

[[Page 138]]

    Winter throughput (%)--Part of throughput or activity for the three 
winter months (December, January, February, all from the same year, 
e.g., Winter 2000 = January 2000 + February, 2000 + December 2000). See 
the definition of Fall Throughput.
    Wk/yr in operation--Weeks per year that the emitting process 
operates.
    Work Weekday--Any day of the week except Saturday or Sunday.
    X stack coordinate (latitude)--An object's north-south geographical 
coordinate. Y stack coordinate (longitude)--An object's east-west 
geographical coordinate.

Subparts B--E [Reserved]



                   Subpart F--Procedural Requirements

    Authority: 42 U.S.C. 7401, 7411, 7412, 7413, 7414, 7470-7479, 7501-
7508, 7601, and 7602.



Sec. 51.100  Definitions.

    As used in this part, all terms not defined herein will have the 
meaning given them in the Act:
    (a) Act means the Clean Air Act (42 U.S.C. 7401 et seq., as amended 
by Pub. L. 91-604, 84 Stat. 1676 Pub. L. 95-95, 91 Stat., 685 and Pub. 
L. 95-190, 91 Stat., 1399.)
    (b) Administrator means the Administrator of the Environmental 
Protection Agency (EPA) or an authorized representative.
    (c) Primary standard means a national primary ambient air quality 
standard promulgated pursuant to section 109 of the Act.
    (d) Secondary standard means a national secondary ambient air 
quality standard promulgated pursuant to section 109 of the Act.
    (e) National standard means either a primary or secondary standard.
    (f) Owner or operator means any person who owns, leases, operates, 
controls, or supervises a facility, building, structure, or installation 
which directly or indirectly result or may result in emissions of any 
air pollutant for which a national standard is in effect.
    (g) Local agency means any local government agency other than the 
State agency, which is charged with responsibility for carrying out a 
portion of the plan.
    (h) Regional Office means one of the ten (10) EPA Regional Offices.
    (i) State agency means the air pollution control agency primarily 
responsible for development and implementation of a plan under the Act.
    (j) Plan means an implementation plan approved or promulgated under 
section 110 of 172 of the Act.
    (k) Point source means the following:
    (1) For particulate matter, sulfur oxides, carbon monoxide, volatile 
organic compounds (VOC) and nitrogen dioxide--
    (i) Any stationary source the actual emissions of which are in 
excess of 90.7 metric tons (100 tons) per year of the pollutant in a 
region containing an area whose 1980 urban place population, as defined 
by the U.S. Bureau of the Census, was equal to or greater than 1 
million.
    (ii) Any stationary source the actual emissions of which are in 
excess of 22.7 metric tons (25 tons) per year of the pollutant in a 
region containing an area whose 1980 urban place population, as defined 
by the U.S. Bureau of the Census, was less than 1 million; or
    (2) For lead or lead compounds measured as elemental lead, any 
stationary source that actually emits a total of 4.5 metric tons (5 
tons) per year or more.
    (l) Area source means any small residential, governmental, 
institutional, commercial, or industrial fuel combustion operations; 
onsite solid waste disposal facility; motor vehicles, aircraft vessels, 
or other transportation facilities or other miscellaneous sources 
identified through inventory techniques similar to those described in 
the ``AEROS Manual series, Vol. II AEROS User's Manual,'' EPA-450/2-76-
029 December 1976.
    (m) Region means an area designated as an air quality control region 
(AQCR) under section 107(c) of the Act.
    (n) Control strategy means a combination of measures designated to 
achieve the aggregate reduction of emissions necessary for attainment 
and maintenance of national standards including, but not limited to, 
measures such as:
    (1) Emission limitations.

[[Page 139]]

    (2) Federal or State emission charges or taxes or other economic 
incentives or disincentives.
    (3) Closing or relocation of residential, commercial, or industrial 
facilities.
    (4) Changes in schedules or methods of operation of commercial or 
industrial facilities or transportation systems, including, but not 
limited to, short-term changes made in accordance with standby plans.
    (5) Periodic inspection and testing of motor vehicle emission 
control systems, at such time as the Administrator determines that such 
programs are feasible and practicable.
    (6) Emission control measures applicable to in-use motor vehicles, 
including, but not limited to, measures such as mandatory maintenance, 
installation of emission control devices, and conversion to gaseous 
fuels.
    (7) Any transportation control measure including those 
transportation measures listed in section 108(f) of the Clean Air Act as 
amended.
    (8) Any variation of, or alternative to any measure delineated 
herein.
    (9) Control or prohibition of a fuel or fuel additive used in motor 
vehicles, if such control or prohibition is necessary to achieve a 
national primary or secondary air quality standard and is approved by 
the Administrator under section 211(c)(4)(C) of the Act.
    (o) Reasonably available control technology (RACT) means devices, 
systems, process modifications, or other apparatus or techniques that 
are reasonably available taking into account:
    (1) The necessity of imposing such controls in order to attain and 
maintain a national ambient air quality standard;
    (2) The social, environmental, and economic impact of such controls; 
and
    (3) Alternative means of providing for attainment and maintenance of 
such standard. (This provision defines RACT for the purposes of 
Sec. 51.341(b) only.)
    (p) Compliance schedule means the date or dates by which a source or 
category of sources is required to comply with specific emission 
limitations contained in an implementation plan and with any increments 
of progress toward such compliance.
    (q) Increments of progress means steps toward compliance which will 
be taken by a specific source, including:
    (1) Date of submittal of the source's final control plan to the 
appropriate air pollution control agency;
    (2) Date by which contracts for emission control systems or process 
modifications will be awarded; or date by which orders will be issued 
for the purchase of component parts to accomplish emission control or 
process modification;
    (3) Date of initiation of on-site construction or installation of 
emission control equipment or process change;
    (4) Date by which on-site construction or installation of emission 
control equipment or process modification is to be completed; and
    (5) Date by which final compliance is to be achieved.
    (r) Transportation control measure means any measure that is 
directed toward reducing emissions of air pollutants from transportation 
sources. Such measures include, but are not limited to, those listed in 
section 108(f) of the Clean Air Act.
    (s) Volatile organic compounds (VOC) means any compound of carbon, 
excluding carbon monoxide, carbon dioxide, carbonic acid, metallic 
carbides or carbonates, and ammonium carbonate, which participates in 
atmospheric photochemical reactions.
    (1) This includes any such organic compound other than the 
following, which have been determined to have negligible photochemical 
reactivity: methane; ethane; methylene chloride (dichloromethane); 
1,1,1-trichloroethane (methyl chloroform); 1,1,2-trichloro-1,2,2-
trifluoroethane (CFC-113); trichlorofluoromethane (CFC-11); 
dichlorodifluoromethane (CFC-12); chlorodifluoromethane (HCFC-22); 
trifluoromethane (HFC-23); 1,2-dichloro 1,1,2,2-tetrafluoroethane (CFC-
114); chloropentafluoroethane (CFC-115); 1,1,1-trifluoro 2,2-
dichloroethane (HCFC-123); 1,1,1,2-tetrafluoroethane (HFC-134a); 1,1-
dichloro 1-fluoroethane (HCFC-141b); 1-chloro 1,1-difluoroethane (HCFC-
142b); 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124); pentafluoroethane 
(HFC-125); 1,1,2,2-tetrafluoroethane (HFC-134); 1,1,1-trifluoroethane 
(HFC-143a); 1,1-

[[Page 140]]

difluoroethane (HFC-152a); parachlorobenzotrifluoride (PCBTF); cyclic, 
branched, or linear completely methylated siloxanes; acetone; 
perchloroethylene (tetrachloroethylene); 3,3-dichloro-1,1,1,2,2-
pentafluoropropane (HCFC-225ca); 1,3-dichloro-1,1,2,2,3-
pentafluoropropane (HCFC-225cb); 1,1,1,2,3,4,4,5,5,5-decafluoropentane 
(HFC 43-10mee); difluoromethane (HFC-32); ethylfluoride (HFC-161); 
1,1,1,3,3,3-hexafluoropropane (HFC-236fa); 1,1,2,2,3-pentafluoropropane 
(HFC-245ca); 1,1,2,3,3-pentafluoropropane (HFC-245ea); 1,1,1,2,3-
pentafluoropropane (HFC-245eb); 1,1,1,3,3-pentafluoropropane (HFC-
245fa); 1,1,1,2,3,3-hexafluoropropane (HFC-236ea); 1,1,1,3,3-
pentafluorobutane (HFC-365mfc); chlorofluoromethane (HCFC-31); 1 chloro-
1-fluoroethane (HCFC-151a); 1,2-dichloro-1,1,2-trifluoroethane (HCFC-
123a); 1,1,1,2,2,3,3,4,4-nonafluoro-4-methoxy-butane 
(C4F9OCH3); 2-(difluoromethoxymethyl)-
1,1,1,2,3,3,3-heptafluoropropane 
((CF3)2CFCF2OCH3); 1-ethoxy-
1,1,2,2,3,3,4,4,4-nonafluorobutane 
(C4F9OC2H5); 2-
(ethoxydifluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane 
((CF3)2CFCF2OC2H5)
; methyl acetate and perfluorocarbon compounds which fall into these 
classes:
    (i) Cyclic, branched, or linear, completely fluorinated alkanes;
    (ii) Cyclic, branched, or linear, completely fluorinated ethers with 
no unsaturations;
    (iii) Cyclic, branched, or linear, completely fluorinated tertiary 
amines with no unsaturations; and
    (iv) Sulfur containing perfluorocarbons with no unsaturations and 
with sulfur bonds only to carbon and fluorine.
    (2) For purposes of determining compliance with emissions limits, 
VOC will be measured by the test methods in the approved State 
implementation plan (SIP) or 40 CFR part 60, appendix A, as applicable. 
Where such a method also measures compounds with negligible 
photochemical reactivity, these negligibility-reactive compounds may be 
excluded as VOC if the amount of such compounds is accurately 
quantified, and such exclusion is approved by the enforcement authority.
    (3) As a precondition to excluding these compounds as VOC or at any 
time thereafter, the enforcement authority may require an owner or 
operator to provide monitoring or testing methods and results 
demonstrating, to the satisfaction of the enforcement authority, the 
amount of negligibly-reactive compounds in the source's emissions.
    (4) For purposes of Federal enforcement for a specific source, the 
EPA shall use the test methods specified in the applicable EPA-approved 
SIP, in a permit issued pursuant to a program approved or promulgated 
under title V of the Act, or under 40 CFR part 51, subpart I or appendix 
S, or under 40 CFR parts 52 or 60. The EPA shall not be bound by any 
State determination as to appropriate methods for testing or monitoring 
negligibly-reactive compounds if such determination is not reflected in 
any of the above provisions.
    (t)-(w) [Reserved]
    (x) Time period means any period of time designated by hour, month, 
season, calendar year, averaging time, or other suitable 
characteristics, for which ambient air quality is estimated.
    (y) Variance means the temporary deferral of a final compliance date 
for an individual source subject to an approved regulation, or a 
temporary change to an approved regulation as it applies to an 
individual source.
    (z) Emission limitation and emission standard mean a requirement 
established by a State, local government, or the Administrator which 
limits the quantity, rate, or concentration of emissions of air 
pollutants on a continuous basis, including any requirements which limit 
the level of opacity, prescribe equipment, set fuel specifications, or 
prescribe operation or maintenance procedures for a source to assure 
continuous emission reduction.
    (aa) Capacity factor means the ratio of the average load on a 
machine or equipment for the period of time considered to the capacity 
rating of the machine or equipment.
    (bb) Excess emissions means emissions of an air pollutant in excess 
of an emission standard.

[[Page 141]]

    (cc) Nitric acid plant means any facility producing nitric acid 30 
to 70 percent in strength by either the pressure or atmospheric pressure 
process.
    (dd) Sulfuric acid plant means any facility producing sulfuric acid 
by the contact process by burning elemental sulfur, alkylation acid, 
hydrogen sulfide, or acid sludge, but does not include facilities where 
conversion to sulfuric acid is utilized primarily as a means of 
preventing emissions to the atmosphere of sulfur dioxide or other sulfur 
compounds.
    (ee) Fossil fuel-fired steam generator means a furnance or bioler 
used in the process of burning fossil fuel for the primary purpose of 
producing steam by heat transfer.
    (ff) Stack means any point in a source designed to emit solids, 
liquids, or gases into the air, including a pipe or duct but not 
including flares.
    (gg) A stack in existence means that the owner or operator had (1) 
begun, or caused to begin, a continuous program of physical on-site 
construction of the stack or (2) entered into binding agreements or 
contractual obligations, which could not be cancelled or modified 
without substantial loss to the owner or operator, to undertake a 
program of construction of the stack to be completed within a reasonable 
time.
    (hh)(1) Dispersion technique means any technique which attempts to 
affect the concentration of a pollutant in the ambient air by:
    (i) Using that portion of a stack which exceeds good engineering 
practice stack height:
    (ii) Varying the rate of emission of a pollutant according to 
atmospheric conditions or ambient concentrations of that pollutant; or
    (iii) Increasing final exhaust gas plume rise by manipulating source 
process parameters, exhaust gas parameters, stack parameters, or 
combining exhaust gases from several existing stacks into one stack; or 
other selective handling of exhaust gas streams so as to increase the 
exhaust gas plume rise.
    (2) The preceding sentence does not include:
    (i) The reheating of a gas stream, following use of a pollution 
control system, for the purpose of returning the gas to the temperature 
at which it was originally discharged from the facility generating the 
gas stream;
    (ii) The merging of exhaust gas streams where:
    (A) The source owner or operator demonstrates that the facility was 
originally designed and constructed with such merged gas streams;
    (B) After July 8, 1985 such merging is part of a change in operation 
at the facility that includes the installation of pollution controls and 
is accompanied by a net reduction in the allowable emissions of a 
pollutant. This exclusion from the definition of dispersion techniques 
shall apply only to the emission limitation for the pollutant affected 
by such change in operation; or
    (C) Before July 8, 1985, such merging was part of a change in 
operation at the facility that included the installation of emissions 
control equipment or was carried out for sound economic or engineering 
reasons. Where there was an increase in the emission limitation or, in 
the event that no emission limitation was in existence prior to the 
merging, an increase in the quantity of pollutants actually emitted 
prior to the merging, the reviewing agency shall presume that merging 
was significantly motivated by an intent to gain emissions credit for 
greater dispersion. Absent a demonstration by the source owner or 
operator that merging was not significantly motivated by such intent, 
the reviewing agency shall deny credit for the effects of such merging 
in calculating the allowable emissions for the source;
    (iii) Smoke management in agricultural or silvicultural prescribed 
burning programs;
    (iv) Episodic restrictions on residential woodburning and open 
burning; or
    (v) Techniques under Sec. 51.100(hh)(1)(iii) which increase final 
exhaust gas plume rise where the resulting allowable emissions of sulfur 
dioxide from the facility do not exceed 5,000 tons per year.
    (ii) Good engineering practice (GEP) stack height means the greater 
of:
    (1) 65 meters, measured from the ground-level elevation at the base 
of the stack:
    (2)(i) For stacks in existence on January 12, 1979, and for which 
the owner

[[Page 142]]

or operator had obtained all applicable permits or approvals required 
under 40 CFR parts 51 and 52.

Hg = 2.5H,


provided the owner or operator produces evidence that this equation was 
actually relied on in establishing an emission limitation:
    (ii) For all other stacks,

Hg = H + 1.5L

where:

Hg = good engineering practice stack height, measured from 
the ground-level elevation at the base of the stack,
H = height of nearby structure(s) measured from the ground-level 
elevation at the base of the stack.
L = lesser dimension, height or projected width, of nearby structure(s)


provided that the EPA, State or local control agency may require the use 
of a field study or fluid model to verify GEP stack height for the 
source; or
    (3) The height demonstrated by a fluid model or a field study 
approved by the EPA State or local control agency, which ensures that 
the emissions from a stack do not result in excessive concentrations of 
any air pollutant as a result of atmospheric downwash, wakes, or eddy 
effects created by the source itself, nearby structures or nearby 
terrain features.
    (jj) Nearby as used in Sec. 51.100(ii) of this part is defined for a 
specific structure or terrain feature and
    (1) For purposes of applying the formulae provided in 
Sec. 51.100(ii)(2) means that distance up to five times the lesser of 
the height or the width dimension of a structure, but not greater than 
0.8 km (\1/2\ mile), and
    (2) For conducting demonstrations under Sec. 51.100(ii)(3) means not 
greater than 0.8 km (\1/2\ mile), except that the portion of a terrain 
feature may be considered to be nearby which falls within a distance of 
up to 10 times the maximum height (Ht) of the feature, not to 
exceed 2 miles if such feature achieves a height (Ht) 0.8 km 
from the stack that is at least 40 percent of the GEP stack height 
determined by the formulae provided in Sec. 51.100(ii)(2)(ii) of this 
part or 26 meters, whichever is greater, as measured from the ground-
level elevation at the base of the stack. The height of the structure or 
terrain feature is measured from the ground-level elevation at the base 
of the stack.
    (kk) Excessive concentration is defined for the purpose of 
determining good engineering practice stack height under 
Sec. 51.100(ii)(3) and means:
    (1) For sources seeking credit for stack height exceeding that 
established under Sec. 51.100(ii)(2) a maximum ground-level 
concentration due to emissions from a stack due in whole or part to 
downwash, wakes, and eddy effects produced by nearby structures or 
nearby terrain features which individually is at least 40 percent in 
excess of the maximum concentration experienced in the absence of such 
downwash, wakes, or eddy effects and which contributes to a total 
concentration due to emissions from all sources that is greater than an 
ambient air quality standard. For sources subject to the prevention of 
significant deterioration program (40 CFR 51.166 and 52.21), an 
excessive concentration alternatively means a maximum ground-level 
concentration due to emissions from a stack due in whole or part to 
downwash, wakes, or eddy effects produced by nearby structures or nearby 
terrain features which individually is at least 40 percent in excess of 
the maximum concentration experienced in the absence of such downwash, 
wakes, or eddy effects and greater than a prevention of significant 
deterioration increment. The allowable emission rate to be used in 
making demonstrations under this part shall be prescribed by the new 
source performance standard that is applicable to the source category 
unless the owner or operator demonstrates that this emission rate is 
infeasible. Where such demonstrations are approved by the authority 
administering the State implementation plan, an alternative emission 
rate shall be established in consultation with the source owner or 
operator.
    (2) For sources seeking credit after October 11, 1983, for increases 
in existing stack heights up to the heights established under 
Sec. 51.100(ii)(2), either (i) a maximum ground-level concentration due 
in whole or part to downwash, wakes or eddy effects as provided in

[[Page 143]]

paragraph (kk)(1) of this section, except that the emission rate 
specified by any applicable State implementation plan (or, in the 
absence of such a limit, the actual emission rate) shall be used, or 
(ii) the actual presence of a local nuisance caused by the existing 
stack, as determined by the authority administering the State 
implementation plan; and
    (3) For sources seeking credit after January 12, 1979 for a stack 
height determined under Sec. 51.100(ii)(2) where the authority 
administering the State implementation plan requires the use of a field 
study or fluid model to verify GEP stack height, for sources seeking 
stack height credit after November 9, 1984 based on the aerodynamic 
influence of cooling towers, and for sources seeking stack height credit 
after December 31, 1970 based on the aerodynamic influence of structures 
not adequately represented by the equations in Sec. 51.100(ii)(2), a 
maximum ground-level concentration due in whole or part to downwash, 
wakes or eddy effects that is at least 40 percent in excess of the 
maximum concentration experienced in the absence of such downwash, 
wakes, or eddy effects.
    (ll)-(mm) [Reserved]
    (nn) Intermittent control system (ICS) means a dispersion technique 
which varies the rate at which pollutants are emitted to the atmosphere 
according to meteorological conditions and/or ambient concentrations of 
the pollutant, in order to prevent ground-level concentrations in excess 
of applicable ambient air quality standards. Such a dispersion technique 
is an ICS whether used alone, used with other dispersion techniques, or 
used as a supplement to continuous emission controls (i.e., used as a 
supplemental control system).
    (oo) Particulate matter means any airborne finely divided solid or 
liquid material with an aerodynamic diameter smaller than 100 
micrometers.
    (pp) Particulate matter emissions means all finely divided solid or 
liquid material, other than uncombined water, emitted to the ambient air 
as measured by applicable reference methods, or an equivalent or 
alternative method, specified in this chapter, or by a test method 
specified in an approved State implementation plan.
    (qq) PM10 means particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers as measured by a 
reference method based on appendix J of part 50 of this chapter and 
designated in accordance with part 53 of this chapter or by an 
equivalent method designated in accordance with part 53 of this chapter.
    (rr) PM10 emissions means finely divided solid or liquid 
material, with an aerodynamic diameter less than or equal to a nominal 
10 micrometers emitted to the ambient air as measured by an applicable 
reference method, or an equivalent or alternative method, specified in 
this chapter or by a test method specified in an approved State 
implementation plan.
    (ss) Total suspended particulate means particulate matter as 
measured by the method described in appendix B of part 50 of this 
chapter.

[51 FR 40661, Nov. 7, 1986, as amended at 52 FR 24712, July 1, 1987; 57 
FR 3945, Feb. 3, 1992; 61 FR 4590, Feb. 7, 1996; 61 FR 16060, Apr. 11, 
1996; 61 FR 30162, June 14, 1996; 61 FR 52850, Oct. 8, 1996; 62 FR 
44903, Aug. 25, 1997; 63 FR 9151, Feb. 24, 1998; 63 FR 17333, Apr. 9, 
1998]



Sec. 51.101  Stipulations.

    Nothing in this part will be construed in any manner:
    (a) To encourage a State to prepare, adopt, or submit a plan which 
does not provide for the protection and enhancement of air quality so as 
to promote the public health and welfare and productive capacity.
    (b) To encourage a State to adopt any particular control strategy 
without taking into consideration the cost-effectiveness of such control 
strategy in relation to that of alternative control strategies.
    (c) To preclude a State from employing techniques other than those 
specified in this part for purposes of estimating air quality or 
demonstrating the adequacy of a control strategy, provided that such 
other techniques are shown to be adequate and appropriate for such 
purposes.
    (d) To encourage a State to prepare, adopt, or submit a plan without 
taking into consideration the social and economic impact of the control 
strategy

[[Page 144]]

set forth in such plan, including, but not limited to, impact on 
availability of fuels, energy, transportation, and employment.
    (e) To preclude a State from preparing, adopting, or submitting a 
plan which provides for attainment and maintenance of a national 
standard through the application of a control strategy not specifically 
identified or described in this part.
    (f) To preclude a State or political subdivision thereof from 
adopting or enforcing any emission limitations or other measures or 
combinations thereof to attain and maintain air quality better than that 
required by a national standard.
    (g) To encourage a State to adopt a control strategy uniformly 
applicable throughout a region unless there is no satisfactory 
alternative way of providing for attainment and maintenance of a 
national standard throughout such region.

[61 FR 30163, June 14, 1996]



Sec. 51.102  Public hearings.

    (a) Except as otherwise provided in paragraph (c) of this section, 
States must conduct one or more public hearings on the following prior 
to adoption and submission to EPA of:
    (1) Any plan or revision of it required by Sec. 51.104(a).
    (2) Any individual compliance schedule under (Sec. 51.260).
    (3) Any revision under Sec. 51.104(d).
    (b) Separate hearings may be held for plans to implement primary and 
secondary standards.
    (c) No hearing will be required for any change to an increment of 
progress in an approved individual compliance schedule unless such 
change is likely to cause the source to be unable to comply with the 
final compliance date in the schedule. The requirements of Secs. 51.104 
and 51.105 will be applicable to such schedules, however.
    (d) Any hearing required by paragraph (a) of this section will be 
held only after reasonable notice, which will be considered to include, 
at least 30 days prior to the date of such hearing(s):
    (1) Notice given to the public by prominent advertisement in the 
area affected announcing the date(s), time(s), and place(s) of such 
hearing(s);
    (2) Availability of each proposed plan or revision for public 
inspection in at least one location in each region to which it will 
apply, and the availability of each compliance schedule for public 
inspection in at least one location in the region in which the affected 
source is located;
    (3) Notification to the Administrator (through the appropriate 
Regional Office);
    (4) Notification to each local air pollution control agency which 
will be significantly impacted by such plan, schedule or revision;
    (5) In the case of an interstate region, notification to any other 
States included, in whole or in part, in the regions which are 
significantly impacted by such plan or schedule or revision.
    (e) The State must prepare and retain, for inspection by the 
Administrator upon request, a record of each hearing. The record must 
contain, as a minimum, a list of witnesses together with the text of 
each presentation.
    (f) The State must submit with the plan, revision, or schedule a 
certification that the hearing required by paragraph (a) of this section 
was held in accordance with the notice required by paragraph (d) of this 
section.
    (g) Upon written application by a State agency (through the 
appropriate Regional Office), the Administrator may approve State 
procedures for public hearings. The following criteria apply:
    (1) Procedures approved under this section shall be deemed to 
satisfy the requirement of this part regarding public hearings.
    (2) Procedures different from this part may be approved if they--
    (i) Ensure public participation in matters for which hearings are 
required; and
    (ii) Provide adequate public notification of the opportunity to 
participate.
    (3) The Administrator may impose any conditions on approval he or 
she deems necessary.

[36 FR 22938, Nov. 25, 1971, as amended at 65 FR 8657, Feb. 22, 2000]

[[Page 145]]



Sec. 51.103  Submission of plans, preliminary review of plans.

    (a) The State makes an official plan submission to EPA only when the 
submission conforms to the requirements of appendix V to this part, and 
the State delivers five copies of the plan to the appropriate Regional 
Office, with a letter giving notice of such action.
    (b) Upon request of a State, the Administrator will provide 
preliminary review of a plan or portion thereof submitted in advance of 
the date such plan is due. Such requests must be made in writing to the 
appropriate Regional Office and must be accompanied by five copies of 
the materials to be reviewed. Requests for preliminary review do not 
relieve a State of the responsibility of adopting and submitting plans 
in accordance with prescribed due dates.

[51 FR 40661, Nov. 7, 1986, as amended at 55 FR 5830, Feb. 16, 1990; 63 
FR 9151, Feb. 24, 1998]



Sec. 51.104  Revisions.

    (a) States may revise the plan from time to time consistent with the 
requirements applicable to implementation plans under this part.
    (b) The States must submit any revision of any regulation or any 
compliance schedule under paragraph (c) of this section to the 
Administrator no later than 60 days after its adoption.
    (c) EPA will approve revisions only after applicable hearing 
requirements of Sec. 51.102 have been satisfied.
    (d) In order for a variance to be considered for approval as a 
revision to the State implementation plan, the State must submit it in 
accordance with the requirements of this section.

[51 FR 40661, Nov. 7, 1986, as amended at 61 FR 16060, Apr. 11, 1996]



Sec. 51.105  Approval of plans.

    Revisions of a plan, or any portion thereof, will not be considered 
part of an applicable plan until such revisions have been approved by 
the Administrator in accordance with this part.

[51 FR 40661, Nov. 7, 1986, as amended at 60 FR 33922, June 29, 1995]



                       Subpart G--Control Strategy

    Source: 51 FR 40665, Nov. 7, 1986, unless otherwise noted.



Sec. 51.110  Attainment and maintenance of national standards.

    (a) Each plan providing for the attainment of a primary or secondary 
standard must specify the projected attainment date.
    (b)-(f) [Reserved]
    (g) During developing of the plan, EPA encourages States to identify 
alternative control strategies, as well as the costs and benefits of 
each such alternative for attainment or maintenance of the national 
standard.

[51 FR 40661 Nov. 7, 1986 as amended at 61 FR 16060, Apr. 11, 1996; 61 
FR 30163, June 14, 1996]



Sec. 51.111  Description of control measures.

    Each plan must set forth a control strategy which includes the 
following:
    (a) A description of enforcement methods including, but not limited 
to:
    (1) Procedures for monitoring compliance with each of the selected 
control measures,
    (2) Procedures for handling violations, and
    (3) A designation of agency responsibility for enforcement of 
implementation.
    (b) [Reserved]

[51 FR 40665, Nov. 7, 1986, as amended at 60 FR 33922, June 29, 1995]



Sec. 51.112  Demonstration of adequacy.

    (a) Each plan must demonstrate that the measures, rules, and 
regulations contained in it are adequate to provide for the timely 
attainment and maintenance of the national standard that it implements.
    (1) The adequacy of a control strategy shall be demonstrated by 
means of applicable air quality models, data bases, and other 
requirements specified in appendix W of this part (Guideline on Air 
Quality Models).
    (2) Where an air quality model specified in appendix W of this part 
(Guideline on Air Quality Models) is inappropriate, the model may be 
modified or another model substituted. Such a modification or 
substitution of a model

[[Page 146]]

may be made on a case-by-case basis or, where appropriate, on a generic 
basis for a specific State program. Written approval of the 
Administrator must be obtained for any modification or substitution. In 
addition, use of a modified or substituted model must be subject to 
notice and opportunity for public comment under procedures set forth in 
Sec. 51.102.
    (b) The demonstration must include the following:
    (1) A summary of the computations, assumptions, and judgments used 
to determine the degree of reduction of emissions (or reductions in the 
growth of emissions) that will result from the implementation of the 
control strategy.
    (2) A presentation of emission levels expected to result from 
implementation of each measure of the control strategy.
    (3) A presentation of the air quality levels expected to result from 
implementation of the overall control strategy presented either in 
tabular form or as an isopleth map showing expected maximum pollutant 
concentrations.
    (4) A description of the dispersion models used to project air 
quality and to evaluate control strategies.
    (5) For interstate regions, the analysis from each constituent State 
must, where practicable, be based upon the same regional emission 
inventory and air quality baseline.

[51 FR 40665, Nov. 7, 1986, as amended at 58 FR 38821, July 20, 1993; 60 
FR 40468, Aug. 9, 1995; 61 FR 41840, Aug. 12, 1996]



Sec. 51.113  [Reserved]



Sec. 51.114  Emissions data and projections.

    (a) Except for lead, each plan must contain a detailed inventory of 
emissions from point and area sources. Lead requirements are specified 
in Sec. 51.117. The inventory must be based upon measured emissions or, 
where measured emissions are not available, documented emission factors.
    (b) Each plan must contain a summary of emission levels projected to 
result from application of the new control strategy.
    (c) Each plan must identify the sources of the data used in the 
projection of emissions.



Sec. 51.115  Air quality data and projections.

    (a) Each plan must contain a summary of data showing existing air 
quality.
    (b) Each plan must:
    (1) Contain a summary of air quality concentrations expected to 
result from application of the control strategy, and
    (2) Identify and describe the dispersion model, other air quality 
model, or receptor model used.
    (c) Actual measurements of air quality must be used where available 
if made by methods specified in appendix C to part 58 of this chapter. 
Estimated air quality using appropriate modeling techniques may be used 
to supplement measurements.
    (d) For purposes of developing a control strategy, background 
concentration shall be taken into consideration with respect to 
particulate matter. As used in this subpart, background concentration is 
that portion of the measured ambient levels that cannot be reduced by 
controlling emissions from man-made sources.
    (e) In developing an ozone control strategy for a particular area, 
background ozone concentrations and ozone transported into an area must 
be considered. States may assume that the ozone standard will be 
attained in upwind areas.



Sec. 51.116  Data availability.

    (a) The State must retain all detailed data and calculations used in 
the preparation of each plan or each plan revision, and make them 
available for public inspection and submit them to the Administrator at 
his request.
    (b) The detailed data and calculations used in the preparation of 
plan revisions are not considered a part of the plan.
    (c) Each plan must provide for public availability of emission data 
reported by source owners or operators or otherwise obtained by a State 
or local agency. Such emission data must be correlated with applicable 
emission limitations or other measures. As used in

[[Page 147]]

this paragraph, correlated means presented in such a manner as to show 
the relationship between measured or estimated amounts of emissions and 
the amounts of such emissions allowable under the applicable emission 
limitations or other measures.



Sec. 51.117  Additional provisions for lead.

    In addition to other requirements in Secs. 51.100 through 51.116 the 
following requirements apply to lead. To the extent they conflict, there 
requirements are controlling over those of the proceeding sections.
    (a) Control strategy demonstration. Each plan must contain a 
demonstration showing that the plan will attain and maintain the 
standard in the following areas:
    (1) Areas in the vicinity of the following point sources of lead: 
Primary lead smelters, Secondary lead smelters, Primary copper smelters, 
Lead gasoline additive plants, Lead-acid storage battery manufacturing 
plants that produce 2,000 or more batteries per day. Any other 
stationary source that actually emits 25 or more tons per year of lead 
or lead compounds measured as elemental lead.
    (2) Any other area that has lead air concentrations in excess of the 
national ambient air quality standard concentration for lead, measured 
since January 1, 1974.
    (b) Time period for demonstration of adequacy. The demonstration of 
adequacy of the control strategy required under Sec. 51.112 may cover a 
longer period if allowed by the appropriate EPA Regional Administrator.
    (c) Special modeling provisions. (1) For urbanized areas with 
measured lead concentrations in excess of 4.0 [mu]g/m\3\, quarterly mean 
measured since January 1, 1974, the plan must employ the modified 
rollback model for the demonstration of attainment as a minimum, but may 
use an atmospheric dispersion model if desired, consistent with 
requirements contained in Sec. 51.112(a). If a proportional model is 
used, the air quality data should be the same year as the emissions 
inventory required under the paragraph e.
    (2) For each point source listed in Sec. 51.117(a), that plan must 
employ an atmospheric dispersion model for demonstration of attainment, 
consistent with requirements contained in Sec. 51.112(a).
    (3) For each area in the vicinity of an air quality monitor that has 
recorded lead concentrations in excess of the lead national standard 
concentration, the plan must employ the modified rollback model as a 
minimum, but may use an atmospheric dispersion model if desired for the 
demonstration of attainment, consistent with requirements contained in 
Sec. 51.112(a).
    (d) Air quality data and projections. (1) Each State must submit to 
the appropriate EPA Regional Office with the plan, but not part of the 
plan, all lead air quality data measured since January 1, 1974. This 
requirement does not apply if the data has already been submitted.
    (2) The data must be submitted in accordance with the procedures and 
data forms specified in Chapter 3.4.0 of the ``AEROS User's Manual'' 
concerning storage and retrieval of aerometric data (SAROAD) except 
where the Regional Administrator waives this requirement.
    (3) If additional lead air quality data are desired to determine 
lead air concentrations in areas suspected of exceeding the lead 
national ambient air quality standard, the plan may include data from 
any previously collected filters from particulate matter high volume 
samplers. In determining the lead content of the filters for control 
strategy demonstration purposes, a State may use, in addition to the 
reference method, X-ray fluorescence or any other method approved by the 
Regional Administrator.
    (e) Emissions data. (1) The point source inventory on which the 
summary of the baseline lead emissions inventory is based must contain 
all sources that emit five or more tons of lead per year.
    (2) Each State must submit lead emissions data to the appropriate 
EPA Regional Office with the original plan. The submission must be made 
with the plan, but not as part of the plan, and must include emissions 
data and information related to point and area source emissions. The 
emission data and information should include the

[[Page 148]]

information identified in the Hazardous and Trace Emissions System 
(HATREMS) point source coding forms for all point sources and the area 
source coding forms for all sources that are not point sources, but need 
not necessarily be in the format of those forms.

[41 FR 18388, May 3, 1976, as amended at 58 FR 38822, July 20, 1993]



Sec. 51.118  Stack height provisions.

    (a) The plan must provide that the degree of emission limitation 
required of any source for control of any air pollutant must not be 
affected by so much of any source's stack height that exceeds good 
engineering practice or by any other dispersion technique, except as 
provided in Sec. 51.118(b). The plan must provide that before a State 
submits to EPA a new or revised emission limitation that is based on a 
good engineering practice stack height that exceeds the height allowed 
by Sec. 51.100(ii) (1) or (2), the State must notify the public of the 
availabilty of the demonstration study and must provide opportunity for 
a public hearing on it. This section does not require the plan to 
restrict, in any manner, the actual stack height of any source.
    (b) The provisions of Sec. 51.118(a) shall not apply to (1) stack 
heights in existence, or dispersion techniques implemented on or before 
December 31, 1970, except where pollutants are being emitted from such 
stacks or using such dispersion techniques by sources, as defined in 
section 111(a)(3) of the Clean Air Act, which were constructed, or 
reconstructed, or for which major modifications, as defined in 
Secs. 51.165(a)(1)(v)(A), 51.166(b)(2)(i) and 52.21(b)(2)(i), were 
carried out after December 31, 1970; or (2) coal-fired steam electric 
generating units subject to the provisions of section 118 of the Clean 
Air Act, which commenced operation before July 1, 1957, and whose stacks 
were construced under a construction contract awarded before February 8, 
1974.



Sec. 51.119  Intermittent control systems.

    (a) The use of an intermittent control system (ICS) may be taken 
into account in establishing an emission limitation for a pollutant 
under a State implementation plan, provided:
    (1) The ICS was implemented before December 31, 1970, according to 
the criteria specified in Sec. 51.119(b).
    (2) The extent to which the ICS is taken into account is limited to 
reflect emission levels and associated ambient pollutant concentrations 
that would result if the ICS was the same as it was before December 31, 
1970, and was operated as specified by the operating system of the ICS 
before December 31, 1970.
    (3) The plan allows the ICS to compensate only for emissions from a 
source for which the ICS was implemented before December 31, 1970, and, 
in the event the source has been modified, only to the extent the 
emissions correspond to the maximum capacity of the source before 
December 31, 1970. For purposes of this paragraph, a source for which 
the ICS was implemented is any particular structure or equipment the 
emissions from which were subject to the ICS operating procedures.
    (4) The plan requires the continued operation of any constant 
pollution control system which was in use before December 31, 1970, or 
the equivalent of that system.
    (5) The plan clearly defines the emission limits affected by the ICS 
and the manner in which the ICS is taken into account in establishing 
those limits.
    (6) The plan contains requirements for the operation and maintenance 
of the qualifying ICS which, together with the emission limitations and 
any other necessary requirements, will assure that the national ambient 
air quality standards and any applicable prevention of significant 
deterioration increments will be attained and maintained. These 
requirements shall include, but not necessarily be limited to, the 
following:
    (i) Requirements that a source owner or operator continuously 
operate and maintain the components of the ICS specified at 
Sec. 51.119(b)(3) (ii)-(iv) in a manner which assures that the ICS is

[[Page 149]]

at least as effective as it was before December 31, 1970. The air 
quality monitors and meteorological instrumentation specified at 
Sec. 51.119(b) may be operated by a local authority or other entity 
provided the source has ready access to the data from the monitors and 
instrumentation.
    (ii) Requirements which specify the circumstances under which, the 
extent to which, and the procedures through which, emissions shall be 
curtailed through the activation of ICS.
    (iii) Requirements for recordkeeping which require the owner or 
operator of the source to keep, for periods of at least 3 years, records 
of measured ambient air quality data, meteorological information 
acquired, and production data relating to those processes affected by 
the ICS.
    (iv) Requirements for reporting which require the owner or operator 
of the source to notify the State and EPA within 30 days of a NAAQS 
violation pertaining to the pollutant affected by the ICS.
    (7) Nothing in this paragraph affects the applicability of any new 
source review requirements or new source performance standards contained 
in the Clean Air Act or 40 CFR subchapter C. Nothing in this paragraph 
precludes a State from taking an ICS into account in establishing 
emission limitations to any extent less than permitted by this 
paragraph.
    (b) An intermittent control system (ICS) may be considered 
implemented for a pollutant before December 31, 1970, if the following 
criteria are met:
    (1) The ICS must have been established and operational with respect 
to that pollutant prior to December 31, 1970, and reductions in 
emissions of that pollutant must have occurred when warranted by 
meteorological and ambient monitoring data.
    (2) The ICS must have been designed and operated to meet an air 
quality objective for that pollutant such as an air quality level or 
standard.
    (3) The ICS must, at a minimum, have included the following 
components prior to December 31, 1970:
    (i) Air quality monitors. An array of sampling stations whose 
location and type were consistent with the air quality objective and 
operation of the system.
    (ii) Meteorological instrumentation. A meteorological data 
acquisition network (may be limited to a single station) which provided 
meteorological prediction capabilities sufficient to determine the need 
for, and degree of, emission curtailments necessary to achieve the air 
quality design objective.
    (iii) Operating system. A system of established procedures for 
determining the need for curtailments and for accomplishing such 
curtailments. Documentation of this system, as required by paragraph 
(n)(4), may consist of a compendium of memoranda or comparable material 
which define the criteria and procedures for curtailments and which 
identify the type and number of personnel authorized to initiate 
curtailments.
    (iv) Meteorologist. A person, schooled in meteorology, capable of 
interpreting data obtained from the meteorological network and qualified 
to forecast meteorological incidents and their effect on ambient air 
quality. Sources may have obtained meteorological services through a 
consultant. Services of such a consultant could include sufficient 
training of source personnel for certain operational procedures, but not 
for design, of the ICS.
    (4) Documentation sufficient to support the claim that the ICS met 
the criteria listed in this paragraph must be provided. Such 
documentation may include affidavits or other documentation.



Sec. 51.120  Requirements for State Implementation Plan revisions relating 
to new motor vehicles.

    (a) The EPA Administrator finds that the State Implementation Plans 
(SIPs) for the States of Connecticut, Delaware, Maine, Maryland, 
Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode 
Island, and Vermont, the portion of Virginia included (as of November 
15, 1990) within the Consolidated Metropolitan Statistical Area that 
includes the District of Columbia, are substantially inadequate to 
comply with the requirements of section 110(a)(2)(D) of the Clean Air

[[Page 150]]

Act, 42 U.S.C. 7410(a)(2)(D), and to mitigate adequately the interstate 
pollutant transport described in section 184 of the Clean Air Act, 42 
U.S.C. 7511C, to the extent that they do not provide for emission 
reductions from new motor vehicles in the amount that would be achieved 
by the Ozone Transport Commission low emission vehicle (OTC LEV) program 
described in paragraph (c) of this section. This inadequacy will be 
deemed cured for each of the aforementioned States (including the 
District of Columbia) in the event that EPA determines through 
rulemaking that a national LEV-equivalent new motor vehicle emission 
control program is an acceptable alternative for OTC LEV and finds that 
such program is in effect. In the event no such finding is made, each of 
those States must adopt and submit to EPA by February 15, 1996 a SIP 
revision meeting the requirements of paragraph (b) of this section in 
order to cure the SIP inadequacy.
    (b) If a SIP revision is required under paragraph (a) of this 
section, it must contain the OTC LEV program described in paragraph (c) 
of this section unless the State adopts and submits to EPA, as a SIP 
revision, other emission-reduction measures sufficient to meet the 
requirements of paragraph (d) of this section. If a State adopts and 
submits to EPA, as a SIP revision, other emission-reduction measures 
pursuant to paragraph (d) of this section, then for purposes of 
determining whether such a SIP revision is complete within the meaning 
of section 110(k)(1) (and hence is eligible at least for consideration 
to be approved as satisfying paragraph (d) of this section), such a SIP 
revision must contain other adopted emission-reduction measures that, 
together with the identified potentially broadly practicable measures, 
achieve at least the minimum level of emission reductions that could 
potentially satisfy the requirements of paragraph (d) of this section. 
All such measures must be fully adopted and enforceable.
    (c) The OTC LEV program is a program adopted pursuant to section 177 
of the Clean Air Act.
    (1) The OTC LEV program shall contain the following elements:
    (i) It shall apply to all new 1999 and later model year passenger 
cars and light-duty trucks (0-5750 pounds loaded vehicle weight), as 
defined in Title 13, California Code of Regulations, section 1900(b)(11) 
and (b)(8), respectively, that are sold, imported, delivered, purchased, 
leased, rented, acquired, received, or registered in any area of the 
State that is in the Northeast Ozone Transport Region as of December 19, 
1994.
    (ii) All vehicles to which the OTC LEV program is applicable shall 
be required to have a certificate from the California Air Resources 
Board (CARB) affirming compliance with California standards.
    (iii) All vehicles to which this LEV program is applicable shall be 
required to meet the mass emission standards for Non-Methane Organic 
Gases (NMOG), Carbon Monoxide (CO), Oxides of Nitrogen (NOX), 
Formaldehyde (HCHO), and particulate matter (PM) as specified in Title 
13, California Code of Regulations, section 1960.1(f)(2) (and 
formaldehyde standards under section 1960.1(e)(2), as applicable) or as 
specified by California for certification as a TLEV (Transitional Low-
Emission Vehicle), LEV (Low-Emission Vehicle), ULEV (Ultra-Low-Emission 
Vehicle), or ZEV (Zero-Emission Vehicle) under section 1960.1(g)(1) (and 
section 1960.1(e)(3), for formaldehyde standards, as applicable).
    (iv) All manufacturers of vehicles subject to the OTC LEV program 
shall be required to meet the fleet average NMOG exhaust emission values 
for production and delivery for sale of their passenger cars, light-duty 
trucks 0-3750 pounds loaded vehicle weight, and light-duty trucks 3751-
5750 pounds loaded vehicle weight specified in Title 13, California Code 
of Regulations, section 1960.1(g)(2) for each model year beginning in 
1999. A State may determine not to implement the NMOG fleet average in 
the first model year of the program if the State begins implementation 
of the program late in a calendar year. However, all States must 
implement the NMOG fleet average in any full model years of the LEV 
program.
    (v) All manufacturers shall be allowed to average, bank and trade 
credits in the same manner as allowed

[[Page 151]]

under the program specified in Title 13, California Code of Regulations, 
section 1960.1(g)(2) footnote 7 for each model year beginning in 1999. 
States may account for credits banked by manufacturers in California or 
New York in years immediately preceding model year 1999, in a manner 
consistent with California banking and discounting procedures.
    (vi) The provisions for small volume manufacturers and intermediate 
volume manufacturers, as applied by Title 13, California Code of 
Regulations to California's LEV program, shall apply. Those 
manufacturers defined as small volume manufacturers and intermediate 
volume manufacturers in California under California's regulations shall 
be considered small volume manufacturers and intermediate volume 
manufacturers under this program.
    (vii) The provisions for hybrid electric vehicles (HEVs), as defined 
in Title 13 California Code of Regulations, section 1960.1, shall apply 
for purposes of calculating fleet average NMOG values.
    (viii) The provisions for fuel-flexible vehicles and dual-fuel 
vehicles specified in Title 13, California Code of Regulations, section 
1960.1(g)(1) footnote 4 shall apply.
    (ix) The provisions for reactivity adjustment factors, as defined by 
Title 13, California Code of Regulations, shall apply.
    (x) The aforementioned State OTC LEV standards shall be identical to 
the aforementioned California standards as such standards exist on 
December 19, 1994.
    (xi) All States' OTC LEV programs must contain any other provisions 
of California's LEV program specified in Title 13, California Code of 
Regulations necessary to comply with section 177 of the Clean Air Act.
    (2) States are not required to include the mandate for production of 
ZEVs specified in Title 13, California Code of Regulations, section 
1960.1(g)(2) footnote 9.
    (3) Except as specified elsewhere in this section, States may 
implement the OTC LEV program in any manner consistent with the Act that 
does not decrease the emissions reductions or jeopardize the 
effectiveness of the program.
    (d) The SIP revision that paragraph (b) of this section describes as 
an alternative to the OTC LEV program described in paragraph (c) of this 
section must contain a set of State-adopted measures that provides at 
least the following amount of emission reductions in time to bring 
serious ozone nonattainment areas into attainment by their 1999 
attainment date:
    (1) Reductions at least equal to the difference between:
    (i) The nitrogen oxides (NOX) emission reductions from 
the 1990 statewide emissions inventory achievable through implementation 
of all of the Clean Air Act-mandated and potentially broadly practicable 
control measures throughout all portions of the State that are within 
the Northeast Ozone Transport Region created under section 184(a) of the 
Clean Air Act as of December 19, 1994; and
    (ii) A reduction in NOX emissions from the 1990 statewide 
inventory in such portions of the State of 50% or whatever greater 
reduction is necessary to prevent significant contribution to 
nonattainment in, or interference with maintenance by, any downwind 
State.
    (2) Reductions at least equal to the difference between:
    (i) The VOC emission reductions from the 1990 statewide emissions 
inventory achievable through implementation of all of the Clean Air Act-
mandated and potentially broadly practicable control measures in all 
portions of the State in, or near and upwind of, any of the serious or 
severe ozone nonattainment areas lying in the series of such areas 
running northeast from the Washington, DC, ozone nonattainment area to 
and including the Portsmouth, New Hampshire ozone nonattainment area; 
and
    (ii) A reduction in VOC emissions from the 1990 emissions inventory 
in all such areas of 50% or whatever greater reduction is necessary to 
prevent significant contribution to nonattainment in, or interference 
with maintenance by, any downwind State.

[60 FR 4736, Jan. 24, 1995]

[[Page 152]]



Sec. 51.121  Findings and requirements for submission of State implementation 
plan revisions relating to emissions of oxides of nitrogen.

    (a)(1) The Administrator finds that the State implementation plan 
(SIP) for each jurisdiction listed in paragraph (c) of this section is 
substantially inadequate to comply with the requirements of section 
110(a)(2)(D)(i)(I) of the Clean Air Act (CAA), 42 U.S.C. 
7410(a)(2)(D)(i)(I), because the SIP does not include adequate 
provisions to prohibit sources and other activities from emitting 
nitrogen oxides (``NOX'') in amounts that will contribute 
significantly to nonattainment in one or more other States with respect 
to the 1-hour ozone national ambient air quality standards (NAAQS). Each 
of the jurisdictions listed in paragraph (c) of this section must submit 
to EPA a SIP revision that cures the inadequacy.
    (2) Under section 110(a)(1) of the CAA, 42 U.S.C. 7410(a)(1), the 
Administrator determines that each jurisdiction listed in paragraph (c) 
of this section must submit a SIP revision to comply with the 
requirements of section 110(a)(2)(D)(i)(I), 42 U.S.C. 
7410(a)(2)(D)(i)(I), through the adoption of adequate provisions 
prohibiting sources and other activities from emitting NOX in 
amounts that will contribute significantly to nonattainment in, or 
interfere with maintenance by, one or more other States with respect to 
the 8-hour ozone NAAQS.
    (b)(1) For each jurisdiction listed in paragraph (c) of this 
section, the SIP revision required under paragraph (a) of this section 
will contain adequate provisions, for purposes of complying with section 
110(a)(2)(D)(i)(I) of the CAA, 42 U.S.C. 7410(a)(2)(D)(i)(I), only if 
the SIP revision:
    (i) Contains control measures adequate to prohibit emissions of 
NOX that would otherwise be projected, in accordance with 
paragraph (g) of this section, to cause the jurisdiction's overall 
NOX emissions to be in excess of the budget for that 
jurisdiction described in paragraph (e) of this section (except as 
provided in paragraph (b)(2) of this section),
    (ii) Requires full implementation of all such control measures by no 
later than May 1, 2003, and
    (iii) Meets the other requirements of this section. The SIP 
revision's compliance with the requirement of paragraph (b)(1)(i) of 
this section shall be considered compliance with the jurisdiction's 
budget for purposes of this section.
    (2) The requirements of paragraph (b)(1)(i) of this section shall be 
deemed satisfied, for the portion of the budget covered by an interstate 
trading program, if the SIP revision:
    (i) Contains provisions for an interstate trading program that EPA 
determines will, in conjunction with interstate trading programs for one 
or more other jurisdictions, prohibit NOX emissions in excess 
of the sum of the portion of the budgets covered by the trading programs 
for those jurisdictions; and
    (ii) Conforms to the following criteria:
    (A) Emissions reductions used to demonstrate compliance with the 
revision must occur during the ozone season.
    (B) Emissions reductions occurring prior to the year 2003 may be 
used by a source to demonstrate compliance with the SIP revision for the 
2003 and 2004 ozone seasons, provided the SIP's provisions regarding 
such use comply with the requirements of paragraph (e)(3) of this 
section.
    (C) Emissions reduction credits or emissions allowances held by a 
source or other person following the 2003 ozone season or any ozone 
season thereafter that are not required to demonstrate compliance with 
the SIP for the relevant ozone season may be banked and used to 
demonstrate compliance with the SIP in a subsequent ozone season.
    (D) Early reductions created according to the provisions in 
paragraph (b)(2)(ii)(B) of this section and used in the 2003 ozone 
season are not subject to the flow control provisions set forth in 
paragraph (b)(2)(ii)(E) of this section.
    (E) Starting with the 2004 ozone season, the SIP shall include 
provisions to limit the use of banked emissions reduction credits or 
emissions allowances

[[Page 153]]

beyond a predetermined amount as calculated by one of the following 
approaches:
    (1) Following the determination of compliance after each ozone 
season, if the total number of emissions reduction credits or banked 
allowances held by sources or other persons subject to the trading 
program exceeds 10 percent of the sum of the allowable ozone season 
NOX emissions for all sources subject to the trading program, 
then all banked allowances used for compliance for the following ozone 
season shall be subject to the following:
    (i) A ratio will be established according to the following formula: 
(0.10) x (the sum of the allowable ozone season NOX emissions 
for all sources subject to the trading program) / (the total number of 
banked emissions reduction credits or emissions allowances held by all 
sources or other persons subject to the trading program).
    (ii) The ratio, determined using the formula specified in paragraph 
(b)(2)(ii)(E)(1)(i) of this section, will be multiplied by the number of 
banked emissions reduction credits or emissions allowances held in each 
account at the time of compliance determination. The resulting product 
is the number of banked emissions reduction credits or emissions 
allowances in the account which can be used in the current year's ozone 
season at a rate of 1 credit or allowance for every 1 ton of emissions. 
The SIP shall specify that banked emissions reduction credits or 
emissions allowances in excess of the resulting product either may not 
be used for compliance, or may only be used for compliance at a rate no 
less than 2 credits or allowances for every 1 ton of emissions.
    (2) At the time of compliance determination for each ozone season, 
if the total number of banked emissions reduction credits or emissions 
allowances held by a source subject to the trading program exceeds 10 
percent of the source's allowable ozone season NOX emissions, 
all banked emissions reduction credits or emissions allowances used for 
compliance in such ozone season by the source shall be subject to the 
following:
    (i) The source may use an amount of banked emissions reduction 
credits or emissions allowances not greater than 10 percent of the 
source's allowable ozone season NOX emissions for compliance 
at a rate of 1 credit or allowance for every 1 ton of emissions.
    (ii) The SIP shall specify that banked emissions reduction credits 
or emissions allowances in excess of 10 percent of the source's 
allowable ozone season NOX emissions may not be used for 
compliance, or may only be used for compliance at a rate no less than 2 
credits or allowances for every 1 ton of emissions.
    (c) The following jurisdictions (hereinafter referred to as 
``States'') are subject to the requirements of this section: Alabama, 
Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, 
Massachusetts, Michigan, Missouri, New Jersey, New York, North Carolina, 
Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, 
West Virginia, Wisconsin, and the District of Columbia.
    (d)(1) The SIP submissions required under paragraph (a) of this 
section must be submitted to EPA by no later than September 30, 1999.
    (2) The State makes an official submission of its SIP revision to 
EPA only when:
    (i) The submission conforms to the requirements of appendix V to 
this part; and
    (ii) The State delivers five copies of the plan to the appropriate 
Regional Office, with a letter giving notice of such action.
    (e)(1) The NOX budget for a State listed in paragraph (c) 
of this section is defined as the total amount of NOX 
emissions from all sources in that State, as indicated in paragraph 
(e)(2) of this section with respect to that State, which the State must 
demonstrate that it will not exceed in the 2007 ozone season pursuant to 
paragraph (g)(1) of this section.
    (2) The State-by-State amounts of the NOX budget, 
expressed in tons per ozone season, are as follows:

------------------------------------------------------------------------
                           State                                Budget
------------------------------------------------------------------------
Alabama....................................................      172,619
Connecticut................................................       42,849
Delaware...................................................       22,861
District of Columbia.......................................        6,658
Georgia....................................................      188,572
Illinois...................................................      270,560
Indiana....................................................      229,965

[[Page 154]]

 
Kentucky...................................................      162,272
Maryland...................................................       81,898
Massachusetts..............................................       84,848
Michigan...................................................      229,702
Missouri...................................................      125,603
New Jersey.................................................       96,876
New York...................................................      240,288
North Carolina.............................................      165,022
Ohio.......................................................      249,274
Pennsylvania...............................................      257,592
Rhode Island...............................................        9,378
South Carolina.............................................      123,105
Tennessee..................................................      198,045
Virginia...................................................      180,195
West Virginia..............................................       83,833
Wisconsin..................................................      135,771
                                                            ------------
    Total..................................................    3,357,786
------------------------------------------------------------------------

    (3)(i) Notwithstanding the State's obligation to comply with the 
budgets set forth in paragraph (e)(2) of this section, a SIP revision 
may allow sources required by the revision to implement NOX 
emission control measures by May 1, 2003 to demonstrate compliance in 
the 2003 and 2004 ozone seasons using credit issued from the State's 
compliance supplement pool, as set forth in paragraph (e)(3)(iii) of 
this section.
    (ii) A source may not use credit from the compliance supplement pool 
to demonstrate compliance after the 2004 ozone season.
    (iii) The State-by-State amounts of the compliance supplement pool 
are as follows:

------------------------------------------------------------------------
                                                              Compliance
                                                              supplement
                           State                              pool (tons
                                                               of NOX)
------------------------------------------------------------------------
Alabama....................................................       11,687
Connecticut................................................          569
Delaware...................................................          168
District of Columbia.......................................            0
Georgia....................................................       11,440
Illinois...................................................       17,688
Indiana....................................................       19,915
Kentucky...................................................       13,520
Maryland...................................................        3,882
Massachusetts..............................................          404
Michigan...................................................       11,356
Missouri...................................................       11,199
New Jersey.................................................        1,550
New York...................................................        2,764
North Carolina.............................................       10,737
Ohio.......................................................       22,301
Pennsylvania...............................................       15,763
Rhode Island...............................................           15
South Carolina.............................................        5,344
Tennessee..................................................       10,565
Virginia...................................................        5,504
West Virginia..............................................       16,709
Wisconsin..................................................        6,920
                                                            ------------
    Total..................................................      200,000
------------------------------------------------------------------------

    (iv) The SIP revision may provide for the distribution of the 
compliance supplement pool to sources that are required to implement 
control measures using one or both of the following two mechanisms:
    (A) The State may issue some or all of the compliance supplement 
pool to sources that implement emissions reductions during the ozone 
season beyond all applicable requirements in years prior to the year 
2003 according to the following provisions:
    (1) The State shall complete the issuance process by no later than 
May 1, 2003.
    (2) The emissions reduction may not be required by the State's SIP 
or be otherwise required by the CAA.
    (3) The emissions reduction must be verified by the source as 
actually having occurred during an ozone season between September 30, 
1999 and May 1, 2003.
    (4) The emissions reduction must be quantified according to 
procedures set forth in the SIP revision and approved by EPA. Emissions 
reductions implemented by sources serving electric generators with a 
nameplate capacity greater than 25 MWe, or boilers, combustion turbines 
or combined cycle units with a maximum design heat input greater than 
250 mmBtu/hr, must be quantified according to the requirements in 
paragraph (i)(4) of this section.
    (5) If the SIP revision contains approved provisions for an 
emissions trading program, sources that receive credit according to the 
requirements of this paragraph may trade the credit to other sources or 
persons according to the provisions in the trading program.
    (B) The State may issue some or all of the compliance supplement 
pool to sources that demonstrate a need for an extension of the May 1, 
2003 compliance deadline according to the following provisions:
    (1) The State shall initiate the issuance process by the later date 
of September 30, 2002 or after the State issues credit according to the 
procedures in paragraph (e)(3)(iv)(A) of this section.
    (2) The State shall complete the issuance process by no later than 
May 1, 2003.

[[Page 155]]

    (3) The State shall issue credit to a source only if the source 
demonstrates the following:
    (i) For a source used to generate electricity, compliance with the 
SIP revision's applicable control measures by May 1, 2003, would create 
undue risk for the reliability of the electricity supply. This 
demonstration must include a showing that it would not be feasible to 
import electricity from other electricity generation systems during the 
installation of control technologies necessary to comply with the SIP 
revision.
    (ii) For a source not used to generate electricity, compliance with 
the SIP revision's applicable control measures by May 1, 2003, would 
create undue risk for the source or its associated industry to a degree 
that is comparable to the risk described in paragraph 
(e)(3)(iv)(B)(3)(i) of this section.
    (iii) For a source subject to an approved SIP revision that allows 
for early reduction credits in accordance with paragraph (e)(3)(iv)(A) 
of this section, it was not possible for the source to comply with 
applicable control measures by generating early reduction credits or 
acquiring early reduction credits from other sources.
    (iv) For a source subject to an approved emissions trading program, 
it was not possible to comply with applicable control measures by 
acquiring sufficient credit from other sources or persons subject to the 
emissions trading program.
    (4) The State shall ensure the public an opportunity, through a 
public hearing process, to comment on the appropriateness of allocating 
compliance supplement pool credits to a source under paragraph 
(e)(3)(iv)(B) of this section.
    (4) If, no later than February 22, 1999, any member of the public 
requests revisions to the source-specific data and vehicle miles 
traveled (VMT) and nonroad mobile growth rates, VMT distribution by 
vehicle class, average speed by roadway type, inspection and maintenance 
program parameters, and other input parameters used to establish the 
State budgets set forth in paragraph (e)(2) of this section or the 2007 
baseline sub-inventory information set forth in paragraph (g)(2)(ii) of 
this section, then EPA will act on that request no later than April 23, 
1999 provided:
    (i) The request is submitted in electronic format;
    (ii) Information is provided to corroborate and justify the need for 
the requested modification;
    (iii) The request includes the following data information regarding 
any electricity-generating source at issue:
    (A) Federal Information Placement System (FIPS) State Code;
    (B) FIPS County Code;
    (C) Plant name;
    (D) Plant ID numbers (ORIS code preferred, State agency tracking 
number also or otherwise);
    (E) Unit ID numbers (a unit is a boiler or other combustion device);
    (F) Unit type;
    (G) Primary fuel on a heat input basis;
    (H) Maximum rated heat input capacity of unit;
    (I) Nameplate capacity of the largest generator the unit serves;
    (J) Ozone season heat inputs for the years 1995 and 1996;
    (K) 1996 (or most recent) average NOX rate for the ozone 
season;
    (L) Latitude and longitude coordinates;
    (M) Stack parameter information ;
    (N) Operating parameter information;
    (O) Identification of specific change to the inventory; and
    (P) Reason for the change;
    (iv) The request includes the following data information regarding 
any non-electricity generating point source at issue:
    (A) FIPS State Code;
    (B) FIPS County Code;
    (C) Plant name;
    (D) Facility primary standard industrial classification code (SIC);
    (E) Plant ID numbers (NEDS, AIRS/AFS, and State agency tracking 
number also or otherwise);
    (F) Unit ID numbers (a unit is a boiler or other combustion device);
    (G) Primary source classification code (SCC);
    (H) Maximum rated heat input capacity of unit;
    (I) 1995 ozone season or typical ozone season daily NOX 
emissions;

[[Page 156]]

    (J) 1995 existing NOX control efficiency;
    (K) Latitude and longitude coordinates;
    (L) Stack parameter information;
    (M) Operating parameter information;
    (N) Identification of specific change to the inventory; and
    (O) Reason for the change;
    (v) The request includes the following data information regarding 
any stationary area source or nonroad mobile source at issue:
    (A) FIPS State Code;
    (B) FIPS County Code;
    (C) Primary source classification code (SCC);
    (D) 1995 ozone season or typical ozone season daily NOX 
emissions;
    (E) 1995 existing NOX control efficiency;
    (F) Identification of specific change to the inventory; and
    (G) Reason for the change;
    (vi) The request includes the following data information regarding 
any highway mobile source at issue:
    (A) FIPS State Code;
    (B) FIPS County Code;
    (C) Primary source classification code (SCC) or vehicle type;
    (D) 1995 ozone season or typical ozone season daily vehicle miles 
traveled (VMT);
    (E) 1995 existing NOX control programs;
    (F) identification of specific change to the inventory; and
    (G) reason for the change.
    (f) Each SIP revision must set forth control measures to meet the 
NOX budget in accordance with paragraph (b)(1)(i) of this 
section, which include the following:
    (1) A description of enforcement methods including, but not limited 
to:
    (i) Procedures for monitoring compliance with each of the selected 
control measures;
    (ii) Procedures for handling violations; and
    (iii) A designation of agency responsibility for enforcement of 
implementation.
    (2) Should a State elect to impose control measures on fossil fuel-
fired NOX sources serving electric generators with a 
nameplate capacity greater than 25 MWe or boilers, combustion turbines 
or combined cycle units with a maximum design heat input greater than 
250 mmBtu/hr as a means of meeting its NOX budget, then those 
measures must:
    (i)(A) Impose a NOX mass emissions cap on each source;
    (B) Impose a NOX emissions rate limit on each source and 
assume maximum operating capacity for every such source for purposes of 
estimating mass NOX emissions; or
    (C) Impose any other regulatory requirement which the State has 
demonstrated to EPA provides equivalent or greater assurance than 
options in paragraphs (f)(2)(i)(A) or (f)(2)(i)(B) of this section that 
the State will comply with its NOX budget in the 2007 ozone 
season; and
    (ii) Impose enforceable mechanisms, in accordance with paragraphs 
(b)(1) (i) and (ii) of this section, to assure that collectively all 
such sources, including new or modified units, will not exceed in the 
2007 ozone season the total NOX emissions projected for such 
sources by the State pursuant to paragraph (g) of this section.
    (3) For purposes of paragraph (f)(2) of this section, the term 
``fossil fuel-fired'' means, with regard to a NOX source:
    (i) The combustion of fossil fuel, alone or in combination with any 
other fuel, where fossil fuel actually combusted comprises more than 50 
percent of the annual heat input on a Btu basis during any year starting 
in 1995 or, if a NOX source had no heat input starting in 
1995, during the last year of operation of the NOX source 
prior to 1995; or
    (ii) The combustion of fossil fuel, alone or in combination with any 
other fuel, where fossil fuel is projected to comprise more than 50 
percent of the annual heat input on a Btu basis during any year; 
provided that the NOX source shall be ``fossil fuel-fired'' 
as of the date, during such year, on which the NOX source 
begins combusting fossil fuel.
    (g)(1) Each SIP revision must demonstrate that the control measures 
contained in it are adequate to provide for the timely compliance with 
the State's NOX budget during the 2007 ozone season.

[[Page 157]]

    (2) The demonstration must include the following:
    (i) Each revision must contain a detailed baseline inventory of 
NOX mass emissions from the following sources in the year 
2007, absent the control measures specified in the SIP submission: 
electric generating units (EGU), non-electric generating units (non-
EGU), area, nonroad and highway sources. The State must use the same 
baseline emissions inventory that EPA used in calculating the State's 
NOX budget, as set forth for the State in paragraph 
(g)(2)(ii) of this section, except that EPA may direct the State to use 
different baseline inventory information if the State fails to certify 
that it has implemented all of the control measures assumed in 
developing the baseline inventory.
    (ii) The revised NOX emissions sub-inventories for each 
State, expressed in tons per ozone season, are as follows:

----------------------------------------------------------------------------------------------------------------
                     State                          EGU      Non-EGU    Area     Nonroad    Highway      Total
----------------------------------------------------------------------------------------------------------------
Alabama.......................................      29,022    43,415    28,762    20,146      51,274     172,619
Connecticut...................................       2,652     5,216     4,821    10,736      19,424      42,849
Delaware......................................       5,250     2,473     1,129     5,651       8,358      22,861
District of Columbia..........................         207       282       830     3,135       2,204       6,658
Georgia.......................................      30,402    29,716    13,212    26,467      88,775     188,572
Illinois......................................      32,372    59,577     9,369    56,724     112,518     270,560
Indiana.......................................      47,731    47,363    29,070    26,494      79,307     229,965
Kentucky......................................      36,503    25,669    31,807    15,025      53,268     162,272
Maryland......................................      14,656    12,585     4,448    20,026      30,183      81,898
Massachusetts.................................      15,146    10,298    11,048    20,166      28,190      84,848
Michigan......................................      32,228    60,055    31,721    26,935      78,763     229,702
Missouri......................................      24,216    21,602     7,341    20,829      51,615     125,603
New Jersey....................................      10,250    15,464    12,431    23,565      35,166      96,876
New York......................................      31,036    25,477    17,423    42,091     124,261     240,288
North Carolina................................      31,821    26,434    11,067    22,005      73,695     165,022
Ohio..........................................      48,990    40,194    21,860    43,380      94,850     249,274
Pennsylvania..................................      47,469    70,132    17,842    30,571      91,578     257,592
Rhode Island..................................         997     1,635       448     2,455       3,843       9,378
South Carolina................................      16,772    27,787     9,415    14,637      54,494     123,105
Tennessee.....................................      25,814    39,636    13,333    52,920      66,342     198,045
Virginia......................................      17,187    35,216    27,738    27,859      72,195     180,195
West Virginia.................................      26,859    20,238     5,459    10,433      20,844      83,833
Wisconsin.....................................      17,381    19,853    11,253    17,965      69,319     135,771
                                               -----------------------------------------------------------------
    Total.....................................     544,961   640,317   321,827   540,215   1,310,466  3,357,786
----------------------------------------------------------------------------------------------------------------
Note to paragraph (g)(2)(ii): Totals may not sum due to rounding.

    (iii) Each revision must contain a summary of NOX mass 
emissions in 2007 projected to result from implementation of each of the 
control measures specified in the SIP submission and from all 
NOX sources together following implementation of all such 
control measures, compared to the baseline 2007 NOX emissions 
inventory for the State described in paragraph (g)(2)(i) of this 
section. The State must provide EPA with a summary of the computations, 
assumptions, and judgments used to determine the degree of reduction in 
projected 2007 NOX emissions that will be achieved from the 
implementation of the new control measures compared to the baseline 
emissions inventory.
    (iv) Each revision must identify the sources of the data used in the 
projection of emissions.
    (h) Each revision must comply with Sec. 51.116 of this part 
(regarding data availability).
    (i) Each revision must provide for monitoring the status of 
compliance with any control measures adopted to meet the NOX 
budget. Specifically, the revision must meet the following requirements:
    (1) The revision must provide for legally enforceable procedures for 
requiring owners or operators of stationary sources to maintain records 
of and periodically report to the State:
    (i) Information on the amount of NOX emissions from the 
stationary sources; and

[[Page 158]]

    (ii) Other information as may be necessary to enable the State to 
determine whether the sources are in compliance with applicable portions 
of the control measures;
    (2) The revision must comply with Sec. 51.212 of this part 
(regarding testing, inspection, enforcement, and complaints);
    (3) If the revision contains any transportation control measures, 
then the revision must comply with Sec. 51.213 of this part (regarding 
transportation control measures);
    (4) If the revision contains measures to control fossil fuel-fired 
NOX sources serving electric generators with a nameplate 
capacity greater than 25 MWe or boilers, combustion turbines or combined 
cycle units with a maximum design heat input greater than 250 mmBtu/hr, 
then the revision must require such sources to comply with the 
monitoring provisions of part 75, subpart H.
    (5) For purposes of paragraph (i)(4) of this section, the term 
``fossil fuel-fired'' means, with regard to a NOX source:
    (i) The combustion of fossil fuel, alone or in combination with any 
other fuel, where fossil fuel actually combusted comprises more than 50 
percent of the annual heat input on a Btu basis during any year starting 
in 1995 or, if a NOX source had no heat input starting in 
1995, during the last year of operation of the NOX source 
prior to 1995; or
    (ii) The combustion of fossil fuel, alone or in combination with any 
other fuel, where fossil fuel is projected to comprise more than 50 
percent of the annual heat input on a Btu basis during any year, 
provided that the NOX source shall be ``fossil fuel-fired'' 
as of the date, during such year, on which the NOX source 
begins combusting fossil fuel.
    (j) Each revision must show that the State has legal authority to 
carry out the revision, including authority to:
    (1) Adopt emissions standards and limitations and any other measures 
necessary for attainment and maintenance of the State's NOX 
budget specified in paragraph (e) of this section;
    (2) Enforce applicable laws, regulations, and standards, and seek 
injunctive relief;
    (3) Obtain information necessary to determine whether air pollution 
sources are in compliance with applicable laws, regulations, and 
standards, including authority to require recordkeeping and to make 
inspections and conduct tests of air pollution sources;
    (4) Require owners or operators of stationary sources to install, 
maintain, and use emissions monitoring devices and to make periodic 
reports to the State on the nature and amounts of emissions from such 
stationary sources; also authority for the State to make such data 
available to the public as reported and as correlated with any 
applicable emissions standards or limitations.
    (k)(1) The provisions of law or regulation which the State 
determines provide the authorities required under this section must be 
specifically identified, and copies of such laws or regulations must be 
submitted with the SIP revision.
    (2) Legal authority adequate to fulfill the requirements of 
paragraphs (j)(3) and (4) of this section may be delegated to the State 
under section 114 of the CAA.
    (l)(1) A revision may assign legal authority to local agencies in 
accordance with Sec. 51.232 of this part.
    (2) Each revision must comply with Sec. 51.240 of this part 
(regarding general plan requirements).
    (m) Each revision must comply with Sec. 51.280 of this part 
(regarding resources).
    (n) For purposes of the SIP revisions required by this section, EPA 
may make a finding as applicable under section 179(a)(1)-(4) of the CAA, 
42 U.S.C. 7509(a)(1)-(4), starting the sanctions process set forth in 
section 179(a) of the CAA. Any such finding will be deemed a finding 
under Sec. 52.31(c) of this part and sanctions will be imposed in 
accordance with the order of sanctions and the terms for such sanctions 
established in Sec. 52.31 of this part.
    (o) Each revision must provide for State compliance with the 
reporting requirements set forth in Sec. 51.122 of this part.
    (p)(1) Notwithstanding any other provision of this section, if a 
State adopts regulations substantively identical to 40 CFR part 96 (the 
model NOX budget

[[Page 159]]

trading program for SIPs), incorporates such part by reference into its 
regulations, or adopts regulations that differ substantively from such 
part only as set forth in paragraph (p)(2) of this section, then that 
portion of the State's SIP revision is automatically approved as 
satisfying the same portion of the State's NOX emission 
reduction obligations as the State projects such regulations will 
satisfy, provided that:
    (i) The State has the legal authority to take such action and to 
implement its responsibilities under such regulations, and
    (ii) The SIP revision accurately reflects the NOX 
emissions reductions to be expected from the State's implementation of 
such regulations.
    (2) If a State adopts an emissions trading program that differs 
substantively from 40 CFR part 96 in only the following respects, then 
such portion of the State's SIP revision is approved as set forth in 
paragraph (p)(1) of this section:
    (i) The State may expand the applicability provisions of the trading 
program to include units (as defined in 40 CFR 96.2) that are smaller 
than the size criteria thresholds set forth in 40 CFR 96.4(a);
    (ii) The State may decline to adopt the exemption provisions set 
forth in 40 CFR 96.4(b);
    (iii) The State may decline to adopt the opt-in provisions set forth 
in subpart I of 40 CFR part 96;
    (iv) The State may decline to adopt the allocation provisions set 
forth in subpart E of 40 CFR part 96 and may instead adopt any 
methodology for allocating NOX allowances to individual 
sources, provided that:
    (A) The State's methodology does not allow the State to allocate 
NOX allowances in excess of the total amount of 
NOX emissions which the State has assigned to its trading 
program; and
    (B) The State's methodology conforms with the timing requirements 
for submission of allocations to the Administrator set forth in 40 CFR 
96.41; and
    (v) The State may decline to adopt the early reduction credit 
provisions set forth in 40 CFR 96.55(c) and may instead adopt any 
methodology for issuing credit from the State's compliance supplement 
pool that complies with paragraph (e)(3) of this section.
    (3) If a State adopts an emissions trading program that differs 
substantively from 40 CFR part 96 other than as set forth in paragraph 
(p)(2) of this section, then such portion of the State's SIP revision is 
not automatically approved as set forth in paragraph (p)(1) of this 
section but will be reviewed by the Administrator for approvability in 
accordance with the other provisions of this section.
    (q) Stay of Findings of Significant Contribution with respect to the 
8-hour standard. Notwithstanding any other provisions of this subpart, 
the effectiveness of paragraph (a)(2) of this section is stayed.

[63 FR 57491, Oct. 27, 1998, as amended at 63 FR 71225, Dec. 24, 1998; 
64 FR 26305, May 14, 1999; 65 FR 11230, Mar. 2, 2000; 65 FR 56251, Sept. 
18, 2000]



Sec. 51.122  Emissions reporting requirements for SIP revisions relating 
to budgets for NOX emissions.

    (a) For its transport SIP revision under Sec. 51.121 of this part, 
each State must submit to EPA NOX emissions data as described 
in this section.
    (b) Each revision must provide for periodic reporting by the State 
of NOX emissions data to demonstrate whether the State's 
emissions are consistent with the projections contained in its approved 
SIP submission.
    (1) Annual reporting. Each revision must provide for annual 
reporting of NOX emissions data as follows:
    (i) The State must report to EPA emissions data from all 
NOX sources within the State for which the State specified 
control measures in its SIP submission under Sec. 51.121(g) of this 
part. This would include all sources for which the State has adopted 
measures that differ from the measures incorporated into the baseline 
inventory for the year 2007 that the State developed in accordance with 
Sec. 51.121(g) of this part.
    (ii) If sources report NOX emissions data to EPA annually 
pursuant to a trading program approved under Sec. 51.121(p) of this part 
or pursuant to the monitoring and reporting requirements of subpart H of 
40 CFR part 75,

[[Page 160]]

then the State need not provide annual reporting to EPA for such 
sources.
    (2) Triennial reporting. Each plan must provide for triennial (i.e., 
every third year) reporting of NOX emissions data from all 
sources within the State.
    (3) Year 2007 reporting. Each plan must provide for reporting of 
year 2007 NOX emissions data from all sources within the 
State.
    (4) The data availability requirements in Sec. 51.116 of this part 
must be followed for all data submitted to meet the requirements of 
paragraphs (b)(1),(2) and (3) of this section.
    (c) The data reported in paragraph (b) of this section for 
stationary point sources must meet the following minimum criteria:
    (1) For annual data reporting purposes the data must include the 
following minimum elements:
    (i) Inventory year.
    (ii) State Federal Information Placement System code.
    (iii) County Federal Information Placement System code.
    (iv) Federal ID code (plant).
    (v) Federal ID code (point).
    (vi) Federal ID code (process).
    (vii) Federal ID code (stack).
    (vii) Site name.
    (viii) Physical address.
    (ix) SCC.
    (x) Pollutant code.
    (xi) Ozone season emissions.
    (xii) Area designation.
    (2) In addition, the annual data must include the following minimum 
elements as applicable to the emissions estimation methodology.
    (i) Fuel heat content (annual).
    (ii) Fuel heat content (seasonal).
    (iii) Source of fuel heat content data.
    (iv) Activity throughput (annual).
    (v) Activity throughput (seasonal).
    (vi) Source of activity/throughput data.
    (vii) Spring throughput (%).
    (viii) Summer throughput (%).
    (ix) Fall throughput (%).
    (x) Work weekday emissions.
    (xi) Emission factor.
    (xii) Source of emission factor.
    (xiii) Hour/day in operation.
    (xiv) Operations Start time (hour).
    (xv) Day/week in operation.
    (xvi) Week/year in operation.
    (3) The triennial and 2007 inventories must include the following 
data elements:
    (i) The data required in paragraphs (c)(1) and (c)(2) of this 
section.
    (ii) X coordinate (latitude).
    (iii) Y coordinate (longitude).
    (iv) Stack height.
    (v) Stack diameter.
    (vi) Exit gas temperature.
    (vii) Exit gas velocity.
    (viii) Exit gas flow rate.
    (ix) SIC.
    (x) Boiler/process throughput design capacity.
    (xi) Maximum design rate.
    (xii) Maximum capacity.
    (xiii) Primary control efficiency.
    (xiv) Secondary control efficiency.
    (xv) Control device type.
    (d) The data reported in paragraph (b) of this section for area 
sources must include the following minimum elements:
    (1) For annual inventories it must include:
    (i) Inventory year.
    (ii) State FIPS code.
    (iii) County FIPS code.
    (iv) SCC.
    (v) Emission factor.
    (vi) Source of emission factor.
    (vii) Activity/throughput level (annual).
    (viii) Activity throughput level (seasonal).
    (ix) Source of activity/throughput data.
    (x) Spring throughput (%).
    (xi) Summer throughput (%).
    (xii) Fall throughput (%).
    (xiii) Control efficiency (%).
    (xiv) Pollutant code.
    (xv) Ozone season emissions.
    (xvi) Source of emissions data.
    (xvii) Hour/day in operation.
    (xviii) Day/week in operation.
    (xix) Week/year in operations.
    (2) The triennial and 2007 inventories must contain, at a minimum, 
all the data required in paragraph (d)(1) of this section.
    (e) The data reported in paragraph (b) of this section for mobile 
sources must meet the following minimum criteria:
    (1) For the annual, triennial, and 2007 inventory purposes, the 
following data must be reported:
    (i) Inventory year.

[[Page 161]]

    (ii) State FIPS code.
    (iii) County FIPS code.
    (iv) SCC.
    (v) Emission factor.
    (vi) Source of emission factor.
    (vii) Activity (this must be reported for both highway and nonroad 
activity. Submit nonroad activity in the form of hours of activity at 
standard load (either full load or average load) for each engine type, 
application, and horsepower range. Submit highway activity in the form 
of vehicle miles traveled (VMT) by vehicle class on each roadway type. 
Report both highway and nonroad activity for a typical ozone season 
weekday day, if the State uses EPA's default weekday/weekend activity 
ratio. If the State uses a different weekday/weekend activity ratio, 
submit separate activity level information for weekday days and weekend 
days).
    (viii) Source of activity data.
    (ix) Pollutant code.
    (x) Summer work weekday emissions.
    (xi) Ozone season emissions.
    (xii) Source of emissions data.
    (2) [Reserved]
    (f) Approval of ozone season calculation by EPA. Each State must 
submit for EPA approval an example of the calculation procedure used to 
calculate ozone season emissions along with sufficient information for 
EPA to verify the calculated value of ozone season emissions.
    (g) Reporting schedules. (1) Annual reports are to begin with data 
for emissions occurring in the year 2003.
    (2) Triennial reports are to begin with data for emissions occurring 
in the year 2002.
    (3) Year 2007 data are to be submitted for emissions occurring in 
the year 2007.
    (4) States must submit data for a required year no later than 12 
months after the end of the calendar year for which the data are 
collected.
    (h) Data reporting procedures. When submitting a formal 
NOX budget emissions report and associated data, States shall 
notify the appropriate EPA Regional Office.
    (1) States are required to report emissions data in an electronic 
format to one of the locations listed in this paragraph (h). Several 
options are available for data reporting.
    (2) An agency may choose to continue reporting to the EPA Aerometric 
Information Retrieval System (AIRS) system using the AIRS facility 
subsystem (AFS) format for point sources. (This option will continue for 
point sources for some period of time after AIRS is reengineered (before 
2002), at which time this choice may be discontinued or modified.)
    (3) An agency may convert its emissions data into the Emission 
Inventory Improvement Program/Electronic Data Interchange (EIIP/EDI) 
format. This file can then be made available to any requestor, either 
using E-mail, floppy disk, or value added network (VAN), or can be 
placed on a file transfer protocol (FTP) site.
    (4) An agency may submit its emissions data in a proprietary format 
based on the EIIP data model.
    (5) For options in paragraphs (h)(3) and (4) of this section, the 
terms submitting and reporting data are defined as either providing the 
data in the EIIP/EDI format or the EIIP based data model proprietary 
format to EPA, Office of Air Quality Planning and Standards, Emission 
Factors and Inventory Group, directly or notifying this group that the 
data are available in the specified format and at a specific electronic 
location (e.g., FTP site).
    (6) For annual reporting (not for triennial reports), a State may 
have sources submit the data directly to EPA to the extent the sources 
are subject to a trading program that qualifies for approval under 
Sec. 51.121(q) of this part, and the State has agreed to accept data in 
this format. The EPA will make both the raw data submitted in this 
format and summary data available to any State that chooses this option.
    (i) Definitions. As used in this section, the following words and 
terms shall have the meanings set forth below:
    (1) Annual emissions. Actual emissions for a plant, point, or 
process, either measured or calculated.
    (2) Ash content. Inert residual portion of a fuel.
    (3) Area designation. The designation of the area in which the 
reporting source is located with regard to the

[[Page 162]]

ozone NAAQS. This would include attainment or nonattainment 
designations. For nonattainment designations, the classification of the 
nonattainment area must be specified, i.e., transitional, marginal, 
moderate, serious, severe, or extreme.
    (4) Boiler design capacity. A measure of the size of a boiler, based 
on the reported maximum continuous steam flow. Capacity is calculated in 
units of MMBtu/hr.
    (5) Control device type. The name of the type of control device 
(e.g., wet scrubber, flaring, or process change).
    (6) Control efficiency. The emissions reduction efficiency of a 
primary control device, which shows the amount of reductions of a 
particular pollutant from a process' emissions due to controls or 
material change. Control efficiency is usually expressed as a percentage 
or in tenths.
    (7) Day/week in operations. Days per week that the emitting process 
operates.
    (8) Emission factor. Ratio relating emissions of a specific 
pollutant to an activity or material throughput level.
    (9) Exit gas flow rate. Numeric value of stack gas flow rate.
    (10) Exit gas temperature. Numeric value of an exit gas stream 
temperature.
    (11) Exit gas velocity. Numeric value of an exit gas stream 
velocity.
    (12) Fall throughput (%). Portion of throughput for the 3 fall 
months (September, October, November). This represents the expression of 
annual activity information on the basis of four seasons, typically 
spring, summer, fall, and winter. It can be represented either as a 
percentage of the annual activity (e.g., production in summer is 40 
percent of the year's production), or in terms of the units of the 
activity (e.g., out of 600 units produced, spring = 150 units, summer = 
250 units, fall = 150 units, and winter = 50 units).
    (13) Federal ID code (plant). Unique codes for a plant or facility, 
containing one or more pollutant-emitting sources.
    (14) Federal ID code (point). Unique codes for the point of 
generation of emissions, typically a physical piece of equipment.
    (15) Federal ID code (stack number). Unique codes for the point 
where emissions from one or more processes are released into the 
atmosphere.
    (16) Federal Information Placement System (FIPS). The system of 
unique numeric codes developed by the government to identify States, 
counties, towns, and townships for the entire United States, Puerto 
Rico, and Guam.
    (17) Heat content. The thermal heat energy content of a solid, 
liquid, or gaseous fuel. Fuel heat content is typically expressed in 
units of Btu/lb of fuel, Btu/gal of fuel, joules/kg of fuel, etc.
    (18) Hr/day in operations. Hours per day that the emitting process 
operates.
    (19) Maximum design rate. Maximum fuel use rate based on the 
equipment's or process' physical size or operational capabilities.
    (20) Maximum nameplate capacity. A measure of the size of a 
generator which is put on the unit's nameplate by the manufacturer. The 
data element is reported in megawatts (MW) or kilowatts (KW).
    (21) Mobile source. A motor vehicle, nonroad engine or nonroad 
vehicle, where:
    (i) Motor vehicle means any self-propelled vehicle designed for 
transporting persons or property on a street or highway;
    (ii) Nonroad engine means an internal combustion engine (including 
the fuel system) that is not used in a motor vehicle or a vehicle used 
solely for competition, or that is not subject to standards promulgated 
under section 111 or section 202 of the CAA;
    (iii) Nonroad vehicle means a vehicle that is powered by a nonroad 
engine and that is not a motor vehicle or a vehicle used solely for 
competition.
    (22) Ozone season. The period May 1 through September 30 of a year.
    (23) Physical address. Street address of facility.
    (24) Point source. A non-mobile source which emits 100 tons of 
NOX or more per year unless the State designates as a point 
source a non-mobile source emitting at a specified level lower than 100 
tons of NOX per year. A non-mobile source which emits less 
NOX per year than the point source threshold is an area 
source.

[[Page 163]]

    (25) Pollutant code. A unique code for each reported pollutant that 
has been assigned in the EIIP Data Model. Character names are used for 
criteria pollutants, while Chemical Abstracts Service (CAS) numbers are 
used for all other pollutants. Some States may be using storage and 
retrieval of aerometric data (SAROAD) codes for pollutants, but these 
should be able to be mapped to the EIIP Data Model pollutant codes.
    (26) Process rate/throughput. A measurable factor or parameter that 
is directly or indirectly related to the emissions of an air pollution 
source. Depending on the type of source category, activity information 
may refer to the amount of fuel combusted, the amount of a raw material 
processed, the amount of a product that is manufactured, the amount of a 
material that is handled or processed, population, employment, number of 
units, or miles traveled. Activity information is typically the value 
that is multiplied against an emission factor to generate an emissions 
estimate.
    (27) SCC. Source category code. A process-level code that describes 
the equipment or operation emitting pollutants.
    (28) Secondary control efficiency (%). The emissions reductions 
efficiency of a secondary control device, which shows the amount of 
reductions of a particular pollutant from a process' emissions due to 
controls or material change. Control efficiency is usually expressed as 
a percentage or in tenths.
    (29) SIC. Standard Industrial Classification code. U.S. Department 
of Commerce's categorization of businesses by their products or 
services.
    (30) Site name. The name of the facility.
    (31) Spring throughput (%). Portion of throughput or activity for 
the 3 spring months (March, April, May). See the definition of Fall 
Throughput.
    (32) Stack diameter. Stack physical diameter.
    (33) Stack height. Stack physical height above the surrounding 
terrain.
    (34) Start date (inventory year). The calendar year that the 
emissions estimates were calculated for and are applicable to.
    (35) Start time (hour). Start time (if available) that was 
applicable and used for calculations of emissions estimates.
    (36) Summer throughput (%). Portion of throughput or activity for 
the 3 summer months (June, July, August). See the definition of Fall 
Throughput.
    (37) Summer work weekday emissions. Average day's emissions for a 
typical day.
    (38) VMT by Roadway Class. This is an expression of vehicle activity 
that is used with emission factors. The emission factors are usually 
expressed in terms of grams per mile of travel. Since VMT does not 
directly correlate to emissions that occur while the vehicle is not 
moving, these non-moving emissions are incorporated into EPA's MOBILE 
model emission factors.
    (39) Week/year in operation. Weeks per year that the emitting 
process operates.
    (40) Work Weekday. Any day of the week except Saturday or Sunday.
    (41) X coordinate (latitude). East-west geographic coordinate of an 
object.
    (42) Y coordinate (longitude). North-south geographic coordinate of 
an object.

[63 FR 57496, Oct. 27, 1998]



        Subpart H--Prevention of Air Pollution Emergency Episodes

    Source: 51 FR 40668, Nov. 7, 1986, unless otherwise noted.



Sec. 51.150  Classification of regions for episode plans.

    (a) This section continues the classification system for episode 
plans. Each region is classified separately with respect to each of the 
following pollutants: Sulfur oxides, particulate matter, carbon 
monoxide, nitrogen dioxide, and ozone.
    (b) Priority I Regions means any area with greater ambient 
concentrations than the following:
    (1) Sulfur dioxide--100 [mu]g/m\3\ (0.04 ppm) annual arithmetic 
mean; 455 [mu]g/m\3\ (0.17 ppm) 24-hour maximum.
    (2) Particulate matter--95 [mu]g/m\3\ annual geometric mean; 325 
[mu]g/m\3\ 24-hour maximum.

[[Page 164]]

    (3) Carbon monoxide--55 mg/m\3\ (48 ppm) 1-hour maximum; 14 mg/m\3\ 
(12 ppm) 8-hour maximum.
    (4) Nitrogen dioxide--100 [mu]g/m\3\ (0.06 ppm) annual arithmetic 
mean.
    (5) Ozone--195 [mu]g/m\3\ (0.10 ppm) 1-hour maximum.
    (c) Priority IA Region means any area which is Priority I primarily 
because of emissions from a single point source.
    (d) Priority II Region means any area which is not a Priority I 
region and has ambient concentrations between the following:
    (1) Sulfur Dioxides--60-100 [mu]g/m\3\ (0.02-0.04 ppm) annual 
arithmetic mean; 260-445 [mu]g/m\3\ (0.10-0.17 ppm) 24-hour maximum; any 
concentration above 1,300 [mu]g/m\3\ (0.50 ppm) three-hour average.
    (2) Particulate matter--60-95 [mu]g/m\3\ annual geometric mean; 150-
325 [mu]g/m\3\ 24-hour maximum.
    (e) In the absence of adequate monitoring data, appropriate models 
must be used to classify an area under paragraph (b) of this section, 
consistent with the requirements contained in Sec. 51.112(a).
    (f) Areas which do not meet the above criteria are classified 
Priority III.

[51 FR 40668, Nov. 7, 1986, as amended at 58 FR 38822, July 20, 1993]



Sec. 51.151  Significant harm levels.

    Each plan for a Priority I region must include a contingency plan 
which must, as a mimimum, provide for taking action necessary to prevent 
ambient pollutant concentrations at any location in such region from 
reaching the following levels:

Sulfur dioxide--2.620 [mu]g/m\3\ (1.0 ppm) 24-hour average.
PM10--600 micrograms/cubic meter; 24-hour average.
Carbon monoxide--57.5 mg/m\3\ (50 ppm) 8-hour average; 86.3 mg/m\3\ (75 
ppm) 4-hour average; 144 mg/m\3\ (125 ppm) 1-hour average.
Ozone--1,200 ug/m\3\ (0.6 ppm) 2-hour average.
Nitrogen dioxide--3.750 ug/m\3\ (2.0 ppm) 1-hour average; 938 ug/m\3\ 
(0.5 ppm) 24-hour average.

[51 FR 40668, Nov. 7, 1986, as amended at 52 FR 24713, July 1, 1987]



Sec. 51.152  Contingency plans.

    (a) Each contingency plan must--
    (1) Specify two or more stages of episode criteria such as those set 
forth in appendix L to this part, or their equivalent;
    (2) Provide for public announcement whenever any episode stage has 
been determined to exist; and
    (3) Specify adequate emission control actions to be taken at each 
episode stage. (Examples of emission control actions are set forth in 
appendix L.)
    (b) Each contingency plan for a Priority I region must provide for 
the following:
    (1) Prompt acquisition of forecasts of atmospheric stagnation 
conditions and of updates of such forecasts as frequently as they are 
issued by the National Weather Service.
    (2) Inspection of sources to ascertain compliance with applicable 
emission control action requirements.
    (3) Communications procedures for transmitting status reports and 
orders as to emission control actions to be taken during an episode 
stage, including procedures for contact with public officials, major 
emission sources, public health, safety, and emergency agencies and news 
media.
    (c) Each plan for a Priority IA and II region must include a 
contingency plan that meets, as a minimum, the requirements of 
paragraphs (b)(1) and (b)(2) of this section. Areas classified Priority 
III do not need to develop episode plans.
    (d) Notwithstanding the requirements of paragraphs (b) and (c) of 
this section, the Administrator may, at his discretion--
    (1) Exempt from the requirements of this section those portions of 
Priority I, IA, or II regions which have been designated as attainment 
or unclassifiable for national primary and secondary standards under 
section 107 of the Act; or
    (2) Limit the requirements pertaining to emission control actions in 
Priority I regions to--
    (i) Urbanized areas as identified in the most recent United States 
Census, and
    (ii) Major emitting facilities, as defined by section 169(1) of the 
Act, outside the urbanized areas.

[[Page 165]]



Sec. 51.153  Reevaluation of episode plans.

    (a) States should periodically reevaluate priority classifications 
of all Regions or portion of Regions within their borders. The 
reevaluation must consider the three most recent years of air quality 
data. If the evaluation indicates a change to a higher priority 
classification, appropriate changes in the episode plan must be made as 
expeditiously as practicable.
    (b) [Reserved]



           Subpart I--Review of New Sources and Modifications

    Source: 51 FR 40669, Nov. 7, 1986, unless otherwise noted.



Sec. 51.160  Legally enforceable procedures.

    (a) Each plan must set forth legally enforceable procedures that 
enable the State or local agency to determine whether the construction 
or modification of a facility, building, structure or installation, or 
combination of these will result in--
    (1) A violation of applicable portions of the control strategy; or
    (2) Interference with attainment or maintenance of a national 
standard in the State in which the proposed source (or modification) is 
located or in a neighboring State.
    (b) Such procedures must include means by which the State or local 
agency responsible for final decisionmaking on an application for 
approval to construct or modify will prevent such construction or 
modification if--
    (1) It will result in a violation of applicable portions of the 
control strategy; or
    (2) It will interfere with the attainment or maintenance of a 
national standard.
    (c) The procedures must provide for the submission, by the owner or 
operator of the building, facility, structure, or installation to be 
constructed or modified, of such information on--
    (1) The nature and amounts of emissions to be emitted by it or 
emitted by associated mobile sources;
    (2) The location, design, construction, and operation of such 
facility, building, structure, or installation as may be necessary to 
permit the State or local agency to make the determination referred to 
in paragraph (a) of this section.
    (d) The procedures must provide that approval of any construction or 
modification must not affect the responsibility to the owner or operator 
to comply with applicable portions of the control strategy.
    (e) The procedures must identify types and sizes of facilities, 
buildings, structures, or installations which will be subject to review 
under this section. The plan must discuss the basis for determining 
which facilities will be subject to review.
    (f) The procedures must discuss the air quality data and the 
dispersion or other air quality modeling used to meet the requirements 
of this subpart.
    (1) All applications of air quality modeling involved in this 
subpart shall be based on the applicable models, data bases, and other 
requirements specified in appendix W of this part (Guideline on Air 
Quality Models).
    (2) Where an air quality model specified in appendix W of this part 
(Guideline on Air Quality Models) is inappropriate, the model may be 
modified or another model substituted. Such a modification or 
substitution of a model may be made on a case-by-case basis or, where 
appropriate, on a generic basis for a specific State program. Written 
approval of the Administrator must be obtained for any modification or 
substitution. In addition, use of a modified or substituted model must 
be subject to notice and opportunity for public comment under procedures 
set forth in Sec. 51.102.

[51 FR 40669, Nov. 7, 1986, as amended at 58 FR 38822, July 20, 1993; 60 
FR 40468, Aug. 9, 1995; 61 FR 41840, Aug. 12, 1996]



Sec. 51.161  Public availability of information.

    (a) The legally enforceable procedures in Sec. 51.160 must also 
require the State or local agency to provide opportunity for public 
comment on information submitted by owners and operators. The public 
information must include the agency's analysis of the effect of 
construction or modification on ambient air quality, including the

[[Page 166]]

agency's proposed approval or disapproval.
    (b) For purposes of paragraph (a) of this section, opportunity for 
public comment shall include, as a minimum--
    (1) Availability for public inspection in at least one location in 
the area affected of the information submitted by the owner or operator 
and of the State or local agency's analysis of the effect on air 
quality;
    (2) A 30-day period for submittal of public comment; and
    (3) A notice by prominent advertisement in the area affected of the 
location of the source information and analysis specified in paragraph 
(b)(1) of this section.
    (c) Where the 30-day comment period required in paragraph (b) of 
this section would conflict with existing requirements for acting on 
requests for permission to construct or modify, the State may submit for 
approval a comment period which is consistent with such existing 
requirements.
    (d) A copy of the notice required by paragraph (b) of this section 
must also be sent to the Administrator through the appropriate Regional 
Office, and to all other State and local air pollution control agencies 
having jurisdiction in the region in which such new or modified 
installation will be located. The notice also must be sent to any other 
agency in the region having responsibility for implementing the 
procedures required under this subpart. For lead, a copy of the notice 
is required for all point sources. The definition of point for lead is 
given in Sec. 51.100(k)(2).



Sec. 51.162  Identification of responsible agency.

    Each plan must identify the State or local agency which will be 
responsible for meeting the requirements of this subpart in each area of 
the State. Where such responsibility rests with an agency other than an 
air pollution control agency, such agency will consult with the 
appropriate State or local air pollution control agency in carrying out 
the provisions of this subpart.



Sec. 51.163  Administrative procedures.

    The plan must include the administrative procedures, which will be 
followed in making the determination specified in paragraph (a) of 
Sec. 51.160.



Sec. 51.164  Stack height procedures.

    Such procedures must provide that the degree of emission limitation 
required of any source for control of any air pollutant must not be 
affected by so much of any source's stack height that exceeds good 
engineering practice or by any other dispersion technique, except as 
provided in Sec. 51.118(b). Such procedures must provide that before a 
State issues a permit to a source based on a good engineering practice 
stack height that exceeds the height allowed by Sec. 51.100(ii) (1) or 
(2), the State must notify the public of the availability of the 
demonstration study and must provide opportunity for public hearing on 
it. This section does not require such procedures to restrict in any 
manner the actual stack height of any source.



Sec. 51.165  Permit requirements.

    (a) State Implementation Plan and Tribal Implementation Plan 
provisions satisfying sections 172(c)(5) and 173 of the Act shall meet 
the following conditions:
    (1) All such plans shall use the specific definitions. Deviations 
from the following wording will be approved only if the State 
specifically demonstrates that the submitted definition is more 
stringent, or at least as stringent, in all respects as the 
corresponding definition below:
    (i) Stationary source means any building, structure, facility, or 
installation which emits or may emit a regulated NSR pollutant.
    (ii) Building, structure, facility, or installation means all of the 
pollutant-emitting activities which belong to the same industrial 
grouping, are located on one or more contiguous or adjacent properties, 
and are under the control of the same person (or persons under common 
control) except the activities of any vessel. Pollutant-emitting 
activities shall be considered as part of the same industrial grouping 
if they belong to the same Major Group (i.e., which have the same two-
digit code) as described in the Standard Industrial Classification 
Manual, 1972, as amended by the 1977 Supplement (U.S. Government

[[Page 167]]

Printing Office stock numbers 4101-0065 and 003-005-00176-0, 
respectively).
    (iii) Potential to emit means the maximum capacity of a stationary 
source to emit a pollutant under its physical and operational design. 
Any physical or operational limitation on the capacity of the source to 
emit a pollutant, including air pollution control equipment and 
restrictions on hours of operation or on the type or amount of material 
combusted, stored, or processed, shall be treated as part of its design 
only if the limitation or the effect it would have on emissions is 
federally enforceable. Secondary emissions do not count in determining 
the potential to emit of a stationary source.
    (iv)(A) Major stationary source means:
    (1) Any stationary source of air pollutants which emits, or has the 
potential to emit 100 tons per year or more of any regulated NSR 
pollutant, or
    (2) Any physical change that would occur at a stationary source not 
qualifying under paragraph (a)(1)(iv)(A)(1) as a major stationary 
source, if the change would constitute a major stationary source by 
itself.
    (B) A major stationary source that is major for volatile organic 
compounds shall be considered major for ozone
    (C) The fugitive emissions of a stationary source shall not be 
included in determining for any of the purposes of this paragraph 
whether it is a major stationary source, unless the source belongs to 
one of the following categories of stationary sources:
    (1) Coal cleaning plants (with thermal dryers);
    (2) Kraft pulp mills;
    (3) Portland cement plants;
    (4) Primary zinc smelters;
    (5) Iron and steel mills;
    (6) Primary aluminum ore reduction plants;
    (7) Primary copper smelters;
    (8) Municipal incinerators capable of charging more than 250 tons of 
refuse per day;
    (9) Hydrofluoric, sulfuric, or nitric acid plants;
    (10) Petroleum refineries;
    (11) Lime plants;
    (12) Phosphate rock processing plants;
    (13) Coke oven batteries;
    (14) Sulfur recovery plants;
    (15) Carbon black plants (furnace process);
    (16) Primary lead smelters;
    (17) Fuel conversion plants;
    (18) Sintering plants;
    (19) Secondary metal production plants;
    (20) Chemical process plants;
    (21) Fossil-fuel boilers (or combination thereof) totaling more than 
250 million British thermal units per hour heat input;
    (22) Petroleum storage and transfer units with a total storage 
capacity exceeding 300,000 barrels;
    (23) Taconite ore processing plants;
    (24) Glass fiber processing plants;
    (25) Charcoal production plants;
    (26) Fossil fuel-fired steam electric plants of more than 250 
million British thermal units per hour heat input; and
    (27) Any other stationary source category which, as of August 7, 
1980, is being regulated under section 111 or 112 of the Act.
    (v)(A) Major modification means any physical change in or change in 
the method of operation of a major stationary source that would result 
in:
    (1) A significant emissions increase of a regulated NSR pollutant 
(as defined in paragraph (a)(1)(xxxvii) of this section); and
    (2) A significant net emissions increase of that pollutant from the 
major stationary source.
    (B) Any significant emissions increase (as defined in paragraph 
(a)(1)(xxvii) of this section) from any emissions units or net emissions 
increase (as defined in paragraph (a)(1)(vi) of this section) at a major 
stationary source that is significant for volatile organic compounds 
shall be considered significant for ozone.
    (C) A physical change or change in the method of operation shall not 
include:
    (1) Routine maintenance, repair and replacement;
    (2) Use of an alternative fuel or raw material by reason of an order 
under sections 2 (a) and (b) of the Energy Supply and Environmental 
Coordination Act of 1974 (or any superseding legislation) or by reason 
of a natural gas curtailment plan pursuant to the Federal Power Act;

[[Page 168]]

    (3) Use of an alternative fuel by reason of an order or rule section 
125 of the Act;
    (4) Use of an alternative fuel at a steam generating unit to the 
extent that the fuel is generated from municipal solid waste;
    (5) Use of an alternative fuel or raw material by a stationary 
source which;
    (i) The source was capable of accommodating before December 21, 
1976, unless such change would be prohibited under any federally 
enforceable permit condition which was established after December 12, 
1976 pursuant to 40 CFR 52.21 or under regulations approved pursuant to 
40 CFR subpart I or Sec. 51.166, or
    (ii) The source is approved to use under any permit issued under 
regulations approved pursuant to this section;
    (6) An increase in the hours of operation or in the production rate, 
unless such change is prohibited under any federally enforceable permit 
condition which was established after December 21, 1976 pursuant to 40 
CFR 52.21 or regulations approved pursuant to 40 CFR part 51 subpart I 
or 40 CFR 51.166.
    (7) Any change in ownership at a stationary source.
    (8) The addition, replacement, or use of a PCP, as defined in 
paragraph (a)(1)(xxv) of this section, at an existing emissions unit 
meeting the requirements of paragraph (e) of this section. A replacement 
control technology must provide more effective emissions control than 
that of the replaced control technology to qualify for this exclusion.
    (9) The installation, operation, cessation, or removal of a 
temporary clean coal technology demonstration project, provided that the 
project complies with:
    (i) The State Implementation Plan for the State in which the project 
is located, and
    (ii) Other requirements necessary to attain and maintain the 
national ambient air quality standard during the project and after it is 
terminated.
    (D) This definition shall not apply with respect to a particular 
regulated NSR pollutant when the major stationary source is complying 
with the requirements under paragraph (f) of this section for a PAL for 
that pollutant. Instead, the definition at paragraph (f)(2)(viii) of 
this section shall apply.
    (vi)(A) Net emissions increase means, with respect to any regulated 
NSR pollutant emitted by a major stationary source, the amount by which 
the sum of the following exceeds zero:
    (1) The increase in emissions from a particular physical change or 
change in the method of operation at a stationary source as calculated 
pursuant to paragraph (a)(2)(ii) of this section; and
    (2) Any other increases and decreases in actual emissions at the 
major stationary source that are contemporaneous with the particular 
change and are otherwise creditable. Baseline actual emissions for 
calculating increases and decreases under this paragraph 
(a)(1)(vi)(A)(2) shall be determined as provided in paragraph 
(a)(1)(xxxv) of this section, except that paragraphs (a)(1)(xxxv)(A)(3) 
and (a)(1)(xxxv)(B)(4) of this section shall not apply.
    (B) An increase or decrease in actual emissions is contemporaneous 
with the increase from the particular change only if it occurs before 
the date that the increase from the particular change occurs;
    (C) An increase or decrease in actual emissions is creditable only 
if:
    (1) It occurs within a reasonable period to be specified by the 
reviewing authority; and
    (2) The reviewing authority has not relied on it in issuing a permit 
for the source under regulations approved pursuant to this section, 
which permit is in effect when the increase in actual emissions from the 
particular change occurs; and
    (3) The increase or decrease in emissions did not occur at a Clean 
Unit, except as provided in paragraphs (c)(8) and (d)(10) of this 
section.
    (D) An increase in actual emissions is creditable only to the extent 
that the new level of actual emissions exceeds the old level.
    (E) A decrease in actual emissions is creditable only to the extent 
that:
    (1) The old level of actual emission or the old level of allowable 
emissions

[[Page 169]]

whichever is lower, exceeds the new level of actual emissions;
    (2) It is enforceable as a practical matter at and after the time 
that actual construction on the particular change begins; and
    (3) The reviewing authority has not relied on it in issuing any 
permit under regulations approved pursuant to 40 CFR part 51 subpart I 
or the State has not relied on it in demonstrating attainment or 
reasonable further progress;
    (4) It has approximately the same qualitative significance for 
public health and welfare as that attributed to the increase from the 
particular change; and
    (5) The decrease in actual emissions did not result from the 
installation of add-on control technology or application of pollution 
prevention practices that were relied on in designating an emissions 
unit as a Clean Unit under 40 CFR 52.21(y) or under regulations approved 
pursuant to paragraph (d) of this section or Sec. 51.166(u). That is, 
once an emissions unit has been designated as a Clean Unit, the owner or 
operator cannot later use the emissions reduction from the air pollution 
control measures that the Clean Unit designation is based on in 
calculating the net emissions increase for another emissions unit (i.e., 
must not use that reduction in a ``netting analysis'' for another 
emissions unit). However, any new emissions reductions that were not 
relied upon in a PCP excluded pursuant to paragraph (e) of this section 
or for a Clean Unit designation are creditable to the extent they meet 
the requirements in paragraphs (e)(6)(iv) of this section for the PCP 
and paragraphs (c)(8) or (d)(10) of this section for a Clean Unit.
    (F) An increase that results from a physical change at a source 
occurs when the emissions unit on which construction occurred becomes 
operational and begins to emit a particular pollutant. Any replacement 
unit that requires shakedown becomes operational only after a reasonable 
shakedown period, not to exceed 180 days.
    (G) Paragraph (a)(1)(xii)(B) of this section shall not apply for 
determining creditable increases and decreases or after a change.
    (vii) Emissions unit means any part of a stationary source that 
emits or would have the potential to emit any regulated NSR pollutant 
and includes an electric steam generating unit as defined in paragraph 
(a)(1)(xx) of this section. For purposes of this section, there are two 
types of emissions units as described in paragraphs (a)(1)(vii)(A) and 
(B) of this section.
    (A) A new emissions unit is any emissions unit which is (or will be) 
newly constructed and which has existed for less than 2 years from the 
date such emissions unit first operated.
    (B) An existing emissions unit is any emissions unit that does not 
meet the requirements in paragraph (a)(1)(vii)(A) of this section.
    (viii) Secondary emissons means emissions which would occur as a 
result of the construction or operation of a major stationary source or 
major modification, but do not come from the major stationary source or 
major modification itself. For the purpose of this section, secondary 
emissions must be specific, well defined, quantifiable, and impact the 
same general area as the stationary source or modification which causes 
the secondary emissions. Secondary emissions include emissions from any 
offsite support facility which would not be constructed or increase its 
emissions except as a result of the construction of operation of the 
major stationary source of major modification. Secondary emissions do 
not include any emissions which come directly from a mobile source such 
as emissions from the tailpipe of a motor vehicle, from a train, or from 
a vessel.
    (ix) Fugitive emissions means those emissions which could not 
reasonably pass through a stack, chimney, vent or other functionally 
equivalent opening.
    (x) Significant means, in reference to a net emissions increase pr 
the potential of a source to emit any of the following pollutions, as 
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
Lead: 0.6 tpy


[[Page 170]]


    (xi) Allowable emissions means the emissions rate of a stationary 
source calculated using the maximum rated capacity of the source (unless 
the source is subject to federally enforceable limits which restrict the 
operating rate, or hours of operation, or both) and the most stringent 
of the following:
    (A) The applicable standards set forth in 40 CFR part 60 or 61;
    (B) Any applicable State Implementation Plan emissions limitation 
including those with a future compliance date; or
    (C) The emissions rate specified as a federally enforceable permit 
condition, including those with a future compliance date.
    (xii)(A) Actual emissions means the actual rate of emissions of a 
regulated NSR pollutant from an emissions unit, as determined in 
accordance with paragraphs (a)(1)(xii)(B) through (D) of this section, 
except that this definition shall not apply for calculating whether a 
significant emissions increase has occurred, or for establishing a PAL 
under paragraph (f) of this section. Instead, paragraphs (a)(1)(xxviii) 
and (xxxv) of this section shall apply for those purposes.
    (B) In general, actual emissions as of a particular date shall equal 
the average rate, in tons per year, at which the unit actually emitted 
the pollutant during a consecutive 24-month period which precedes the 
particular date and which is representative of normal source operation. 
The reviewing authority shall allow the use of a different time period 
upon a determination that it is more representative of normal source 
operation. Actual emissions shall be calculated using the unit's actual 
operating hours, production rates, and types of materials processed, 
stored, or combusted during the selected time period.
    (C) The reviewing authority may presume that source-specific 
allowable emissions for the unit are equivalent to the actual emissions 
of the unit.
    (D) For any emissions unit that has not begun normal operations on 
the particular date, actual emissions shall equal the potential to emit 
of the unit on that date.
    (xiii) Lowest achievable emission rate (LAER) means, for any source, 
the more stringent rate of emissions based on the following:
    (A) The most stringent emissions limitation which is contained in 
the implementation plan of any State for such class or category of 
stationary source, unless the owner or operator of the proposed 
stationary source demonstrates that such limitations are not achievable; 
or
    (B) The most stringent emissions limitation which is achieved in 
practice by such class or category of stationary sources. This 
limitation, when applied to a modification, means the lowest achievable 
emissions rate for the new or modified emissions units within or 
stationary source. In no event shall the application of the term permit 
a proposed new or modified stationary source to emit any pollutant in 
excess of the amount allowable under an applicable new source standard 
of performance.
    (xiv) Federally enforceable means all limitations and conditions 
which are enforceable by the Administrator, including those requirements 
developed pursuant to 40 CFR parts 60 and 61, requirements within any 
applicable State implementation plan, any permit requirements 
established pursuant to 40 CFR 52.21 or under regulations approved 
pursuant to 40 CFR part 51, subpart I, including operating permits 
issued under an EPA-approved program that is incorporated into the State 
implementation plan and expressly requires adherence to any permit 
issued under such program.
    (xv) Begin actual construction means in general, initiation of 
physical on-site construction activities on an emissions unit which are 
of a permanent nature. Such activities include, but are not limited to, 
installation of building supports and foundations, laying of underground 
pipework, and construction of permanent storage structures. With respect 
to a change in method of operating this term refers to those on-site 
activities other than preparatory activities which mark the initiation 
of the change.
    (xvi) Commence as applied to construction of a major stationary 
source or major modification means that the

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owner or operator has all necessary preconstruction approvals or permits 
and either has:
    (A) Begun, or caused to begin, a continuous program of actual on-
site construction of the source, to be completed within a reasonable 
time; or
    (B) Entered into binding agreements or contractual obligations, 
which cannot be canceled or modified without substantial loss to the 
owner or operator, to undertake a program of actual construction of the 
source to be completed within a reasonable time.
    (xvii) Necessary preconstruction approvals or permits means those 
Federal air quality control laws and regulations and those air quality 
control laws and regulations which are part of the applicable State 
Implementation Plan.
    (xviii) Construction means any physical change or change in the 
method of operation (including fabrication, erection, installation, 
demolition, or modification of an emissions unit) that would result in a 
change in emissions.
    (xix)Volatile organic compounds (VOC) is as defined in 
Sec. 51.100(s) of this part.
    (xx) Electric utility steam generating unit means any steam electric 
generating unit that is constructed for the purpose of supplying more 
than one-third of its potential electric output capacity and more than 
25 MW electrical output to any utility power distribution system for 
sale. Any steam supplied to a steam distribution system for the purpose 
of providing steam to a steam-electric generator that would produce 
electrical energy for sale is also considered in determining the 
electrical energy output capacity of the affected facility.
    (xxi) [Reserved]
    (xxii) Temporary clean coal technology demonstration project means a 
clean coal technology demonstration project that is operated for a 
period of 5 years or less, and which complies with the State 
Implementation Plan for the State in which the project is located and 
other requirements necessary to attain and maintain the national ambient 
air quality standards during the project and after it is terminated.
    (xxiii) Clean coal technology means any technology, including 
technologies applied at the precombustion, combustion, or post 
combustion stage, at a new or existing facility which will achieve 
significant reductions in air emissions of sulfur dioxide or oxides of 
nitrogen associated with the utilization of coal in the generation of 
electricity, or process steam which was not in widespread use as of 
November 15, 1990.
    (xxiv) Clean coal technology demonstration project means a project 
using funds appropriated under the heading ``Department of Energy-Clean 
Coal Technology,'' up to a total amount of $2,500,000,000 for commercial 
demonstration of clean coal technology, or similar projects funded 
through appropriations for the Environmental Protection Agency. The 
Federal contribution for a qualifying project shall be at least 20 
percent of the total cost of the demonstration project.
    (xxv) Pollution control project (PCP) means any activity, set of 
work practices or project (including pollution prevention as defined 
under paragraph (a)(1)(xxvi) of this section) undertaken at an existing 
emissions unit that reduces emissions of air pollutants from such unit. 
Such qualifying activities or projects can include the replacement or 
upgrade of an existing emissions control technology with a more 
effective unit. Other changes that may occur at the source are not 
considered part of the PCP if they are not necessary to reduce emissions 
through the PCP. Projects listed in paragraphs (a)(1)(xxv)(A) through 
(F) of this section are presumed to be environmentally beneficial 
pursuant to paragraph (e)(2)(i) of this section. Projects not listed in 
these paragraphs may qualify for a case-specific PCP exclusion pursuant 
to the requirements of paragraphs (e)(2) and (e)(5) of this section.
    (A) Conventional or advanced flue gas desulfurization or sorbent 
injection for control of SO2.
    (B) Electrostatic precipitators, baghouses, high efficiency 
multiclones, or scrubbers for control of particulate matter or other 
pollutants.
    (C) Flue gas recirculation, low-NOX burners or 
combustors, selective non-catalytic reduction, selective catalytic 
reduction, low emission combustion (for IC engines), and oxidation/
absorption catalyst for control of NOX.

[[Page 172]]

    (D) Regenerative thermal oxidizers, catalytic oxidizers, condensers, 
thermal incinerators, hydrocarbon combustion flares, biofiltration, 
absorbers and adsorbers, and floating roofs for storage vessels for 
control of volatile organic compounds or hazardous air pollutants. For 
the purpose of this section, ``hydrocarbon combustion flare'' means 
either a flare used to comply with an applicable NSPS or MACT standard 
(including uses of flares during startup, shutdown, or malfunction 
permitted under such a standard), or a flare that serves to control 
emissions of waste streams comprised predominately of hydrocarbons and 
containing no more than 230 mg/dscm hydrogen sulfide.
    (E) Activities or projects undertaken to accommodate switching (or 
partially switching) to an inherently less polluting fuel, to be limited 
to the following fuel switches:
    (1) Switching from a heavier grade of fuel oil to a lighter fuel 
oil, or any grade of oil to 0.05 percent sulfur diesel (i.e., from a 
higher sulfur content 2 fuel or from 6 fuel, to CA 
0.05 percent sulfur 2 diesel);
    (2) Switching from coal, oil, or any solid fuel to natural gas, 
propane, or gasified coal;
    (3) Switching from coal to wood, excluding construction or 
demolition waste, chemical or pesticide treated wood, and other forms of 
``unclean'' wood;
    (4) Switching from coal to 2 fuel oil (0.5 percent maximum 
sulfur content); and
    (5) Switching from high sulfur coal to low sulfur coal (maximum 1.2 
percent sulfur content).
    (F) Activities or projects undertaken to accommodate switching from 
the use of one ozone depleting substance (ODS) to the use of a substance 
with a lower or zero ozone depletion potential (ODP), including changes 
to equipment needed to accommodate the activity or project, that meet 
the requirements of paragraphs (a)(1)(xxv)(F)(1) and (2) of this 
section.
    (1) The productive capacity of the equipment is not increased as a 
result of the activity or project.
    (2) The projected usage of the new substance is lower, on an ODP-
weighted basis, than the baseline usage of the replaced ODS. To make 
this determination, follow the procedure in paragraphs 
(a)(1)(xxv)(F)(2)(i) through (iv) of this section.
    (i) Determine the ODP of the substances by consulting 40 CFR part 
82, subpart A, appendices A and B.
    (ii) Calculate the replaced ODP-weighted amount by multiplying the 
baseline actual usage (using the annualized average of any 24 
consecutive months of usage within the past 10 years) by the ODP of the 
replaced ODS.
    (iii) Calculate the projected ODP-weighted amount by multiplying the 
projected future annual usage of the new substance by its ODP.
    (iv) If the value calculated in paragraph (a)(1)(xxv)(F)(2)(ii) of 
this section is more than the value calculated in paragraph 
(a)(1)(xxv)(F)(2)(iii) of this section, then the projected use of the 
new substance is lower, on an ODP-weighted basis, than the baseline 
usage of the replaced ODS.
    (xxvi) Pollution prevention means any activity that through process 
changes, product reformulation or redesign, or substitution of less 
polluting raw materials, eliminates or reduces the release of air 
pollutants (including fugitive emissions) and other pollutants to the 
environment prior to recycling, treatment, or disposal; it does not mean 
recycling (other than certain ``in-process recycling'' practices), 
energy recovery, treatment, or disposal.
    (xxvii) Significant emissions increase means, for a regulated NSR 
pollutant, an increase in emissions that is significant (as defined in 
paragraph (a)(1)(x) of this section) for that pollutant.
    (xxviii)(A) Projected actual emissions means, the maximum annual 
rate, in tons per year, at which an existing emissions unit is projected 
to emit a regulated NSR pollutant in any one of the 5 years (12-month 
period) following the date the unit resumes regular operation after the 
project, or in any one of the 10 years following that date, if the 
project involves increasing the emissions unit's design capacity or its 
potential to emit of that regulated NSR pollutant and full utilization 
of the unit would result in a significant emissions increase or a 
significant net

[[Page 173]]

emissions increase at the major stationary source.
    (B) In determining the projected actual emissions under paragraph 
(a)(1)(xxviii)(A) of this section before beginning actual construction, 
the owner or operator of the major stationary source:
    (1) Shall consider all relevant information, including but not 
limited to, historical operational data, the company's own 
representations, the company's expected business activity and the 
company's highest projections of business activity, the company's 
filings with the State or Federal regulatory authorities, and compliance 
plans under the approved plan; and
    (2) Shall include fugitive emissions to the extent quantifiable, and 
emissions associated with startups, shutdowns, and malfunctions; and
    (3) Shall exclude, in calculating any increase in emissions that 
results from the particular project, that portion of the unit's 
emissions following the project that an existing unit could have 
accommodated during the consecutive 24-month period used to establish 
the baseline actual emissions under paragraph (a)(1)(xxxv) of this 
section and that are also unrelated to the particular project, including 
any increased utilization due to product demand growth; or,
    (4) In lieu of using the method set out in paragraphs 
(a)(1)(xxviii)(B)(1) through (3) of this section, may elect to use the 
emissions unit's potential to emit, in tons per year, as defined under 
paragraph (a)(1)(iii) of this section.
    (xxix) Clean Unit means any emissions unit that has been issued a 
major NSR permit that requires compliance with BACT or LAER, that is 
complying with such BACT/LAER requirements, and qualifies as a Clean 
Unit pursuant to regulations approved by the Administrator in accordance 
with paragraph (c) of this section; or any emissions unit that has been 
designated by a reviewing authority as a Clean Unit, based on the 
criteria in paragraphs (d)(3)(i) through (iv) of this section, using a 
plan-approved permitting process; or any emissions unit that has been 
designated as a Clean Unit by the Administrator in accordance with 
Sec. 52.21(y)(3)(i) through (iv) of this chapter.
    (xxx) Nonattainment major new source review (NSR) program means a 
major source preconstruction permit program that has been approved by 
the Administrator and incorporated into the plan to implement the 
requirements of this section, or a program that implements part 51, 
appendix S, Sections I through VI of this chapter. Any permit issued 
under such a program is a major NSR permit.
    (xxxi) Continuous emissions monitoring system (CEMS) means all of 
the equipment that may be required to meet the data acquisition and 
availability requirements of this section, to sample, condition (if 
applicable), analyze, and provide a record of emissions on a continuous 
basis.
    (xxxii) Predictive emissions monitoring system (PEMS) means all of 
the equipment necessary to monitor process and control device 
operational parameters (for example, control device secondary voltages 
and electric currents) and other information (for example, gas flow 
rate, O2 or CO2 concentrations), and calculate and 
record the mass emissions rate (for example, lb/hr) on a continuous 
basis.
    (xxxiii) Continuous parameter monitoring system (CPMS) means all of 
the equipment necessary to meet the data acquisition and availability 
requirements of this section, to monitor process and control device 
operational parameters (for example, control device secondary voltages 
and electric currents) and other information (for example, gas flow 
rate, O2 or CO2 concentrations), and to record 
average operational parameter value(s) on a continuous basis.
    (xxxiv) Continuous emissions rate monitoring system (CERMS) means 
the total equipment required for the determination and recording of the 
pollutant mass emissions rate (in terms of mass per unit of time).
    (xxxv) Baseline actual emissions means the rate of emissions, in 
tons per year, of a regulated NSR pollutant, as determined in accordance 
with paragraphs (a)(1)(xxxv)(A) through (D) of this section.
    (A) For any existing electric utility steam generating unit, 
baseline actual

[[Page 174]]

emissions means the average rate, in tons per year, at which the unit 
actually emitted the pollutant during any consecutive 24-month period 
selected by the owner or operator within the 5-year period immediately 
preceding when the owner or operator begins actual construction of the 
project. The reviewing authority shall allow the use of a different time 
period upon a determination that it is more representative of normal 
source operation.
    (1) The average rate shall include fugitive emissions to the extent 
quantifiable, and emissions associated with startups, shutdowns, and 
malfunctions.
    (2) The average rate shall be adjusted downward to exclude any non-
compliant emissions that occurred while the source was operating above 
any emission limitation that was legally enforceable during the 
consecutive 24-month period.
    (3) For a regulated NSR pollutant, when a project involves multiple 
emissions units, only one consecutive 24-month period must be used to 
determine the baseline actual emissions for the emissions units being 
changed. A different consecutive 24-month period can be used for each 
regulated NSR pollutant.
    (4) The average rate shall not be based on any consecutive 24-month 
period for which there is inadequate information for determining annual 
emissions, in tons per year, and for adjusting this amount if required 
by paragraph (a)(1)(xxxv)(A)(2) of this section.
    (B) For an existing emissions unit (other than an electric utility 
steam generating unit), baseline actual emissions means the average 
rate, in tons per year, at which the emissions unit actually emitted the 
pollutant during any consecutive 24-month period selected by the owner 
or operator within the 10-year period immediately preceding either the 
date the owner or operator begins actual construction of the project, or 
the date a complete permit application is received by the reviewing 
authority for a permit required either under this section or under a 
plan approved by the Administrator, whichever is earlier, except that 
the 10-year period shall not include any period earlier than November 
15, 1990.
    (1) The average rate shall include fugitive emissions to the extent 
quantifiable, and emissions associated with startups, shutdowns, and 
malfunctions.
    (2) The average rate shall be adjusted downward to exclude any non-
compliant emissions that occurred while the source was operating above 
an emission limitation that was legally enforceable during the 
consecutive 24-month period.
    (3) The average rate shall be adjusted downward to exclude any 
emissions that would have exceeded an emission limitation with which the 
major stationary source must currently comply, had such major stationary 
source been required to comply with such limitations during the 
consecutive 24-month period. However, if an emission limitation is part 
of a maximum achievable control technology standard that the 
Administrator proposed or promulgated under part 63 of this chapter, the 
baseline actual emissions need only be adjusted if the State has taken 
credit for such emissions reductions in an attainment demonstration or 
maintenance plan consistent with the requirements of paragraph 
(a)(3)(ii)(G) of this section.
    (4) For a regulated NSR pollutant, when a project involves multiple 
emissions units, only one consecutive 24-month period must be used to 
determine the baseline actual emissions for the emissions units being 
changed. A different consecutive 24-month period can be used For each 
regulated NSR pollutant.
    (5) The average rate shall not be based on any consecutive 24-month 
period for which there is inadequate information for determining annual 
emissions, in tons per year, and for adjusting this amount if required 
by paragraphs (a)(1)(xxxv)(B)(2) and (3) of this section.
    (C) For a new emissions unit, the baseline actual emissions for 
purposes of determining the emissions increase that will result from the 
initial construction and operation of such unit shall equal zero; and 
thereafter, for all other purposes, shall equal the unit's potential to 
emit.
    (D) For a PAL for a major stationary source, the baseline actual 
emissions shall be calculated for existing electric

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utility steam generating units in accordance with the procedures 
contained in paragraph (a)(1)(xxxv)(A) of this section, for other 
existing emissions units in accordance with the procedures contained in 
paragraph (a)(1)(xxxv)(B) of this section, and for a new emissions unit 
in accordance with the procedures contained in paragraph (a)(1)(xxxv)(C) 
of this section.
    (xxxvi) [Reserved]
    (xxxvii) Regulated NSR pollutant, for purposes of this section, 
means the following:
    (A) Nitrogen oxides or any volatile organic compounds;
    (B) Any pollutant for which a national ambient air quality standard 
has been promulgated; or
    (C) Any pollutant that is a constituent or precursor of a general 
pollutant listed under paragraphs (a)(1)(xxxvii)(A) or (B) of this 
section, provided that a constituent or precursor pollutant may only be 
regulated under NSR as part of regulation of the general pollutant.
    (xxxviii) Reviewing authority means the State air pollution control 
agency, local agency, other State agency, Indian tribe, or other agency 
authorized by the Administrator to carry out a permit program under this 
section and Sec. 51.166, or the Administrator in the case of EPA-
implemented permit programs under Sec. 52.21.
    (xxxix) Project means a physical change in, or change in the method 
of operation of, an existing major stationary source.
    (xl) Best available control technology (BACT) means an emissions 
limitation (including a visible emissions standard) based on the maximum 
degree of reduction for each regulated NSR pollutant which would be 
emitted from any proposed major stationary source or major modification 
which the reviewing authority, on a case-by-case basis, taking into 
account energy, environmental, and economic impacts and other costs, 
determines is achievable for such source or modification through 
application of production processes or available methods, systems, and 
techniques, including fuel cleaning or treatment or innovative fuel 
combustion techniques for control of such pollutant. In no event shall 
application of best available control technology result in emissions of 
any pollutant which would exceed the emissions allowed by any applicable 
standard under 40 CFR part 60 or 61. If the reviewing authority 
determines that technological or economic limitations on the application 
of measurement methodology to a particular emissions unit would make the 
imposition of an emissions standard infeasible, a design, equipment, 
work practice, operational standard, or combination thereof, may be 
prescribed instead to satisfy the requirement for the application of 
BACT. Such standard shall, to the degree possible, set forth the 
emissions reduction achievable by implementation of such design, 
equipment, work practice or operation, and shall provide for compliance 
by means which achieve equivalent results.
    (xli) Prevention of Significant Deterioration (PSD) permit means any 
permit that is issued under a major source preconstruction permit 
program that has been approved by the Administrator and incorporated 
into the plan to implement the requirements of Sec. 51.166 of this 
chapter, or under the program in Sec. 52.21 of this chapter.
    (xlii) Federal Land Manager means, with respect to any lands in the 
United States, the Secretary of the department with authority over such 
lands.
    (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 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.
    (ii) Each plan shall use the specific provisions of paragraphs 
(a)(2)(ii)(A) through (F) of this section. Deviations from these 
provisions will be approved only if the State specifically demonstrates 
that the submitted provisions are more stringent than or at least as 
stringent in all respects as the

[[Page 176]]

corresponding provisions in paragraphs (a)(2)(ii)(A) through (F) of this 
section.
    (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 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.
    (B) The procedure for calculating (before beginning actual 
construction) whether a significant emissions increase (i.e., the first 
step of the process) will occur depends upon the type of emissions units 
being modified, according to paragraphs (a)(2)(ii)(C) through (F) of 
this section. The procedure for calculating (before beginning actual 
construction) whether a significant net emissions increase will occur at 
the major stationary source (i.e., the second step of the process) is 
contained in the definition in paragraph (a)(1)(vi) of this section. 
Regardless of any such preconstruction projections, a major modification 
results if the project causes a significant emissions increase and a 
significant net emissions increase.
    (C) Actual-to-projected-actual applicability test for projects that 
only involve existing emissions units. A significant emissions increase 
of a regulated NSR pollutant is projected to occur if the sum of the 
difference between the projected actual emissions (as defined in 
paragraph (a)(1)(xxviii) of this section) and the baseline actual 
emissions (as defined in paragraphs (a)(1)(xxxv)(A) and (B) of this 
section, as applicable), for each existing emissions unit, equals or 
exceeds the significant amount for that pollutant (as defined in 
paragraph (a)(1)(x) of this section).
    (D) Actual-to-potential test for projects that only involve 
construction of a new emissions unit(s). A significant emissions 
increase of a regulated NSR pollutant is projected to occur if the sum 
of the difference between the potential to emit (as defined in paragraph 
(a)(1)(iii) of this section) from each new emissions unit following 
completion of the project and the baseline actual emissions (as defined 
in paragraph (a)(1)(xxxv)(C) of this section) of these units before the 
project equals or exceeds the significant amount for that pollutant (as 
defined in paragraph (a)(1)(x) of this section).
    (E) Emission test for projects that involve Clean Units. For a 
project that will be constructed and operated at a Clean Unit without 
causing the emissions unit to lose its Clean Unit designation, no 
emissions increase is deemed to occur.
    (F) Hybrid test for projects that involve multiple types of 
emissions units. A significant emissions increase of a regulated NSR 
pollutant is projected to occur if the sum of the emissions increases 
for each emissions unit, using the method specified in paragraphs 
(a)(2)(ii)(C) through (E) of this section as applicable with respect to 
each emissions unit, for each type of emissions unit equals or exceeds 
the significant amount for that pollutant (as defined in paragraph 
(a)(1)(x) of this section). For example, if a project involves both an 
existing emissions unit and a Clean Unit, the projected increase is 
determined by summing the values determined using the method specified 
in paragraph (a)(2)(ii)(C) of this section for the existing unit and 
using the method specified in paragraph (a)(2)(ii)(E) of this section 
for the Clean Unit.
    (iii) The plan shall require that for any major stationary source 
for a PAL for a regulated NSR pollutant, the major stationary source 
shall comply with requirements under paragraph (f) of this section.
    (iv) The plan shall require that an owner or operator undertaking a 
PCP (as defined in paragraph (a)(1)(xxv) of this section) shall comply 
with the requirements under paragraph (e) of this section.
    (3)(i) Each plan shall provide that for sources and modifications 
subject to any preconstruction review program

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adopted pursuant to this subsection the baseline for determining credit 
for emissions reductions is the emissions limit under the applicable 
State Implementation Plan in effect at the time the application to 
construct is filed, except that the offset baseline shall be the actual 
emissions of the source from which offset credit is obtained where;
    (A) The demonstration of reasonable further progress and attainment 
of ambient air quality standards is based upon the actual emissions of 
sources located within a designated nonattainment area for which the 
preconstruction review program was adopted; or
    (B) The applicable State Implementation Plan does not contain an 
emissions limitation for that source or source category.
    (ii) The plan shall further provide that:
    (A) Where the emissions limit under the applicable State 
Implementation Plan allows greater emissions than the potential to emit 
of the source, emissions offset credit will be allowed only for control 
below this potential;
    (B) For an existing fuel combustion source, credit shall be based on 
the allowable emissions under the applicable State Implementation Plan 
for the type of fuel being burned at the time the application to 
construct is filed. If the existing source commits to switch to a 
cleaner fuel at some future date, emissions offset credit based on the 
allowable (or actual) emissions for the fuels involved is not 
acceptable, unless the permit is conditioned to require the use of a 
specified alternative control measure which would achieve the same 
degree of emissions reduction should the source switch back to a dirtier 
fuel at some later date. The reviewing authority should ensure that 
adequate long-term supplies of the new fuel are available before 
granting emissions offset credit for fuel switches,
    (C)(1) Emissions reductions achieved by shutting down an existing 
source or curtailing production or operating hours below baseline levels 
may be generally credited if such reductions are permanent, 
quantifiable, and federally enforceable, and if the area has an EPA-
approved attainment plan. In addition, the shutdown or curtailment is 
creditable only if it occurred on or after the date specified for this 
purpose in the plan, and if such date is on or after the date of the 
most recent emissions inventory used in the plan's demonstration of 
attainment. Where the plan does not specify a cutoff date for shutdown 
credits, the date of the most recent emissions inventory or attainment 
demonstration, as the case may be, shall apply. However, in no event may 
credit be given for shutdowns which occurred prior to August 7, 1977. 
For purposes of this paragraph, a permitting authority may choose to 
consider a prior shutdown or curtailment to have occurred after the date 
of its most recent emissions inventory, if the inventory explicitly 
includes as current existing emissions the emissions from such 
previously shutdown or curtailed sources.
    (2) Such reductions may be credited in the absence of an approved 
attainment demonstration only if the shutdown or curtailment occurred on 
or after the date the new source permit application is filed, or, if the 
applicant can establish that the proposed new source is a replacement 
for the shutdown or curtailed source, and the cutoff date provisions of 
Sec. 51.165(a)(3)(ii)(C)(1) are observed.
    (D) No emissions credit may be allowed for replacing one hydrocarbon 
compound with another of lesser reactivity, except for those compounds 
listed in Table 1 of EPA's ``Recommended Policy on Control of Volatile 
Organic Compounds'' (42 FR 35314, July 8, 1977; (This document is also 
available from Mr. Ted Creekmore, Office of Air Quality Planning and 
Standards, (MD-15) Research Triangle Park, NC 27711.))
    (E) All emission reductions claimed as offset credit shall be 
federally enforceable;
    (F) Procedures relating to the permissible location of offsetting 
emissions shall be followed which are at least as stringent as those set 
out in 40 CFR part 51 appendix S section IV.D.
    (G) Credit for an emissions reduction can be claimed to the extent 
that the reviewing authority has not relied on it in issuing any permit 
under regulations approved pursuant to 40 CFR part 51 subpart I or the 
State has not relied

[[Page 178]]

on it in demonstration attainment or reasonable further progress.
    (H) Decreases in actual emissions resulting from the installation of 
add-on control technology or application of pollution prevention 
measures that were relied upon in designating an emissions unit as a 
Clean Unit or a project as a PCP cannot be used as offsets.
    (I) Decreases in actual emissions occurring at a Clean Unit cannot 
be used as offsets, except as provided in paragraphs (c)(8) and (d)(10) 
of this section. Similarly, decreases in actual emissions occurring at a 
PCP cannot be used as offsets, except as provided in paragraph 
(e)(6)(iv) of this section.
    (J) The total tonnage of increased emissions, in tons per year, 
resulting from a major modification that must be offset in accordance 
with section 173 of the Act shall be determined by summing the 
difference between the allowable emissions after the modification (as 
defined by paragraph (a)(1)(xi) of this section) and the actual 
emissions before the modification (as defined in paragraph (a)(1)(xii) 
of this section) for each emissions unit.
    (4) Each plan may provide that the provisions of this paragraph do 
not apply to a source or modification that would be a major stationary 
source or major modification only if fugitive emission to the extent 
quantifiable are considered in calculating the potential to emit of the 
stationary source or modification and the source does not belong to any 
of the following categories:
    (i) Coal cleaning plants (with thermal dryers);
    (ii) Kraft pulp mills;
    (iii) Portland cement plants;
    (iv) Primary zinc smelters;
    (v) Iron and steel mills;
    (vi) Primary aluminum ore reduction plants;
    (vii) Primary copper smelters;
    (viii) Municipal incinerators capable of charging more than 250 tons 
of refuse per day;
    (ix) Hydrofluoric, sulfuric, or citric acid plants;
    (x) Petroleum refineries;
    (xi) Lime plants;
    (xii) Phosphate rock processing plants;
    (xiii) Coke oven batteries;
    (xiv) Sulfur recovery plants;
    (xv) Carbon black plants (furnace process);
    (xvi) Primary lead smelters;
    (xvii) Fuel conversion plants;
    (xviii) Sintering plants;
    (xix) Secondary metal production plants;
    (xx) Chemical process plants;
    (xxi) Fossil-fuel boilers (or combination thereof) totaling more 
than 250 million British thermal units per hour heat input;
    (xxii) Petroleum storage and transfer units with a total storage 
capacity exceeding 300,000 barrels;
    (xxiii) Taconite ore processing plants;
    (xxiv) Glass fiber processing plants;
    (xxv) Charcoal production plants;
    (xxvi) Fossil fuel-fired steam electric plants of more than 250 
million British thermal units per hour heat input;
    (xxvii) Any other stationary source category which, as of August 7, 
1980, is being regulated under section 111 or 112 of the Act.
    (5) Each plan shall include enforceable procedures to provide that:
    (i) Approval to construct shall not relieve any owner or operator of 
the responsibility to comply fully with applicable provision of the plan 
and any other requirements under local, State or Federal law.
    (ii) At such time that a particular source or modification becomes a 
major stationary source or major modification solely by virtue of a 
relaxation in any enforcement limitation which was established after 
August 7, 1980, on the capacity of the source or modification otherwise 
to emit a pollutant, such as a restriction on hours of operation, then 
the requirements of regulations approved pursuant to this section shall 
apply to the source or modification as though construction had not yet 
commenced on the source or modification;
    (6) Each plan shall provide that the following specific provisions 
apply to projects at existing emissions units at a major stationary 
source (other than projects at a Clean Unit or at a source with a PAL) 
in circumstances where there is a reasonable possibility that a project 
that is not a part of a major

[[Page 179]]

modification may result in a significant emissions increase and the 
owner or operator elects to use the method specified in paragraphs 
(a)(1)(xxviii)(B)(1) through (3) of this section for calculating 
projected actual emissions. Deviations from these provisions will be 
approved only if the State specifically demonstrates that the submitted 
provisions are more stringent than or at least as stringent in all 
respects as the corresponding provisions in paragraphs (a)(6)(i) through 
(v) of this section.
    (i) Before beginning actual construction of the project, the owner 
or operator shall document and maintain a record of the following 
information:
    (A) A description of the project;
    (B) Identification of the emissions unit(s) whose emissions of a 
regulated NSR pollutant could be affected by the project; and
    (C) A description of the applicability test used to determine that 
the project is not a major modification for any regulated NSR pollutant, 
including the baseline actual emissions, the projected actual emissions, 
the amount of emissions excluded under paragraph (a)(1)(xxviii)(B)(3) of 
this section and an explanation for why such amount was excluded, and 
any netting calculations, if applicable.
    (ii) If the emissions unit is an existing electric utility steam 
generating unit, before beginning actual construction, the owner or 
operator shall provide a copy of the information set out in paragraph 
(a)(6)(i) of this section to the reviewing authority. Nothing in this 
paragraph (a)(6)(ii) shall be construed to require the owner or operator 
of such a unit to obtain any determination from the reviewing authority 
before beginning actual construction.
    (iii) The owner or operator shall monitor the emissions of any 
regulated NSR pollutant that could increase as a result of the project 
and that is emitted by any emissions units identified in paragraph 
(a)(6)(i)(B) of this section; and calculate and maintain a record of the 
annual emissions, in tons per year on a calendar year basis, for a 
period of 5 years following resumption of regular operations after the 
change, or for a period of 10 years following resumption of regular 
operations after the change if the project increases the design capacity 
or potential to emit of that regulated NSR pollutant at such emissions 
unit.
    (iv) If the unit is an existing electric utility steam generating 
unit, the owner or operator shall submit a report to the reviewing 
authority within 60 days after the end of each year during which records 
must be generated under paragraph (a)(6)(iii) of this section setting 
out the unit's annual emissions during the year that preceded submission 
of the report.
    (v) If the unit is an existing unit other than an electric utility 
steam generating unit, the owner or operator shall submit a report to 
the reviewing authority if the annual emissions, in tons per year, from 
the project identified in paragraph (a)(6)(i) of this section, exceed 
the baseline actual emissions (as documented and maintained pursuant to 
paragraph (a)(6)(i)(C) of this section, by a significant amount (as 
defined in paragraph (a)(1)(x) of this section) for that regulated NSR 
pollutant, and if such emissions differ from the preconstruction 
projection as documented and maintained pursuant to paragraph 
(a)(6)(i)(C) of this section. Such report shall be submitted to the 
reviewing authority within 60 days after the end of such year. The 
report shall contain the following:
    (A) The name, address and telephone number of the major stationary 
source;
    (B) The annual emissions as calculated pursuant to paragraph 
(a)(6)(iii) of this section; and
    (C) Any other information that the owner or operator wishes to 
include in the report (e.g., an explanation as to why the emissions 
differ from the preconstruction projection).
    (7) Each plan shall provide that the owner or operator of the source 
shall make the information required to be documented and maintained 
pursuant to paragraph (a)(6) of this section available for review upon a 
request for inspection by the reviewing authority or the general public 
pursuant to the requirements contained in Sec. 70.4(b)(3)(viii) of this 
chapter.
    (b)(1) Each plan shall include a preconstruction review permit 
program or its equivalent to satisfy the requirements of section 
110(a)(2)(D)(i) of the

[[Page 180]]

Act for any new major stationary source or major modification as defined 
in paragraphs (a)(1) (iv) and (v) of this section. Such a program shall 
apply to any such source or modification that would locate in any area 
designated as attainment or unclassifiable for any national ambient air 
quality standard pursuant to section 107 of the Act, when it would cause 
or contribute to a violation of any national ambient air quality 
standard.
    (2) A major source or major modification will be considered to cause 
or contribute to a violation of a national ambient air quality standard 
when such source or modification would, at a minimum, exceed the 
following significance levels at any locality that does not or would not 
meet the applicable national standard:

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Averaging time (hours)
             Pollutant                       Annual         --------------------------------------------------------------------------------------------
                                                                       24                      8                      3                      1
--------------------------------------------------------------------------------------------------------------------------------------------------------
SO2................................  1.0 [mu]g/m\3\........  5 [mu]g/m\3\..........    ...................  25 [mu]g/m\3\........
PM10...............................  1.0 [mu]g/m\3\........  5 [mu]g/m\3\..........    ...................    ...................
NO2................................  1.0 [mu]g/m\3\........    ....................    ...................    ...................
CO.................................    ....................    ....................  0.5 mg/m\3\..........    ...................  2 mg/m\3\
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (3) Such a program may include a provision which allows a proposed 
major source or major modification subject to paragraph (b) of this 
section to reduce the impact of its emissions upon air quality by 
obtaining sufficient emission reductions to, at a minimum, compensate 
for its adverse ambient impact where the major source or major 
modification would otherwise cause or contribute to a violation of any 
national ambient air quality standard. The plan shall require that, in 
the absence of such emission reductions, the State or local agency shall 
deny the proposed construction.
    (4) The requirements of paragraph (b) of this section shall not 
apply to a major stationary source or major modification with respect to 
a particular pollutant if the owner or operator demonstrates that, as to 
that pollutant, the source or modification is located in an area 
designated as nonattainment pursuant to section 107 of the Act.
    (c) Clean Unit Test for emissions units that are subject to LAER. 
The plan shall provide an owner or operator of a major stationary source 
the option of using the Clean Unit Test to determine whether emissions 
increases at a Clean Unit are part of a project that is a major 
modification according to the provisions in paragraphs (c)(1) through 
(9) of this section.
    (1) Applicability. The provisions of this paragraph (c) apply to any 
emissions unit for which the reviewing authority has issued a major NSR 
permit within the past 10 years.
    (2) General provisions for Clean Units. The provisions in paragraphs 
(c)(2)(i) through (v) of this section apply to a Clean Unit.
    (i) Any project for which the owner or operator begins actual 
construction after the effective date of the Clean Unit designation (as 
determined in accordance with paragraph (c)(4) of this section) and 
before the expiration date (as determined in accordance with paragraph 
(c)(5) of this section) will be considered to have occurred while the 
emissions unit was a Clean Unit.
    (ii) If a project at a Clean Unit does not cause the need for a 
change in the emission limitations or work practice requirements in the 
permit for the unit that were adopted in conjunction with LAER and the 
project would not alter any physical or operational characteristics that 
formed the basis for the LAER determination as specified in paragraph 
(c)(6)(iv) of this section, the emissions unit remains a Clean Unit.
    (iii) If a project causes the need for a change in the emission 
limitations or work practice requirements in the permit for the unit 
that were adopted in conjunction with LAER or the project would alter 
any physical or operational characteristics that formed the basis for 
the LAER determination as specified in paragraph (c)(6)(iv) of this 
section, then the emissions unit loses its designation as a Clean Unit 
upon

[[Page 181]]

issuance of the necessary permit revisions (unless the unit requalifies 
as a Clean Unit pursuant to paragraph (c)(3)(iii) of this section). If 
the owner or operator begins actual construction on the project without 
first applying to revise the emissions unit's permit, the Clean Unit 
designation ends immediately prior to the time when actual construction 
begins.
    (iv) A project that causes an emissions unit to lose its designation 
as a Clean Unit is subject to the applicability requirements of 
paragraphs (a)(2)(ii)(A) through (D) and paragraph (a)(2)(ii)(F) of this 
section as if the emissions unit is not a Clean Unit.
    (v) Certain Emissions Units with PSD permits. For emissions units 
that meet the requirements of paragraphs (c)(2)(v)(A) and (B) of this 
section, the BACT level of emissions reductions and/or work practice 
requirements shall satisfy the requirement for LAER in meeting the 
requirements for Clean Units under paragraphs (c)(3) through (8) of this 
section. For these emissions units, all requirements for the LAER 
determination under paragraphs (c)(2)(ii) and (iii) of this section 
shall also apply to the BACT permit terms and conditions. In addition, 
the requirements of paragraph (c)(7)(i)(B) of this section do not apply 
to emissions units that qualify for Clean Unit status under this 
paragraph (c)(2)(v).
    (A) The emissions unit must have received a PSD permit within the 
last 10 years and such permit must require the emissions unit to comply 
with BACT.
    (B) The emissions unit must be located in an area that was 
redesignated as nonattainment for the relevant pollutant(s) after 
issuance of the PSD permit and before the effective date of the Clean 
Unit Test provisions in the area.
    (3) Qualifying or re-qualifying to use the Clean Unit applicability 
test. An emissions unit automatically qualifies as a Clean Unit when the 
unit meets the criteria in paragraphs (c)(3)(i) and (ii) of this 
section. After the original Clean Unit designation expires in accordance 
with paragraph (c)(5) of this section or is lost pursuant to paragraph 
(c)(2)(iii) of this section, such emissions unit may re-qualify as a 
Clean Unit under either paragraph (c)(3)(iii) of this section, or under 
the Clean Unit provisions in paragraph (d) of this section. To re-
qualify as a Clean Unit under paragraph (c)(3)(iii) of this section, the 
emissions unit must obtain a new major NSR permit issued through the 
applicable nonattainment major NSR program and meet all the criteria in 
paragraph (c)(3)(iii) of this section. Clean Unit designation applies 
individually for each pollutant emitted by the emissions unit.
    (i) Permitting requirement. The emissions unit must have received a 
major NSR permit within the past 10 years. The owner or operator must 
maintain and be able to provide information that would demonstrate that 
this permitting requirement is met.
    (ii) Qualifying air pollution control technologies. Air pollutant 
emissions from the emissions unit must be reduced through the use of an 
air pollution control technology (which includes pollution prevention as 
defined under paragraph (a)(1)(xxvi) of this section or work practices) 
that meets both the following requirements in paragraphs (c)(3)(ii)(A) 
and (B) of this section.
    (A) The control technology achieves the LAER level of emissions 
reductions as determined through issuance of a major NSR permit within 
the past 10 years. However, the emissions unit is not eligible for Clean 
Unit designation if the LAER determination resulted in no requirement to 
reduce emissions below the level of a standard, uncontrolled, new 
emissions unit of the same type.
    (B) The owner or operator made an investment to install the control 
technology. For the purpose of this determination, an investment 
includes expenses to research the application of a pollution prevention 
technique to the emissions unit or expenses to apply a pollution 
prevention technique to an emissions unit.
    (iii) Re-qualifying for the Clean Unit designation. The emissions 
unit must obtain a new major NSR permit that requires compliance with 
the current-day LAER, and the emissions unit must meet the requirements 
in paragraphs (c)(3)(i) and (c)(3)(ii) of this section.

[[Page 182]]

    (4) Effective date of the Clean Unit designation. The effective date 
of an emissions unit's Clean Unit designation (that is, the date on 
which the owner or operator may begin to use the Clean Unit Test to 
determine whether a project at the emissions unit is a major 
modification) is determined according to the applicable paragraph 
(c)(4)(i) or (c)(4)(ii) of this section.
    (i) Original Clean Unit designation, and emissions units that re-
qualify as Clean Units by implementing a new control technology to meet 
current-day LAER. The effective date is the date the emissions unit's 
air pollution control technology is placed into service, or 3 years 
after the issuance date of the major NSR permit, whichever is earlier, 
but no sooner than the date that provisions for the Clean Unit 
applicability test are approved by the Administrator for incorporation 
into the plan and become effective for the State in which the unit is 
located.
    (ii) Emissions units that re-qualify for the Clean Unit designation 
using an existing control technology. The effective date is the date the 
new, major NSR permit is issued.
    (5) Clean Unit expiration. An emissions unit's Clean Unit 
designation expires (that is, the date on which the owner or operator 
may no longer use the Clean Unit Test to determine whether a project 
affecting the emissions unit is, or is part of, a major modification) 
according to the applicable paragraph (c)(5)(i) or (ii) of this section.
    (i) Original Clean Unit designation, and emissions units that re-
qualify by implementing new control technology to meet current-day LAER. 
For any emissions unit that automatically qualifies as a Clean Unit 
under paragraphs (c)(3)(i) and (ii) of this section, the Clean Unit 
designation expires 10 years after the effective date, or the date the 
equipment went into service, whichever is earlier; or, it expires at any 
time the owner or operator fails to comply with the provisions for 
maintaining Clean Unit designation in paragraph (c)(7) of this section.
    (ii) Emissions units that re-qualify for the Clean Unit designation 
using an existing control technology. For any emissions unit that re-
qualifies as a Clean Unit under paragraph (c)(3)(iii) of this section, 
the Clean Unit designation expires 10 years after the effective date; 
or, it expires any time the owner or operator fails to comply with the 
provisions for maintaining the Clean Unit Designation in paragraph 
(c)(7) of this section.
    (6) Required title V permit content for a Clean Unit. After the 
effective date of the Clean Unit designation, and in accordance with the 
provisions of the applicable title V permit program under part 70 or 
part 71 of this chapter, but no later than when the title V permit is 
renewed, the title V permit for the major stationary source must include 
the following terms and conditions in paragraphs (c)(6)(i) through (vi) 
of this section related to the Clean Unit.
    (i) A statement indicating that the emissions unit qualifies as a 
Clean Unit and identifying the pollutant(s) for which this Clean Unit 
designation applies.
    (ii) The effective date of the Clean Unit designation. If this date 
is not known when the Clean Unit designation is initially recorded in 
the title V permit (e.g., because the air pollution control technology 
is not yet in service), the permit must describe the event that will 
determine the effective date (e.g., the date the control technology is 
placed into service). Once the effective date is determined, the owner 
or operator must notify the reviewing authority of the exact date. This 
specific effective date must be added to the source's title V permit at 
the first opportunity, such as a modification, revision, reopening, or 
renewal of the title V permit for any reason, whichever comes first, but 
in no case later than the next renewal.
    (iii) The expiration date of the Clean Unit designation. If this 
date is not known when the Clean Unit designation is initially recorded 
into the title V permit (e.g., because the air pollution control 
technology is not yet in service), then the permit must describe the 
event that will determine the expiration date (e.g., the date the 
control technology is placed into service). Once the expiration date is 
determined, the owner or operator must notify the reviewing authority of 
the exact date. The expiration date must be added to

[[Page 183]]

the source's title V permit at the first opportunity, such as a 
modification, revision, reopening, or renewal of the title V permit for 
any reason, whichever comes first, but in no case later than the next 
renewal.
    (iv) All emission limitations and work practice requirements adopted 
in conjunction with the LAER, and any physical or operational 
characteristics that formed the basis for the LAER determination (e.g., 
possibly the emissions unit's capacity or throughput).
    (v) Monitoring, recordkeeping, and reporting requirements as 
necessary to demonstrate that the emissions unit continues to meet the 
criteria for maintaining the Clean Unit designation. (See paragraph 
(c)(7) of this section.)
    (vi) Terms reflecting the owner or operator's duties to maintain the 
Clean Unit designation and the consequences of failing to do so, as 
presented in paragraph (c)(7) of this section.
    (7) Maintaining the Clean Unit designation. To maintain the Clean 
Unit designation, the owner or operator must conform to all the 
restrictions listed in paragraphs (c)(7)(i) through (iii) of this 
section. This paragraph (c)(7) applies independently to each pollutant 
for which the emissions unit has the Clean Unit designation. That is, 
failing to conform to the restrictions for one pollutant affects Clean 
Unit designation only for that pollutant.
    (i) The Clean Unit must comply with the emission limitation(s) and/
or work practice requirements adopted in conjunction with the LAER that 
is recorded in the major NSR permit, and subsequently reflected in the 
title V permit.
    (A) The owner or operator may not make a physical change in or 
change in the method of operation of the Clean Unit that causes the 
emissions unit to function in a manner that is inconsistent with the 
physical or operational characteristics that formed the basis for the 
LAER determination (e.g., possibly the emissions unit's capacity or 
throughput).
    (B) The Clean Unit may not emit above a level that has been offset.
    (ii) The Clean Unit must comply with any terms and conditions in the 
title V permit related to the unit's Clean Unit designation.
    (iii) The Clean Unit must continue to control emissions using the 
specific air pollution control technology that was the basis for its 
Clean Unit designation. If the emissions unit or control technology is 
replaced, then the Clean Unit designation ends.
    (8) Offsets and netting at Clean Units. Emissions changes that occur 
at a Clean Unit must not be included in calculating a significant net 
emissions increase (that is, must not be used in a ``netting 
analysis''), or be used for generating offsets unless such use occurs 
before the effective date of the Clean Unit designation, or after the 
Clean Unit designation expires; or, unless the emissions unit reduces 
emissions below the level that qualified the unit as a Clean Unit. 
However, if the Clean Unit reduces emissions below the level that 
qualified the unit as a Clean Unit, then, the owner or operator may 
generate a credit for the difference between the level that qualified 
the unit as a Clean Unit and the new emission limitation if such 
reductions are surplus, quantifiable, and permanent. For purposes of 
generating offsets, the reductions must also be federally enforceable. 
For purposes of determining creditable net emissions increases and 
decreases, the reductions must also be enforceable as a practical 
matter.
    (9) Effect of redesignation on the Clean Unit designation. The Clean 
Unit designation of an emissions unit is not affected by redesignation 
of the attainment status of the area in which it is located. That is, if 
a Clean Unit is located in an attainment area and the area is 
redesignated to nonattainment, its Clean Unit designation is not 
affected. Similarly, redesignation from nonattainment to attainment does 
not affect the Clean Unit designation. However, if an existing Clean 
Unit designation expires, it must re-qualify under the requirements that 
are currently applicable in the area.
    (d) Clean Unit provisions for emissions units that achieve an 
emission limitation comparable to LAER. The plan shall provide an owner 
or operator of a major stationary source the option of using the Clean 
Unit Test to determine whether emissions increases at a Clean

[[Page 184]]

Unit are part of a project that is a major modification according to the 
provisions in paragraphs (d)(1) through (11) of this section.
    (1) Applicability. The provisions of this paragraph (d) apply to 
emissions units which do not qualify as Clean Units under paragraph (c) 
of this section, but which are achieving a level of emissions control 
comparable to LAER, as determined by the reviewing authority in 
accordance with this paragraph (d).
    (2) General provisions for Clean Units. The provisions in paragraphs 
(d)(2)(i) through (iv) of this section apply to a Clean Unit (designated 
under this paragraph (d)).
    (i) Any project for which the owner or operator begins actual 
construction after the effective date of the Clean Unit designation (as 
determined in accordance with paragraph (d)(5) of this section) and 
before the expiration date (as determined in accordance with paragraph 
(d)(6) of this section) will be considered to have occurred while the 
emissions unit was a Clean Unit.
    (ii) If a project at a Clean Unit does not cause the need for a 
change in the emission limitations or work practice requirements in the 
permit for the unit that have been determined (pursuant to paragraph 
(d)(4) of this section) to be comparable to LAER, and the project would 
not alter any physical or operational characteristics that formed the 
basis for determining that the emissions unit's control technology 
achieves a level of emissions control comparable to LAER as specified in 
paragraph (d)(8)(iv) of this section, the emissions unit remains a Clean 
Unit.
    (iii) If a project causes the need for a change in the emission 
limitations or work practice requirements in the permit for the unit 
that have been determined (pursuant to paragraph (d)(4) of this section) 
to be comparable to LAER, or the project would alter any physical or 
operational characteristics that formed the basis for determining that 
the emissions unit's control technology achieves a level of emissions 
control comparable to LAER as specified in paragraph (d)(8)(iv) of this 
section, then the emissions unit loses its designation as a Clean Unit 
upon issuance of the necessary permit revisions (unless the unit re-
qualifies as a Clean Unit pursuant to paragraph (d)(3)(iv) of this 
section). If the owner or operator begins actual construction on the 
project without first applying to revise the emissions unit's permit, 
the Clean Unit designation ends immediately prior to the time when 
actual construction begins.
    (iv) A project that causes an emissions unit to lose its designation 
as a Clean Unit is subject to the applicability requirements of 
paragraphs (a)(2)(ii)(A) through (D) and paragraph (a)(2)(ii)(F) of this 
section as if the emissions unit were never a Clean Unit.
    (3) Qualifying or re-qualifying to use the Clean Unit applicability 
test. An emissions unit qualifies as a Clean Unit when the unit meets 
the criteria in paragraphs (d)(3)(i) through (iii) of this section. 
After the original Clean Unit designation expires in accordance with 
paragraph (d)(6) of this section or is lost pursuant to paragraph 
(d)(2)(iii) of this section, such emissions unit may re-qualify as a 
Clean Unit under either paragraph (d)(3)(iv) of this section, or under 
the Clean Unit provisions in paragraph (c) of this section. To re-
qualify as a Clean Unit under paragraph (d)(3)(iv) of this section, the 
emissions unit must obtain a new permit issued pursuant to the 
requirements in paragraphs (d)(7) and (8) of this section and meet all 
the criteria in paragraph (d)(3)(iv) of this section. The reviewing 
authority will make a separate Clean Unit designation for each pollutant 
emitted by the emissions unit for which the emissions unit qualifies as 
a Clean Unit.
    (i) Qualifying air pollution control technologies. Air pollutant 
emissions from the emissions unit must be reduced through the use of air 
pollution control technology (which includes pollution prevention as 
defined under paragraph (a)(1)(xxvi) of this section or work practices) 
that meets both the following requirements in paragraphs (d)(3)(i)(A) 
and (B) of this section.
    (A) The owner or operator has demonstrated that the emissions unit's 
control technology is comparable to LAER according to the requirements 
of paragraph (d)(4) of this section. However, the emissions unit is not 
eligible

[[Page 185]]

for the Clean Unit designation if its emissions are not reduced below 
the level of a standard, uncontrolled emissions unit of the same type 
(e.g., if the LAER determinations to which it is compared have resulted 
in a determination that no control measures are required).
    (B) The owner or operator made an investment to install the control 
technology. For the purpose of this determination, an investment 
includes expenses to research the application of a pollution prevention 
technique to the emissions unit or to retool the unit to apply a 
pollution prevention technique.
    (ii) Impact of emissions from the unit. The reviewing authority must 
determine that the allowable emissions from the emissions unit will not 
cause or contribute to a violation of any national ambient air quality 
standard or PSD increment, or adversely impact an air quality related 
value (such as visibility) that has been identified for a Federal Class 
I area by a Federal Land Manager and for which information is available 
to the general public.
    (iii) Date of installation. An emissions unit may qualify as a Clean 
Unit even if the control technology, on which the Clean Unit designation 
is based, was installed before the effective date of plan requirements 
to implement the requirements of this paragraph (d)(3)(iii). However, 
for such emissions units, the owner or operator must apply for the Clean 
Unit designation within 2 years after the plan requirements become 
effective. For technologies installed after the plan requirements become 
effective, the owner or operator must apply for the Clean Unit 
designation at the time the control technology is installed.
    (iv) Re-qualifying as a Clean Unit. The emissions unit must obtain a 
new permit (pursuant to requirements in paragraphs (d)(7) and (8) of 
this section) that demonstrates that the emissions unit's control 
technology is achieving a level of emission control comparable to 
current-day LAER, and the emissions unit must meet the requirements in 
paragraphs (d)(3)(i)(A) and (d)(3)(ii) of this section.
    (4) Demonstrating control effectiveness comparable to LAER. The 
owner or operator may demonstrate that the emissions unit's control 
technology is comparable to LAER for purposes of paragraph (d)(3)(i) of 
this section according to either paragraph (d)(4)(i) or (ii) of this 
section. Paragraph (d)(4)(iii) of this section specifies the time for 
making this comparison.
    (i) Comparison to previous LAER determinations. The administrator 
maintains an on-line data base of previous determinations of RACT, BACT, 
and LAER in the RACT/BACT/LAER Clearinghouse (RBLC). The emissions 
unit's control technology is presumed to be comparable to LAER if it 
achieves an emission limitation that is at least as stringent as any one 
of the five best-performing similar sources for which a LAER 
determination has been made within the preceding 5 years, and for which 
information has been entered into the RBLC. The reviewing authority 
shall also compare this presumption to any additional LAER 
determinations of which it is aware, and shall consider any information 
on achieved-in-practice pollution control technologies provided during 
the public comment period, to determine whether any presumptive 
determination that the control technology is comparable to LAER is 
correct.
    (ii) The substantially-as-effective test. The owner or operator may 
demonstrate that the emissions unit's control technology is 
substantially as effective as LAER. In addition, any other person may 
present evidence related to whether the control technology is 
substantially as effective as LAER during the public participation 
process required under paragraph (d)(7) of this section. The reviewing 
authority shall consider such evidence on a case-by-case basis and 
determine whether the emissions unit's air pollution control technology 
is substantially as effective as LAER.
    (iii) Time of comparison--(A) Emissions units with control 
technologies that are installed before the effective date of plan 
requirements implementing this paragraph. The owner or operator of an 
emissions unit whose control technology is installed before the 
effective date of plan requirements implementing this paragraph (d) may, 
at its option, either demonstrate that the emission limitation achieved 
by the

[[Page 186]]

emissions unit's control technology is comparable to the LAER 
requirements that applied at the time the control technology was 
installed, or demonstrate that the emission limitation achieved by the 
emissions unit's control technology is comparable to current-day LAER 
requirements. The expiration date of the Clean Unit designation will 
depend on which option the owner or operator uses, as specified in 
paragraph (d)(6) of this section.
    (B) Emissions units with control technologies that are installed 
after the effective date of plan requirements implementing this 
paragraph. The owner or operator must demonstrate that the emission 
limitation achieved by the emissions unit's control technology is 
comparable to current-day LAER requirements.
    (5) Effective date of the Clean Unit designation. The effective date 
of an emissions unit's Clean Unit designation (that is, the date on 
which the owner or operator may begin to use the Clean Unit Test to 
determine whether a project involving the emissions unit is a major 
modification) is the date that the permit required by paragraph (d)(7) 
of this section is issued or the date that the emissions unit's air 
pollution control technology is placed into service, whichever is later.
    (6) Clean Unit expiration. If the owner or operator demonstrates 
that the emission limitation achieved by the emissions unit's control 
technology is comparable to the LAER requirements that applied at the 
time the control technology was installed, then the Clean Unit 
designation expires 10 years from the date that the control technology 
was installed. For all other emissions units, the Clean Unit designation 
expires 10 years from the effective date of the Clean Unit designation, 
as determined according to paragraph (d)(5) of this section. In 
addition, for all emissions units, the Clean Unit designation expires 
any time the owner or operator fails to comply with the provisions for 
maintaining the Clean Unit designation in paragraph (d)(9) of this 
section.
    (7) Procedures for designating emissions units as Clean Units. The 
reviewing authority shall designate an emissions unit a Clean Unit only 
by issuing a permit through a permitting program that has been approved 
by the Administrator and that conforms with the requirements of 
Secs. 51.160 through 51.164 of this chapter including requirements for 
public notice of the proposed Clean Unit designation and opportunity for 
public comment. Such permit must also meet the requirements in paragraph 
(d)(8).
    (8) Required permit content. The permit required by paragraph (d)(7) 
of this section shall include the terms and conditions set forth in 
paragraphs (d)(8)(i) through (vi) of this section. Such terms and 
conditions shall be incorporated into the major stationary source's 
title V permit in accordance with the provisions of the applicable title 
V permit program under part 70 or part 71 of this chapter, but no later 
than when the title V permit is renewed.
    (i) A statement indicating that the emissions unit qualifies as a 
Clean Unit and identifying the pollutant(s) for which this designation 
applies.
    (ii) The effective date of the Clean Unit designation. If this date 
is not known when the reviewing authority issues the permit (e.g., 
because the air pollution control technology is not yet in service), 
then the permit must describe the event that will determine the 
effective date (e.g., the date the control technology is placed into 
service). Once the effective date is known, then the owner or operator 
must notify the reviewing authority of the exact date. This specific 
effective date must be added to the source's title V permit at the first 
opportunity, such as a modification, revision, reopening, or renewal of 
the title V permit for any reason, whichever comes first, but in no case 
later than the next renewal.
    (iii) The expiration date of the Clean Unit designation. If this 
date is not known when the reviewing authority issues the permit (e.g., 
because the air pollution control technology is not yet in service), 
then the permit must describe the event that will determine the 
expiration date (e.g., the date the control technology is placed into 
service). Once the expiration date is known, then the owner or operator 
must notify the reviewing authority of the exact date. The expiration 
date

[[Page 187]]

must be added to the source's title V permit at the first opportunity, 
such as a modification, revision, reopening, or renewal of the title V 
permit for any reason, whichever comes first, but in no case later than 
the next renewal.
    (iv) All emission limitations and work practice requirements adopted 
in conjunction with emission limitations necessary to assure that the 
control technology continues to achieve an emission limitation 
comparable to LAER, and any physical or operational characteristics that 
formed the basis for determining that the emissions unit's control 
technology achieves a level of emissions control comparable to LAER 
(e.g., possibly the emissions unit's capacity or throughput).
    (v) Monitoring, recordkeeping, and reporting requirements as 
necessary to demonstrate that the emissions unit continues to meet the 
criteria for maintaining its Clean Unit designation. (See paragraph 
(d)(9) of this section.)
    (vi) Terms reflecting the owner or operator's duties to maintain the 
Clean Unit designation and the consequences of failing to do so, as 
presented in paragraph (d)(9) of this section.
    (9) Maintaining Clean Unit designation. To maintain Clean Unit 
designation, the owner or operator must conform to all the restrictions 
listed in paragraphs (d)(9)(i) through (v) of this section. This 
paragraph (d)(9) applies independently to each pollutant for which the 
reviewing authority has designated the emissions unit a Clean Unit. That 
is, failing to conform to the restrictions for one pollutant affects the 
Clean Unit designation only for that pollutant.
    (i) The Clean Unit must comply with the emission limitation(s) and/
or work practice requirements adopted to ensure that the control 
technology continues to achieve emission control comparable to LAER.
    (ii) The owner or operator may not make a physical change in or 
change in the method of operation of the Clean Unit that causes the 
emissions unit to function in a manner that is inconsistent with the 
physical or operational characteristics that formed the basis for the 
determination that the control technology is achieving a level of 
emission control that is comparable to LAER (e.g., possibly the 
emissions unit's capacity or throughput).
    (iii) The Clean Unit may not emit above a level that has been 
offset.
    (iv) The Clean Unit must comply with any terms and conditions in the 
title V permit related to the unit's Clean Unit designation.
    (v) The Clean Unit must continue to control emissions using the 
specific air pollution control technology that was the basis for its 
Clean Unit designation. If the emissions unit or control technology is 
replaced, then the Clean Unit designation ends.
    (10) Offsets and Netting at Clean Units. Emissions changes that 
occur at a Clean Unit must not be included in calculating a significant 
net emissions increase (that is, must not be used in a ``netting 
analysis''), or be used for generating offsets unless such use occurs 
before the effective date of plan requirements adopted to implement this 
paragraph (d) or after the Clean Unit designation expires; or, unless 
the emissions unit reduces emissions below the level that qualified the 
unit as a Clean Unit. However, if the Clean Unit reduces emissions below 
the level that qualified the unit as a Clean Unit, then the owner or 
operator may generate a credit for the difference between the level that 
qualified the unit as a Clean Unit and the emissions unit's new emission 
limitation if such reductions are surplus, quantifiable, and permanent. 
For purposes of generating offsets, the reductions must also be 
federally enforceable. For purposes of determining creditable net 
emissions increases and decreases, the reductions must also be 
enforceable as a practical matter.
    (11) Effect of redesignation on the Clean Unit designation. The 
Clean Unit designation of an emissions unit is not affected by 
redesignation of the attainment status of the area in which it is 
located. That is, if a Clean Unit is located in an attainment area and 
the area is redesignated to nonattainment, its Clean Unit designation is 
not affected. Similarly, redesignation from nonattainment to attainment 
does not affect the Clean Unit designation. However, if a Clean Unit's 
designation expires or is lost pursuant to paragraphs (c)(2)(iii) and 
(d)(2)(iii) of this section,

[[Page 188]]

it must re-qualify under the requirements that are currently applicable.
    (e) PCP exclusion procedural requirements. Each plan shall include 
provisions for PCPs equivalent to those contained in paragraphs (e)(1) 
through (6) of this section.
    (1) Before an owner or operator begins actual construction of a PCP, 
the owner or operator must either submit a notice to the reviewing 
authority if the project is listed in paragraphs (a)(1)(xxv)(A) through 
(F) of this section, or if the project is not listed in paragraphs 
(a)(1)(xxv)(A) through (F) of this section, then the owner or operator 
must submit a permit application and obtain approval to use the PCP 
exclusion from the reviewing authority consistent with the requirements 
in paragraph (e)(5) of this section. Regardless of whether the owner or 
operator submits a notice or a permit application, the project must meet 
the requirements in paragraph (e)(2) of this section, and the notice or 
permit application must contain the information required in paragraph 
(e)(3) of this section.
    (2) Any project that relies on the PCP exclusion must meet the 
requirements in paragraphs (e)(2)(i) and (ii) of this section.
    (i) Environmentally beneficial analysis. The environmental benefit 
from the emission reductions of pollutants regulated under the Act must 
outweigh the environmental detriment of emissions increases in 
pollutants regulated under the Act. A statement that a technology from 
paragraphs (a)(1)(xxv)(A) through (F) of this section is being used 
shall be presumed to satisfy this requirement.
    (ii) Air quality analysis. The emissions increases from the project 
will not cause or contribute to a violation of any national ambient air 
quality standard or PSD increment, or adversely impact an air quality 
related value (such as visibility) that has been identified for a 
Federal Class I area by a Federal Land Manager and for which information 
is available to the general public.
    (3) Content of notice or permit application. In the notice or permit 
application sent to the reviewing authority, the owner or operator must 
include, at a minimum, the information listed in paragraphs (e)(3)(i) 
through (v) of this section.
    (i) A description of the project.
    (ii) The potential emissions increases and decreases of any 
pollutant regulated under the Act and the projected emissions increases 
and decreases using the methodology in paragraph (a)(2)(ii) of this 
section, that will result from the project, and a copy of the 
environmentally beneficial analysis required by paragraph (e)(2)(i) of 
this section.
    (iii) A description of monitoring and recordkeeping, and all other 
methods, to be used on an ongoing basis to demonstrate that the project 
is environmentally beneficial. Methods should be sufficient to meet the 
requirements in part 70 and part 71.
    (iv) A certification that the project will be designed and operated 
in a manner that is consistent with proper industry and engineering 
practices, in a manner that is consistent with the environmentally 
beneficial analysis and air quality analysis required by paragraphs 
(e)(2)(i) and (ii) of this section, with information submitted in the 
notice or permit application, and in such a way as to minimize, within 
the physical configuration and operational standards usually associated 
with the emissions control device or strategy, emissions of collateral 
pollutants.
    (v) Demonstration that the PCP will not have an adverse air quality 
impact (e.g., modeling, screening level modeling results, or a statement 
that the collateral emissions increase is included within the parameters 
used in the most recent modeling exercise) as required by paragraph 
(e)(2)(ii) of this section. An air quality impact analysis is not 
required for any pollutant which will not experience a significant 
emissions increase as a result of the project.
    (4) Notice process for listed projects. For projects listed in 
paragraphs (a)(1)(xxv)(A) through (F) of this section, the owner or 
operator may begin actual construction of the project immediately after 
notice is sent to the reviewing authority (unless otherwise prohibited 
under requirements of the applicable plan). The owner or operator

[[Page 189]]

shall respond to any requests by its reviewing authority for additional 
information that the reviewing authority determines is necessary to 
evaluate the suitability of the project for the PCP exclusion.
    (5) Permit process for unlisted projects. Before an owner or 
operator may begin actual construction of a PCP project that is not 
listed in paragraphs (a)(1)(xxv)(A) through (F) of this section, the 
project must be approved by the reviewing authority and recorded in a 
plan-approved permit or title V permit using procedures that are 
consistent with Secs. 51.160 and 51.161 of this chapter. This includes 
the requirement that the reviewing authority provide the public with 
notice of the proposed approval, with access to the environmentally 
beneficial analysis and the air quality analysis, and provide at least a 
30-day period for the public and the Administrator to submit comments. 
The reviewing authority must address all material comments received by 
the end of the comment period before taking final action on the permit.
    (6) Operational requirements. Upon installation of the PCP, the 
owner or operator must comply with the requirements of paragraphs 
(e)(6)(i) through (iii) of this section.
    (i) General duty. The owner or operator must operate the PCP in a 
manner consistent with proper industry and engineering practices, in a 
manner that is consistent with the environmentally beneficial analysis 
and air quality analysis required by paragraphs (e)(2)(i) and (ii) of 
this section, with information submitted in the notice or permit 
application required by paragraph (e)(3) of this section, and in such a 
way as to minimize, within the physical configuration and operational 
standards usually associated with the emissions control device or 
strategy, emissions of collateral pollutants.
    (ii) Recordkeeping. The owner or operator must maintain copies on 
site of the environmentally beneficial analysis, the air quality impacts 
analysis, and monitoring and other emission records to prove that the 
PCP operated consistent with the general duty requirements in paragraph 
(e)(6)(i) of this section.
    (iii) Permit requirements. The owner or operator must comply with 
any provisions in the plan-approved permit or title V permit related to 
use and approval of the PCP exclusion.
    (iv) Generation of emission reduction credits. Emission reductions 
created by a PCP shall not be included in calculating a significant net 
emissions increase, or be used for generating offsets, unless the 
emissions unit further reduces emissions after qualifying for the PCP 
exclusion (e.g., taking an operational restriction on the hours of 
operation). The owner or operator may generate a credit for the 
difference between the level of reduction which was used to qualify for 
the PCP exclusion and the new emission limitation if such reductions are 
surplus, quantifiable, and permanent. For purposes of generating 
offsets, the reductions must also be federally enforceable. For purposes 
of determining creditable net emissions increases and decreases, the 
reductions must also be enforceable as a practical matter.
    (f) Actuals PALs. The plan shall provide for PALs according to the 
provisions in paragraphs (f)(1) through (15) of this section.
    (1) Applicability.
    (i) The reviewing authority may approve the use of an actuals PAL 
for any existing major stationary source (except as provided in 
paragraph (f)(1)(ii) of this section) if the PAL meets the requirements 
in paragraphs (f)(1) through (15) of this section. The term ``PAL'' 
shall mean ``actuals PAL'' throughout paragraph (f) of this section.
    (ii) The reviewing authority shall not allow an actuals PAL for VOC 
or NOX for any major stationary source located in an extreme 
ozone nonattainment area.
    (iii) Any physical change in or change in the method of operation of 
a major stationary source that maintains its total source-wide emissions 
below the PAL level, meets the requirements in paragraphs (f)(1) through 
(15) of this section, and complies with the PAL permit:
    (A) Is not a major modification for the PAL pollutant;

[[Page 190]]

    (B) Does not have to be approved through the plan's nonattainment 
major NSR program; and
    (C) Is not subject to the provisions in paragraph (a)(5)(ii) of this 
section (restrictions on relaxing enforceable emission limitations that 
the major stationary source used to avoid applicability of the 
nonattainment major NSR program).
    (iv) Except as provided under paragraph (f)(1)(iii)(C) of this 
section, a major stationary source shall continue to comply with all 
applicable Federal or State requirements, emission limitations, and work 
practice requirements that were established prior to the effective date 
of the PAL.
    (2) Definitions. The plan shall use the definitions in paragraphs 
(f)(2)(i) through (xi) of this section for the purpose of developing and 
implementing regulations that authorize the use of actuals PALs 
consistent with paragraphs (f)(1) through (15) of this section. When a 
term is not defined in these paragraphs, it shall have the meaning given 
in paragraph (a)(1) of this section or in the Act.
    (i) Actuals PAL for a major stationary source means a PAL based on 
the baseline actual emissions (as defined in paragraph (a)(1)(xxxv) of 
this section) of all emissions units (as defined in paragraph 
(a)(1)(vii) of this section) at the source, that emit or have the 
potential to emit the PAL pollutant.
    (ii) Allowable emissions means ``allowable emissions'' as defined in 
paragraph (a)(1)(xi) of this section, except as this definition is 
modified according to paragraphs (f)(2)(ii)(A) through (B) of this 
section.
    (A) The allowable emissions for any emissions unit shall be 
calculated considering any emission limitations that are enforceable as 
a practical matter on the emissions unit's potential to emit.
    (B) An emissions unit's potential to emit shall be determined using 
the definition in paragraph (a)(1)(iii) of this section, except that the 
words ``or enforceable as a practical matter'' should be added after 
``federally enforceable.''
    (iii) Small emissions unit means an emissions unit that emits or has 
the potential to emit the PAL pollutant in an amount less than the 
significant level for that PAL pollutant, as defined in paragraph 
(a)(1)(x) of this section or in the Act, whichever is lower.
    (iv) Major emissions unit means:
    (A) Any emissions unit that emits or has the potential to emit 100 
tons per year or more of the PAL pollutant in an attainment area; or
    (B) Any emissions unit that emits or has the potential to emit the 
PAL pollutant in an amount that is equal to or greater than the major 
source threshold for the PAL pollutant as defined by the Act for 
nonattainment areas. For example, in accordance with the definition of 
major stationary source in section 182(c) of the Act, an emissions unit 
would be a major emissions unit for VOC if the emissions unit is located 
in a serious ozone nonattainment area and it emits or has the potential 
to emit 50 or more tons of VOC per year.
    (v) Plantwide applicability limitation (PAL) means an emission 
limitation expressed in tons per year, for a pollutant at a major 
stationary source, that is enforceable as a practical matter and 
established source-wide in accordance with paragraphs (f)(1) through 
(f)(15) of this section.
    (vi) PAL effective date generally means the date of issuance of the 
PAL permit. However, the PAL effective date for an increased PAL is the 
date any emissions unit which is part of the PAL major modification 
becomes operational and begins to emit the PAL pollutant.
    (vii) PAL effective period means the period beginning with the PAL 
effective date and ending 10 years later.
    (viii) PAL major modification means, notwithstanding paragraphs 
(a)(1)(v) and (vi) of this section (the definitions for major 
modification and net emissions increase), any physical change in or 
change in the method of operation of the PAL source that causes it to 
emit the PAL pollutant at a level equal to or greater than the PAL.
    (ix) PAL permit means the major NSR permit, the minor NSR permit, or 
the State operating permit under a program that is approved into the 
plan, or the title V permit issued by the reviewing authority that 
establishes a PAL for a major stationary source.

[[Page 191]]

    (x) PAL pollutant means the pollutant for which a PAL is established 
at a major stationary source.
    (xi) Significant emissions unit means an emissions unit that emits 
or has the potential to emit a PAL pollutant in an amount that is equal 
to or greater than the significant level (as defined in paragraph 
(a)(1)(x) of this section or in the Act, whichever is lower) for that 
PAL pollutant, but less than the amount that would qualify the unit as a 
major emissions unit as defined in paragraph (f)(2)(iv) of this section.
    (3) Permit application requirements. As part of a permit application 
requesting a PAL, the owner or operator of a major stationary source 
shall submit the following information to the reviewing authority for 
approval:
    (i) A list of all emissions units at the source designated as small, 
significant or major based on their potential to emit. In addition, the 
owner or operator of the source shall indicate which, if any, Federal or 
State applicable requirements, emission limitations or work practices 
apply to each unit.
    (ii) Calculations of the baseline actual emissions (with supporting 
documentation). Baseline actual emissions are to include emissions 
associated not only with operation of the unit, but also emissions 
associated with startup, shutdown and malfunction.
    (iii) The calculation procedures that the major stationary source 
owner or operator proposes to use to convert the monitoring system data 
to monthly emissions and annual emissions based on a 12-month rolling 
total for each month as required by paragraph (f)(13)(i) of this 
section.
    (4) General requirements for establishing PALs. (i) The plan allows 
the reviewing authority to establish a PAL at a major stationary source, 
provided that at a minimum, the requirements in paragraphs (f)(4)(i)(A) 
through (G) of this section are met.
    (A) The PAL shall impose an annual emission limitation in tons per 
year, that is enforceable as a practical matter, for the entire major 
stationary source. For each month during the PAL effective period after 
the first 12 months of establishing a PAL, the major stationary source 
owner or operator shall show that the sum of the monthly emissions from 
each emissions unit under the PAL for the previous 12 consecutive months 
is less than the PAL (a 12-month average, rolled monthly). For each 
month during the first 11 months from the PAL effective date, the major 
stationary source owner or operator shall show that the sum of the 
preceding monthly emissions from the PAL effective date for each 
emissions unit under the PAL is less than the PAL.
    (B) The PAL shall be established in a PAL permit that meets the 
public participation requirements in paragraph (f)(5) of this section.
    (C) The PAL permit shall contain all the requirements of paragraph 
(f)(7) of this section.
    (D) The PAL shall include fugitive emissions, to the extent 
quantifiable, from all emissions units that emit or have the potential 
to emit the PAL pollutant at the major stationary source.
    (E) Each PAL shall regulate emissions of only one pollutant.
    (F) Each PAL shall have a PAL effective period of 10 years.
    (G) The owner or operator of the major stationary source with a PAL 
shall comply with the monitoring, recordkeeping, and reporting 
requirements provided in paragraphs (f)(12) through (14) of this section 
for each emissions unit under the PAL through the PAL effective period.
    (ii) At no time (during or after the PAL effective period) are 
emissions reductions of a PAL pollutant, which occur during the PAL 
effective period, creditable as decreases for purposes of offsets under 
paragraph (a)(3)(ii) of this section unless the level of the PAL is 
reduced by the amount of such emissions reductions and such reductions 
would be creditable in the absence of the PAL.
    (5) Public participation requirement for PALs. PALs for existing 
major stationary sources shall be established, renewed, or increased 
through a procedure that is consistent with Secs. 51.160 and 51.161 of 
this chapter. This includes the requirement that the reviewing authority 
provide the public with notice of the proposed approval of a PAL permit 
and at least a 30-day period for

[[Page 192]]

submittal of public comment. The reviewing authority must address all 
material comments before taking final action on the permit.
    (6) Setting the 10-year actuals PAL level. The plan shall provide 
that the actuals PAL level for a major stationary source shall be 
established as the sum of the baseline actual emissions (as defined in 
paragraph (a)(1)(xxxv) of this section) of the PAL pollutant for each 
emissions unit at the source; plus an amount equal to the applicable 
significant level for the PAL pollutant under paragraph (a)(1)(x) of 
this section or under the Act, whichever is lower. When establishing the 
actuals PAL level, for a PAL pollutant, only one consecutive 24-month 
period must be used to determine the baseline actual emissions for all 
existing emissions units. However, a different consecutive 24-month 
period may be used for each different PAL pollutant. Emissions 
associated with units that were permanently shutdown after this 24-month 
period must be subtracted from the PAL level. Emissions from units on 
which actual construction began after the 24-month period must be added 
to the PAL level in an amount equal to the potential to emit of the 
units. The reviewing authority shall specify a reduced PAL level(s) (in 
tons/yr) in the PAL permit to become effective on the future compliance 
date(s) of any applicable Federal or State regulatory requirement(s) 
that the reviewing authority is aware of prior to issuance of the PAL 
permit. For instance, if the source owner or operator will be required 
to reduce emissions from industrial boilers in half from baseline 
emissions of 60 ppm NOX to a new rule limit of 30 ppm, then 
the permit shall contain a future effective PAL level that is equal to 
the current PAL level reduced by half of the original baseline emissions 
of such unit(s).
    (7) Contents of the PAL permit. The plan shall require that the PAL 
permit contain, at a minimum, the information in paragraphs (f)(7)(i) 
through (x) of this section.
    (i) The PAL pollutant and the applicable source-wide emission 
limitation in tons per year.
    (ii) The PAL permit effective date and the expiration date of the 
PAL (PAL effective period).
    (iii) Specification in the PAL permit that if a major stationary 
source owner or operator applies to renew a PAL in accordance with 
paragraph (f)(10) of this section before the end of the PAL effective 
period, then the PAL shall not expire at the end of the PAL effective 
period. It shall remain in effect until a revised PAL permit is issued 
by the reviewing authority.
    (iv) A requirement that emission calculations for compliance 
purposes include emissions from startups, shutdowns and malfunctions.
    (v) A requirement that, once the PAL expires, the major stationary 
source is subject to the requirements of paragraph (f)(9) of this 
section.
    (vi) The calculation procedures that the major stationary source 
owner or operator shall use to convert the monitoring system data to 
monthly emissions and annual emissions based on a 12-month rolling total 
for each month as required by paragraph (f)(13)(i) of this section.
    (vii) A requirement that the major stationary source owner or 
operator monitor all emissions units in accordance with the provisions 
under paragraph (f)(12) of this section.
    (viii) A requirement to retain the records required under paragraph 
(f)(13) of this section on site. Such records may be retained in an 
electronic format.
    (ix) A requirement to submit the reports required under paragraph 
(f)(14) of this section by the required deadlines.
    (x) Any other requirements that the reviewing authority deems 
necessary to implement and enforce the PAL.
    (8) PAL effective period and reopening of the PAL permit. The plan 
shall require the information in paragraphs (f)(8)(i) and (ii) of this 
section.
    (i) PAL effective period. The reviewing authority shall specify a 
PAL effective period of 10 years.
    (ii) Reopening of the PAL permit. (A) During the PAL effective 
period, the plan shall require the reviewing authority to reopen the PAL 
permit to:

[[Page 193]]

    (1) Correct typographical/calculation errors made in setting the PAL 
or reflect a more accurate determination of emissions used to establish 
the PAL.
    (2) Reduce the PAL if the owner or operator of the major stationary 
source creates creditable emissions reductions for use as offsets under 
paragraph (a)(3)(ii) of this section.
    (3) Revise the PAL to reflect an increase in the PAL as provided 
under paragraph (f)(11) of this section.
    (B) The plan shall provide the reviewing authority discretion to 
reopen the PAL permit for the following:
    (1) Reduce the PAL to reflect newly applicable Federal requirements 
(for example, NSPS) with compliance dates after the PAL effective date.
    (2) Reduce the PAL consistent with any other requirement, that is 
enforceable as a practical matter, and that the State may impose on the 
major stationary source under the plan.
    (3) Reduce the PAL if the reviewing authority determines that a 
reduction is necessary to avoid causing or contributing to a NAAQS or 
PSD increment violation, or to an adverse impact on an air quality 
related value that has been identified for a Federal Class I area by a 
Federal Land Manager and for which information is available to the 
general public.
    (C) Except for the permit reopening in paragraph (f)(8)(ii)(A)(1) of 
this section for the correction of typographical/calculation errors that 
do not increase the PAL level, all other reopenings shall be carried out 
in accordance with the public participation requirements of paragraph 
(f)(5) of this section.
    (9) Expiration of a PAL. Any PAL which is not renewed in accordance 
with the procedures in paragraph (f)(10) of this section shall expire at 
the end of the PAL effective period, and the requirements in paragraphs 
(f)(9)(i) through (v) of this section shall apply.
    (i) Each emissions unit (or each group of emissions units) that 
existed under the PAL shall comply with an allowable emission limitation 
under a revised permit established according to the procedures in 
paragraphs (f)(9)(i)(A) through (B) of this section.
    (A) Within the time frame specified for PAL renewals in paragraph 
(f)(10)(ii) of this section, the major stationary source shall submit a 
proposed allowable emission limitation for each emissions unit (or each 
group of emissions units, if such a distribution is more appropriate as 
decided by the reviewing authority) by distributing the PAL allowable 
emissions for the major stationary source among each of the emissions 
units that existed under the PAL. If the PAL had not yet been adjusted 
for an applicable requirement that became effective during the PAL 
effective period, as required under paragraph (f)(10)(v) of this 
section, such distribution shall be made as if the PAL had been 
adjusted.
    (B) The reviewing authority shall decide whether and how the PAL 
allowable emissions will be distributed and issue a revised permit 
incorporating allowable limits for each emissions unit, or each group of 
emissions units, as the reviewing authority determines is appropriate.
    (ii) Each emissions unit(s) shall comply with the allowable emission 
limitation on a 12-month rolling basis. The reviewing authority may 
approve the use of monitoring systems (source testing, emission factors, 
etc.) other than CEMS, CERMS, PEMS or CPMS to demonstrate compliance 
with the allowable emission limitation.
    (iii) Until the reviewing authority issues the revised permit 
incorporating allowable limits for each emissions unit, or each group of 
emissions units, as required under paragraph (f)(9)(i)(A) of this 
section, the source shall continue to comply with a source-wide, multi-
unit emissions cap equivalent to the level of the PAL emission 
limitation.
    (iv) Any physical change or change in the method of operation at the 
major stationary source will be subject to the nonattainment major NSR 
requirements if such change meets the definition of major modification 
in paragraph (a)(1)(v) of this section.
    (v) The major stationary source owner or operator shall continue to 
comply with any State or Federal applicable requirements (BACT, RACT, 
NSPS, etc.) that may have applied either during the PAL effective period 
or prior to the PAL effective period except for those emission 
limitations

[[Page 194]]

that had been established pursuant to paragraph (a)(5)(ii) of this 
section, but were eliminated by the PAL in accordance with the 
provisions in paragraph (f)(1)(iii)(C) of this section.
    (10) Renewal of a PAL. (i) The reviewing authority shall follow the 
procedures specified in paragraph (f)(5) of this section in approving 
any request to renew a PAL for a major stationary source, and shall 
provide both the proposed PAL level and a written rationale for the 
proposed PAL level to the public for review and comment. During such 
public review, any person may propose a PAL level for the source for 
consideration by the reviewing authority.
    (ii) Application deadline. The plan shall require that a major 
stationary source owner or operator shall submit a timely application to 
the reviewing authority to request renewal of a PAL. A timely 
application is one that is submitted at least 6 months prior to, but not 
earlier than 18 months from, the date of permit expiration. This 
deadline for application submittal is to ensure that the permit will not 
expire before the permit is renewed. If the owner or operator of a major 
stationary source submits a complete application to renew the PAL within 
this time period, then the PAL shall continue to be effective until the 
revised permit with the renewed PAL is issued.
    (iii) Application requirements. The application to renew a PAL 
permit shall contain the information required in paragraphs 
(f)(10)(iii)(A) through (D) of this section.
    (A) The information required in paragraphs (f)(3)(i) through (iii) 
of this section.
    (B) A proposed PAL level.
    (C) The sum of the potential to emit of all emissions units under 
the PAL (with supporting documentation).
    (D) Any other information the owner or operator wishes the reviewing 
authority to consider in determining the appropriate level for renewing 
the PAL.
    (iv) PAL adjustment. In determining whether and how to adjust the 
PAL, the reviewing authority shall consider the options outlined in 
paragraphs (f)(10)(iv)(A) and (B) of this section. However, in no case 
may any such adjustment fail to comply with paragraph (f)(10)(iv)(C) of 
this section.
    (A) If the emissions level calculated in accordance with paragraph 
(f)(6) of this section is equal to or greater than 80 percent of the PAL 
level, the reviewing authority may renew the PAL at the same level 
without considering the factors set forth in paragraph (f)(10)(iv)(B) of 
this section; or
    (B) The reviewing authority may set the PAL at a level that it 
determines to be more representative of the source's baseline actual 
emissions, or that it determines to be appropriate considering air 
quality needs, advances in control technology, anticipated economic 
growth in the area, desire to reward or encourage the source's voluntary 
emissions reductions, or other factors as specifically identified by the 
reviewing authority in its written rationale.
    (C) Notwithstanding paragraphs (f)(10)(iv)(A) and (B) of this 
section,
    (1) If the potential to emit of the major stationary source is less 
than the PAL, the reviewing authority shall adjust the PAL to a level no 
greater than the potential to emit of the source; and
    (2) The reviewing authority shall not approve a renewed PAL level 
higher than the current PAL, unless the major stationary source has 
complied with the provisions of paragraph (f)(11) of this section 
(increasing a PAL).
    (v) If the compliance date for a State or Federal requirement that 
applies to the PAL source occurs during the PAL effective period, and if 
the reviewing authority has not already adjusted for such requirement, 
the PAL shall be adjusted at the time of PAL permit renewal or title V 
permit renewal, whichever occurs first.
    (11) Increasing a PAL during the PAL effective period. (i) The plan 
shall require that the reviewing authority may increase a PAL emission 
limitation only if the major stationary source complies with the 
provisions in paragraphs (f)(11)(i)(A) through (D) of this section.
    (A) The owner or operator of the major stationary source shall 
submit a complete application to request an increase in the PAL limit 
for a PAL major modification. Such application

[[Page 195]]

shall identify the emissions unit(s) contributing to the increase in 
emissions so as to cause the major stationary source's emissions to 
equal or exceed its PAL.
    (B) As part of this application, the major stationary source owner 
or operator shall demonstrate that the sum of the baseline actual 
emissions of the small emissions units, plus the sum of the baseline 
actual emissions of the significant and major emissions units assuming 
application of BACT equivalent controls, plus the sum of the allowable 
emissions of the new or modified emissions unit(s) exceeds the PAL. The 
level of control that would result from BACT equivalent controls on each 
significant or major emissions unit shall be determined by conducting a 
new BACT analysis at the time the application is submitted, unless the 
emissions unit is currently required to comply with a BACT or LAER 
requirement that was established within the preceding 10 years. In such 
a case, the assumed control level for that emissions unit shall be equal 
to the level of BACT or LAER with which that emissions unit must 
currently comply.
    (C) The owner or operator obtains a major NSR permit for all 
emissions unit(s) identified in paragraph (f)(11)(i)(A) of this section, 
regardless of the magnitude of the emissions increase resulting from 
them (that is, no significant levels apply). These emissions unit(s) 
shall comply with any emissions requirements resulting from the 
nonattainment major NSR program process (for example, LAER), even though 
they have also become subject to the PAL or continue to be subject to 
the PAL.
    (D) The PAL permit shall require that the increased PAL level shall 
be effective on the day any emissions unit that is part of the PAL major 
modification becomes operational and begins to emit the PAL pollutant.
    (ii) The reviewing authority shall calculate the new PAL as the sum 
of the allowable emissions for each modified or new emissions unit, plus 
the sum of the baseline actual emissions of the significant and major 
emissions units (assuming application of BACT equivalent controls as 
determined in accordance with paragraph (f)(11)(i)(B)), plus the sum of 
the baseline actual emissions of the small emissions units.
    (iii) The PAL permit shall be revised to reflect the increased PAL 
level pursuant to the public notice requirements of paragraph (f)(5) of 
this section.
    (12) Monitoring requirements for PALs--(i) General requirements.
    (A) Each PAL permit must contain enforceable requirements for the 
monitoring system that accurately determines plantwide emissions of the 
PAL pollutant in terms of mass per unit of time. Any monitoring system 
authorized for use in the PAL permit must be based on sound science and 
meet generally acceptable scientific procedures for data quality and 
manipulation. Additionally, the information generated by such system 
must meet minimum legal requirements for admissibility in a judicial 
proceeding to enforce the PAL permit.
    (B) The PAL monitoring system must employ one or more of the four 
general monitoring approaches meeting the minimum requirements set forth 
in paragraphs (f)(12)(ii)(A) through (D) of this section and must be 
approved by the reviewing authority.
    (C) Notwithstanding paragraph (f)(12)(i)(B) of this section, you may 
also employ an alternative monitoring approach that meets paragraph 
(f)(12)(i)(A) of this section if approved by the reviewing authority.
    (D) Failure to use a monitoring system that meets the requirements 
of this section renders the PAL invalid.
    (ii) Minimum Performance Requirements for Approved Monitoring 
Approaches. The following are acceptable general monitoring approaches 
when conducted in accordance with the minimum requirements in paragraphs 
(f)(12)(iii) through (ix) of this section:
    (A) Mass balance calculations for activities using coatings or 
solvents;
    (B) CEMS;
    (C) CPMS or PEMS; and
    (D) Emission Factors.
    (iii) Mass Balance Calculations. An owner or operator using mass 
balance calculations to monitor PAL pollutant emissions from activities 
using coating or solvents shall meet the following requirements:

[[Page 196]]

    (A) Provide a demonstrated means of validating the published content 
of the PAL pollutant that is contained in or created by all materials 
used in or at the emissions unit;
    (B) Assume that the emissions unit emits all of the PAL pollutant 
that is contained in or created by any raw material or fuel used in or 
at the emissions unit, if it cannot otherwise be accounted for in the 
process; and
    (C) Where the vendor of a material or fuel, which is used in or at 
the emissions unit, publishes a range of pollutant content from such 
material, the owner or operator must use the highest value of the range 
to calculate the PAL pollutant emissions unless the reviewing authority 
determines there is site-specific data or a site-specific monitoring 
program to support another content within the range.
    (iv) CEMS. An owner or operator using CEMS to monitor PAL pollutant 
emissions shall meet the following requirements:
    (A) CEMS must comply with applicable Performance Specifications 
found in 40 CFR part 60, appendix B; and
    (B) CEMS must sample, analyze and record data at least every 15 
minutes while the emissions unit is operating.
    (v) CPMS or PEMS. An owner or operator using CPMS or PEMS to monitor 
PAL pollutant emissions shall meet the following requirements:
    (A) The CPMS or the PEMS must be based on current site-specific data 
demonstrating a correlation between the monitored parameter(s) and the 
PAL pollutant emissions across the range of operation of the emissions 
unit; and
    (B) Each CPMS or PEMS must sample, analyze, and record data at least 
every 15 minutes, or at another less frequent interval approved by the 
reviewing authority, while the emissions unit is operating.
    (vi) Emission factors. An owner or operator using emission factors 
to monitor PAL pollutant emissions shall meet the following 
requirements:
    (A) All emission factors shall be adjusted, if appropriate, to 
account for the degree of uncertainty or limitations in the factors' 
development;
    (B) The emissions unit shall operate within the designated range of 
use for the emission factor, if applicable; and
    (C) If technically practicable, the owner or operator of a 
significant emissions unit that relies on an emission factor to 
calculate PAL pollutant emissions shall conduct validation testing to 
determine a site-specific emission factor within 6 months of PAL permit 
issuance, unless the reviewing authority determines that testing is not 
required.
    (vii) A source owner or operator must record and report maximum 
potential emissions without considering enforceable emission limitations 
or operational restrictions for an emissions unit during any period of 
time that there is no monitoring data, unless another method for 
determining emissions during such periods is specified in the PAL 
permit.
    (viii) Notwithstanding the requirements in paragraphs (f)(12)(iii) 
through (vii) of this section, where an owner or operator of an 
emissions unit cannot demonstrate a correlation between the monitored 
parameter(s) and the PAL pollutant emissions rate at all operating 
points of the emissions unit, the reviewing authority shall, at the time 
of permit issuance:
    (A) Establish default value(s) for determining compliance with the 
PAL based on the highest potential emissions reasonably estimated at 
such operating point(s); or
    (B) Determine that operation of the emissions unit during operating 
conditions when there is no correlation between monitored parameter(s) 
and the PAL pollutant emissions is a violation of the PAL.
    (ix) Re-validation. All data used to establish the PAL pollutant 
must be re-validated through performance testing or other scientifically 
valid means approved by the reviewing authority. Such testing must occur 
at least once every 5 years after issuance of the PAL.
    (13) Recordkeeping requirements. (i) The PAL permit shall require an 
owner or operator to retain a copy of all records necessary to determine 
compliance with any requirement of paragraph (f) of this section and of 
the PAL, including a determination of each

[[Page 197]]

emissions unit's 12-month rolling total emissions, for 5 years from the 
date of such record.
    (ii) The PAL permit shall require an owner or operator to retain a 
copy of the following records for the duration of the PAL effective 
period plus 5 years:
    (A) A copy of the PAL permit application and any applications for 
revisions to the PAL; and
    (B) Each annual certification of compliance pursuant to title V and 
the data relied on in certifying the compliance.
    (14) Reporting and notification requirements. The owner or operator 
shall submit semi-annual monitoring reports and prompt deviation reports 
to the reviewing authority in accordance with the applicable title V 
operating permit program. The reports shall meet the requirements in 
paragraphs (f)(14)(i) through (iii).
    (i) Semi-Annual Report. The semi-annual report shall be submitted to 
the reviewing authority within 30 days of the end of each reporting 
period. This report shall contain the information required in paragraphs 
(f)(14)(i)(A) through (G) of this section.
    (A) The identification of owner and operator and the permit number.
    (B) Total annual emissions (tons/year) based on a 12-month rolling 
total for each month in the reporting period recorded pursuant to 
paragraph (f)(13)(i) of this section.
    (C) All data relied upon, including, but not limited to, any Quality 
Assurance or Quality Control data, in calculating the monthly and annual 
PAL pollutant emissions.
    (D) A list of any emissions units modified or added to the major 
stationary source during the preceding 6-month period.
    (E) The number, duration, and cause of any deviations or monitoring 
malfunctions (other than the time associated with zero and span 
calibration checks), and any corrective action taken.
    (F) A notification of a shutdown of any monitoring system, whether 
the shutdown was permanent or temporary, the reason for the shutdown, 
the anticipated date that the monitoring system will be fully 
operational or replaced with another monitoring system, and whether the 
emissions unit monitored by the monitoring system continued to operate, 
and the calculation of the emissions of the pollutant or the number 
determined by method included in the permit, as provided by paragraph 
(f)(12)(vii) of this section.
    (G) A signed statement by the responsible official (as defined by 
the applicable title V operating permit program) certifying the truth, 
accuracy, and completeness of the information provided in the report.
    (ii) Deviation report. The major stationary source owner or operator 
shall promptly submit reports of any deviations or exceedance of the PAL 
requirements, including periods where no monitoring is available. A 
report submitted pursuant to Sec. 70.6(a)(3)(iii)(B) of this chapter 
shall satisfy this reporting requirement. The deviation reports shall be 
submitted within the time limits prescribed by the applicable program 
implementing Sec. 70.6(a)(3)(iii)(B) of this chapter. The reports shall 
contain the following information:
    (A) The identification of owner and operator and the permit number;
    (B) The PAL requirement that experienced the deviation or that was 
exceeded;
    (C) Emissions resulting from the deviation or the exceedance; and
    (D) A signed statement by the responsible official (as defined by 
the applicable title V operating permit program) certifying the truth, 
accuracy, and completeness of the information provided in the report.
    (iii) Re-validation results. The owner or operator shall submit to 
the reviewing authority the results of any re-validation test or method 
within 3 months after completion of such test or method.
    (15) Transition requirements. (i) No reviewing authority may issue a 
PAL that does not comply with the requirements in paragraphs (f)(1) 
through (15) of this section after the Administrator has approved 
regulations incorporating these requirements into a plan.
    (ii) The reviewing authority may supersede any PAL which was 
established prior to the date of approval of the plan by the 
Administrator with a PAL

[[Page 198]]

that complies with the requirements of paragraphs (f)(1) through (15) of 
this section.
    (g) If any provision of this section, or the application of such 
provision to any person or circumstance, is held invalid, the remainder 
of this section, or the application of such provision to persons or 
circumstances other than those as to which it is held invalid, shall not 
be affected thereby.

[51 FR 40669, Nov. 7, 1986, as amended at 52 FR 24713, July 1, 1987; 52 
FR 29386, Aug 7, 1987; 54 FR 27285, 27299 June 28, 1989; 57 FR 3946, 
Feb. 3, 1992; 57 FR 32334, July 21, 1992; 67 FR 80244, Dec. 31, 2002]



Sec. 51.166  Prevention of significant deterioration of air quality.

    (a)(1) Plan requirements. In accordance with the policy of section 
101(b)(1) of the Act and the purposes of section 160 of the Act, each 
applicable State Implementation Plan and each applicable Tribal 
Implementation Plan shall contain emission limitations and such other 
measures as may be necessary to prevent significant deterioration of air 
quality.
    (2) Plan revisions. If a State Implementation Plan revision would 
result in increased air quality deterioration over any baseline 
concentration, the plan revision shall include a demonstration that it 
will not cause or contribute to a violation of the applicable 
increment(s). If a plan revision proposing less restrictive requirements 
was submitted after August 7, 1977 but on or before any applicable 
baseline date and was pending action by the Administrator on that date, 
no such demonstration is necessary with respect to the area for which a 
baseline date would be established before final action is taken on the 
plan revision. Instead, the assessment described in paragraph (a)(4) of 
this section, shall review the expected impact to the applicable 
increment(s).
    (3) Required plan revision. If the State or the Administrator 
determines that a plan is substantially inadequate to prevent 
significant deterioration or that an applicable increment is being 
violated, the plan shall be revised to correct the inadequacy or the 
violation. The plan shall be revised within 60 days of such a finding by 
a State or within 60 days following notification by the Administrator, 
or by such later date as prescribed by the Administrator after 
consultation with the State.
    (4) Plan assessment. The State shall review the adequacy of a plan 
on a periodic basis and within 60 days of such time as information 
becomes available that an applicable increment is being violated.
    (5) Public participation. Any State action taken under this 
paragraph shall be subject to the opportunity for public hearing in 
accordance with procedures equivalent to those established in 
Sec. 51.102.
    (6) Amendments. (i) Any State required to revise its implementation 
plan by reason of an amendment to this section, including any amendment 
adopted simultaneously with this paragraph (a)(6)(i), shall adopt and 
submit such plan revision to the Administrator for approval no later 
than three years after such amendment is published in the Federal 
Register.
    (ii) Any revision to an implementation plan that would amend the 
provisions for the prevention of significant air quality deterioration 
in the plan shall specify when and as to what sources and modifications 
the revision is to take effect.
    (iii) Any revision to an implementation plan that an amendment to 
this section required shall take effect no later than the date of its 
approval and may operate prospectively.
    (7) Applicability. Each plan shall contain procedures that 
incorporate the requirements in paragraphs (a)(7)(i) through (vi) of 
this section.
    (i) The requirements of this section apply to the construction of 
any new major stationary source (as defined in paragraph (b)(1) of this 
section) or any project at an existing major stationary source in an 
area designated as attainment or unclassifiable under sections 
107(d)(1)(A)(ii) or (iii) of the Act.
    (ii) The requirements of paragraphs (j) through (r) of this section 
apply to the construction of any new major stationary source or the 
major modification of any existing major stationary source, except as 
this section otherwise provides.

[[Page 199]]

    (iii) No new major stationary source or major modification to which 
the requirements of paragraphs (j) through (r)(5) of this section apply 
shall begin actual construction without a permit that states that the 
major stationary source or major modification will meet those 
requirements.
    (iv) Each plan shall use the specific provisions of paragraphs 
(a)(7)(iv)(a) through (f) of this section. Deviations from these 
provisions will be approved only if the State specifically demonstrates 
that the submitted provisions are more stringent than or at least as 
stringent in all respects as the corresponding provisions in paragraphs 
(a)(7)(iv)(a) through (f) of this section.
    (a) Except as otherwise provided in paragraphs (a)(7)(v) and (vi) of 
this section, and consistent with the definition of major modification 
contained in paragraph (b)(2) of this section, a project is a major 
modification for a regulated NSR pollutant if it causes two types of 
emissions increases--a significant emissions increase (as defined in 
paragraph (b)(39) of this section), and a significant net emissions 
increase (as defined in paragraphs (b)(3) and (b)(23) 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.
    (b) The procedure for calculating (before beginning actual 
construction) whether a significant emissions increase (i.e., the first 
step of the process) will occur depends upon the type of emissions units 
being modified, according to paragraphs (a)(7)(iv)(c) through (f) of 
this section. The procedure for calculating (before beginning actual 
construction) whether a significant net emissions increase will occur at 
the major stationary source (i.e., the second step of the process) is 
contained in the definition in paragraph (b)(3) of this section. 
Regardless of any such preconstruction projections, a major modification 
results if the project causes a significant emissions increase and a 
significant net emissions increase.
    (c) Actual-to-projected-actual applicability test for projects that 
only involve existing emissions units. A significant emissions increase 
of a regulated NSR pollutant is projected to occur if the sum of the 
difference between the projected actual emissions (as defined in 
paragraph (b)(40) of this section) and the baseline actual emissions (as 
defined in paragraphs (b)(47)(i) and (ii) of this section) for each 
existing emissions unit, equals or exceeds the significant amount for 
that pollutant (as defined in paragraph (b)(23) of this section).
    (d) Actual-to-potential test for projects that only involve 
construction of a new emissions unit(s). A significant emissions 
increase of a regulated NSR pollutant is projected to occur if the sum 
of the difference between the potential to emit (as defined in paragraph 
(b)(4) of this section) from each new emissions unit following 
completion of the project and the baseline actual emissions (as defined 
in paragraph (b)(47)(iii) of this section) of these units before the 
project equals or exceeds the significant amount for that pollutant (as 
defined in paragraph (b)(23) of this section).
    (e) Emission test for projects that involve Clean Units. For a 
project that will be constructed and operated at a Clean Unit without 
causing the emissions unit to lose its Clean Unit designation, no 
emissions increase is deemed to occur.
    (f) Hybrid test for projects that involve multiple types of 
emissions units. A significant emissions increase of a regulated NSR 
pollutant is projected to occur if the sum of the emissions increases 
for each emissions unit, using the method specified in paragraphs 
(a)(7)(iv)(c) through (e) of this section as applicable with respect to 
each emissions unit, for each type of emissions unit equals or exceeds 
the significant amount for that pollutant (as defined in paragraph 
(b)(23) of this section). For example, if a project involves both an 
existing emissions unit and a Clean Unit, the projected increase is 
determined by summing the values determined using the method specified 
in paragraph (a)(7)(iv)(c) of this section for the existing unit and 
determined using the method specified

[[Page 200]]

in paragraph (a)(7)(iv)(e) of this section for the Clean Unit.
    (v) The plan shall require that for any major stationary source for 
a PAL for a regulated NSR pollutant, the major stationary source shall 
comply with requirements under paragraph (w) of this section.
    (vi) The plan shall require that an owner or operator undertaking a 
PCP (as defined in paragraph (b)(31) of this section) shall comply with 
the requirements under paragraph (v) of this section.
    (b) Definitions. All State plans shall use the following definitions 
for the purposes of this section. Deviations from the following wording 
will be approved only if the State specifically demonstrates that the 
submitted definition is more stringent, or at least as stringent, in all 
respects as the corresponding definitions below:
    (1)(i) Major stationary source means:
    (a) Any of the following stationary sources of air pollutants which 
emits, or has the potential to emit, 100 tons per year or more of any a 
regulated NSR pollutant: Fossil fuel-fired steam electric plants of more 
than 250 million British thermal units per hour heat input, coal 
cleaning plants (with thermal dryers), kraft pulp mills, portland cement 
plants, primary zinc smelters, iron and steel mill plants, primary 
aluminum ore reduction plants, primary copper smelters, municipal 
incinerators capable of charging more than 250 tons of refuse per day, 
hydrofluoric, sulfuric, and nitric acid plants, petroleum refineries, 
lime plants, phosphate rock processing plants, coke oven batteries, 
sulfur recovery plants, carbon black plants (furnace process), primary 
lead smelters, fuel conversion plants, sintering plants, secondary metal 
production plants, chemical process plants, fossil fuel boilers (or 
combinations thereof) totaling more than 250 million British thermal 
units per hour heat input, petroleum storage and transfer units with a 
total storage capacity exceeding 300,000 barrels, taconite ore 
processing plants, glass fiber processing plants, and charcoal 
production plants;
    (b) Notwithstanding the stationary source size specified in 
paragraph (b)(1)(i)(a) of this section, any stationary source which 
emits, or has the potential to emit, 250 tons per year or more of a 
regulated NSR pollutant; or
    (c) Any physical change that would occur at a stationary source not 
otherwise qualifying under paragraph (b)(1) of this section, as a major 
stationary source if the change would constitute a major stationary 
source by itself.
    (ii) A major source that is major for volatile organic compounds 
shall be considered major for ozone.
    (iii) The fugitive emissions of a stationary source shall not be 
included in determining for any of the purposes of this section whether 
it is a major stationary source, unless the source belongs to one of the 
following categories of stationary sources:
    (a) Coal cleaning plants (with thermal dryers);
    (b) Kraft pulp mills;
    (c) Portland cement plants;
    (d) Primary zinc smelters;
    (e) Iron and steel mills;
    (f) Primary aluminum ore reduction plants;
    (g) Primary copper smelters;
    (h) Municipal incinerators capable of charging more than 250 tons of 
refuse per day;
    (i) Hydrofluoric, sulfuric, or nitric acid plants;
    (j) Petroleum refineries;
    (k) Lime plants;
    (l) Phosphate rock processing plants;
    (m) Coke oven batteries;
    (n) Sulfur recovery plants;
    (o) Carbon black plants (furnace process);
    (p) Primary lead smelters;
    (q) Fuel conversion plants;
    (r) Sintering plants;
    (s) Secondary metal production plants;
    (t) Chemical process plants;
    (u) Fossil-fuel boilers (or combination thereof) totaling more than 
250 million British thermal units per hour heat input;
    (v) Petroleum storage and transfer units with a total storage 
capacity exceeding 300,000 barrels;
    (w) Taconite ore processing plants;
    (x) Glass fiber processing plants;
    (y) Charcoal production plants;
    (z) Fossil fuel-fired steam electric plants of more that 250 million 
British thermal units per hour heat input;

[[Page 201]]

    (aa) Any other stationary source category which, as of August 7, 
1980, is being regulated under section 111 or 112 of the Act.
    (2)(i) Major modification means any physical change in or change in 
the method of operation of a major stationary source that would result 
in: a significant emissions increase (as defined in paragraph (b)(39) of 
this section) of a regulated NSR pollutant (as defined in paragraph 
(b)(49) of this section); and a significant net emissions increase of 
that pollutant from the major stationary source.
    (ii) Any significant emissions increase (as defined at paragraph 
(b)(39) of this section) from any emissions units or net emissions 
increase (as defined at paragraph (b)(3) of this section) at a major 
stationary source that is significant for volatile organic compounds 
shall be considered significant for ozone.
    (iii) A physical change or change in the method of operation shall 
not include:
    (a) Routine maintenance, repair, and replacement;
    (b) Use of an alternative fuel or raw material by reason of any 
order under section 2 (a) and (b) of the Energy Supply and Environmental 
Coordination Act of 1974 (or any superseding legislation) or by reason 
of a natural gas curtailment plan pursuant to the Federal Power Act;
    (c) Use of an alternative fuel by reason of an order or rule under 
section 125 of the Act;
    (d) Use of an alternative fuel at a steam generating unit to the 
extent that the fuel is generated from municipal solid waste;
    (e) Use of an alternative fuel or raw material by a stationary 
source which:
    (1) The source was capable of accommodating before January 6, 1975, 
unless such change would be prohibited under any federally enforceable 
permit condition which was established after January 6, 1975 pursuant to 
40 CFR 52.21 or under regulations approved pursuant to 40 CFR subpart I 
or Sec. 51.166; or
    (2) The source is approved to use under any permit issued under 40 
CFR 52.21 or under regulations approved pursuant to 40 CFR 51.166;
    (f) An increase in the hours of operation or in the production rate, 
unless such change would be prohibited under any federally enforceable 
permit condition which was established after January 6, 1975, pursuant 
to 40 CFR 52.21 or under regulations approved pursuant to 40 CFR subpart 
I or Sec. 51.166.
    (g) Any change in ownership at a stationary source.
    (h) The addition, replacement, or use of a PCP, as defined in 
paragraph (b)(31) of this section, at an existing emissions unit meeting 
the requirements of paragraph (v) of this section. A replacement control 
technology must provide more effective emission control than that of the 
replaced control technology to qualify for this exclusion.
    (i) The installation, operation, cessation, or removal of a 
temporary clean coal technology demonstration project, provided that the 
project complies with:
    (1) The State implementation plan for the State in which the project 
is located; and
    (2) Other requirements necessary to attain and maintain the national 
ambient air quality standards during the project and after it is 
terminated.
    (j) The installation or operation of a permanent clean coal 
technology demonstration project that constitutes repowering, provided 
that the project does not result in an increase in the potential to emit 
of any regulated pollutant emitted by the unit. This exemption shall 
apply on a pollutant-by-pollutant basis.
    (k) The reactivation of a very clean coal-fired electric utility 
steam generating unit.
    (iv) This definition shall not apply with respect to a particular 
regulated NSR pollutant when the major stationary source is complying 
with the requirements under paragraph (w) of this section for a PAL for 
that pollutant. Instead, the definition at paragraph (w)(2)(viii) of 
this section shall apply.
    (3)(i) Net emissions increase means, with respect to any regulated 
NSR pollutant emitted by a major stationary source, the amount by which 
the sum of the following exceeds zero:

[[Page 202]]

    (a) The increase in emissions from a particular physical change or 
change in the method of operation at a stationary source as calculated 
pursuant to paragraph (a)(7)(iv) of this section; and
    (b) Any other increases and decreases in actual emissions at the 
major stationary source that are contemporaneous with the particular 
change and are otherwise creditable. Baseline actual emissions for 
calculating increases and decreases under this paragraph (b)(3)(i)(b) 
shall be determined as provided in paragraph (b)(47), except that 
paragraphs (b)(47)(i)(c) and (b)(47)(ii)(d) of this section shall not 
apply.
    (ii) An increase or decrease in actual emissions is contemporaneous 
with the increase from the particular change only if it occurs within a 
reasonable period (to be specified by the State) before the date that 
the increase from the particular change occurs.
    (iii) An increase or decrease in actual emissions is creditable only 
if:
    (a) It occurs within a reasonable period (to be specified by the 
reviewing authority); and
    (b) The reviewing authority has not relied on it in issuing a permit 
for the source under regulations approved pursuant to this section, 
which permit is in effect when the increase in actual emissions from the 
particular change occurs; and
    (c) The increase or decrease in emissions did not occur at a Clean 
Unit, except as provided in paragraphs (t)(8) and (u)(10) of this 
section.
    (iv) An increase or decrease in actual emissions of sulfur dioxide, 
particulate matter, or nitrogen oxides that occurs before the applicable 
minor source baseline date is creditable only if it is required to be 
considered in calculating the amount of maximum allowable increases 
remaining available.
    (v) An increase in actual emissions is creditable only to the extent 
that the new level of actual emissions exceeds the old level.
    (vi) A decrease in actual emissions is creditable only to the extent 
that:
    (a) The old level of actual emissions or the old level of allowable 
emissions, whichever is lower, exceeds the new level of actual 
emissions;
    (b) It is enforceable as a practical matter at and after the time 
that actual construction on the particular change begins;
    (c) It has approximately the same qualitative significance for 
public health and welfare as that attributed to the increase from the 
particular change; and
    (d) The decrease in actual emissions did not result from the 
installation of add-on control technology or application of pollution 
prevention practices that were relied on in designating an emissions 
unit as a Clean Unit under Sec. 52.21(y) or under regulations approved 
pursuant to paragraph (u) of this section or Sec. 51.165(d). That is, 
once an emissions unit has been designated as a Clean Unit, the owner or 
operator cannot later use the emissions reduction from the air pollution 
control measures that the Clean Unit designation is based on in 
calculating the net emissions increase for another emissions unit (i.e., 
must not use that reduction in a ``netting analysis'' for another 
emissions unit). However, any new emissions reductions that were not 
relied upon in a PCP excluded pursuant to paragraph (v) of this section 
or for the Clean Unit designation are creditable to the extent they meet 
the requirements in paragraph (v)(6)(iv) of this section for the PCP and 
paragraph (t)(8) or (u)(10) of this section for a Clean Unit.
    (vii) An increase that results from a physical change at a source 
occurs when the emissions unit on which construction occurred becomes 
operational and begins to emit a particular pollutant. Any replacement 
unit that requires shakedown becomes operational only after a reasonable 
shakedown period, not to exceed 180 days.
    (viii) Paragraph (b)(21)(ii) of this section shall not apply for 
determining creditable increases and decreases.
    (4) Potential to emit means the maximum capacity of a stationary 
source to emit a pollutant under its physical and operational design. 
Any physical or operational limitation on the capacity of the source to 
emit a pollutant, including air pollution control equipment and 
restrictions on hours of operation or on the type or amount of material 
combusted, stored, or processed,

[[Page 203]]

shall be treated as part of its design if the limitation or the effect 
it would have on emissions is federally enforceable. Secondary emissions 
do not count in determining the potential to emit of a stationary 
source.
    (5) Stationary source means any building, structure, facility, or 
installation which emits or may emit a regulated NSR pollutant.
    (6) Building, structure, facility, or installation means all of the 
pollutant-emitting activities which belong to the same industrial 
grouping, are located on one or more contiguous or adjacent properties, 
and are under the control of the same person (or persons under common 
control) except the activities of any vessel. Pollutant-emitting 
activities shall be considered as part of the same industrial grouping 
if they belong to the same Major Group (i.e., which have the same two-
digit code) as described in the Standard Industrial Classification 
Manual, 1972, as amended by the 1977 Supplement (U.S. Government 
Printing Office stock numbers 4101-0066 and 003-005-00176-0, 
respectively).
    (7) Emissions unit means any part of a stationary source that emits 
or would have the potential to emit any regulated NSR pollutant and 
includes an electric utility steam generating unit as defined in 
paragraph (b)(30) of this section. For purposes of this section, there 
are two types of emissions units as described in paragraphs (b)(7)(i) 
and (ii) of this section.
    (i) A new emissions unit is any emissions unit that is (or will be) 
newly constructed and that has existed for less than 2 years from the 
date such emissions unit first operated.
    (ii) An existing emissions unit is any emissions unit that does not 
meet the requirements in paragraph (b)(7)(i) of this section.
    (8) Construction means any physical change or change in the method 
of operation (including fabrication, erection, installation, demolition, 
or modification of an emissions unit) that would result in a change in 
emissions.
    (9) Commence as applied to construction of a major stationary source 
or major modification means that the owner or operator has all necessary 
preconstruction approvals or permits and either has:
    (i) Begun, or caused to begin, a continuous program of actual on-
site construction of the source, to be completed within a reasonable 
time; or
    (ii) Entered into binding agreements or contractual obligations, 
which cannot be cancelled or modified without substantial loss to the 
owner or operator, to undertake a program of actual construction of the 
source to be completed within a reasonable time.
    (10) Necessary preconstruction approvals or permits means those 
permits or approvals required under Federal air quality control laws and 
regulations and those air quality control laws and regulations which are 
part of the applicable State Implementation Plan.
    (11) Begin actual construction means, in general, initiation of 
physical on-site construction activities on an emissions unit which are 
of a permanent nature. Such activities include, but are not limited to, 
installation of building supports and foundations, laying of underground 
pipework, and construction of permanent storage structures. With respect 
to a change in method of operation this term refers to those on-site 
activities, other than preparatory activities, which mark the initiation 
of the change.
    (12) Best available control technology means an emissions limitation 
(including a visible emissions standard) based on the maximum degree of 
reduction for each a regulated NSR pollutant which would be emitted from 
any proposed major stationary source or major modification which the 
reviewing authority, on a case-by-case basis, taking into account 
energy, environmental, and economic impacts and other costs, determines 
is achievable for such source or modification through application of 
production processes or available methods, systems, and techniques, 
including fuel cleaning or treatment or innovative fuel combination 
techniques for control of such pollutant. In no event shall application 
of best available control technology result in emissions of any 
pollutant which would exceed the emissions allowed by any applicable 
standard under 40 CFR parts 60 and 61. If the reviewing authority 
determines that technological or economic limitations on the application 
of

[[Page 204]]

measurement methodology to a particular emissions unit would make the 
imposition of an emissions standard infeasible, a design, equipment, 
work practice, operational standard or combination thereof, may be 
prescribed instead to satisfy the requirement for the application of 
best available control technology. Such standard shall, to the degree 
possible, set forth the emissions reduction achievable by implementation 
of such design, equipment, work practice or operation, and shall provide 
for compliance by means which achieve equivalent results.
    (13)(i) Baseline concentration means that ambient concentration 
level that exists in the baseline area at the time of the applicable 
minor source baseline date. A baseline concentration is determined for 
each pollutant for which a minor source baseline date is established and 
shall include:
    (a) The actual emissions, as defined in paragraph (b)(21) of this 
section, representative of sources in existence on the applicable minor 
source baseline date, except as provided in paragraph (b)(13)(ii) of 
this section;
    (b) The allowable emissions of major stationary sources that 
commenced construction before the major source baseline date, but were 
not in operation by the applicable minor source baseline date.
    (ii) The following will not be included in the baseline 
concentration and will affect the applicable maximum allowable 
increase(s):
    (a) Actual emissions, as defined in paragraph (b)(21) of this 
section, from any major stationary source on which construction 
commenced after the major source baseline date; and
    (b) Actual emissions increases and decreases, as defined in 
paragraph (b)(21) of this section, at any stationary source occurring 
after the minor source baseline date.
    (14)(i) Major source baseline date means:
    (a) In the case of particulate matter and sulfur dioxide, January 6, 
1975, and
    (b) In the case of nitrogen dioxide, February 8, 1988.
    (ii) Minor source baseline date means the earliest date after the 
trigger date on which a major stationary source or a major modification 
subject to 40 CFR 52.21 or to regulations approved pursuant to 40 CFR 
51.166 submits a complete application under the relevant regulations. 
The trigger date is:
    (a) In the case of particulate matter and sulfur dioxide, August 7, 
1977, and
    (b) In the case of nitrogen dioxide, February 8, 1988.
    (iii) The baseline date is established for each pollutant for which 
increments or other equivalent measures have been established if:
    (a) The area in which the proposed source or modification would 
construct is designated as attainment or unclassifiable under section 
107(d)(i) (D) or (E) of the Act for the pollutant on the date of its 
complete application under 40 CFR 52.21 or under regulations approved 
pursuant to 40 CFR 51.166; and
    (b) In the case of a major stationary source, the pollutant would be 
emitted in significant amounts, or, in the case of a major modification, 
there would be a significant net emissions increase of the pollutant.
    (iv) Any minor source baseline date established originally for the 
TSP increments shall remain in effect and shall apply for purposes of 
determining the amount of available PM-10 increments, except that the 
reviewing authority may rescind any such minor source baseline date 
where it can be shown, to the satisfaction of the reviewing authority, 
that the emissions increase from the major stationary source, or the net 
emissions increase from the major modification, responsible for 
triggering that date did not result in a significant amount of PM-10 
emissions.
    (15)(i) Baseline area means any intrastate area (and every part 
thereof) designated as attainment or unclassifiable under section 
107(d)(1) (D) or (E) of the Act in which the major source or major 
modification establishing the minor source baseline date would construct 
or would have an air quality impact equal to or greater than 1 [mu]g/
m\3\ (annual average) of the pollutant for which the minor source 
baseline date is established.
    (ii) Area redesignations under section 107(d)(1) (D) or (E) of the 
Act cannot intersect or be smaller than the area of impact of any major 
stationary source or major modification which:

[[Page 205]]

    (a) Establishes a minor source baseline date; or
    (b) Is subject to 40 CFR 52.21 or under regulations approved 
pursuant to 40 CFR 51.166, and would be constructed in the same State as 
the State proposing the redesignation.
    (iii) Any baseline area established originally for the TSP 
increments shall remain in effect and shall apply for purposes of 
determining the amount of available PM-10 increments, except that such 
baseline area shall not remain in effect if the permit authority 
rescinds the corresponding minor source baseline date in accordance with 
paragraph (b)(14)(iv) of this section.
    (16) Allowable emissions means the emissions rate of a stationary 
source calculated using the maximum rated capacity of the source (unless 
the source is subject to federally enforceable limits which restrict the 
operating rate, or hours of operation, or both) and the most stringent 
of the following:
    (i) The applicable standards as set forth in 40 CFR parts 60 and 61;
    (ii) The applicable State Implementation Plan emissions limitation, 
including those with a future compliance date; or
    (iii) The emissions rate specified as a federally enforceable permit 
condition.
    (17) Federally enforceable means all limitations and conditions 
which are enforceable by the Administrator, including those requirements 
developed pursuant to 40 CFR parts 60 and 61, requirements within any 
applicable State implementation plan, any permit requirements 
established pursuant to 40 CFR 52.21 or under regulations approved 
pursuant to 40 CFR part 51, subpart I, including operating permits 
issued under an EPA-approved program that is incorporated into the State 
implementation plan and expressly requires adherence to any permit 
issued under such program.
    (18) Secondary emissions means emissions which occur as a result of 
the construction or operation of a major stationary source or major 
modification, but do not come from the major stationary source or major 
modification itself. For the purposes of this section, secondary 
emissions must be specific, well defined, quantifiable, and impact the 
same general areas the stationary source modification which causes the 
secondary emissions. Secondary emissions include emissions from any 
offsite support facility which would not be constructed or increase its 
emissions except as a result of the construction or operation of the 
major stationary source or major modification. Secondary emissions do 
not include any emissions which come directly from a mobile source, such 
as emissions from the tailpipe of a motor vehicle, from a train, or from 
a vessel.
    (19) Innovative control technology means any system of air pollution 
control that has not been adequately demonstrated in practice, but would 
have a substantial likelihood of achieving greater continuous emissions 
reduction than any control system in current practice or of achieving at 
least comparable reductions at lower cost in terms of energy, economics, 
or nonair quality environmental impacts.
    (20) Fugitive emissions means those emissions which could not 
reasonably pass through a stack, chimney, vent, or other functionally 
equivalent opening.
    (21)(i) Actual emissions means the actual rate of emissions of a 
regulated NSR pollutant from an emissions unit, as determined in 
accordance with paragraphs (b)(21)(ii) through (iv) of this section, 
except that this definition shall not apply for calculating whether a 
significant emissions increase has occurred, or for establishing a PAL 
under paragraph (w) of this section. Instead, paragraphs (b)(40) and 
(b)(47) of this section shall apply for those purposes.
    (ii) In general, actual emissions as of a particular date shall 
equal the average rate, in tons per year, at which the unit actually 
emitted the pollutant during a consecutive 24-month period which 
precedes the particular date and which is representative of normal 
source operation. The reviewing authority shall allow the use of a 
different time period upon a determination that it is more 
representative of normal source operation. Actual emissions shall be 
calculated using the unit's actual operating hours, production rates, 
and types of materials processed, stored, or combusted during the 
selected time period.

[[Page 206]]

    (iii) The reviewing authority may presume that source-specific 
allowable emissions for the unit are equivalent to the actual emissions 
of the unit.
    (iv) For any emissions unit that has not begun normal operations on 
the particular date, actual emissions shall equal the potential to emit 
of the unit on that date.
    (22) Complete means, in reference to an application for a permit, 
that the application contains all the information necessary for 
processing the application. Designating an application complete for 
purposes of permit processing does not preclude the reviewing authority 
from requesting or accepting any additional information.
    (23)(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
Particulate matter: 25 tpy of particulate matter emissions. 15 tpy of 
PM10 emissions.
Ozone: 40 tpy of volatile organic compounds
Lead: 0.6 tpy
Fluorides: 3 tpy
Sulfuric acid mist: 7 tpy
Hydrogen sulfide (H2 S): 10 tpy
Total reduced sulfur (including H2 S): 10 tpy
Reduced sulfur compounds (including H2 S): 10 tpy
Municipal waste combustor organics (measured as total tetra- through 
octa-chlorinated dibenzo-p-dioxins and dibenzofurans): 3.2 x 
10-6 megagrams per year (3.5 x 10-6 tons per year)
Municipal waste combustor metals (measured as articulate matter): 14 
megagrams per year (15 tons per year) Municipal waste combustor acid 
gases (measured as sulfur dioxide and hydrogen chloride): 36 megagrams 
per year (40 tons per year)
Municipal solid waste landfill emissions (measured as nonmethane organic 
compounds): 45 megagrams per year (50 tons per year)

    (ii) Significant means, in reference to a net emissions increase or 
the potential of a source to emit a a regulated NSR pollutant that 
paragraph (b)(23)(i) of this section, does not list, any emissions rate.
    (iii) Notwithstanding paragraph (b)(23)(i) of this section, 
significant means any emissions rate or any net emissions increase 
associated with a major stationary source or major modification, which 
would construct within 10 kilometers of a Class I area, and have an 
impact on such area equal to or greater than 1 [mu]g/m\3\ (24-hour 
average).
    (24) Federal Land Manager means, with respect to any lands in the 
United States, the Secretary of the department with authority over such 
lands.
    (25) High terrain means any area having an elevation 900 feet or 
more above the base of the stack of a source.
    (26) Low terrain means any area other than high terrain.
    (27) Indian Reservation means any federally recognized reservation 
established by Treaty, Agreement, Executive Order, or Act of Congress.
    (28) Indian Governing Body means the governing body of any tribe, 
band, or group of Indians subject to the jurisdiction of the United 
States and recognized by the United States as possessing power of self-
government.
    (29) Volatile organic compounds (VOC) is as defined in 
Sec. 51.100(s) of this part.
    (30) Electric utility steam generating unit means any steam electric 
generating unit that is constructed for the purpose of supplying more 
than one-third of its potential electric output capacity and more than 
25 MW electrical output to any utility power distribution system for 
sale. Any steam supplied to a steam distribution system for the purpose 
of providing steam to a steam-electric generator that would produce 
electrical energy for sale is also considered in determining the 
electrical energy output capacity of the affected facility.
    (31) Pollution control project (PCP) means any activity, set of work 
practices or project (including pollution prevention as defined under 
paragraph (b)(38) of this section) undertaken at an existing emissions 
unit that reduces emissions of air pollutants from such unit. Such 
qualifying activities or projects can include the replacement or upgrade 
of an existing emissions control technology with a more effective unit. 
Other changes that may occur at the source are not considered part of 
the PCP if they are not necessary to reduce emissions through the

[[Page 207]]

PCP. Projects listed in paragraphs (b)(31)(i) through (vi) of this 
section are presumed to be environmentally beneficial pursuant to 
paragraph (v)(2)(i) of this section. Projects not listed in these 
paragraphs may qualify for a case-specific PCP exclusion pursuant to the 
requirements of paragraphs (v)(2) and (v)(5) of this section.
    (i) Conventional or advanced flue gas desulfurization or sorbent 
injection for control of SO2.
    (ii) Electrostatic precipitators, baghouses, high efficiency 
multiclones, or scrubbers for control of particulate matter or other 
pollutants.
    (iii) Flue gas recirculation, low-NOX burners or 
combustors, selective non-catalytic reduction, selective catalytic 
reduction, low emission combustion (for IC engines), and oxidation/
absorption catalyst for control of NOX.
    (iv) Regenerative thermal oxidizers, catalytic oxidizers, 
condensers, thermal incinerators, hydrocarbon combustion flares, 
biofiltration, absorbers and adsorbers, and floating roofs for storage 
vessels for control of volatile organic compounds or hazardous air 
pollutants. For the purpose of this section, ``hydrocarbon combustion 
flare'' means either a flare used to comply with an applicable NSPS or 
MACT standard (including uses of flares during startup, shutdown, or 
malfunction permitted under such a standard), or a flare that serves to 
control emissions of waste streams comprised predominately of 
hydrocarbons and containing no more than 230 mg/dscm hydrogen sulfide.
    (v) Activities or projects undertaken to accommodate switching (or 
partially switching) to an inherently less polluting fuel, to be limited 
to the following fuel switches:
    (a) Switching from a heavier grade of fuel oil to a lighter fuel 
oil, or any grade of oil to 0.05 percent sulfur diesel (i.e., from a 
higher sulfur content 2 fuel or from 6 fuel, to CA 
0.05 percent sulfur 2 diesel);
    (b) Switching from coal, oil, or any solid fuel to natural gas, 
propane, or gasified coal;
    (c) Switching from coal to wood, excluding construction or 
demolition waste, chemical or pesticide treated wood, and other forms of 
``unclean'' wood;
    (d) Switching from coal to 2 fuel oil (0.5 percent maximum 
sulfur content); and
    (e) Switching from high sulfur coal to low sulfur coal (maximum 1.2 
percent sulfur content).
    (vi) Activities or projects undertaken to accommodate switching from 
the use of one ozone depleting substance (ODS) to the use of a substance 
with a lower or zero ozone depletion potential (ODP), including changes 
to equipment needed to accommodate the activity or project, that meet 
the requirements of paragraphs (b)(31)(vi)(a) and (b) of this section.
    (a) The productive capacity of the equipment is not increased as a 
result of the activity or project.
    (b) The projected usage of the new substance is lower, on an ODP-
weighted basis, than the baseline usage of the replaced ODS. To make 
this determination, follow the procedure in paragraphs (b)(31)(vi)(b)(1) 
through (4) of this section.
    (1) Determine the ODP of the substances by consulting 40 CFR part 
82, subpart A, appendices A and B.
    (2) Calculate the replaced ODP-weighted amount by multiplying the 
baseline actual usage (using the annualized average of any 24 
consecutive months of usage within the past 10 years) by the ODP of the 
replaced ODS.
    (3) Calculate the projected ODP-weighted amount by multiplying the 
projected annual usage of the new substance by its ODP.
    (4) If the value calculated in paragraph (b)(31)(vi)(b)(2) of this 
section is more than the value calculated in paragraph (b)(31)(vi)(b)(3) 
of this section, then the projected use of the new substance is lower, 
on an ODP-weighted basis, than the baseline usage of the replaced ODS.
    (32) [Reserved]
    (33) Clean coal technology means any technology, including 
technologies applied at the precombustion, combustion, or post 
combustion stage, at a new or existing facility which will achieve 
significant reductions in air emissions of sulfur dioxide or oxides of

[[Page 208]]

nitrogen associated with the utilization of coal in the generation of 
electricity, or process steam which was not in widespread use as of 
November 15, 1990.
    (34) Clean coal technology demonstration project means a project 
using funds appropriated under the heading ``Department of Energy--Clean 
Coal Technology'', up to a total amount of $2,500,000,000 for commercial 
demonstration of clean coal technology, or similar projects funded 
through appropriations for the Environmental Protection Agency. The 
Federal contribution for a qualifying project shall be at least 20 
percent of the total cost of the demonstration project.
    (35) Temporary clean coal technology demonstration project means a 
clean coal technology demonstration project that is operated for a 
period of 5 years or less, and which complies with the State 
implementation plan for the State in which the project is located and 
other requirements necessary to attain and maintain the national ambient 
air quality standards during and after the project is terminated.
    (36)(i) Repowering means replacement of an existing coal-fired 
boiler with one of the following clean coal technologies: atmospheric or 
pressurized fluidized bed combustion, integrated gasification combined 
cycle, magnetohydrodynamics, direct and indirect coal-fired turbines, 
integrated gasification fuel cells, or as determined by the 
Administrator, in consultation with the Secretary of Energy, a 
derivative of one or more of these technologies, and any other 
technology capable of controlling multiple combustion emissions 
simultaneously with improved boiler or generation efficiency and with 
significantly greater waste reduction relative to the performance of 
technology in widespread commercial use as of November 15, 1990.
    (ii) Repowering shall also include any oil and/or gas-fired unit 
which has been awarded clean coal technology demonstration funding as of 
January 1, 1991, by the Department of Energy.
    (iii) The reviewing authority shall give expedited consideration to 
permit applications for any source that satisfies the requirements of 
this subsection and is granted an extension under section 409 of the 
Clean Air Act.
    (37) Reactivation of a very clean coal-fired electric utility steam 
generating unit means any physical change or change in the method of 
operation associated with the commencement of commercial operations by a 
coal-fired utility unit after a period of discontinued operation where 
the unit:
    (i) Has not been in operation for the two-year period prior to the 
enactment of the Clean Air Act Amendments of 1990, and the emissions 
from such unit continue to be carried in the permitting authority's 
emissions inventory at the time of enactment;
    (ii) Was equipped prior to shutdown with a continuous system of 
emissions control that achieves a removal efficiency for sulfur dioxide 
of no less than 85 percent and a removal efficiency for particulates of 
no less than 98 percent;
    (iii) Is equipped with low-NOX burners prior to the time 
of commencement of operations following reactivation; and
    (iv) Is otherwise in compliance with the requirements of the Clean 
Air Act.
    (38) Pollution prevention means any activity that through process 
changes, product reformulation or redesign, or substitution of less 
polluting raw materials, eliminates or reduces the release of air 
pollutants (including fugitive emissions) and other pollutants to the 
environment prior to recycling, treatment, or disposal; it does not mean 
recycling (other than certain ``in-process recycling'' practices), 
energy recovery, treatment, or disposal.
    (39) Significant emissions increase means, for a regulated NSR 
pollutant, an increase in emissions that is significant (as defined in 
paragraph (b)(23) of this section) for that pollutant.
    (40)(i) Projected actual emissions means the maximum annual rate, in 
tons per year, at which an existing emissions unit is projected to emit 
a regulated NSR pollutant in any one of the 5 years (12-month period) 
following the date the unit resumes regular operation after the project, 
or in any one of the 10 years following that date, if the project 
involves increasing the emissions unit's design capacity or its 
potential to emit that regulated NSR pollutant, and full utilization of 
the unit

[[Page 209]]

would result in a significant emissions increase, or a significant net 
emissions increase at the major stationary source.
    (ii) In determining the projected actual emissions under paragraph 
(b)(40)(i) of this section (before beginning actual construction), the 
owner or operator of the major stationary source:
    (a) Shall consider all relevant information, including but not 
limited to, historical operational data, the company's own 
representations, the company's expected business activity and the 
company's highest projections of business activity, the company's 
filings with the State or Federal regulatory authorities, and compliance 
plans under the approved plan; and
    (b) Shall include fugitive emissions to the extent quantifiable and 
emissions associated with startups, shutdowns, and malfunctions; and
    (c) Shall exclude, in calculating any increase in emissions that 
results from the particular project, that portion of the unit's 
emissions following the project that an existing unit could have 
accommodated during the consecutive 24-month period used to establish 
the baseline actual emissions under paragraph (b)(47) of this section 
and that are also unrelated to the particular project, including any 
increased utilization due to product demand growth; or,
    (d) In lieu of using the method set out in paragraphs (b)(40)(ii)(a) 
through (c) of this section, may elect to use the emissions unit's 
potential to emit, in tons per year, as defined under paragraph (b)(4) 
of this section.
    (41) Clean Unit means any emissions unit that has been issued a 
major NSR permit that requires compliance with BACT or LAER, is 
complying with such BACT/LAER requirements, and qualifies as a Clean 
Unit pursuant to regulations approved by the Administrator in accordance 
with paragraph (t) of this section; or any emissions unit that has been 
designated by a reviewing authority as a Clean Unit, based on the 
criteria in paragraphs (u)(3)(i) through (iv) of this section, using a 
plan-approved permitting process; or any emissions unit that has been 
designated as a Clean Unit by the Administrator in accordance with 52.21 
(y)(3)(i) through (iv) of this chapter.
    (42) Prevention of Significant Deterioration Program (PSD) program 
means a major source preconstruction permit program that has been 
approved by the Administrator and incorporated into the plan to 
implement the requirements of this section, or the program in Sec. 52.21 
of this chapter. Any permit issued under such a program is a major NSR 
permit.
    (43) Continuous emissions monitoring system (CEMS) means all of the 
equipment that may be required to meet the data acquisition and 
availability requirements of this section, to sample, condition (if 
applicable), analyze, and provide a record of emissions on a continuous 
basis.
    (44) Predictive emissions monitoring system (PEMS) means all of the 
equipment necessary to monitor process and control device operational 
parameters (for example, control device secondary voltages and electric 
currents) and other information (for example, gas flow rate, O\2\ or 
CO\2\ concentrations), and calculate and record the mass emissions rate 
(for example, lb/hr) on a continuous basis.
    (45) Continuous parameter monitoring system (CPMS) means all of the 
equipment necessary to meet the data acquisition and availability 
requirements of this section, to monitor process and control device 
operational parameters (for example, control device secondary voltages 
and electric currents) and other information (for example, gas flow 
rate, O\2\ or CO\2\ concentrations), and to record average operational 
parameter value(s) on a continuous basis.
    (46) Continuous emissions rate monitoring system (CERMS) means the 
total equipment required for the determination and recording of the 
pollutant mass emissions rate (in terms of mass per unit of time).
    (47) Baseline actual emissions means the rate of emissions, in tons 
per year, of a regulated NSR pollutant, as determined in accordance with 
paragraphs (b)(47)(i) through (iv) of this section.
    (i) For any existing electric utility steam generating unit, 
baseline actual emissions means the average rate, in tons per year, at 
which the unit actually emitted the pollutant during any

[[Page 210]]

consecutive 24-month period selected by the owner or operator within the 
5-year period immediately preceding when the owner or operator begins 
actual construction of the project. The reviewing authority shall allow 
the use of a different time period upon a determination that it is more 
representative of normal source operation.
    (a) The average rate shall include fugitive emissions to the extent 
quantifiable, and emissions associated with startups, shutdowns, and 
malfunctions.
    (b) The average rate shall be adjusted downward to exclude any non-
compliant emissions that occurred while the source was operating above 
an emission limitation that was legally enforceable during the 
consecutive 24-month period.
    (c) For a regulated NSR pollutant, when a project involves multiple 
emissions units, only one consecutive 24-month period must be used to 
determine the baseline actual emissions for the emissions units being 
changed. A different consecutive 24-month period can be used For each 
regulated NSR pollutant.
    (d) The average rate shall not be based on any consecutive 24-month 
period for which there is inadequate information for determining annual 
emissions, in tons per year, and for adjusting this amount if required 
by paragraph (b)(47)(i)(b) of this section.
    (ii) For an existing emissions unit (other than an electric utility 
steam generating unit), baseline actual emissions means the average 
rate, in tons per year, at which the emissions unit actually emitted the 
pollutant during any consecutive 24-month period selected by the owner 
or operator within the 10-year period immediately preceding either the 
date the owner or operator begins actual construction of the project, or 
the date a complete permit application is received by the reviewing 
authority for a permit required either under this section or under a 
plan approved by the Administrator, whichever is earlier, except that 
the 10-year period shall not include any period earlier than November 
15, 1990.
    (a) The average rate shall include fugitive emissions to the extent 
quantifiable, and emissions associated with startups, shutdowns, and 
malfunctions.
    (b) The average rate shall be adjusted downward to exclude any non-
compliant emissions that occurred while the source was operating above 
an emission limitation that was legally enforceable during the 
consecutive 24-month period.
    (c) The average rate shall be adjusted downward to exclude any 
emissions that would have exceeded an emission limitation with which the 
major stationary source must currently comply, had such major stationary 
source been required to comply with such limitations during the 
consecutive 24-month period. However, if an emission limitation is part 
of a maximum achievable control technology standard that the 
Administrator proposed or promulgated under part 63 of this chapter, the 
baseline actual emissions need only be adjusted if the State has taken 
credit for such emissions reductions in an attainment demonstration or 
maintenance plan consistent with the requirements of 
Sec. 51.165(a)(3)(ii)(G).
    (d) For a regulated NSR pollutant, when a project involves multiple 
emissions units, only one consecutive 24-month period must be used to 
determine the baseline actual emissions for the emissions units being 
changed. A different consecutive 24-month period can be used For each 
regulated NSR pollutant.
    (e) The average rate shall not be based on any consecutive 24-month 
period for which there is inadequate information for determining annual 
emissions, in tons per year, and for adjusting this amount if required 
by paragraphs (b)(47)(ii)(b) and (c) of this section.
    (iii) For a new emissions unit, the baseline actual emissions for 
purposes of determining the emissions increase that will result from the 
initial construction and operation of such unit shall equal zero; and 
thereafter, for all other purposes, shall equal the unit's potential to 
emit.
    (iv) For a PAL for a stationary source, the baseline actual 
emissions shall be calculated for existing electric utility steam 
generating units in accordance with the procedures contained in 
paragraph (b)(47)(i) of this section, for other existing emissions

[[Page 211]]

units in accordance with the procedures contained in paragraph 
(b)(47)(ii) of this section, and for a new emissions unit in accordance 
with the procedures contained in paragraph (b)(47)(iii) of this section.
    (48) [Reserved]
    (49) Regulated NSR pollutant, for purposes of this section, means 
the following:
    (i) Any pollutant for which a national ambient air quality standard 
has been promulgated and any constituents or precursors for such 
pollutants identified by the Administrator (e.g., volatile organic 
compounds are precursors for ozone);
    (ii) Any pollutant that is subject to any standard promulgated under 
section 111 of the Act;
    (iii) Any Class I or II substance subject to a standard promulgated 
under or established by title VI of the Act; or
    (iv) Any pollutant that otherwise is subject to regulation under the 
Act; except that any or all hazardous air pollutants either listed in 
section 112 of the Act or added to the list pursuant to section 
112(b)(2) of the Act, which have not been delisted pursuant to section 
112(b)(3) of the Act, are not regulated NSR pollutants unless the listed 
hazardous air pollutant is also regulated as a constituent or precursor 
of a general pollutant listed under section 108 of the Act.
    (50) Reviewing authority means the State air pollution control 
agency, local agency, other State agency, Indian tribe, or other agency 
authorized by the Administrator to carry out a permit program under 
Sec. 51.165 and this section, or the Administrator in the case of EPA-
implemented permit programs under Sec. 52.21 of this chapter.
    (51) Project means a physical change in, or change in method of 
operation of, an existing major stationary source.
    (52) Lowest achievable emission rate (LAER) is as defined in 
Sec. 51.165(a)(1)(xiii).
    (c) Ambient air increments. The plan shall contain emission 
limitations and such other measures as may be necessary to assure that 
in areas designated as Class I, II, or III, increases in pollutant 
concentration over the baseline concentration shall be limited to the 
following:

------------------------------------------------------------------------
                                                               Maximum
                                                              allowable
                                                               increase
                         Pollutant                           (micrograms
                                                              per cubic
                                                                meter)
------------------------------------------------------------------------
                                 Class I
------------------------------------------------------------------------
 
Particulate matter:
    PM-10, annual arithmetic mean..........................          4
    PM-10, 24-hr maximum...................................          8
Sulfur dioxide:
    Annual arithmetic mean.................................          2
    24-hr maximum..........................................          5
    3-hr maximum...........................................         25
Nitrogen dioxide: Annual arithmetic mean...................        2.5
 
------------------------------------------------------------------------
                                Class II
------------------------------------------------------------------------
 
Particulate matter:
    PM-10, annual arithmetic mean..........................         17
    PM-10, 24-hr maximum...................................         30
Sulfur dioxide:
    Annual arithmetic mean.................................         20
    24-hr maximum..........................................         91
    3-hr maximum...........................................        512
Nitrogen dioxide:
    Annual arithmetic mean.................................         25
 
------------------------------------------------------------------------
                                Class III
 
------------------------------------------------------------------------
Particulate matter:
    PM-10, annual arithmetic mean..........................         34
    PM-10, 24-hr maximum...................................         60
Sulfur dioxide:
    Annual arithmetic mean.................................         40
    24-hr maximum..........................................        182
    3-hr maximum...........................................        700
Nitrogen dioxide: Annual arithmetic mean...................         50
------------------------------------------------------------------------


For any period other than an annual period, the applicable maximum 
allowable increase may be exceeded during one such period per year at 
any one location.
    (d) Ambient air ceilings. The plan shall provide that no 
concentration of a pollutant shall exceed:
    (1) The concentration permitted under the national secondary ambient 
air quality standard, or
    (2) The concentration permitted under the national primary ambient 
air quality standard, whichever concentration is lowest for the 
pollutant for a period of exposure.
    (e) Restrictions on area classifications. The plan shall provide 
that--
    (1) All of the following areas which were in existence on August 7, 
1977, shall be Class I areas and may not be redesignated:
    (i) International parks,
    (ii) National wilderness areas which exceed 5,000 acres in size,

[[Page 212]]

    (iii) National memorial parks which exceed 5,000 acres in size, and
    (iv) National parks which exceed 6,000 acres in size.
    (2) Areas which were redesignated as Class I under regulations 
promulgated before August 7, 1977, shall remain Class I, but may be 
redesignated as provided in this section.
    (3) Any other area, unless otherwise specified in the legislation 
creating such an area, is initially designated Class II, but may be 
redesignated as provided in this section.
    (4) The following areas may be redesignated only as Class I or II:
    (i) An area which as of August 7, 1977, exceeded 10,000 acres in 
size and was a national monument, a national primitive area, a national 
preserve, a national recreational area, a national wild and scenic 
river, a national wildlife refuge, a national lakeshore or seashore; and
    (ii) A national park or national wilderness area established after 
August 7, 1977, which exceeds 10,000 acres in size.
    (f) Exclusions from increment consumption. (1) The plan may provide 
that the following concentrations shall be excluded in determining 
compliance with a maximum allowable increase:
    (i) Concentrations attributable to the increase in emissions from 
stationary sources which have converted from the use of petroleum 
products, natural gas, or both by reason of an order in effect under 
section 2 (a) and (b) of the Energy Supply and Environmental 
Coordination Act of 1974 (or any superseding legislation) over the 
emissions from such sources before the effective date of such an order;
    (ii) Concentrations attributable to the increase in emissions from 
sources which have converted from using natural gas by reason of natural 
gas curtailment plan in effect pursuant to the Federal Power Act over 
the emissions from such sources before the effective date of such plan;
    (iii) Concentrations of particulate matter attributable to the 
increase in emissions from construction or other temporary emission-
related activities of new or modified sources;
    (iv) The increase in concentrations attributable to new sources 
outside the United States over the concentrations attributable to 
existing sources which are included in the baseline concentration; and
    (v) Concentrations attributable to the temporary increase in 
emissions of sulfur dioxide, particulate matter, or nitrogen oxides from 
stationary sources which are affected by plan revisions approved by the 
Administrator as meeting the criteria specified in paragraph (f)(4) of 
this section.
    (2) If the plan provides that the concentrations to which paragraph 
(f)(1) (i) or (ii) of this section, refers shall be excluded, it shall 
also provide that no exclusion of such concentrations shall apply more 
than five years after the effective date of the order to which paragraph 
(f)(1)(i) of this section, refers or the plan to which paragraph 
(f)(1)(ii) of this section, refers, whichever is applicable. If both 
such order and plan are applicable, no such exclusion shall apply more 
than five years after the later of such effective dates.
    (3) [Reserved]
    (4) For purposes of excluding concentrations pursuant to paragraph 
(f)(1)(v) of this section, the Administrator may approve a plan revision 
that:
    (i) Specifies the time over which the temporary emissions increase 
of sulfur dioxide, particulate matter, or nitrogen oxides would occur. 
Such time is not to exceed 2 years in duration unless a longer time is 
approved by the Administrator.
    (ii) Specifies that the time period for excluding certain 
contributions in accordance with paragraph (f)(4)(i) of this section, is 
not renewable;
    (iii) Allows no emissions increase from a stationary source which 
would:
    (a) Impact a Class I area or an area where an applicable increment 
is known to be violated; or
    (b) Cause or contribute to the violation of a national ambient air 
quality standard;
    (iv) Requires limitations to be in effect the end of the time period 
specified in accordance with paragraph (f)(4)(i) of this section, which 
would ensure that the emissions levels from stationary sources affected 
by the plan revision would not exceed those levels occurring from such 
sources before the plan revision was approved.

[[Page 213]]

    (g) Redesignation. (1) The plan shall provide that all areas of the 
State (except as otherwise provided under paragraph (e) of this section) 
shall be designated either Class I, Class II, or Class III. Any 
designation other than Class II shall be subject to the redesignation 
procedures of this paragraph. Redesignation (except as otherwise 
precluded by paragraph (e) of this section) may be proposed by the 
respective States or Indian Governing Bodies, as provided below, subject 
to approval by the Administrator as a revision to the applicable State 
implementation plan.
    (2) The plan may provide that the State may submit to the 
Administrator a proposal to redesignate areas of the State Class I or 
Class II: Provided, That:
    (i) At least one public hearing has been held in accordance with 
procedures established in Sec. 51.102.
    (ii) Other States, Indian Governing Bodies, and Federal Land 
Managers whose lands may be affected by the proposed redesignation were 
notified at least 30 days prior to the public hearing;
    (iii) A discussion of the reasons for the proposed redesignation, 
including a satisfactory description and analysis of the health, 
environmental, economic, social, and energy effects of the proposed 
redesignation, was prepared and made available for public inspection at 
least 30 days prior to the hearing and the notice announcing the hearing 
contained appropriate notification of the availability of such 
discussion;
    (iv) Prior to the issuance of notice respecting the redesignation of 
an area that includes any Federal lands, the State has provided written 
notice to the appropriate Federal Land Manager and afforded adequate 
opportunity (not in excess of 60 days) to confer with the State 
respecting the redesignation and to submit written comments and 
recommendations. In redesignating any area with respect to which any 
Federal Land Manager had submitted written comments and recommendations, 
the State shall have published a list of any inconsistency between such 
redesignation and such comments and recommendations (together with the 
reasons for making such redesignation against the recommendation of the 
Federal Land Manager); and
    (v) The State has proposed the redesignation after consultation with 
the elected leadership of local and other substate general purpose 
governments in the area covered by the proposed redesignation.
    (3) The plan may provide that any area other than an area to which 
paragraph (e) of this section refers may be redesignated as Class III 
if--
    (i) The redesignation would meet the requirements of provisions 
established in accordance with paragraph (g)(2) of this section;
    (ii) The redesignation, except any established by an Indian 
Governing Body, has been specifically approved by the Governor of the 
State, after consultation with the appropriate committees of the 
legislature, if it is in session, or with the leadership of the 
legislature, if it is not in session (unless State law provides that 
such redesignation must be specifically approved by State legislation) 
and if general purpose units of local government representing a majority 
of the residents of the area to be redesignated enact legislation 
(including resolutions where appropriate) concurring in the 
redesignation;
    (iii) The redesignation would not cause, or contribute to, a 
concentration of any air pollutant which would exceed any maximum 
allowable increase permitted under the classification of any other area 
or any national ambient air quality standard; and
    (iv) Any permit application for any major stationary source or major 
modification subject to provisions established in accordance with 
paragraph (l) of this section which could receive a permit only if the 
area in question were redesignated as Class III, and any material 
submitted as part of that application, were available, insofar as was 
practicable, for public inspection prior to any public hearing on 
redesignation of any area as Class III.
    (4) The plan shall provide that lands within the exterior boundaries 
of Indian Reservations may be redesignated only by the appropriate 
Indian Governing Body. The appropriate Indian Governing Body may submit 
to the Administrator a proposal to redesignate

[[Page 214]]

areas Class I, Class II, or Class III: Provided, That:
    (i) The Indian Governing Body has followed procedures equivalent to 
those required of a State under paragraphs (g) (2), (3)(iii), and 
(3)(iv) of this section; and
    (ii) Such redesignation is proposed after consultation with the 
State(s) in which the Indian Reservation is located and which border the 
Indian Reservation.
    (5) The Administrator shall disapprove, within 90 days of 
submission, a proposed redesignation of any area only if he finds, after 
notice and opportunity for public hearing, that such redesignation does 
not meet the procedural requirements of this section or is inconsistent 
with paragraph (e) of this section. If any such disapproval occurs, the 
classification of the area shall be that which was in effect prior to 
the redesignation which was disapproved.
    (6) If the Administrator disapproves any proposed area designation, 
the State or Indian Governing Body, as appropriate, may resubmit the 
proposal after correcting the deficiencies noted by the Administrator.
    (h) Stack heights. The plan shall provide, as a minimum, that the 
degree of emission limitation required for control of any air pollutant 
under the plan shall not be affected in any manner by--
    (1) So much of a stack height, not in existence before December 31, 
1970, as exceeds good engineering practice, or
    (2) Any other dispersion technique not implemented before then.
    (i) Exemptions.
    (1) The plan may provide that requirements equivalent to those 
contained in paragraphs (j) through (r) of this section do not apply to 
a particular major stationary source or major modification if:
    (i) The major stationary source would be a nonprofit health or 
nonprofit educational institution or a major modification that would 
occur at such an institution; or
    (ii) The source or modification would be a major stationary source 
or major modification only if fugitive emissions, to the extent 
quantifiable, are considered in calculating the potential to emit of the 
stationary source or modification and such source does not belong to any 
following categories:
    (a) Coal cleaning plants (with thermal dryers);
    (b) Kraft pulp mills;
    (c) Portland cement plants;
    (d) Primary zinc smelters;
    (e) Iron and steel mills;
    (f) Primary aluminum ore reduction plants;
    (g) Primary copper smelters;
    (h) Municipal incinerators capable of charging more than 250 tons of 
refuse per day;
    (i) Hydrofluoric, sulfuric, or nitric acid plants;
    (j) Petroleum refineries;
    (k) Lime plants;
    (l) Phosphate rock processing plants;
    (m) Coke oven batteries;
    (n) Sulfur recovery plants;
    (o) Carbon black plants (furnace process);
    (p) Primary lead smelters;
    (q) Fuel conversion plants;
    (r) Sintering plants;
    (s) Secondary metal production plants;
    (t) Chemical process plants;
    (u) Fossil-fuel boilers (or combination thereof) totaling more than 
250 million British thermal units per hour heat input;
    (v) Petroleum storage and transfer units with a total storage 
capacity exceeding 300,000 barrels;
    (w) Taconite ore processing plants;
    (x) Glass fiber processing plants;
    (y) Charcoal production plants;
    (z) Fossil fuel-fired steam electric plants of more than 250 million 
British thermal units per hour heat input;
    (aa) Any other stationary source category which, as of August 7, 
1980, is being regulated under section 111 or 112 of the Act; or
    (iii) The source or modification is a portable stationary source 
which has previously received a permit under requirements equivalent to 
those contained in paragraphs (j) through (r) of this section, if:
    (a) The source proposes to relocate and emissions of the source at 
the new location would be temporary; and
    (b) The emissions from the source would not exceed its allowable 
emissions; and
    (c) The emissions from the source would impact no Class I area and 
no

[[Page 215]]

area where an applicable increment is known to be violated; and
    (d) Reasonable notice is given to the reviewing authority prior to 
the relocation identifying the proposed new location and the probable 
duration of operation at the new location. Such notice shall be given to 
the reviewing authority not less than 10 days in advance of the proposed 
relocation unless a different time duration is previously approved by 
the reviewing authority.
    (2) The plan may provide that requirements equivalent to those 
contained in paragraphs (j) through (r) of this section do not apply to 
a major stationary source or major modification with respect to a 
particular pollutant if the owner or operator demonstrates that, as to 
that pollutant, the source or modification is located in an area 
designated as nonattainment under section 107 of the Act.
    (3) The plan may provide that requirements equivalent to those 
contained in paragraphs (k), (m), and (o) of this section do not apply 
to a proposed major stationary source or major modification with respect 
to a particular pollutant, if the allowable emissions of that pollutant 
from a new source, or the net emissions increase of that pollutant from 
a modification, would be temporary and impact no Class I area and no 
area where an applicable increment is known to be violated.
    (4) The plan may provide that requirements equivalent to those 
contained in paragraphs (k), (m), and (o) of this section as they relate 
to any maximum allowable increase for a Class II area do not apply to a 
modification of a major stationary source that was in existence on March 
1, 1978, if the net increase in allowable emissions of each a regulated 
NSR pollutant from the modification after the application of best 
available control technology would be less than 50 tons per year.
    (5) The plan may provide that the reviewing authority may exempt a 
proposed major stationary source or major modification from the 
requirements of paragraph (m) of this section, with respect to 
monitoring for a particular pollutant, if:
    (i) The emissions increase of the pollutant from a new stationary 
source or the net emissions increase of the pollutant from a 
modification would cause, in any area, air quality impacts less than the 
following amounts:
    (a) Carbon monoxide--575 ug/m\3\, 8-hour average;
    (b) Nitrogen dioxide--14 ug/m\3\, annual average;
    (c) Particulate matter--10 [mu]g/m\3\ of PM-10, 24-hour average.
    (d) Sulfur dioxide--13 ug/m\3\, 24-hour average;
    (e) Ozone; \1\
---------------------------------------------------------------------------

    \1\ No de minimis air quality level is provided for ozone. However, 
any net increase of 100 tons per year or more of volatile organic 
compounds subject to PSD would be required to perform and ambient impact 
analysis, including the gathering of ambient air quality data.
---------------------------------------------------------------------------

    (f) Lead--0.1 [mu]g/m\3\, 3-month average.
    (g) Fluorides--0.25 [mu]g/m3, 24-hour average;
    (h) Total reduced sulfur--10 [mu]g/m3, 1-hour average
    (i) Hydrogen sulfide--0.2 [mu]g/m3, 1-hour average;
    (j) Reduced sulfur compounds--10 [mu]g/m3, 1-hour 
average; or
    (ii) The concentrations of the pollutant in the area that the source 
or modification would affect are less than the concentrations listed in 
(i)(8)(i) of this section; or
    (iii) The pollutants is not listed in paragraph (i)(8)(i) of this 
section.
    (6) If EPA approves a plan revision under 40 CFR 51.166 as in effect 
before August 7, 1980, any subsequent revision which meets the 
requirements of this section may contain transition provisions which 
parallel the transition provisions of 40 CFR 52.21(i)(9), (i)(10) and 
(m)(1)(v) as in effect on that date, which provisions relate to 
requirements for best available control technology and air quality 
analyses. Any such subsequent revision may not contain any transition 
provision which in the context of the revision would operate any less 
stringently than would its counterpart in 40 CFR 52.21.
    (7) If EPA approves a plan revision under Sec. 51.166 as in effect 
[before July 31, 1987], any subsequent revision which meets the 
requirements of this section may contain transition provisions which 
parallel the transition provisions of Sec. 52.21 (i)(11), and (m)(1) 
(vii)

[[Page 216]]

and (viii) of this chapter as in effect on that date, these provisions 
being related to monitoring requirements for particulate matter. Any 
such subsequent revision may not contain any transition provision which 
in the context of the revision would operate any less stringently than 
would its counterpart in Sec. 52.21 of this chapter.
    (8) The plan may provide that the permitting requirements equivalent 
to those contained in paragraph (k)(2) of this section do not apply to a 
stationary source or modification with respect to any maximum allowable 
increase for nitrogen oxides if the owner or operator of the source or 
modification submitted an application for a permit under the applicable 
permit program approved or promulgated under the Act before the 
provisions embodying the maximum allowable increase took effect as part 
of the plan and the permitting authority subsequently determined that 
the application as submitted before that date was complete.
    (9) The plan may provide that the permitting requirements equivalent 
to those contained in paragraph (k)(2) of this section shall not apply 
to a stationary source or modification with respect to any maximum 
allowable increase for PM-10 if (i) the owner or operator of the source 
or modification submitted an application for a permit under the 
applicable permit program approved under the Act before the provisions 
embodying the maximum allowable increases for PM-10 took effect as part 
of the plan, and (ii) the permitting authority subsequently determined 
that the application as submitted before that date was complete. 
Instead, the applicable requirements equivalent to paragraph (k)(2) 
shall apply with respect to the maximum allowable increases for TSP as 
in effect on the date the application was submitted.
    (j) Control technology review. The plan shall provide that:
    (1) A major stationary source or major modification shall meet each 
applicable emissions limitation under the State Implementation Plan and 
each applicable emission standards and standard of performance under 40 
CFR parts 60 and 61.
    (2) A new major stationary source shall apply best available control 
technology for each a regulated NSR pollutant that it would have the 
potential to emit in significant amounts.
    (3) A major modification shall apply best available control 
technology for each a regulated NSR pollutant for which it would be a 
significant net emissions increase at the source. This requirement 
applies to each proposed emissions unit at which a net emissions 
increase in the pollutant would occur as a result of a physical change 
or change in the method of operation in the unit.
    (4) For phased construction projects, the determination of best 
available control technology shall be reviewed and modified as 
appropriate at the least reasonable time which occurs no later than 18 
months prior to commencement of construction of each independent phase 
of the project. At such time, the owner or operator of the applicable 
stationary source may be required to demonstrate the adequacy of any 
previous determination of best available control technology for the 
source.
    (k) Source impact analysis. The plan shall provide that the owner or 
operator of the proposed source or modification shall demonstrate that 
allowable emission increases from the proposed source or modification, 
in conjunction with all other applicable emissions increases or 
reduction (including secondary emissions) would not cause or contribute 
to air pollution in violation of:
    (1) Any national ambient air quality standard in any air quality 
control region; or
    (2) Any applicable maximum allowable increase over the baseline 
concentration in any area.
    (l) Air quality models. The plan shall provide for procedures which 
specify that--
    (1) All applications of air quality modeling involved in this 
subpart shall be based on the applicable models, data bases, and other 
requirements specified in appendix W of this part (Guideline on Air 
Quality Models).

[[Page 217]]

    (2) Where an air quality model specified in appendix W of this part 
(Guideline on Air Quality Models) is inappropriate, the model may be 
modified or another model substituted. Such a modification or 
substitution of a model may be made on a case-by-case basis or, where 
appropriate, on a generic basis for a specific State program. Written 
approval of the Administrator must be obtained for any modification or 
substitution. In addition, use of a modified or substituted model must 
be subject to notice and opportunity for public comment under procedures 
set forth in Sec. 51.102.
    (m) Air quality analysis--(1) Preapplication analysis. (i) The plan 
shall provide that any application for a permit under regulations 
approved pursuant to this section shall contain an analysis of ambient 
air quality in the area that the major stationary source or major 
modification would affect for each of the following pollutants:
    (a) For the source, each pollutant that it would have the potential 
to emit in a significant amount;
    (b) For the modification, each pollutant for which it would result 
in a significant net emissions increase.
    (ii) The plan shall provide that, with respect to any such pollutant 
for which no National Ambient Air Quality Standard exists, the analysis 
shall contain such air quality monitoring data as the reviewing 
authority determines is necessary to assess ambient air quality for that 
pollutant in any area that the emissions of that pollutant would affect.
    (iii) The plan shall provide that with respect to any such pollutant 
(other than nonmethane hydrocarbons) for which such a standard does 
exist, the analysis shall contain continuous air quality monitoring data 
gathered for purposes of determining whether emissions of that pollutant 
would cause or contribute to a violation of the standard or any maxiumum 
allowable increase.
    (iv) The plan shall provide that, in general, the continuous air 
monitoring data that is required shall have been gathered over a period 
of one year and shall represent the year preceding receipt of the 
application, except that, if the reviewing authority determines that a 
complete and adequate analysis can be accomplished with monitoring data 
gathered over a period shorter than one year (but not to be less than 
four months), the data that is required shall have been gathered over at 
least that shorter period.
    (v) The plan may provide that the owner or operator of a proposed 
major stationary source or major modification of volatile organic 
compounds who satisfies all conditions of 40 CFR part 51 appendix S, 
section IV may provide postapproval monitoring data for ozone in lieu of 
providing preconstruction data as required under paragraph (m)(1) of 
this section.
    (2) Post-construction monitoring. The plan shall provide that the 
owner or operator of a major stationary source or major modification 
shall, after construction of the stationary source or modification, 
conduct such ambient monitoring as the reviewing authority determines is 
necessary to determine the effect emissions from the stationary source 
or modification may have, or are having, on air quality in any area.
    (3) Operation of monitoring stations. The plan shall provide that 
the owner or operator of a major stationary source or major modification 
shall meet the requirements of appendix B to part 58 of this chapter 
during the operation of monitoring stations for purposes of satisfying 
paragraph (m) of this section.
    (n) Source information. (1) The plan shall provide that the owner or 
operator of a proposed source or modification shall submit all 
information necessary to perform any analysis or make any determination 
required under procedures established in accordance with this section.
    (2) The plan may provide that such information shall include:
    (i) A description of the nature, location, design capacity, and 
typical operating schedule of the source or modification, including 
specifications and drawings showing its design and plant layout;
    (ii) A detailed schedule for construction of the source or 
modification;

[[Page 218]]

    (iii) A detailed description as to what system of continuous 
emission reduction is planned by the source or modification, emission 
estimates, and any other information as necessary to determine that best 
available control technology as applicable would be applied;
    (3) The plan shall provide that upon request of the State, the owner 
or operator shall also provide information on:
    (i) The air quality impact of the source or modification, including 
meteorological and topographical data necessary to estimate such impact; 
and
    (ii) The air quality impacts and the nature and extent of any or all 
general commercial, residential, industrial, and other growth which has 
occurred since August 7, 1977, in the area the source or modification 
would affect.
    (o) Additional impact analyses. The plan shall provide that--
    (1) The owner or operator shall provide an analysis of the 
impairment to visibility, soils, and vegetation that would occur as a 
result of the source or modification and general commercial, 
residential, industrial, and other growth associated with the source or 
modification. The owner or operator need not provide an analysis of the 
impact on vegetation having no significant commercial or recreational 
value.
    (2) The owner or operator shall provide an analysis of the air 
quality impact projected for the area as a result of general commercial, 
residential, industrial, and other growth associated with the source or 
modification.
    (p) Sources impacting Federal Class I areas--additional 
requirements--(1) Notice to EPA. The plan shall provide that the 
reviewing authority shall transmit to the Administrator a copy of each 
permit application relating to a major stationary source or major 
modification and provide notice to the Administrator of every action 
related to the consideration of such permit.
    (2) Federal Land Manager. The Federal Land Manager and the Federal 
official charged with direct responsibility for management of Class I 
lands have an affirmative responsibility to protect the air quality 
related values (including visibility) of any such lands and to consider, 
in consultation with the Administrator, whether a proposed source or 
modification would have an adverse impact on such values.
    (3) Denial--impact on air quality related values. The plan shall 
provide a mechanism whereby a Federal Land Manager of any such lands may 
present to the State, after the reviewing authority's preliminary 
determination required under procedures developed in accordance with 
paragraph (r) of this section, a demonstration that the emissions from 
the proposed source or modification would have an adverse impact on the 
air quality-related values (including visibility) of any Federal 
mandatory Class I lands, notwithstanding that the change in air quality 
resulting from emissions from such source or modification would not 
cause or contribute to concentrations which would exceed the maximum 
allowable increases for a Class I area. If the State concurs with such 
demonstration, the reviewing authority shall not issue the permit.
    (4) Class I Variances. The plan may provide that the owner or 
operator of a proposed source or modification may demonstrate to the 
Federal Land Manager that the emissions from such source would have no 
adverse impact on the air quality related values of such lands 
(including visibility), notwithstanding that the change in air quality 
resulting from emissions from such source or modification would cause or 
contribute to concentrations which would exceed the maximum allowable 
increases for a Class I area. If the Federal land manager concurs with 
such demonstration and so certifies to the State, the reviewing 
authority may: Provided, That applicable requirements are otherwise met, 
issue the permit with such emission limitations as may be necessary to 
assure that emissions of sulfur dioxide, particulate matter, and 
nitrogen oxides would not exceed the following maximum allowable 
increases over minor source baseline concentration for such pollutants:

------------------------------------------------------------------------
                                                               Maximum
                                                              allowable
                                                               increase
                         Pollutant                           (micrograms
                                                              per cubic
                                                                meter)
------------------------------------------------------------------------
Particulate matter:
    PM-10, annual arithmetic mean..........................         17
    PM-10, 24-hour maximum.................................         30

[[Page 219]]

 
Sulfur dioxide:
    Annual arithmetic mean.................................         20
    24-hr maximum..........................................         91
    3-hr maximum...........................................        325
Nitrogen dioxide: Annual arithmetic mean...................         25
------------------------------------------------------------------------

    (5) Sulfur dioxide variance by Governor with Federal Land Manager's 
concurrence. The plan may provide that--
    (i) The owner or operator of a proposed source or modification which 
cannot be approved under procedures developed pursuant to paragraph 
(q)(4) of this section may demonstrate to the Governor that the source 
or modification cannot be constructed by reason of any maximum allowable 
increase for sulfur dioxide for periods of twenty-four hours or less 
applicable to any Class I area and, in the case of Federal mandatory 
Class I areas, that a variance under this clause would not adversely 
affect the air quality related values of the area (including 
visibility);
    (ii) The Governor, after consideration of the Federal Land Manager's 
recommendation (if any) and subject to his concurrence, may grant, after 
notice and an opportunity for a public hearing, a variance from such 
maximum allowable increase; and
    (iii) If such variance is granted, the reviewing authority may issue 
a permit to such source or modification in accordance with provisions 
developed pursuant to paragraph (q)(7) of this section: Provided, That 
the applicable requirements of the plan are otherwise met.
    (6) Variance by the Governor with the President's concurrence. The 
plan may provide that--
    (i) The recommendations of the Governor and the Federal Land Manager 
shall be transferred to the President in any case where the Governor 
recommends a variance in which the Federal Land Manager does not concur;
    (ii) The President may approve the Governor's recommendation if he 
finds that such variance is in the national interest; and
    (iii) If such a variance is approved, the reviewing authority may 
issue a permit in accordance with provisions developed pursuant to the 
requirements of paragraph (q)(7) of this section: Provided, That the 
applicable requirements of the plan are otherwise met.
    (7) Emission limitations for Presidential or gubernatorial variance. 
The plan shall provide that in the case of a permit issued under 
procedures developed pursuant to paragraph (q) (5) or (6) of this 
section, the source or modification shall comply with emission 
limitations as may be necessary to assure that emissions of sulfur 
dioxide from the source or modification would not (during any day on 
which the otherwise applicable maximum allowable increases are exceeded) 
cause or contribute to concentrations which would exceed the following 
maximum allowable increases over the baseline concentration and to 
assure that such emissions would not cause or contribute to 
concentrations which exceed the otherwise applicable maximum allowable 
increases for periods of exposure of 24 hours or less for more than 18 
days, not necessarily consecutive, during any annual period:

                       Maximum Allowable Increase
                      [Micrograms per cubic meter]
------------------------------------------------------------------------
                                                          Terrain areas
                  Period of exposure                   -----------------
                                                          Low      High
------------------------------------------------------------------------
24-hr maximum.........................................       36       62
3-hr maximum..........................................      130      221
------------------------------------------------------------------------

    (q) Public participation. The plan shall provide that--
    (1) The reviewing authority shall notify all applicants within a 
specified time period as to the completeness of the application or any 
deficiency in the application or information submitted. In the event of 
such a deficiency, the date of receipt of the application shall be the 
date on which the reviewing authority received all required information.
    (2) Within one year after receipt of a complete application, the 
reviewing authority shall:
    (i) Make a preliminary determination whether construction should be 
approved, approved with conditions, or disapproved.

[[Page 220]]

    (ii) Make available in at least one location in each region in which 
the proposed source would be constructed a copy of all materials the 
applicant submitted, a copy of the preliminary determination, and a copy 
or summary of other materials, if any, considered in making the 
preliminary determination.
    (iii) Notify the public, by advertisement in a newspaper of general 
circulation in each region in which the proposed source would be 
constructed, of the application, the preliminary determination, the 
degree of increment consumption that is expected from the source or 
modification, and of the opportunity for comment at a public hearing as 
well as written public comment.
    (iv) Send a copy of the notice of public comment to the applicant, 
the Administrator and to officials and agencies having cognizance over 
the location where the proposed construction would occur as follows: Any 
other State or local air pollution control agencies, the chief 
executives of the city and county where the source would be located; any 
comprehensive regional land use planning agency, and any State, Federal 
Land Manager, or Indian Governing body whose lands may be affected by 
emissions from the source or modification.
    (v) Provide opportunity for a public hearing for interested persons 
to appear and submit written or oral comments on the air quality impact 
of the source, alternatives to it, the control technology required, and 
other appropriate considerations.
    (vi) Consider all written comments submitted within a time specified 
in the notice of public comment and all comments received at any public 
hearing(s) in making a final decision on the approvability of the 
application. The reviewing authority shall make all comments available 
for public inspection in the same locations where the reviewing 
authority made available preconstruction information relating to the 
proposed source or modification.
    (vii) Make a final determination whether construction should be 
approved, approved with conditions, or disapproved.
    (viii) Notify the applicant in writing of the final determination 
and make such notification available for public inspection at the same 
location where the reviewing authority made available preconstruction 
information and public comments relating to the source.
    (r) Source obligation. (1) The plan shall include enforceable 
procedures to provide that approval to construct shall not relieve any 
owner or operator of the responsibility to comply fully with applicable 
provisions of the plan and any other requirements under local, State or 
Federal law.
    (2) The plan shall provide that at such time that a particular 
source or modification becomes a major stationary source or major 
modification solely by virtue of a relaxation in any enforceable 
limitation which was established after August 7, 1980, on the capacity 
of the source or modification otherwise to emit a pollutant, such as a 
restriction on hours of operation, then the requirements of paragraphs 
(j) through (s) of this section shall apply to the source or 
modification as though construction had not yet commenced on the source 
or modification.
    (3)-(5) [Reserved]
    (6) Each plan shall provide that the following specific provisions 
apply to projects at existing emissions units at a major stationary 
source (other than projects at a Clean Unit or at a source with a PAL) 
in circumstances where there is a reasonable possibility that a project 
that is not a part of a major modification may result in a significant 
emissions increase and the owner or operator elects to use the method 
specified in paragraphs (b)(40)(ii)(a) through (c) of this section for 
calculating projected actual emissions. Deviations from these provisions 
will be approved only if the State specifically demonstrates that the 
submitted provisions are more stringent than or at least as stringent in 
all respects as the corresponding provisions in paragraphs (r)(6)(i) 
through (v) of this section.
    (i) Before beginning actual construction of the project, the owner 
or operator shall document and maintain a record of the following 
information:
    (a) A description of the project;
    (b) Identification of the emissions unit(s) whose emissions of a 
regulated

[[Page 221]]

NSR pollutant could be affected by the project; and
    (c) A description of the applicability test used to determine that 
the project is not a major modification for any regulated NSR pollutant, 
including the baseline actual emissions, the projected actual emissions, 
the amount of emissions excluded under paragraph (b)(40)(ii)(c) of this 
section and an explanation for why such amount was excluded, and any 
netting calculations, if applicable.
    (ii) If the emissions unit is an existing electric utility steam 
generating unit, before beginning actual construction, the owner or 
operator shall provide a copy of the information set out in paragraph 
(r)(6)(i) of this section to the reviewing authority. Nothing in this 
paragraph (r)(6)(ii) shall be construed to require the owner or operator 
of such a unit to obtain any determination from the reviewing authority 
before beginning actual construction.
    (iii) The owner or operator shall monitor the emissions of any 
regulated NSR pollutant that could increase as a result of the project 
and that is emitted by any emissions unit identified in paragraph 
(r)(6)(i)(b) of this section; and calculate and maintain a record of the 
annual emissions, in tons per year on a calendar year basis, for a 
period of 5 years following resumption of regular operations after the 
change, or for a period of 10 years following resumption of regular 
operations after the change if the project increases the design capacity 
or potential to emit of that regulated NSR pollutant at such emissions 
unit.
    (iv) If the unit is an existing electric utility steam generating 
unit, the owner or operator shall submit a report to the reviewing 
authority within 60 days after the end of each year during which records 
must be generated under paragraph (r)(6)(iii) of this section setting 
out the unit's annual emissions during the calendar year that preceded 
submission of the report.
    (v) If the unit is an existing unit other than an electric utility 
steam generating unit, the owner or operator shall submit a report to 
the reviewing authority if the annual emissions, in tons per year, from 
the project identified in paragraph (r)(6)(i) of this section, exceed 
the baseline actual emissions (as documented and maintained pursuant to 
paragraph (r)(6)(i)(c) of this section) by a significant amount (as 
defined in paragraph (b)(23) of this section) for that regulated NSR 
pollutant, and if such emissions differ from the preconstruction 
projection as documented and maintained pursuant to paragraph 
(r)(6)(i)(c) of this section. Such report shall be submitted to the 
reviewing authority within 60 days after the end of such year. The 
report shall contain the following:
    (a) The name, address and telephone number of the major stationary 
source;
    (b) The annual emissions as calculated pursuant to paragraph 
(r)(6)(iii) of this section; and
    (c) Any other information that the owner or operator wishes to 
include in the report (e.g., an explanation as to why the emissions 
differ from the preconstruction projection).
    (7) Each plan shall provide that the owner or operator of the source 
shall make the information required to be documented and maintained 
pursuant to paragraph (r)(6) of this section available for review upon 
request for inspection by the reviewing authority or the general public 
pursuant to the requirements contained in Sec. 70.4(b)(3)(viii) of this 
chapter.
    (s) Innovative control technology. (1) The plan may provide that an 
owner or operator of a proposed major stationary source or major 
modification may request the reviewing authority to approve a system of 
innovative control technology.
    (2) The plan may provide that the reviewing authority may, with the 
consent of the Governor(s) of other affected State(s), determine that 
the source or modification may employ a system of innovative control 
technology, if:
    (i) The proposed control system would not cause or contribute to an 
unreasonable risk to public health, welfare, or safety in its operation 
or function;
    (ii) The owner or operator agrees to achieve a level of continuous 
emissions reduction equivalent to that which would have been required 
under paragraph (j)(2) of this section, by a date specified by the 
reviewing authority.

[[Page 222]]

Such date shall not be later than 4 years from the time of startup or 7 
years from permit issuance;
    (iii) The source or modification would meet the requirements 
equivalent to those in paragraphs (j) and (k) of this section, based on 
the emissions rate that the stationary source employing the system of 
innovative control technology would be required to meet on the date 
specified by the reviewing authority;
    (iv) The source or modification would not before the date specified 
by the reviewing authority:
    (a) Cause or contribute to any violation of an applicable national 
ambient air quality standard; or
    (b) Impact any area where an applicable increment is known to be 
violated;
    (v) All other applicable requirements including those for public 
participation have been met.
    (vi) The provisions of paragraph (p) of this section (relating to 
Class I areas) have been satisfied with respect to all periods during 
the life of the source or modification.
    (3) The plan shall provide that the reviewing authority shall 
withdraw any approval to employ a system of innovative control 
technology made under this section, if:
    (i) The proposed system fails by the specified date to achieve the 
required continuous emissions reduction rate; or
    (ii) The proposed system fails before the specified date so as to 
contribute to an unreasonable risk to public health, welfare, or safety; 
or
    (iii) The reviewing authority decides at any time that the proposed 
system is unlikely to achieve the required level of control or to 
protect the public health, welfare, or safety.
    (4) The plan may provide that if a source or modification fails to 
meet the required level of continuous emissions reduction within the 
specified time period, or if the approval is withdrawn in accordance 
with paragraph (s)(3) of this section, the reviewing authority may allow 
the source or modification up to an additional 3 years to meet the 
requirement for the application of best available control technology 
through use of a demonstrated system of control.
    (t) Clean Unit Test for emissions units that are subject to BACT or 
LAER. The plan shall provide an owner or operator of a major stationary 
source the option of using the Clean Unit Test to determine whether 
emissions increases at a Clean Unit are part of a project that is a 
major modification according to the provisions in paragraphs (t)(1) 
through (9) of this section.
    (1) Applicability. The provisions of this paragraph (t) apply to any 
emissions unit for which the reviewing authority has issued a major NSR 
permit within the past 10 years.
    (2) General provisions for Clean Units. The provisions in paragraphs 
(t)(2)(i) through (iv) of this section apply to a Clean Unit.
    (i) Any project for which the owner or operator begins actual 
construction after the effective date of the Clean Unit designation (as 
determined in accordance with paragraph (t)(4) of this section) and 
before the expiration date (as determined in accordance with paragraph 
(t)(5) of this section) will be considered to have occurred while the 
emissions unit was a Clean Unit.
    (ii) If a project at a Clean Unit does not cause the need for a 
change in the emission limitations or work practice requirements in the 
permit for the unit that were adopted in conjunction with BACT and the 
project would not alter any physical or operational characteristics that 
formed the basis for the BACT determination as specified in paragraph 
(t)(6)(iv) of this section, the emissions unit remains a Clean Unit.
    (iii) If a project causes the need for a change in the emission 
limitations or work practice requirements in the permit for the unit 
that were adopted in conjunction with BACT or the project would alter 
any physical or operational characteristics that formed the basis for 
the BACT determination as specified in paragraph (t)(6)(iv) of this 
section, then the emissions unit loses its designation as a Clean Unit 
upon issuance of the necessary permit revisions (unless the unit re-
qualifies as a Clean Unit pursuant to paragraph (t)(3)(iii) of this 
section). If the owner or operator begins actual construction on the 
project without first applying to revise the emissions unit's permit, 
the

[[Page 223]]

Clean Unit designation ends immediately prior to the time when actual 
construction begins.
    (iv) A project that causes an emissions unit to lose its designation 
as a Clean Unit is subject to the applicability requirements of 
paragraphs (a)(7)(iv)(a) through (d) and paragraph (a)(7)(iv)(f) of this 
section as if the emissions unit is not a Clean Unit.
    (3) Qualifying or re-qualifying to use the Clean Unit Applicability 
Test. An emissions unit automatically qualifies as a Clean Unit when the 
unit meets the criteria in paragraphs (t)(3)(i) and (ii) of this 
section. After the original Clean Unit designation expires in accordance 
with paragraph (t)(5) of this section or is lost pursuant to paragraph 
(t)(2)(iii) of this section, such emissions unit may re-qualify as a 
Clean Unit under either paragraph (t)(3)(iii) of this section, or under 
the Clean Unit provisions in paragraph (u) of this section. To re-
qualify as a Clean Unit under paragraph (t)(3)(iii) of this section, the 
emissions unit must obtain a new major NSR permit issued through the 
applicable PSD program and meet all the criteria in paragraph 
(t)(3)(iii) of this section. The Clean Unit designation applies 
individually for each pollutant emitted by the emissions unit.
    (i) Permitting requirement. The emissions unit must have received a 
major NSR permit within the past 10 years. The owner or operator must 
maintain and be able to provide information that would demonstrate that 
this permitting requirement is met.
    (ii) Qualifying air pollution control technologies. Air pollutant 
emissions from the emissions unit must be reduced through the use of air 
pollution control technology (which includes pollution prevention as 
defined under paragraph (b)(38) of this section or work practices) that 
meets both the following requirements in paragraphs (t)(3)(ii)(a) and 
(b) of this section.
    (a) The control technology achieves the BACT or LAER level of 
emissions reductions as determined through issuance of a major NSR 
permit within the past 10 years. However, the emissions unit is not 
eligible for the Clean Unit designation if the BACT determination 
resulted in no requirement to reduce emissions below the level of a 
standard, uncontrolled, new emissions unit of the same type.
    (b) The owner or operator made an investment to install the control 
technology. For the purpose of this determination, an investment 
includes expenses to research the application of a pollution prevention 
technique to the emissions unit or expenses to apply a pollution 
prevention technique to an emissions unit.
    (iii) Re-qualifying for the Clean Unit designation. The emissions 
unit must obtain a new major NSR permit that requires compliance with 
the current-day BACT (or LAER), and the emissions unit must meet the 
requirements in paragraphs (t)(3)(i) and (t)(3)(ii) of this section.
    (4) Effective date of the Clean Unit designation. The effective date 
of an emissions unit's Clean Unit designation (that is, the date on 
which the owner or operator may begin to use the Clean Unit Test to 
determine whether a project at the emissions unit is a major 
modification) is determined according to the applicable paragraph 
(t)(4)(i) or (t)(4)(ii) of this section.
    (i) Original Clean Unit designation, and emissions units that re-
qualify as Clean Units by implementing a new control technology to meet 
current-day BACT. The effective date is the date the emissions unit's 
air pollution control technology is placed into service, or 3 years 
after the issuance date of the major NSR permit, whichever is earlier, 
but no sooner than the date that provisions for the Clean Unit 
applicability test are approved by the Administrator for incorporation 
into the plan and become effective for the State in which the unit is 
located.
    (ii) Emissions Units that re-qualify for the Clean Unit designation 
using an existing control technology. The effective date is the date the 
new, major NSR permit is issued.
    (5) Clean Unit expiration. An emissions unit's Clean Unit 
designation expires (that is, the date on which the owner or operator 
may no longer use the Clean Unit Test to determine whether a project 
affecting the emissions unit is, or is part of, a major

[[Page 224]]

modification) according to the applicable paragraph (t)(5)(i) or (ii) of 
this section.
    (i) Original Clean Unit designation, and emissions units that re-
qualify by implementing new control technology to meet current-day BACT. 
For any emissions unit that automatically qualifies as a Clean Unit 
under paragraphs (t)(3)(i) and (ii) of this section or re-qualifies by 
implementing new control technology to meet current-day BACT under 
paragraph (t)(3)(iii) of this section, the Clean Unit designation 
expires 10 years after the effective date, or the date the equipment 
went into service, whichever is earlier; or, it expires at any time the 
owner or operator fails to comply with the provisions for maintaining 
the Clean Unit designation in paragraph (t)(7) of this section.
    (ii) Emissions units that re-qualify for the Clean Unit designation 
using an existing control technology. For any emissions unit that re-
qualifies as a Clean Unit under paragraph (t)(3)(iii) of this section 
using an existing control technology, the Clean Unit designation expires 
10 years after the effective date; or, it expires any time the owner or 
operator fails to comply with the provisions for maintaining the Clean 
Unit designation in paragraph (t)(7) of this section.
    (6) Required title V permit content for a Clean Unit. After the 
effective date of the Clean Unit designation, and in accordance with the 
provisions of the applicable title V permit program under part 70 or 
part 71 of this chapter, but no later than when the title V permit is 
renewed, the title V permit for the major stationary source must include 
the following terms and conditions related to the Clean Unit in 
paragraphs (t)(6)(i) through (vi) of this section.
    (i) A statement indicating that the emissions unit qualifies as a 
Clean Unit and identifying the pollutant(s) for which this Clean Unit 
designation applies.
    (ii) The effective date of the Clean Unit designation. If this date 
is not known when the Clean Unit designation is initially recorded in 
the title V permit (e.g., because the air pollution control technology 
is not yet in service), the permit must describe the event that will 
determine the effective date (e.g., the date the control technology is 
placed into service). Once the effective date is determined, the owner 
or operator must notify the reviewing authority of the exact date. This 
specific effective date must be added to the source's title V permit at 
the first opportunity, such as a modification, revision, reopening, or 
renewal of the title V permit for any reason, whichever comes first, but 
in no case later than the next renewal.
    (iii) The expiration date of the Clean Unit designation. If this 
date is not known when the Clean Unit designation is initially recorded 
into the title V permit (e.g., because the air pollution control 
technology is not yet in service), then the permit must describe the 
event that will determine the expiration date (e.g., the date the 
control technology is placed into service). Once the expiration date is 
determined, the owner or operator must notify the reviewing authority of 
the exact date. The expiration date must be added to the source's title 
V permit at the first opportunity, such as a modification, revision, 
reopening, or renewal of the title V permit for any reason, whichever 
comes first, but in no case later than the next renewal.
    (iv) All emission limitations and work practice requirements adopted 
in conjunction with BACT, and any physical or operational 
characteristics that formed the basis for the BACT determination (e.g., 
possibly the emissions unit's capacity or throughput).
    (v) Monitoring, recordkeeping, and reporting requirements as 
necessary to demonstrate that the emissions unit continues to meet the 
criteria for maintaining the Clean Unit designation. (See paragraph 
(t)(7) of this section.)
    (vi) Terms reflecting the owner or operator's duties to maintain the 
Clean Unit designation and the consequences of failing to do so, as 
presented in paragraph (t)(7) of this section.
    (7) Maintaining the Clean Unit designation. To maintain the Clean 
Unit designation, the owner or operator must conform to all the 
restrictions listed in paragraphs (t)(7)(i) through (iii) of this 
section. This paragraph (t)(7) applies independently to each pollutant 
for which the emissions unit has the Clean

[[Page 225]]

Unit designation. That is, failing to conform to the restrictions for 
one pollutant affects the Clean Unit designation only for that 
pollutant.
    (i) The Clean Unit must comply with the emission limitation(s) and/
or work practice requirements adopted in conjunction with the BACT that 
is recorded in the major NSR permit, and subsequently reflected in the 
title V permit. The owner or operator may not make a physical change in 
or change in the method of operation of the Clean Unit that causes the 
emissions unit to function in a manner that is inconsistent with the 
physical or operational characteristics that formed the basis for the 
BACT determination (e.g., possibly the emissions unit's capacity or 
throughput).
    (ii) The Clean Unit must comply with any terms and conditions in the 
title V permit related to the unit's Clean Unit designation.
    (iii) The Clean Unit must continue to control emissions using the 
specific air pollution control technology that was the basis for its 
Clean Unit designation. If the emissions unit or control technology is 
replaced, then the Clean Unit designation ends.
    (8) Netting at Clean Units. Emissions changes that occur at a Clean 
Unit must not be included in calculating a significant net emissions 
increase (that is, must not be used in a ``netting analysis''), unless 
such use occurs before the effective date of the Clean Unit designation, 
or after the Clean Unit designation expires; or, unless the emissions 
unit reduces emissions below the level that qualified the unit as a 
Clean Unit. However, if the Clean Unit reduces emissions below the level 
that qualified the unit as a Clean Unit, then the owner or operator may 
generate a credit for the difference between the level that qualified 
the unit as a Clean Unit and the new emission limitation if such 
reductions are surplus, quantifiable, and permanent. For purposes of 
generating offsets, the reductions must also be federally enforceable. 
For purposes of determining creditable net emissions increases and 
decreases, the reductions must also be enforceable as a practical 
matter.
    (9) Effect of redesignation on the Clean Unit designation. The Clean 
Unit designation of an emissions unit is not affected by redesignation 
of the attainment status of the area in which it is located. That is, if 
a Clean Unit is located in an attainment area and the area is 
redesignated to nonattainment, its Clean Unit designation is not 
affected. Similarly, redesignation from nonattainment to attainment does 
not affect the Clean Unit designation. However, if an existing Clean 
Unit designation expires, it must re-qualify under the requirements that 
are currently applicable in the area.
    (u) Clean Unit provisions for emissions units that achieve an 
emission limitation comparable to BACT. The plan shall provide an owner 
or operator of a major stationary source the option of using the Clean 
Unit Test to determine whether emissions increases at a Clean Unit are 
part of a project that is a major modification according to the 
provisions in paragraphs (u)(1) through (11) of this section.
    (1) Applicability. The provisions of this paragraph (u) apply to 
emissions units which do not qualify as Clean Units under paragraph (t) 
of this section, but which are achieving a level of emissions control 
comparable to BACT, as determined by the reviewing authority in 
accordance with this paragraph (u).
    (2) General provisions for Clean Units. The provisions in paragraphs 
(u)(2)(i) through (iv) of this section apply to a Clean Unit.
    (i) Any project for which the owner or operator begins actual 
construction after the effective date of the Clean Unit designation (as 
determined in accordance with paragraph (u)(5) of this section) and 
before the expiration date (as determined in accordance with paragraph 
(u)(6) of this section) will be considered to have occurred while the 
emissions unit was a Clean Unit.
    (ii) If a project at a Clean Unit does not cause the need for a 
change in the emission limitations or work practice requirements in the 
permit for the unit that have been determined (pursuant to paragraph 
(u)(4) of this section) to be comparable to BACT, and the project would 
not alter any physical or operational characteristics that formed the 
basis for determining that the emissions unit's control technology

[[Page 226]]

achieves a level of emissions control comparable to BACT as specified in 
paragraph (u)(8)(iv) of this section, the emissions unit remains a Clean 
Unit.
    (iii) If a project causes the need for a change in the emission 
limitations or work practice requirements in the permit for the unit 
that have been determined (pursuant to paragraph (u)(4) of this section) 
to be comparable to BACT, or the project would alter any physical or 
operational characteristics that formed the basis for determining that 
the emissions unit's control technology achieves a level of emissions 
control comparable to BACT as specified in paragraph (u)(8)(iv) of this 
section, then the emissions unit loses its designation as a Clean Unit 
upon issuance of the necessary permit revisions (unless the unit re-
qualifies as a Clean Unit pursuant to paragraph (u)(3)(iv) of this 
section). If the owner or operator begins actual construction on the 
project without first applying to revise the emissions unit's permit, 
the Clean Unit designation ends immediately prior to the time when 
actual construction begins.
    (iv) A project that causes an emissions unit to lose its designation 
as a Clean Unit is subject to the applicability requirements of 
paragraphs (a)(7)(iv)(a) through (d) and paragraph (a)(7)(iv)(f) of this 
section as if the emissions unit is not a Clean Unit.
    (3) Qualifying or re-qualifying to use the Clean Unit applicability 
test. An emissions unit qualifies as a Clean Unit when the unit meets 
the criteria in paragraphs (u)(3)(i) through (iii) of this section. 
After the original Clean Unit designation expires in accordance with 
paragraph (u)(6) of this section or is lost pursuant to paragraph 
(u)(2)(iii) of this section, such emissions unit may re-qualify as a 
Clean Unit under either paragraph (u)(3)(iv) of this section, or under 
the Clean Unit provisions in paragraph (t) of this section. To re-
qualify as a Clean Unit under paragraph (u)(3)(iv) of this section, the 
emissions unit must obtain a new permit issued pursuant to the 
requirements in paragraphs (u)(7) and (8) of this section and meet all 
the criteria in paragraph (u)(3)(iv) of this section. The reviewing 
authority will make a separate Clean Unit designation for each pollutant 
emitted by the emissions unit for which the emissions unit qualifies as 
a Clean Unit.
    (i) Qualifying air pollution control technologies. Air pollutant 
emissions from the emissions unit must be reduced through the use of air 
pollution control technology (which includes pollution prevention as 
defined under paragraph (b)(38) or work practices) that meets both the 
following requirements in paragraphs (u)(3)(i)(a) and (b) of this 
section.
    (a) The owner or operator has demonstrated that the emissions unit's 
control technology is comparable to BACT according to the requirements 
of paragraph (u)(4) of this section. However, the emissions unit is not 
eligible for the Clean Unit designation if its emissions are not reduced 
below the level of a standard, uncontrolled emissions unit of the same 
type (e.g., if the BACT determinations to which it is compared have 
resulted in a determination that no control measures are required).
    (b) The owner or operator made an investment to install the control 
technology. For the purpose of this determination, an investment 
includes expenses to research the application of a pollution prevention 
technique to the emissions unit or to retool the unit to apply a 
pollution prevention technique.
    (ii) Impact of emissions from the unit. The reviewing authority must 
determine that the allowable emissions from the emissions unit will not 
cause or contribute to a violation of any national ambient air quality 
standard or PSD increment, or adversely impact an air quality related 
value (such as visibility) that has been identified for a Federal Class 
I area by a Federal Land Manager and for which information is available 
to the general public.
    (iii) Date of installation. An emissions unit may qualify as a Clean 
Unit even if the control technology, on which the Clean Unit designation 
is based, was installed before the effective date of plan requirements 
to implement the requirements of this paragraph (u)(3)(iii). However, 
for such emissions units, the owner or operator must apply for the Clean 
Unit designation

[[Page 227]]

within 2 years after the plan requirements become effective. For 
technologies installed after the plan requirements become effective, the 
owner or operator must apply for the Clean Unit designation at the time 
the control technology is installed.
    (iv) Re-qualifying as a Clean Unit. The emissions unit must obtain a 
new permit (pursuant to requirements in paragraphs (u)(7) and (8) of 
this section) that demonstrates that the emissions unit's control 
technology is achieving a level of emission control comparable to 
current-day BACT, and the emissions unit must meet the requirements in 
paragraphs (u)(3)(i)(a) and (u)(3)(ii) of this section.
    (4) Demonstrating control effectiveness comparable to BACT. The 
owner or operator may demonstrate that the emissions unit's control 
technology is comparable to BACT for purposes of paragraph (u)(3)(i) of 
this section according to either paragraph (u)(4)(i) or (ii) of this 
section. Paragraph (u)(4)(iii) of this section specifies the time for 
making this comparison.
    (i) Comparison to previous BACT and LAER determinations. The 
Administrator maintains an on-line data base of previous determinations 
of RACT, BACT, and LAER in the RACT/BACT/LAER Clearinghouse (RBLC). The 
emissions unit's control technology is presumed to be comparable to BACT 
if it achieves an emission limitation that is equal to or better than 
the average of the emission limitations achieved by all the sources for 
which a BACT or LAER determination has been made within the preceding 5 
years and entered into the RBLC, and for which it is technically 
feasible to apply the BACT or LAER control technology to the emissions 
unit. The reviewing authority shall also compare this presumption to any 
additional BACT or LAER determinations of which it is aware, and shall 
consider any information on achieved-in-practice pollution control 
technologies provided during the public comment period, to determine 
whether any presumptive determination that the control technology is 
comparable to BACT is correct.
    (ii) The substantially-as-effective test. The owner or operator may 
demonstrate that the emissions unit's control technology is 
substantially as effective as BACT. In addition, any other person may 
present evidence related to whether the control technology is 
substantially as effective as BACT during the public participation 
process required under paragraph (u)(7) of this section. The reviewing 
authority shall consider such evidence on a case-by-case basis and 
determine whether the emissions unit's air pollution control technology 
is substantially as effective as BACT.
    (iii) Time of comparison--(a) Emissions units with control 
technologies that are installed before the effective date of plan 
requirements implementing this paragraph. The owner or operator of an 
emissions unit whose control technology is installed before the 
effective date of plan requirements implementing this paragraph (u) may, 
at its option, either demonstrate that the emission limitation achieved 
by the emissions unit's control technology is comparable to the BACT 
requirements that applied at the time the control technology was 
installed, or demonstrate that the emission limitation achieved by the 
emissions unit's control technology is comparable to current-day BACT 
requirements. The expiration date of the Clean Unit designation will 
depend on which option the owner or operator uses, as specified in 
paragraph (u)(6) of this section.
    (b) Emissions units with control technologies that are installed 
after the effective date of plan requirements implementing this 
paragraph. The owner or operator must demonstrate that the emission 
limitation achieved by the emissions unit's control technology is 
comparable to current-day BACT requirements.
    (5) Effective date of the Clean Unit designation. The effective date 
of an emissions unit's Clean Unit designation (that is, the date on 
which the owner or operator may begin to use the Clean Unit Test to 
determine whether a project involving the emissions unit is a major 
modification) is the date that the permit required by paragraph (u)(7) 
of this section is issued or the date that the emissions unit's air 
pollution control technology is placed into service, whichever is later.

[[Page 228]]

    (6) Clean Unit expiration. If the owner or operator demonstrates 
that the emission limitation achieved by the emissions unit's control 
technology is comparable to the BACT requirements that applied at the 
time the control technology was installed, then the Clean Unit 
designation expires 10 years from the date that the control technology 
was installed. For all other emissions units, the Clean Unit designation 
expires 10 years from the effective date of the Clean Unit designation, 
as determined according to paragraph (u)(5) of this section. In 
addition, for all emissions units, the Clean Unit designation expires 
any time the owner or operator fails to comply with the provisions for 
maintaining the Clean Unit designation in paragraph (u)(9) of this 
section.
    (7) Procedures for designating emissions units as Clean Units. The 
reviewing authority shall designate an emissions unit a Clean Unit only 
by issuing a permit through a permitting program that has been approved 
by the Administrator and that conforms with the requirements of 
Secs. 51.160 through 51.164 of this chapter, including requirements for 
public notice of the proposed Clean Unit designation and opportunity for 
public comment. Such permit must also meet the requirements in paragraph 
(u)(8) of this section.
    (8) Required permit content. The permit required by paragraph (u)(7) 
of this section shall include the terms and conditions set forth in 
paragraphs (u)(8)(i) through (vi). Such terms and conditions shall be 
incorporated into the major stationary source's title V permit in 
accordance with the provisions of the applicable title V permit program 
under part 70 or part 71 of this chapter, but no later than when the 
title V permit is renewed.
    (i) A statement indicating that the emissions unit qualifies as a 
Clean Unit and identifying the pollutant(s) for which the Clean Unit 
designation applies.
    (ii) The effective date of the Clean Unit designation. If this date 
is not known when the reviewing authority issues the permit (e.g., 
because the air pollution control technology is not yet in service), 
then the permit must describe the event that will determine the 
effective date (e.g., the date the control technology is placed into 
service). Once the effective date is known, then the owner or operator 
must notify the reviewing authority of the exact date. This specific 
effective date must be added to the source's title V permit at the first 
opportunity, such as a modification, revision, reopening, or renewal of 
the title V permit for any reason, whichever comes first, but in no case 
later than the next renewal.
    (iii) The expiration date of the Clean Unit designation. If this 
date is not known when the reviewing authority issues the permit (e.g., 
because the air pollution control technology is not yet in service), 
then the permit must describe the event that will determine the 
expiration date (e.g., the date the control technology is placed into 
service). Once the expiration date is known, then the owner or operator 
must notify the reviewing authority of the exact date. The expiration 
date must be added to the source's title V permit at the first 
opportunity, such as a modification, revision, reopening, or renewal of 
the title V permit for any reason, whichever comes first, but in no case 
later than the next renewal.
    (iv) All emission limitations and work practice requirements adopted 
in conjunction with emission limitations necessary to assure that the 
control technology continues to achieve an emission limitation 
comparable to BACT, and any physical or operational characteristics that 
formed the basis for determining that the emissions unit's control 
technology achieves a level of emissions control comparable to BACT 
(e.g., possibly the emissions unit's capacity or throughput).
    (v) Monitoring, recordkeeping, and reporting requirements as 
necessary to demonstrate that the emissions unit continues to meet the 
criteria for maintaining its Clean Unit designation. (See paragraph 
(u)(9) of this section.)
    (vi) Terms reflecting the owner or operator's duties to maintain the 
Clean Unit designation and the consequences of failing to do so, as 
presented in paragraph (u)(9) of this section.
    (9) Maintaining the Clean Unit designation. To maintain the Clean 
Unit designation, the owner or operator must

[[Page 229]]

conform to all the restrictions listed in paragraphs (u)(9)(i) through 
(v) of this section. This paragraph (u)(9) applies independently to each 
pollutant for which the reviewing authority has designated the emissions 
unit a Clean Unit. That is, failing to conform to the restrictions for 
one pollutant affects the Clean Unit designation only for that 
pollutant.
    (i) The Clean Unit must comply with the emission limitation(s) and/
or work practice requirements adopted to ensure that the control 
technology continues to achieve emission control comparable to BACT.
    (ii) The owner or operator may not make a physical change in or 
change in the method of operation of the Clean Unit that causes the 
emissions unit to function in a manner that is inconsistent with the 
physical or operational characteristics that formed the basis for the 
determination that the control technology is achieving a level of 
emission control that is comparable to BACT (e.g., possibly the 
emissions unit's capacity or throughput).
    (iii) [Reserved]
    (iv) The Clean Unit must comply with any terms and conditions in the 
title V permit related to the unit's Clean Unit designation.
    (v) The Clean Unit must continue to control emissions using the 
specific air pollution control technology that was the basis for its 
Clean Unit designation. If the emissions unit or control technology is 
replaced, then the Clean Unit designation ends.
    (10) Netting at Clean Units. Emissions changes that occur at a Clean 
Unit must not be included in calculating a significant net emissions 
increase (that is, must not be used in a ``netting analysis'') unless 
such use occurs before the effective date of plan requirements adopted 
to implement this paragraph (u) or after the Clean Unit designation 
expires; or, unless the emissions unit reduces emissions below the level 
that qualified the unit as a Clean Unit. However, if the Clean Unit 
reduces emissions below the level that qualified the unit as a Clean 
Unit, then the owner or operator may generate a credit for the 
difference between the level that qualified the unit as a Clean Unit and 
the emissions unit's new emission limitation if such reductions are 
surplus, quantifiable, and permanent. For purposes of generating 
offsets, the reductions must also be federally enforceable. For purposes 
of determining creditable net emissions increases and decreases, the 
reductions must also be enforceable as a practical matter.
    (11) Effect of redesignation on the Clean Unit designation. The 
Clean Unit designation of an emissions unit is not affected by 
redesignation of the attainment designation of the area in which it is 
located. That is, if a Clean Unit is located in an attainment area and 
the area is redesignated to nonattainment, its Clean Unit designation is 
not affected. Similarly, redesignation from nonattainment to attainment 
does not affect the Clean Unit designation. However, if a Clean Unit's 
designation expires or is lost pursuant to paragraphs (t)(2)(iii) and 
(u)(2)(iii) of this section, it must re-qualify under the requirements 
that are currently applicable.
    (v) PCP exclusion procedural requirements. Each plan shall include 
provisions for PCPs equivalent to those contained in paragraphs (v)(1) 
through (6) of this section.
    (1) Before an owner or operator begins actual construction of a PCP, 
the owner or operator must either submit a notice to the reviewing 
authority if the project is listed in paragraphs (b)(31)(i) through (vi) 
of this section, or if the project is not listed in paragraphs 
(b)(31)(i) through (vi) of this section, then the owner or operator must 
submit a permit application and obtain approval to use the PCP exclusion 
from the reviewing authority consistent with the requirements in 
paragraph (v)(5) of this section. Regardless of whether the owner or 
operator submits a notice or a permit application, the project must meet 
the requirements in paragraph (v)(2) of this section, and the notice or 
permit application must contain the information required in paragraph 
(v)(3) of this section.
    (2) Any project that relies on the PCP exclusion must meet the 
requirements in paragraphs (v)(2)(i) and (ii) of this section.
    (i) Environmentally beneficial analysis. The environmental benefit 
from the emission reductions of pollutants regulated under the Act must 
outweigh the

[[Page 230]]

environmental detriment of emissions increases in pollutants regulated 
under the Act. A statement that a technology from paragraphs (b)(31)(i) 
through (vi) of this section is being used shall be presumed to satisfy 
this requirement.
    (ii) Air quality analysis. The emissions increases from the project 
will not cause or contribute to a violation of any national ambient air 
quality standard or PSD increment, or adversely impact an air quality 
related value (such as visibility) that has been identified for a 
Federal Class I area by a Federal Land Manager and for which information 
is available to the general public.
    (3) Content of notice or permit application. In the notice or permit 
application sent to the reviewing authority, the owner or operator must 
include, at a minimum, the information listed in paragraphs (v)(3)(i) 
through (v) of this section.
    (i) A description of the project.
    (ii) The potential emissions increases and decreases of any 
pollutant regulated under the Act and the projected emissions increases 
and decreases using the methodology in paragraph (a)(7)(vi) of this 
section, that will result from the project, and a copy of the 
environmentally beneficial analysis required by paragraph (v)(2)(i) of 
this section.
    (iii) A description of monitoring and recordkeeping, and all other 
methods, to be used on an ongoing basis to demonstrate that the project 
is environmentally beneficial. Methods should be sufficient to meet the 
requirements in part 70 and part 71.
    (iv) A certification that the project will be designed and operated 
in a manner that is consistent with proper industry and engineering 
practices, in a manner that is consistent with the environmentally 
beneficial analysis and air quality analysis required by paragraphs 
(v)(2)(i) and (ii) of this section, with information submitted in the 
notice or permit application, and in such a way as to minimize, within 
the physical configuration and operational standards usually associated 
with the emissions control device or strategy, emissions of collateral 
pollutants.
    (v) Demonstration that the PCP will not have an adverse air quality 
impact (e.g., modeling, screening level modeling results, or a statement 
that the collateral emissions increase is included within the parameters 
used in the most recent modeling exercise) as required by paragraph 
(v)(2)(ii) of this section. An air quality impact analysis is not 
required for any pollutant that will not experience a significant 
emissions increase as a result of the project.
    (4) Notice process for listed projects. For projects listed in 
paragraphs (b)(31)(i) through (vi) of this section, the owner or 
operator may begin actual construction of the project immediately after 
notice is sent to the reviewing authority (unless otherwise prohibited 
under requirements of the applicable plan). The owner or operator shall 
respond to any requests by its reviewing authority for additional 
information that the reviewing authority determines is necessary to 
evaluate the suitability of the project for the PCP exclusion.
    (5) Permit process for unlisted projects. Before an owner or 
operator may begin actual construction of a PCP project that is not 
listed in paragraphs (b)(31)(i) through (vi) of this section, the 
project must be approved by the reviewing authority and recorded in a 
plan-approved permit or title V permit using procedures that are 
consistent with Secs. 51.160 and 51.161 of this chapter. This includes 
the requirement that the reviewing authority provide the public with 
notice of the proposed approval, with access to the environmentally 
beneficial analysis and the air quality analysis, and provide at least a 
30-day period for the public and the Administrator to submit comments. 
The reviewing authority must address all material comments received by 
the end of the comment period before taking final action on the permit.
    (6) Operational requirements. Upon installation of the PCP, the 
owner or operator must comply with the requirements of paragraphs 
(v)(6)(i) through (iv) of this section.
    (i) General duty. The owner or operator must operate the PCP 
consistent with proper industry and engineering practices, in a manner 
that is consistent with the environmentally beneficial analysis and air 
quality analysis required by paragraphs (v)(2)(i) and (ii)

[[Page 231]]

of this section, with information submitted in the notice or permit 
application required by paragraph (v)(3), and in such a way as to 
minimize, within the physical configuration and operational standards 
usually associated with the emissions control device or strategy, 
emissions of collateral pollutants.
    (ii) Recordkeeping. The owner or operator must maintain copies on 
site of the environmentally beneficial analysis, the air quality impacts 
analysis, and monitoring and other emission records to prove that the 
PCP operated consistent with the general duty requirements in paragraph 
(v)(6)(i) of this section.
    (iii) Permit requirements. The owner or operator must comply with 
any provisions in the plan-approved permit or title V permit related to 
use and approval of the PCP exclusion.
    (iv) Generation of Emission Reduction Credits. Emission reductions 
created by a PCP shall not be included in calculating a significant net 
emissions increase unless the emissions unit further reduces emissions 
after qualifying for the PCP exclusion (e.g., taking an operational 
restriction on the hours of operation.) The owner or operator may 
generate a credit for the difference between the level of reduction 
which was used to qualify for the PCP exclusion and the new emission 
limitation if such reductions are surplus, quantifiable, and permanent. 
For purposes of generating offsets, the reductions must also be 
federally enforceable. For purposes of determining creditable net 
emissions increases and decreases, the reductions must also be 
enforceable as a practical matter.
    (w) Actuals PALs. The plan shall provide for PALs according to the 
provisions in paragraphs (w)(1) through (15) of this section.
    (1) Applicability. (i) The reviewing authority may approve the use 
of an actuals PAL for any existing major stationary source if the PAL 
meets the requirements in paragraphs (w)(1) through (15) of this 
section. The term ``PAL'' shall mean ``actuals PAL'' throughout 
paragraph (w) of this section.
    (ii) Any physical change in or change in the method of operation of 
a major stationary source that maintains its total source-wide emissions 
below the PAL level, meets the requirements in paragraphs (w)(1) through 
(15) of this section, and complies with the PAL permit:
    (a) Is not a major modification for the PAL pollutant;
    (b) Does not have to be approved through the plan's major NSR 
program; and
    (c) Is not subject to the provisions in paragraph (r)(2) of this 
section (restrictions on relaxing enforceable emission limitations that 
the major stationary source used to avoid applicability of the major NSR 
program).
    (iii) Except as provided under paragraph (w)(1)(ii)(c) of this 
section, a major stationary source shall continue to comply with all 
applicable Federal or State requirements, emission limitations, and work 
practice requirements that were established prior to the effective date 
of the PAL.
    (2) Definitions. The plan shall use the definitions in paragraphs 
(w)(2)(i) through (xi) of this section for the purpose of developing and 
implementing regulations that authorize the use of actuals PALs 
consistent with paragraphs (w)(1) through (15) of this section. When a 
term is not defined in these paragraphs, it shall have the meaning given 
in paragraph (b) of this section or in the Act.
    (i) Actuals PAL for a major stationary source means a PAL based on 
the baseline actual emissions (as defined in paragraph (b)(47) of this 
section) of all emissions units (as defined in paragraph (b)(7) of this 
section) at the source, that emit or have the potential to emit the PAL 
pollutant.
    (ii) Allowable emissions means ``allowable emissions'' as defined in 
paragraph (b)(16) of this section, except as this definition is modified 
according to paragraphs (w)(2)(ii)(a) and (b) of this section.
    (a) The allowable emissions for any emissions unit shall be 
calculated considering any emission limitations that are enforceable as 
a practical matter on the emissions unit's potential to emit.

[[Page 232]]

    (b) An emissions unit's potential to emit shall be determined using 
the definition in paragraph (b)(4) of this section, except that the 
words ``or enforceable as a practical matter'' should be added after 
``federally enforceable.''
    (iii) Small emissions unit means an emissions unit that emits or has 
the potential to emit the PAL pollutant in an amount less than the 
significant level for that PAL pollutant, as defined in paragraph 
(b)(23) of this section or in the Act, whichever is lower.
    (iv) Major emissions unit means:
    (a) Any emissions unit that emits or has the potential to emit 100 
tons per year or more of the PAL pollutant in an attainment area; or
    (b) Any emissions unit that emits or has the potential to emit the 
PAL pollutant in an amount that is equal to or greater than the major 
source threshold for the PAL pollutant as defined by the Act for 
nonattainment areas. For example, in accordance with the definition of 
major stationary source in section 182(c) of the Act, an emissions unit 
would be a major emissions unit for VOC if the emissions unit is located 
in a serious ozone nonattainment area and it emits or has the potential 
to emit 50 or more tons of VOC per year.
    (v) Plantwide applicability limitation (PAL) means an emission 
limitation expressed in tons per year, for a pollutant at a major 
stationary source, that is enforceable as a practical matter and 
established source-wide in accordance with paragraphs (w)(1) through 
(15) of this section.
    (vi) PAL effective date generally means the date of issuance of the 
PAL permit. However, the PAL effective date for an increased PAL is the 
date any emissions unit that is part of the PAL major modification 
becomes operational and begins to emit the PAL pollutant.
    (vii) PAL effective period means the period beginning with the PAL 
effective date and ending 10 years later.
    (viii) PAL major modification means, notwithstanding paragraphs 
(b)(2) and (b)(3) of this section (the definitions for major 
modification and net emissions increase), any physical change in or 
change in the method of operation of the PAL source that causes it to 
emit the PAL pollutant at a level equal to or greater than the PAL.
    (ix) PAL permit means the major NSR permit, the minor NSR permit, or 
the State operating permit under a program that is approved into the 
plan, or the title V permit issued by the reviewing authority that 
establishes a PAL for a major stationary source.
    (x) PAL pollutant means the pollutant for which a PAL is established 
at a major stationary source.
    (xi) Significant emissions unit means an emissions unit that emits 
or has the potential to emit a PAL pollutant in an amount that is equal 
to or greater than the significant level (as defined in paragraph 
(b)(23) of this section or in the Act, whichever is lower) for that PAL 
pollutant, but less than the amount that would qualify the unit as a 
major emissions unit as defined in paragraph (w)(2)(iv) of this section.
    (3) Permit application requirements. As part of a permit application 
requesting a PAL, the owner or operator of a major stationary source 
shall submit the following information in paragraphs (w)(3)(i) through 
(iii) of this section to the reviewing authority for approval.
    (i) A list of all emissions units at the source designated as small, 
significant or major based on their potential to emit. In addition, the 
owner or operator of the source shall indicate which, if any, Federal or 
State applicable requirements, emission limitations, or work practices 
apply to each unit.
    (ii) Calculations of the baseline actual emissions (with supporting 
documentation). Baseline actual emissions are to include emissions 
associated not only with operation of the unit, but also emissions 
associated with startup, shutdown, and malfunction.
    (iii) The calculation procedures that the major stationary source 
owner or operator proposes to use to convert the monitoring system data 
to monthly emissions and annual emissions based on a 12-month rolling 
total for each month as required by paragraph (w)(13)(i) of this 
section.
    (4) General requirements for establishing PALs. (i) The plan allows 
the reviewing authority to establish a PAL at a major stationary source, 
provided that at a minimum, the requirements

[[Page 233]]

in paragraphs (w)(4)(i)(a) through (g) of this section are met.
    (a) The PAL shall impose an annual emission limitation in tons per 
year, that is enforceable as a practical matter, for the entire major 
stationary source. For each month during the PAL effective period after 
the first 12 months of establishing a PAL, the major stationary source 
owner or operator shall show that the sum of the monthly emissions from 
each emissions unit under the PAL for the previous 12 consecutive months 
is less than the PAL (a 12-month average, rolled monthly). For each 
month during the first 11 months from the PAL effective date, the major 
stationary source owner or operator shall show that the sum of the 
preceding monthly emissions from the PAL effective date for each 
emissions unit under the PAL is less than the PAL.
    (b) The PAL shall be established in a PAL permit that meets the 
public participation requirements in paragraph (w)(5) of this section.
    (c) The PAL permit shall contain all the requirements of paragraph 
(w)(7) of this section.
    (d) The PAL shall include fugitive emissions, to the extent 
quantifiable, from all emissions units that emit or have the potential 
to emit the PAL pollutant at the major stationary source.
    (e) Each PAL shall regulate emissions of only one pollutant.
    (f) Each PAL shall have a PAL effective period of 10 years.
    (g) The owner or operator of the major stationary source with a PAL 
shall comply with the monitoring, recordkeeping, and reporting 
requirements provided in paragraphs (w)(12) through (14) of this section 
for each emissions unit under the PAL through the PAL effective period.
    (ii) At no time (during or after the PAL effective period) are 
emissions reductions of a PAL pollutant that occur during the PAL 
effective period creditable as decreases for purposes of offsets under 
Sec. 51.165(a)(3)(ii) of this chapter unless the level of the PAL is 
reduced by the amount of such emissions reductions and such reductions 
would be creditable in the absence of the PAL.
    (5) Public participation requirements for PALs. PALs for existing 
major stationary sources shall be established, renewed, or increased, 
through a procedure that is consistent with Secs. 51.160 and 51.161 of 
this chapter. This includes the requirement that the reviewing authority 
provide the public with notice of the proposed approval of a PAL permit 
and at least a 30-day period for submittal of public comment. The 
reviewing authority must address all material comments before taking 
final action on the permit.
    (6) Setting the 10-year actuals PAL level. The plan shall provide 
that the actuals PAL level for a major stationary source shall be 
established as the sum of the baseline actual emissions (as defined in 
paragraph (b)(47) of this section) of the PAL pollutant for each 
emissions unit at the source; plus an amount equal to the applicable 
significant level for the PAL pollutant under paragraph (b)(23) of this 
section or under the Act, whichever is lower. When establishing the 
actuals PAL level, for a PAL pollutant, only one consecutive 24-month 
period must be used to determine the baseline actual emissions for all 
existing emissions units. However, a different consecutive 24-month 
period may be used for each different PAL pollutant. Emissions 
associated with units that were permanently shutdown after this 24-month 
period must be subtracted from the PAL level. Emissions from units on 
which actual construction began after the 24-month period must be added 
to the PAL level in an amount equal to the potential to emit of the 
units. The reviewing authority shall specify a reduced PAL level(s) (in 
tons/yr) in the PAL permit to become effective on the future compliance 
date(s) of any applicable Federal or State regulatory requirement(s) 
that the reviewing authority is aware of prior to issuance of the PAL 
permit. For instance, if the source owner or operator will be required 
to reduce emissions from industrial boilers in half from baseline 
emissions of 60 ppm NOX to a new rule limit of 30 ppm, then 
the permit shall contain a future effective PAL level that is equal to 
the current PAL level reduced by half of the original baseline emissions 
of such unit(s).

[[Page 234]]

    (7) Contents of the PAL permit. The plan shall require that the PAL 
permit contain, at a minimum, the information in paragraphs (w)(7)(i) 
through (x) of this section.
    (i) The PAL pollutant and the applicable source-wide emission 
limitation in tons per year.
    (ii) The PAL permit effective date and the expiration date of the 
PAL (PAL effective period).
    (iii) Specification in the PAL permit that if a major stationary 
source owner or operator applies to renew a PAL in accordance with 
paragraph (w)(10) of this section before the end of the PAL effective 
period, then the PAL shall not expire at the end of the PAL effective 
period. It shall remain in effect until a revised PAL permit is issued 
by the reviewing authority.
    (iv) A requirement that emission calculations for compliance 
purposes include emissions from startups, shutdowns and malfunctions.
    (v) A requirement that, once the PAL expires, the major stationary 
source is subject to the requirements of paragraph (w)(9) of this 
section.
    (vi) The calculation procedures that the major stationary source 
owner or operator shall use to convert the monitoring system data to 
monthly emissions and annual emissions based on a 12-month rolling total 
for each month as required by paragraph (w)(3)(i) of this section.
    (vii) A requirement that the major stationary source owner or 
operator monitor all emissions units in accordance with the provisions 
under paragraph (w)(13) of this section.
    (viii) A requirement to retain the records required under paragraph 
(w)(13) of this section on site. Such records may be retained in an 
electronic format.
    (ix) A requirement to submit the reports required under paragraph 
(w)(14) of this section by the required deadlines.
    (x) Any other requirements that the reviewing authority deems 
necessary to implement and enforce the PAL.
    (8) PAL effective period and reopening of the PAL permit. The plan 
shall require the information in paragraphs (w)(8)(i) and (ii) of this 
section.
    (i) PAL effective period. The reviewing authority shall specify a 
PAL effective period of 10 years.
    (ii) Reopening of the PAL permit.
    (a) During the PAL effective period, the plan shall require the 
reviewing authority to reopen the PAL permit to:
    (1) Correct typographical/calculation errors made in setting the PAL 
or reflect a more accurate determination of emissions used to establish 
the PAL;
    (2) Reduce the PAL if the owner or operator of the major stationary 
source creates creditable emissions reductions for use as offsets under 
Sec. 51.165(a)(3)(ii) of this chapter; and
    (3) Revise the PAL to reflect an increase in the PAL as provided 
under paragraph (w)(11) of this section.
    (b) The plan shall provide the reviewing authority discretion to 
reopen the PAL permit for the following:
    (1) Reduce the PAL to reflect newly applicable Federal requirements 
(for example, NSPS) with compliance dates after the PAL effective date;
    (2) Reduce the PAL consistent with any other requirement, that is 
enforceable as a practical matter, and that the State may impose on the 
major stationary source under the plan; and
    (3) Reduce the PAL if the reviewing authority determines that a 
reduction is necessary to avoid causing or contributing to a NAAQS or 
PSD increment violation, or to an adverse impact on an AQRV that has 
been identified for a Federal Class I area by a Federal Land Manager and 
for which information is available to the general public.
    (c) Except for the permit reopening in paragraph (w)(8)(ii)(a)(1) of 
this section for the correction of typographical/calculation errors that 
do not increase the PAL level, all reopenings shall be carried out in 
accordance with the public participation requirements of paragraph 
(w)(5) of this section.
    (9) Expiration of a PAL. Any PAL that is not renewed in accordance 
with the procedures in paragraph (w)(10) of this section shall expire at 
the end of the PAL effective period, and the requirements in paragraphs 
(w)(9)(i) through (v) of this section shall apply.
    (i) Each emissions unit (or each group of emissions units) that 
existed

[[Page 235]]

under the PAL shall comply with an allowable emission limitation under a 
revised permit established according to the procedures in paragraphs 
(w)(9)(i)(a) and (b) of this section.
    (a) Within the time frame specified for PAL renewals in paragraph 
(w)(10)(ii) of this section, the major stationary source shall submit a 
proposed allowable emission limitation for each emissions unit (or each 
group of emissions units, if such a distribution is more appropriate as 
decided by the reviewing authority) by distributing the PAL allowable 
emissions for the major stationary source among each of the emissions 
units that existed under the PAL. If the PAL had not yet been adjusted 
for an applicable requirement that became effective during the PAL 
effective period, as required under paragraph (w)(10)(v) of this 
section, such distribution shall be made as if the PAL had been 
adjusted.
    (b) The reviewing authority shall decide whether and how the PAL 
allowable emissions will be distributed and issue a revised permit 
incorporating allowable limits for each emissions unit, or each group of 
emissions units, as the reviewing authority determines is appropriate.
    (ii) Each emissions unit(s) shall comply with the allowable emission 
limitation on a 12-month rolling basis. The reviewing authority may 
approve the use of monitoring systems (source testing,emission factors, 
etc.) other than CEMS, CERMS, PEMS or CPMS to demonstrate compliance 
with the allowable emission limitation.
    (iii) Until the reviewing authority issues the revised permit 
incorporating allowable limits for each emissions unit, or each group of 
emissions units, as required under paragraph (w)(9)(i)(b) of this 
section, the source shall continue to comply with a source-wide, multi-
unit emissions cap equivalent to the level of the PAL emission 
limitation.
    (iv) Any physical change or change in the method of operation at the 
major stationary source will be subject to major NSR requirements if 
such change meets the definition of major modification in paragraph 
(b)(2) of this section.
    (v) The major stationary source owner or operator shall continue to 
comply with any State or Federal applicable requirements (BACT, RACT, 
NSPS, etc.) that may have applied either during the PAL effective period 
or prior to the PAL effective period except for those emission 
limitations that had been established pursuant to paragraph (r)(2) of 
this section, but were eliminated by the PAL in accordance with the 
provisions in paragraph (w)(1)(ii)(c) of this section.
    (10) Renewal of a PAL. (i) The reviewing authority shall follow the 
procedures specified in paragraph (w)(5) of this section in approving 
any request to renew a PAL for a major stationary source, and shall 
provide both the proposed PAL level and a written rationale for the 
proposed PAL level to the public for review and comment. During such 
public review, any person may propose a PAL level for the source for 
consideration by the reviewing authority.
    (ii) Application deadline. The plan shall require that a major 
stationary source owner or operator shall submit a timely application to 
the reviewing authority to request renewal of a PAL. A timely 
application is one that is submitted at least 6 months prior to, but not 
earlier than 18 months from, the date of permit expiration. This 
deadline for application submittal is to ensure that the permit will not 
expire before the permit is renewed. If the owner or operator of a major 
stationary source submits a complete application to renew the PAL within 
this time period, then the PAL shall continue to be effective until the 
revised permit with the renewed PAL is issued.
    (iii) Application requirements. The application to renew a PAL 
permit shall contain the information required in paragraphs (w)(10)(iii) 
(a) through (d) of this section.
    (a) The information required in paragraphs (w)(3)(i) through (iii) 
of this section.
    (b) A proposed PAL level.
    (c) The sum of the potential to emit of all emissions units under 
the PAL (with supporting documentation).
    (d) Any other information the owner or operator wishes the reviewing 
authority to consider in determining the

[[Page 236]]

appropriate level for renewing the PAL.
    (iv) PAL adjustment. In determining whether and how to adjust the 
PAL, the reviewing authority shall consider the options outlined in 
paragraphs (w)(10)(iv) (a) and (b) of this section. However, in no case 
may any such adjustment fail to comply with paragraph (w)(10)(iv)(c) of 
this section.
    (a) If the emissions level calculated in accordance with paragraph 
(w)(6) of this section is equal to or greater than 80 percent of the PAL 
level, the reviewing authority may renew the PAL at the same level 
without considering the factors set forth in paragraph (w)(10)(iv)(b) of 
this section; or
    (b) The reviewing authority may set the PAL at a level that it 
determines to be more representative of the source's baseline actual 
emissions, or that it determines to be appropriate considering air 
quality needs, advances in control technology, anticipated economic 
growth in the area, desire to reward or encourage the source's voluntary 
emissions reductions, or other factors as specifically identified by the 
reviewing authority in its written rationale.
    (c) Notwithstanding paragraphs (w)(10)(iv) (a) and (b) of this 
section:
    (1) If the potential to emit of the major stationary source is less 
than the PAL, the reviewing authority shall adjust the PAL to a level no 
greater than the potential to emit of the source; and
    (2) The reviewing authority shall not approve a renewed PAL level 
higher than the current PAL, unless the major stationary source has 
complied with the provisions of paragraph (w)(11) of this section 
(increasing a PAL).
    (v) If the compliance date for a State or Federal requirement that 
applies to the PAL source occurs during the PAL effective period, and if 
the reviewing authority has not already adjusted for such requirement, 
the PAL shall be adjusted at the time of PAL permit renewal or title V 
permit renewal, whichever occurs first.
    (11) Increasing a PAL during the PAL effective period. (i) The plan 
shall require that the reviewing authority may increase a PAL emission 
limitation only if the major stationary source complies with the 
provisions in paragraphs (w)(11)(i) (a) through (d) of this section.
    (a) The owner or operator of the major stationary source shall 
submit a complete application to request an increase in the PAL limit 
for a PAL major modification. Such application shall identify the 
emissions unit(s) contributing to the increase in emissions so as to 
cause the major stationary source's emissions to equal or exceed its 
PAL.
    (b) As part of this application, the major stationary source owner 
or operator shall demonstrate that the sum of the baseline actual 
emissions of the small emissions units, plus the sum of the baseline 
actual emissions of the significant and major emissions units assuming 
application of BACT equivalent controls, plus the sum of the allowable 
emissions of the new or modified emissions unit(s), exceeds the PAL. The 
level of control that would result from BACT equivalent controls on each 
significant or major emissions unit shall be determined by conducting a 
new BACT analysis at the time the application is submitted, unless the 
emissions unit is currently required to comply with a BACT or LAER 
requirement that was established within the preceding 10 years. In such 
a case, the assumed control level for that emissions unit shall be equal 
to the level of BACT or LAER with which that emissions unit must 
currently comply.
    (c) The owner or operator obtains a major NSR permit for all 
emissions unit(s) identified in paragraph (w)(11)(i)(a) of this section, 
regardless of the magnitude of the emissions increase resulting from 
them (that is, no significant levels apply). These emissions unit(s) 
shall comply with any emissions requirements resulting from the major 
NSR process (for example, BACT), even though they have also become 
subject to the PAL or continue to be subject to the PAL.
    (d) The PAL permit shall require that the increased PAL level shall 
be effective on the day any emissions unit that is part of the PAL major 
modification becomes operational and begins to emit the PAL pollutant.
    (ii) The reviewing authority shall calculate the new PAL as the sum 
of

[[Page 237]]

the allowable emissions for each modified or new emissions unit, plus 
the sum of the baseline actual emissions of the significant and major 
emissions units (assuming application of BACT equivalent controls as 
determined in accordance with paragraph (w)(11)(i)(b) of this section), 
plus the sum of the baseline actual emissions of the small emissions 
units.
    (iii) The PAL permit shall be revised to reflect the increased PAL 
level pursuant to the public notice requirements of paragraph (w)(5) of 
this section.
    (12) Monitoring requirements for PALs--(i) General requirements. (a) 
Each PAL permit must contain enforceable requirements for the monitoring 
system that accurately determines plantwide emissions of the PAL 
pollutant in terms of mass per unit of time. Any monitoring system 
authorized for use in the PAL permit must be based on sound science and 
meet generally acceptable scientific procedures for data quality and 
manipulation. Additionally, the information generated by such system 
must meet minimum legal requirements for admissibility in a judicial 
proceeding to enforce the PAL permit.
    (b) The PAL monitoring system must employ one or more of the four 
general monitoring approaches meeting the minimum requirements set forth 
in paragraphs (w)(12)(ii) (a) through (d) of this section and must be 
approved by the reviewing authority.
    (c) Notwithstanding paragraph (w)(12)(i)(b) of this section, you may 
also employ an alternative monitoring approach that meets paragraph 
(w)(12)(i)(a) of this section if approved by the reviewing authority.
    (d) Failure to use a monitoring system that meets the requirements 
of this section renders the PAL invalid.
    (ii) Minimum performance requirements for approved monitoring 
approaches. The following are acceptable general monitoring approaches 
when conducted in accordance with the minimum requirements in paragraphs 
(w)(12)(iii) through (ix) of this section:
    (a) Mass balance calculations for activities using coatings or 
solvents;
    (b) CEMS;
    (c) CPMS or PEMS; and
    (d) Emission factors.
    (iii) Mass balance calculations. An owner or operator using mass 
balance calculations to monitor PAL pollutant emissions from activities 
using coating or solvents shall meet the following requirements:
    (a) Provide a demonstrated means of validating the published content 
of the PAL pollutant that is contained in or created by all materials 
used in or at the emissions unit;
    (b) Assume that the emissions unit emits all of the PAL pollutant 
that is contained in or created by any raw material or fuel used in or 
at the emissions unit, if it cannot otherwise be accounted for in the 
process; and
    (c) Where the vendor of a material or fuel, which is used in or at 
the emissions unit, publishes a range of pollutant content from such 
material, the owner or operator must use the highest value of the range 
to calculate the PAL pollutant emissions unless the reviewing authority 
determines there is site-specific data or a site-specific monitoring 
program to support another content within the range.
    (iv) CEMS. An owner or operator using CEMS to monitor PAL pollutant 
emissions shall meet the following requirements:
    (a) CEMS must comply with applicable Performance Specifications 
found in 40 CFR part 60, appendix B; and
    (b) CEMS must sample, analyze, and record data at least every 15 
minutes while the emissions unit is operating.
    (v) CPMS or PEMS. An owner or operator using CPMS or PEMS to monitor 
PAL pollutant emissions shall meet the following requirements:
    (a) The CPMS or the PEMS must be based on current site-specific data 
demonstrating a correlation between the monitored parameter(s) and the 
PAL pollutant emissions across the range of operation of the emissions 
unit; and
    (b) Each CPMS or PEMS must sample, analyze, and record data at least 
every 15 minutes, or at another less frequent interval approved by the 
reviewing authority, while the emissions unit is operating.
    (vi) Emission factors. An owner or operator using emission factors 
to

[[Page 238]]

monitor PAL pollutant emissions shall meet the following requirements:
    (a) All emission factors shall be adjusted, if appropriate, to 
account for the degree of uncertainty or limitations in the factors' 
development;
    (b) The emissions unit shall operate within the designated range of 
use for the emission factor, if applicable; and
    (c) If technically practicable, the owner or operator of a 
significant emissions unit that relies on an emission factor to 
calculate PAL pollutant emissions shall conduct validation testing to 
determine a site-specific emission factor within 6 months of PAL permit 
issuance, unless the reviewing authority determines that testing is not 
required.
    (vii) A source owner or operator must record and report maximum 
potential emissions without considering enforceable emission limitations 
or operational restrictions for an emissions unit during any period of 
time that there is no monitoring data, unless another method for 
determining emissions during such periods is specified in the PAL 
permit.
    (viii) Notwithstanding the requirements in paragraphs (w)(12)(iii) 
through (vii) of this section, where an owner or operator of an 
emissions unit cannot demonstrate a correlation between the monitored 
parameter(s) and the PAL pollutant emissions rate at all operating 
points of the emissions unit, the reviewing authority shall, at the time 
of permit issuance:
    (a) Establish default value(s) for determining compliance with the 
PAL based on the highest potential emissions reasonably estimated at 
such operating point(s); or
    (b) Determine that operation of the emissions unit during operating 
conditions when there is no correlation between monitored parameter(s) 
and the PAL pollutant emissions is a violation of the PAL.
    (ix) Re-validation. All data used to establish the PAL pollutant 
must be re-validated through performance testing or other scientifically 
valid means approved by the reviewing authority. Such testing must occur 
at least once every 5 years after issuance of the PAL.
    (13) Recordkeeping requirements.
    (i) The PAL permit shall require an owner or operator to retain a 
copy of all records necessary to determine compliance with any 
requirement of paragraph (w) of this section and of the PAL, including a 
determination of each emissions unit's 12-month rolling total emissions, 
for 5 years from the date of such record.
    (ii) The PAL permit shall require an owner or operator to retain a 
copy of the following records, for the duration of the PAL effective 
period plus 5 years:
    (a) A copy of the PAL permit application and any applications for 
revisions to the PAL; and
    (b) Each annual certification of compliance pursuant to title V and 
the data relied on in certifying the compliance.
    (14) Reporting and notification requirements. The owner or operator 
shall submit semi-annual monitoring reports and prompt deviation reports 
to the reviewing authority in accordance with the applicable title V 
operating permit program. The reports shall meet the requirements in 
paragraphs (w)(14)(i) through (iii) of this section.
    (i) Semi-annual report. The semi-annual report shall be submitted to 
the reviewing authority within 30 days of the end of each reporting 
period. This report shall contain the information required in paragraphs 
(w)(14)(i)(a) through (g) of this section.
    (a) The identification of owner and operator and the permit number.
    (b) Total annual emissions (tons/year) based on a 12-month rolling 
total for each month in the reporting period recorded pursuant to 
paragraph (w)(13)(i) of this section.
    (c) All data relied upon, including, but not limited to, any Quality 
Assurance or Quality Control data, in calculating the monthly and annual 
PAL pollutant emissions.
    (d) A list of any emissions units modified or added to the major 
stationary source during the preceding 6-month period.
    (e) The number, duration, and cause of any deviations or monitoring 
malfunctions (other than the time associated with zero and span 
calibration checks), and any corrective action taken.

[[Page 239]]

    (f) A notification of a shutdown of any monitoring system, whether 
the shutdown was permanent or temporary, the reason for the shutdown, 
the anticipated date that the monitoring system will be fully 
operational or replaced with another monitoring system, and whether the 
emissions unit monitored by the monitoring system continued to operate, 
and the calculation of the emissions of the pollutant or the number 
determined by method included in the permit, as provided by paragraph 
(w)(12)(vii) of this section.
    (g) A signed statement by the responsible official (as defined by 
the applicable title V operating permit program) certifying the truth, 
accuracy, and completeness of the information provided in the report.
    (ii) Deviation report. The major stationary source owner or operator 
shall promptly submit reports of any deviations or exceedance of the PAL 
requirements, including periods where no monitoring is available. A 
report submitted pursuant to Sec. 70.6(a)(3)(iii)(B) of this chapter 
shall satisfy this reporting requirement. The deviation reports shall be 
submitted within the time limits prescribed by the applicable program 
implementing Sec. 70.6(a)(3)(iii)(B) of this chapter. The reports shall 
contain the following information:
    (a) The identification of owner and operator and the permit number;
    (b) The PAL requirement that experienced the deviation or that was 
exceeded;
    (c) Emissions resulting from the deviation or the exceedance; and
    (d) A signed statement by the responsible official (as defined by 
the applicable title V operating permit program) certifying the truth, 
accuracy, and completeness of the information provided in the report.
    (iii) Re-validation results. The owner or operator shall submit to 
the reviewing authority the results of any re-validation test or method 
within three months after completion of such test or method.
    (15) Transition requirements. (i) No reviewing authority may issue a 
PAL that does not comply with the requirements in paragraphs (w)(1) 
through (15) of this section after the Administrator has approved 
regulations incorporating these requirements into a plan.
    (ii) The reviewing authority may supersede any PAL which was 
established prior to the date of approval of the plan by the 
Administrator with a PAL that complies with the requirements of 
paragraphs (w)(1) through (15) of this section.
    (x) If any provision of this section, or the application of such 
provision to any person or circumstance, is held invalid, the remainder 
of this section, or the application of such provision to persons or 
circumstances other than those as to which it is held invalid, shall not 
be affected thereby.

(Secs. 101(b)(1), 110, 160-169, 171-178, and 301(a), Clean Air Act, as 
amended (42 U.S.C. 7401(b)(1), 7410, 7470-7479, 7501-7508, and 7601(a)); 
sec. 129(a), Clean Air Act Amendments of 1977 (Pub. L. 95-95, 91 Stat. 
685 (Aug. 7, 1977)))

[43 FR 26382, June 19, 1978]

    Editorial Note: For Federal Register citations affecting 
Sec. 51.166, see the List of CFR Sections Affected, which appears in the 
Finding Aids section of the printed volume and on GPO Access.



               Subpart J--Ambient Air Quality Surveillance

    Authority: Secs. 110, 301(a), 313, 319, Clean Air Act (42 U.S.C. 
7410, 7601(a), 7613, 7619).



Sec. 51.190  Ambient air quality monitoring requirements.

    The requirements for monitoring ambient air quality for purposes of 
the plan are located in subpart C of part 58 of this chapter.

[44 FR 27569, May 10, 1979]



                     Subpart K--Source Survelliance

    Source: 51 FR 40673, Nov. 7, 1986, unless otherwise noted.



Sec. 51.210  General.

    Each plan must provide for monitoring the status of compliance with 
any rules and regulations that set forth any portion of the control 
strategy. Specifically, the plan must meet the requirements of this 
subpart.

[[Page 240]]



Sec. 51.211  Emission reports and recordkeeping.

    The plan must provide for legally enforceable procedures for 
requiring owners or operators of stationary sources to maintain records 
of and periodically report to the State--
    (a) Information on the nature and amount of emissions from the 
stationary sources; and
    (b) Other information as may be necessary to enable the State to 
determine whether the sources are in compliance with applicable portions 
of the control strategy.



Sec. 51.212  Testing, inspection, enforcement, and complaints.

    The plan must provide for--
    (a) Periodic testing and inspection of stationary sources; and
    (b) Establishment of a system for detecting violations of any rules 
and regulations through the enforcement of appropriate visible emission 
limitations and for investigating complaints.
    (c) Enforceable test methods for each emission limit specified in 
the plan. For the purpose of submitting compliance certifications or 
establishing whether or not a person has violated or is in violation of 
any standard in this part, the plan must not preclude the use, including 
the exclusive use, of any credible evidence or information, relevant to 
whether a source would have been in compliance with applicable 
requirements if the appropriate performance or compliance test or 
procedure had been performed. As an enforceable method, States may use:
    (1) Any of the appropriate methods in appendix M to this part, 
Recommended Test Methods for State Implementation Plans; or
    (2) An alternative method following review and approval of that 
method by the Administrator; or
    (3) Any appropriate method in appendix A to 40 CFR part 60.

[51 FR 40673, Nov. 7, 1986, as amended at 55 FR 14249, Apr. 17, 1990; 62 
FR 8328, Feb. 24, 1997]



Sec. 51.213  Transportation control measures.

    (a) The plan must contain procedures for obtaining and maintaining 
data on actual emissions reductions achieved as a result of implementing 
transportation control measures.
    (b) In the case of measures based on traffic flow changes or 
reductions in vehicle use, the data must include observed changes in 
vehicle miles traveled and average speeds.
    (c) The data must be maintained in such a way as to facilitate 
comparison of the planned and actual efficacy of the transportation 
control measures.

[61 FR 30163, June 14, 1996]



Sec. 51.214  Continuous emission monitoring.

    (a) The plan must contain legally enforceable procedures to--
    (1) Require stationary sources subject to emission standards as part 
of an applicable plan to install, calibrate, maintain, and operate 
equipment for continuously monitoring and recording emissions; and
    (2) Provide other information as specified in appendix P of this 
part.
    (b) The procedures must--
    (1) Identify the types of sources, by source category and capacity, 
that must install the equipment; and
    (2) Identify for each source category the pollutants which must be 
monitored.
    (c) The procedures must, as a minimum, require the types of sources 
set forth in appendix P of this part to meet the applicable requirements 
set forth therein.
    (d)(1) The procedures must contain provisions that require the owner 
or operator of each source subject to continuous emission monitoring and 
recording requirements to maintain a file of all pertinent information 
for at least two years following the date of collection of that 
information.
    (2) The information must include emission measurements, continuous 
monitoring system performance testing measurements, performance 
evaluations, calibration checks, and adjustments and maintenance 
performed on such monitoring systems and other reports and records 
required by appendix P of this part.
    (e) The procedures must require the source owner or operator to 
submit information relating to emissions and operation of the emission 
monitors to the

[[Page 241]]

State to the extent described in appendix P at least as frequently as 
described therein.
    (f)(1) The procedures must provide that sources subject to the 
requirements of paragraph (c) of this section must have installed all 
necessary equipment and shall have begun monitoring and recording within 
18 months after either--
    (i) The approval of a State plan requiring monitoring for that 
source; or
    (ii) Promulgation by the Agency of monitoring requirements for that 
source.
    (2) The State may grant reasonable extensions of this period to 
sources that--
    (i) Have made good faith efforts to purchases, install, and begin 
the monitoring and recording of emission data; and
    (ii) Have been unable to complete the installation within the 
period.



                       Subpart L--Legal Authority

    Source: 51 FR 40673, Nov. 7, 1986, unless otherwise noted.



Sec. 51.230  Requirements for all plans.

    Each plan must show that the State has legal authority to carry out 
the plan, including authority to:
    (a) Adopt emission standards and limitations and any other measures 
necessary for attainment and maintenance of national standards.
    (b) Enforce applicable laws, regulations, and standards, and seek 
injunctive relief.
    (c) Abate pollutant emissions on an emergency basis to prevent 
substantial endangerment to the health of persons, i.e., authority 
comparable to that available to the Administrator under section 305 of 
the Act.
    (d) Prevent construction, modification, or operation of a facility, 
building, structure, or installation, or combination thereof, which 
directly or indirectly results or may result in emissions of any air 
pollutant at any location which will prevent the attainment or 
maintenance of a national standard.
    (e) Obtain information necessary to determine whether air pollution 
sources are in compliance with applicable laws, regulations, and 
standards, including authority to require recordkeeping and to make 
inspections and conduct tests of air pollution sources.
    (f) Require owners or operators of stationary sources to install, 
maintain, and use emission monitoring devices and to make periodic 
reports to the State on the nature and amounts of emissions from such 
stationary sources; also authority for the State to make such data 
available to the public as reported and as correlated with any 
applicable emission standards or limitations.



Sec. 51.231  Identification of legal authority.

    (a) The provisions of law or regulation which the State determines 
provide the authorities required under this section must be specifically 
identified, and copies of such laws or regulations be submitted with the 
plan.
    (b) The plan must show that the legal authorities specified in this 
subpart are available to the State at the time of submission of the 
plan.
    (c) Legal authority adequate to fulfill the requirements of 
Sec. 51.230 (e) and (f) of this subpart may be delegated to the State 
under section 114 of the Act.



Sec. 51.232  Assignment of legal authority to local agencies.

    (a) A State government agency other than the State air pollution 
control agency may be assigned responsibility for carrying out a portion 
of a plan if the plan demonstrates to the Administrator's satisfaction 
that the State governmental agency has the legal authority necessary to 
carry out the portion of plan.
    (b) The State may authorize a local agency to carry out a plan, or 
portion thereof, within such local agency's jurisdiction if--
    (1) The plan demonstrates to the Administrator's satisfaction that 
the local agency has the legal authority necessary to implement the plan 
or portion of it; and
    (2) This authorization does not relieve the State of responsibility 
under the Act for carrying out such plan, or portion thereof.

[[Page 242]]



                Subpart M--Intergovernmental Consultation

    Authority: Secs. 110, 121, 174(a), 301(a), Clean Air Act, as amended 
(42 U.S.C. 7410, 7421, 7504, and 7601(a)).

    Source: 44 FR 35179, June 18, 1979, unless otherwise noted.

                           Agency Designation



Sec. 51.240  General plan requirements.

    Each State implementation plan must identify organizations, by 
official title, that will participate in developing, implementing, and 
enforcing the plan and the responsibilities of such organizations. The 
plan shall include any related agreements or memoranda of understanding 
among the organizations.



Sec. 51.241  Nonattainment areas for carbon monoxide and ozone.

    (a) For each AQCR or portion of an AQCR in which the national 
primary standard for carbon monoxide or ozone will not be attained by 
July 1, 1979, the Governor (or Governors for interstate areas) shall 
certify, after consultation with local officials, the organization 
responsible for developing the revised implementation plan or portions 
thereof for such AQCR.
    (b)-(f) [Reserved]

[44 FR 35179, June 18, 1979, as amended at 48 FR 29302, June 24, 1983; 
60 FR 33922, June 29, 1995; 61 FR 16060, Apr. 11, 1996]



Sec. 51.242  [Reserved]



                     Subpart N--Compliance Schedules

    Source: 51 FR 40673, Nov. 7, 1986, unless otherwise noted.



Sec. 51.260  Legally enforceable compliance schedules.

    (a) Each plan shall contain legally enforceable compliance schedules 
setting forth the dates by which all stationary and mobile sources or 
categories of such sources must be in compliance with any applicable 
requirement of the plan.
    (b) The compliance schedules must contain increments of progress 
required by Sec. 51.262 of this subpart.



Sec. 51.261  Final compliance schedules.

    (a) Unless EPA grants an extension under subpart R, compliance 
schedules designed to provide for attainment of a primary standard must-
-
    (1) Provide for compliance with the applicable plan requirements as 
soon as practicable; or
    (2) Provide for compliance no later than the date specified for 
attainment of the primary standard under;
    (b) Unless EPA grants an extension under subpart R, compliance 
schedules designed to provide for attainment of a secondary standard 
must--
    (1) Provide for compliance with the applicable plan requirements in 
a reasonable time; or
    (2) Provide for compliance no later than the date specified for the 
attainment of the secondary standard under Sec. 51.110(c).



Sec. 51.262  Extension beyond one year.

    (a) Any compliance schedule or revision of it extending over a 
period of more than one year from the date of its adoption by the State 
agency must provide for legally enforceable increments of progress 
toward compliance by each affected source or category of sources. The 
increments of progress must include--
    (1) Each increment of progress specified in Sec. 51.100(q); and
    (2) Additional increments of progress as may be necessary to permit 
close and effective supervision of progress toward timely compliance.
    (b) [Reserved]



           Subpart O--Miscellaneous Plan Content Requirements

    Authority: Secs. 110, 301(a), 313, 319, Clean Air Act (42 U.S.C. 
7410, 7601(a), 7613, 7619).



Sec. 51.280  Resources.

    Each plan must include a description of the resources available to 
the State and local agencies at the date of submission of the plan and 
of any additional resources needed to carry out

[[Page 243]]

the plan during the 5-year period following its submission. The 
description must include projections of the extent to which resources 
will be acquired at 1-, 3-, and 5-year intervals.

[51 FR 40674, Nov. 7, 1986]



Sec. 51.281  Copies of rules and regulations.

    Emission limitations and other measures necessary for attainment and 
maintenance of any national standard, including any measures necessary 
to implement the requirements of subpart L must be adopted as rules and 
regulations enforceable by the State agency. Copies of all such rules 
and regulations must be submitted with the plan. Submittal of a plan 
setting forth proposed rules and regulations will not satisfy the 
requirements of this section nor will it be considered a timely 
submittal.

[51 FR 40674, Nov. 7, 1986]



Sec. 51.285  Public notification.

    By March 1, 1980, the State shall submit a plan revision that 
contains provisions for:
    (a) Notifying the public on a regular basis of instances or areas in 
which any primary standard was exceeded during any portion of the 
preceeding calendar year,
    (b) Advising the public of the health hazards associated with such 
an exceedance of a primary standard, and
    (c) Increasing public awareness of:
    (1) Measures which can be taken to prevent a primary standard from 
being exceeded, and
    (2) Ways in which the public can participate in regulatory and other 
efforts to improve air quality.

[44 FR 27569, May 10, 1979]



                   Subpart P--Protection of Visibility

    Authority: Secs. 110, 114, 121, 160-169, 169A, and 301 of the Clean 
Air Act, (42 U.S.C. 7410, 7414, 7421, 7470-7479, and 7601).

    Source: 45 FR 80089, Dec. 2, 1980, unless otherwise noted.



Sec. 51.300  Purpose and applicability.

    (a) Purpose. The primary purposes of this subpart are to require 
States to develop programs to assure reasonable progress toward meeting 
the national goal of preventing any future, and remedying any existing, 
impairment of visibility in mandatory Class I Federal areas which 
impairment results from manmade air pollution; and to establish 
necessary additional procedures for new source permit applicants, States 
and Federal Land Managers to use in conducting the visibility impact 
analysis required for new sources under Sec. 51.166. This subpart sets 
forth requirements addressing visibility impairment in its two principal 
forms: ``reasonably attributable'' impairment (i.e., impairment 
attributable to a single source/small group of sources) and regional 
haze (i.e., widespread haze from a multitude of sources which impairs 
visibility in every direction over a large area).
    (b) Applicability. (1) General Applicability. The provisions of this 
subpart pertaining to implementation plan requirements for assuring 
reasonable progress in preventing any future and remedying any existing 
visibility impairment are applicable to:
    (i) Each State which has a mandatory Class I Federal area identified 
in part 81, subpart D, of this title, and (ii) each State in which there 
is any source the emissions from which may reasonably be anticipated to 
cause or contribute to any impairment of visibility in any such area.
    (2) The provisions of this subpart pertaining to implementation 
plans to address reasonably attributable visibility impairment are 
applicable to the following States:

Alabama, Alaska, Arizona, Arkansas, California, Colorado, Florida, 
    Georgia, Hawaii, Idaho, Kentucky, Louisiana, Maine, Michigan, 
    Minnesota, Missouri, Montana, Nevada, New Hampshire, New Jersey, New 
    Mexico, North Carolina, North Dakota, Oklahoma, Oregon, South 
    Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, 
    Virgin Islands, Washington, West Virginia, Wyoming.


[[Page 244]]


    (3) The provisions of this subpart pertaining to implementation 
plans to address regional haze visibility impairment are applicable to 
all States as defined in section 302(d) of the Clean Air Act (CAA) 
except Guam, Puerto Rico, American Samoa, and the Northern Mariana 
Islands.

[45 FR 80089, Dec. 2, 1980, as amended at 64 FR 35763, July 1, 1999]



Sec. 51.301  Definitions.

    For purposes of this subpart:
    Adverse impact on visibility means, for purposes of section 307, 
visibility impairment which interferes with the management, protection, 
preservation, or enjoyment of the visitor's visual experience of the 
Federal Class I area. This determination must be made on a case-by-case 
basis taking into account the geographic extent, intensity, duration, 
frequency and time of visibility impairments, and how these factors 
correlate with (1) times of visitor use of the Federal Class I area, and 
(2) the frequency and timing of natural conditions that reduce 
visibility. This term does not include effects on integral vistas.
    Agency means the U.S. Environmental Protection Agency.
    BART-eligible source means an existing stationary facility as 
defined in this section.
    Best Available Retrofit Technology (BART) means an emission 
limitation based on the degree of reduction achievable through the 
application of the best system of continuous emission reduction for each 
pollutant which is emitted by an existing stationary facility. The 
emission limitation must be established, on a case-by-case basis, taking 
into consideration the technology available, the costs of compliance, 
the energy and nonair quality environmental impacts of compliance, any 
pollution control equipment in use or in existence at the source, the 
remaining useful life of the source, and the degree of improvement in 
visibility which may reasonably be anticipated to result from the use of 
such technology.
    Building, structure, or facility means all of the pollutant-emitting 
activities which belong to the same industrial grouping, are located on 
one or more contiguous or adjacent properties, and are under the control 
of the same person (or persons under common control). Pollutant-emitting 
activities must be considered as part of the same industrial grouping if 
they belong to the same Major Group (i.e., which have the same two-digit 
code) as described in the Standard Industrial Classification Manual, 
1972 as amended by the 1977 Supplement (U.S. Government Printing Office 
stock numbers 4101-0066 and 003-005-00176-0 respectively).
    Deciview means a measurement of visibility impairment. A deciview is 
a haze index derived from calculated light extinction, such that uniform 
changes in haziness correspond to uniform incremental changes in 
perception across the entire range of conditions, from pristine to 
highly impaired. The deciview haze index is calculated based on the 
following equation (for the purposes of calculating deciview, the 
atmospheric light extinction coefficient must be calculated from aerosol 
measurements):

Deciview haze index=10 lne (bext/10 
    Mm-1).
Where bext=the atmospheric light extinction coefficient, 
    expressed in inverse megameters (Mm-1).

    Existing stationary facility means any of the following stationary 
sources of air pollutants, including any reconstructed source, which was 
not in operation prior to August 7, 1962, and was in existence on August 
7, 1977, and has the potential to emit 250 tons per year or more of any 
air pollutant. In determining potential to emit, fugitive emissions, to 
the extent quantifiable, must be counted.
    Fossil-fuel fired steam electric plants of more than 250 million 
British thermal units per hour heat input,
    Coal cleaning plants (thermal dryers),
    Kraft pulp mills,
    Portland cement plants,
    Primary zinc smelters,
    Iron and steel mill plants,
    Primary aluminum ore reduction plants,
    Primary copper smelters,
    Municipal incinerators capable of charging more than 250 tons of 
refuse per day,

[[Page 245]]

    Hydrofluoric, sulfuric, and nitric acid plants,
    Petroleum refineries,
    Lime plants,
    Phosphate rock processing plants,
    Coke oven batteries,
    Sulfur recovery plants,
    Carbon black plants (furnace process),
    Primary lead smelters,
    Fuel conversion plants,
    Sintering plants,
    Secondary metal production facilities,
    Chemical process plants,
    Fossil-fuel boilers of more than 250 million British thermal units 
per hour heat input,
    Petroleum storage and transfer facilities with a capacity exceeding 
300,000 barrels,
    Taconite ore processing facilities,
    Glass fiber processing plants, and
    Charcoal production facilities.
    Federal Class I area means any Federal land that is classified or 
reclassified Class I.
    Federal Land Manager means the Secretary of the department with 
authority over the Federal Class I area (or the Secretary's designee) 
or, with respect to Roosevelt-Campobello International Park, the 
Chairman of the Roosevelt-Campobello International Park Commission.
    Federally enforceable means all limitations and conditions which are 
enforceable by the Administrator under the Clean Air Act including those 
requirements developed pursuant to parts 60 and 61 of this title, 
requirements within any applicable State Implementation Plan, and any 
permit requirements established pursuant to Sec. 52.21 of this chapter 
or under regulations approved pursuant to part 51, 52, or 60 of this 
title.
    Fixed capital cost means the capital needed to provide all of the 
depreciable components.
    Fugitive Emissions means those emissions which could not reasonably 
pass through a stack, chimney, vent, or other functionally equivalent 
opening.
    Geographic enhancement for the purpose of Sec. 51.308 means a 
method, procedure, or process to allow a broad regional strategy, such 
as an emissions trading program designed to achieve greater reasonable 
progress than BART for regional haze, to accommodate BART for reasonably 
attributable impairment.
    Implementation plan means, for the purposes of this part, any State 
Implementation Plan, Federal Implementation Plan, or Tribal 
Implementation Plan.
    Indian tribe or tribe means any Indian tribe, band, nation, or other 
organized group or community, including any Alaska Native village, which 
is federally recognized as eligible for the special programs and 
services provided by the United States to Indians because of their 
status as Indians.
    In existence means that the owner or operator has obtained all 
necessary preconstruction approvals or permits required by Federal, 
State, or local air pollution emissions and air quality laws or 
regulations and either has (1) begun, or caused to begin, a continuous 
program of physical on-site construction of the facility or (2) entered 
into binding agreements or contractual obligations, which cannot be 
cancelled or modified without substantial loss to the owner or operator, 
to undertake a program of construction of the facility to be completed 
in a reasonable time.
    In operation means engaged in activity related to the primary design 
function of the source.
    Installation means an identifiable piece of process equipment.
    Integral vista means a view perceived from within the mandatory 
Class I Federal area of a specific landmark or panorama located outside 
the boundary of the mandatory Class I Federal area.
    Least impaired days means the average visibility impairment 
(measured in deciviews) for the twenty percent of monitored days in a 
calendar year with the lowest amount of visibility impairment.
    Major stationary source and major modification mean major stationary 
source and major modification, respectively, as defined in Sec. 51.166.
    Mandatory Class I Federal Area means any area identified in part 81, 
subpart D of this title.
    Most impaired days means the average visibility impairment (measured 
in deciviews) for the twenty percent of monitored days in a calendar 
year with

[[Page 246]]

the highest amount of visibility impairment.
    Natural conditions includes naturally occurring phenomena that 
reduce visibility as measured in terms of light extinction, visual 
range, contrast, or coloration.
    Potential to emit means the maximum capacity of a stationary source 
to emit a pollutant under its physical and operational design. Any 
physical or operational limitation on the capacity of the source to emit 
a pollutant including air pollution control equipment and restrictions 
on hours of operation or on the type or amount of material combusted, 
stored, or processed, shall be treated as part of its design if the 
limitation or the effect it would have on emissions is federally 
enforceable. Secondary emissions do not count in determining the 
potential to emit of a stationary source.
    Reasonably attributable means attributable by visual observation or 
any other technique the State deems appropriate.
    Reasonably attributable visibility impairment means visibility 
impairment that is caused by the emission of air pollutants from one, or 
a small number of sources.
    Reconstruction will be presumed to have taken place where the fixed 
capital cost of the new component exceeds 50 percent of the fixed 
capital cost of a comparable entirely new source. Any final decision as 
to whether reconstruction has occurred must be made in accordance with 
the provisions of Sec. 60.15 (f) (1) through (3) of this title.
    Regional haze means visibility impairment that is caused by the 
emission of air pollutants from numerous sources located over a wide 
geographic area. Such sources include, but are not limited to, major and 
minor stationary sources, mobile sources, and area sources.
    Secondary emissions means emissions which occur as a result of the 
construction or operation of an existing stationary facility but do not 
come from the existing stationary facility. Secondary emissions may 
include, but are not limited to, emissions from ships or trains coming 
to or from the existing stationary facility.
    Significant impairment means, for purposes of Sec. 51.303, 
visibility impairment which, in the judgment of the Administrator, 
interferes with the management, protection, preservation, or enjoyment 
of the visitor's visual experience of the mandatory Class I Federal 
area. This determination must be made on a case-by-case basis taking 
into account the geographic extent, intensity, duration, frequency and 
time of the visibility impairment, and how these factors correlate with 
(1) times of visitor use of the mandatory Class I Federal area, and (2) 
the frequency and timing of natural conditions that reduce visibility.
    State means ``State'' as defined in section 302(d) of the CAA.
    Stationary Source means any building, structure, facility, or 
installation which emits or may emit any air pollutant.
    Visibility impairment means any humanly perceptible change in 
visibility (light extinction, visual range, contrast, coloration) from 
that which would have existed under natural conditions.
    Visibility in any mandatory Class I Federal area includes any 
integral vista associated with that area.

[45 FR 80089, Dec. 2, 1980, as amended at 64 FR 35763, 35774, July 1, 
1999]



Sec. 51.302  Implementation control strategies for reasonably attributable 
visibility impairment.

    (a) Plan Revision Procedures. (1) Each State identified in 
Sec. 51.300(b)(2) must have submitted, not later than September 2, 1981, 
an implementation plan meeting the requirements of this subpart 
pertaining to reasonably attributable visibility impairment.
    (2)(i) The State, prior to adoption of any implementation plan to 
address reasonably attributable visibility impairment required by this 
subpart, must conduct one or more public hearings on such plan in 
accordance with Sec. 51.102.
    (ii) In addition to the requirements in Sec. 51.102, the State must 
provide written notification of such hearings to each affected Federal 
Land Manager, and other affected States, and must state where the public 
can inspect a summary prepared by the Federal Land

[[Page 247]]

Managers of their conclusions and recommendations, if any, on the 
proposed plan revision.
    (3) Submission of plans as required by this subpart must be 
conducted in accordance with the procedures in Sec. 51.103.
    (b) State and Federal Land Manager Coordination. (1) The State must 
identify to the Federal Land Managers, in writing and within 30 days of 
the date of promulgation of these regulations, the title of the official 
to which the Federal Land Manager of any mandatory Class I Federal area 
can submit a recommendation on the implementation of this subpart 
including, but not limited to:
    (i) A list of integral vistas that are to be listed by the State for 
the purpose of implementing section 304,
    (ii) Identification of impairment of visibility in any mandatory 
Class I Federal area(s), and
    (iii) Identification of elements for inclusion in the visibility 
monitoring strategy required by section 305.
    (2) The State must provide opportunity for consultation, in person 
and at least 60 days prior to holding any public hearing on the plan, 
with the Federal Land Manager on the proposed SIP revision required by 
this subpart. This consultation must include the opportunity for the 
affected Federal Land Managers to discuss their:
    (i) Assessment of impairment of visibility in any mandatory Class I 
Federal area, and
    (ii) Recommendations on the development of the long-term strategy.
    (3) The plan must provide procedures for continuing consultation 
between the State and Federal Land Manager on the implementation of the 
visibility protection program required by this subpart.
    (c) General plan requirements for reasonably attributable visibility 
impairment. (1) The affected Federal Land Manager may certify to the 
State, at any time, that there exists reasonably attributable impairment 
of visibility in any mandatory Class I Federal area.
    (2) The plan must contain the following to address reasonably 
attributable impairment:
    (i) A long-term (10-15 years) strategy, as specified in Sec. 51.305 
and Sec. 51.306, including such emission limitations, schedules of 
compliance, and such other measures including schedules for the 
implementation of the elements of the long-term strategy as may be 
necessary to make reasonable progress toward the national goal specified 
in Sec. 51.300(a).
    (ii) An assessment of visibility impairment and a discussion of how 
each element of the plan relates to the preventing of future or 
remedying of existing impairment of visibility in any mandatory Class I 
Federal area within the State.
    (iii) Emission limitations representing BART and schedules for 
compliance with BART for each existing stationary facility identified 
according to paragraph (c)(4) of this section.
    (3) The plan must require each source to maintain control equipment 
required by this subpart and establish procedures to ensure such control 
equipment is properly operated and maintained.
    (4) For any existing reasonably attributable visibility impairment 
the Federal Land Manager certifies to the State under paragraph (c)(1) 
of this section, at least 6 months prior to plan submission or revision:
    (i) The State must identify and analyze for BART each existing 
stationary facility which may reasonably be anticipated to cause or 
contribute to impairment of visibility in any mandatory Class I Federal 
area where the impairment in the mandatory Class I Federal area is 
reasonably attributable to that existing stationary facility. The State 
need not consider any integral vista the Federal Land Manager did not 
identify pursuant to Sec. 51.304(b) at least 6 months before plan 
submission.
    (ii) If the State determines that technologicial or economic 
limitations on the applicability of measurement methodology to a 
particular existing stationary facility would make the imposition of an 
emission standard infeasible it may instead prescribe a design, 
equipment, work practice, or other operational standard, or combination 
thereof, to require the application of BART. Such standard, to the 
degree possible, is to set forth the emission reduction to be achieved 
by implementation of such design, equipment, work

[[Page 248]]

practice or operation, and must provide for compliance by means which 
achieve equivalent results.
    (iii) BART must be determined for fossil-fuel fired generating 
plants having a total generating capacity in excess of 750 megawatts 
pursuant to ``Guidelines for Determining Best Available Retrofit 
Technology for Coal-fired Power Plants and Other Existing Stationary 
Facilities'' (1980), which is incorporated by reference, exclusive of 
appendix E, which was published in the Federal Register on February 6, 
1980 (45 FR 8210). It is EPA publication No. 450/3-80-009b and is for 
sale from the U.S. Department of Commerce, National Technical 
Information Service, 5285 Port Royal Road, Springfield, Virginia 22161. 
It is also available for inspection at the Office of the Federal 
Register Information Center, 800 North Capitol NW., suite 700, 
Washington, DC.
    (iv) The plan must require that each existing stationary facility 
required to install and operate BART do so as expeditiously as 
practicable but in no case later than five years after plan approval.
    (v) The plan must provide for a BART analysis of any existing 
stationary facility that might cause or contribute to impairment of 
visibility in any mandatory Class I Federal area identified under this 
paragraph (c)(4) at such times, as determined by the Administrator, as 
new technology for control of the pollutant becomes reasonably available 
if:
    (A) The pollutant is emitted by that existing stationary facility,
    (B) Controls representing BART for the pollutant have not previously 
been required under this subpart, and
    (C) The impairment of visibility in any mandatory Class I Federal 
area is reasonably attributable to the emissions of that pollutant.

[45 FR 80089, Dec. 2, 1980, as amended at 57 FR 40042, Sept. 1, 1992; 64 
FR 35764, 35774, July 1, 1999]



Sec. 51.303  Exemptions from control.

    (a)(1) Any existing stationary facility subject to the requirement 
under Sec. 51.302 to install, operate, and maintain BART may apply to 
the Administrator for an exemption from that requirement.
    (2) An application under this section must include all available 
documentation relevant to the impact of the source's emissions on 
visibility in any mandatory Class I Federal area and a demonstration by 
the existing stationary facility that it does not or will not, by itself 
or in combination with other sources, emit any air pollutant which may 
be reasonably anticipated to cause or contribute to a significant 
impairment of visibility in any mandatory Class I Federal area.
    (b) Any fossil-fuel fired power plant with a total generating 
capacity of 750 megawatts or more may receive an exemption from BART 
only if the owner or operator of such power plant demonstrates to the 
satisfaction of the Administrator that such power plant is located at 
such a distance from all mandatory Class I Federal areas that such power 
plant does not or will not, by itself or in combination with other 
sources, emit any air pollutant which may reasonably be anticipated to 
cause or contribute to significant impairment of visibility in any such 
mandatory Class I Federal area.
    (c) Application under this Sec. 51.303 must be accompanied by a 
written concurrence from the State with regulatory authority over the 
source.
    (d) The existing stationary facility must give prior written notice 
to all affected Federal Land Managers of any application for exemption 
under this Sec. 51.303.
    (e) The Federal Land Manager may provide an initial recommendation 
or comment on the disposition of such application. Such recommendation, 
where provided, must be part of the exemption application. This 
recommendation is not to be construed as the concurrence required under 
paragraph (h) of this section.
    (f) The Administrator, within 90 days of receipt of an application 
for exemption from control, will provide notice of receipt of an 
exemption application and notice of opportunity for public hearing on 
the application.
    (g) After notice and opportunity for public hearing, the 
Administrator may

[[Page 249]]

grant or deny the exemption. For purposes of judicial review, final EPA 
action on an application for an exemption under this Sec. 51.303 will 
not occur until EPA approves or disapproves the State Implementation 
Plan revision.
    (h) An exemption granted by the Administrator under this Sec. 51.303 
will be effective only upon concurrence by all affected Federal Land 
Managers with the Administrator's determination.

[45 FR 80089, Dec. 2, 1980, as amended by 64 FR 35774, July 1, 1999]



Sec. 51.304  Identification of integral vistas.

    (a) On or before December 31, 1985 the Federal Land Manager may 
identify any integral vista. The integral vista must be identified 
according to criteria the Federal Land Manager develops. These criteria 
must include, but are not limited to, whether the integral vista is 
important to the visitor's visual experience of the mandatory Class I 
Federal area. Adoption of criteria must be preceded by reasonable notice 
and opportunity for public comment on the proposed criteria.
    (b) The Federal Land Manager must notify the State of any integral 
vistas identified under paragraph (a) of this section, and the reasons 
therefor.
    (c) The State must list in its implementation plan any integral 
vista the Federal Land Manager identifies at least six months prior to 
plan submission, and must list in its implementation plan at its 
earliest opportunity, and in no case later than at the time of the 
periodic review of the SIP required by Sec. 51.306(c), any integral 
vista the Federal Land Manager identifies after that time.
    (d) The State need not in its implementation plan list any integral 
vista the indentification of which was not made in accordance with the 
criteria in paragraph (a) of this section. In making this finding, the 
State must carefully consider the expertise of the Federal Land Manager 
in making the judgments called for by the criteria for identification. 
Where the State and the Federal Land Manager disagree on the 
identification of any integral vista, the State must give the Federal 
Land Manager an opportunity to consult with the Governor of the State.

[45 FR 80089, Dec. 2, 1980, as amended by 64 FR 35774, July 1, 1999]



Sec. 51.305  Monitoring for reasonably attributable visibility impairment.

    (a) For the purposes of addressing reasonably attributable 
visibility impairment, each State containing a mandatory Class I Federal 
area must include in the plan a strategy for evaluating reasonably 
attributable visibility impairment in any mandatory Class I Federal area 
by visual observation or other appropriate monitoring techniques. Such 
strategy must take into account current and anticipated visibility 
monitoring research, the availability of appropriate monitoring 
techniques, and such guidance as is provided by the Agency.
    (b) The plan must provide for the consideration of available 
visibility data and must provide a mechanism for its use in decisions 
required by this subpart.

[45 FR 80089, Dec. 2, 1980, as amended at 64 FR 35764, July 1, 1999]



Sec. 51.306  Long-term strategy requirements for reasonably attributable 
visibility impairment.

    (a)(1) For the purposes of addressing reasonably attributable 
visibility impairment, each plan must include a long-term (10-15 years) 
strategy for making reasonable progress toward the national goal 
specified in Sec. 51.300(a). This strategy must cover any existing 
impairment the Federal Land Manager certifies to the State at least 6 
months prior to plan submission, and any integral vista of which the 
Federal Land Manager notifies the State at least 6 months prior to plan 
submission.
    (2) A long-term strategy must be developed for each mandatory Class 
I Federal area located within the State and each mandatory Class I 
Federal area located outside the State which may be affected by sources 
within the State. This does not preclude the development of a single 
comprehensive plan for all such areas.
    (3) The plan must set forth with reasonable specificity why the 
long-term strategy is adequate for making reasonable progress toward the 
national

[[Page 250]]

visibility goal, including remedying existing and preventing future 
impairment.
    (b) The State must coordinate its long-term strategy for an area 
with existing plans and goals, including those provided by the affected 
Federal Land Managers, that may affect impairment of visibility in any 
mandatory Class I Federal area.
    (c) The plan must provide for periodic review and revision, as 
appropriate, of the long-term strategy for addressing reasonably 
attributable visibility impairment. The plan must provide for such 
periodic review and revision not less frequently than every 3 years 
until the date of submission of the State's first plan addressing 
regional haze visibility impairment in accordance with Sec. 51.308(b) 
and (c). On or before this date, the State must revise its plan to 
provide for review and revision of a coordinated long-term strategy for 
addressing reasonably attributable and regional haze visibility 
impairment, and the State must submit the first such coordinated long-
term strategy. Future coordinated long-term strategies must be submitted 
consistent with the schedule for periodic progress reports set forth in 
Sec. 51.308(g). Until the State revises its plan to meet this 
requirement, the State must continue to comply with existing 
requirements for plan review and revision, and with all emission 
management requirements in the plan to address reasonably attributable 
impairment. This requirement does not affect any preexisting deadlines 
for State submittal of a long-term strategy review (or element thereof) 
between August 30, 1999, and the date required for submission of the 
State's first regional haze plan. In addition, the plan must provide for 
review of the long-term strategy as it applies to reasonably 
attributable impairment, and revision as appropriate, within 3 years of 
State receipt of any certification of reasonably attributable impairment 
from a Federal Land Manager. The review process must include 
consultation with the appropriate Federal Land Managers, and the State 
must provide a report to the public and the Administrator on progress 
toward the national goal. This report must include an assessment of:
    (1) The progress achieved in remedying existing impairment of 
visibility in any mandatory Class I Federal area;
    (2) The ability of the long-term strategy to prevent future 
impairment of visibility in any mandatory Class I Federal area;
    (3) Any change in visibility since the last such report, or, in the 
case of the first report, since plan approval;
    (4) Additional measures, including the need for SIP revisions, that 
may be necessary to assure reasonable progress toward the national 
visibility goal;
    (5) The progress achieved in implementing BART and meeting other 
schedules set forth in the long-term strategy;
    (6) The impact of any exemption granted under Sec. 51.303;
    (7) The need for BART to remedy existing visibility impairment of 
any integral vista listed in the plan since the last such report, or, in 
the case of the first report, since plan approval.
    (d) The long-term strategy must provide for review of the impacts 
from any new major stationary source or major modifications on 
visibility in any mandatory Class I Federal area. This review of major 
stationary sources or major modifications must be in accordance with 
Sec. 51.307, Sec. 51.166, Sec. 51.160, and any other binding guidance 
provided by the Agency insofar as these provisions pertain to protection 
of visibility in any mandatory Class I Federal areas.
    (e) The State must consider, at a minimum, the following factors 
during the development of its long-term strategy:
    (1) Emission reductions due to ongoing air pollution control 
programs,
    (2) Additional emission limitations and schedules for compliance,
    (3) Measures to mitigate the impacts of construction activities,
    (4) Source retirement and replacement schedules,
    (5) Smoke management techniques for agricultural and forestry 
management purposes including such plans as currently exist within the 
State for these purposes, and
    (6) Enforceability of emission limitations and control measures.

[[Page 251]]

    (f) The plan must discuss the reasons why the above and other 
reasonable measures considered in the development of the long-term 
strategy were or were not adopted as part of the long-term strategy.
    (g) The State, in developing the long-term strategy, must take into 
account the effect of new sources, and the costs of compliance, the time 
necessary for compliance, the energy and nonair quality environmental 
impacts of compliance, and the remaining useful life of any affected 
existing source and equipment therein.

[45 FR 80089, Dec. 2, 1980, as amended at 64 FR 35764, 35774, July 1, 
1999]



Sec. 51.307  New source review.

    (a) For purposes of new source review of any new major stationary 
source or major modification that would be constructed in an area that 
is designated attainment or unclassified under section 107(d)(1)(D) or 
(E) of the CAA, the State plan must, in any review under Sec. 51.166 
with respect to visibility protection and analyses, provide for:
    (1) Written notification of all affected Federal Land Managers of 
any proposed new major stationary source or major modification that may 
affect visibility in any Federal Class I area. Such notification must be 
made in writing and include a copy of all information relevant to the 
permit application within 30 days of receipt of and at least 60 days 
prior to public hearing by the State on the application for permit to 
construct. Such notification must include an analysis of the anticipated 
impacts on visibility in any Federal Class I area,
    (2) Where the State requires or receives advance notification (e.g. 
early consultation with the source prior to submission of the 
application or notification of intent to monitor under Sec. 51.166) of a 
permit application of a source that may affect visibility the State must 
notify all affected Federal Land Managers within 30 days of such advance 
notification, and
    (3) Consideration of any analysis performed by the Federal Land 
Manager, provided within 30 days of the notification and analysis 
required by paragraph (a)(1) of this section, that such proposed new 
major stationary source or major modification may have an adverse impact 
on visibility in any Federal Class I area. Where the State finds that 
such an analysis does not demonstrate to the satisfaction of the State 
that an adverse impact will result in the Federal Class I area, the 
State must, in the notice of public hearing, either explain its decision 
or give notice as to where the explanation can be obtained.
    (b) The plan shall also provide for the review of any new major 
stationary source or major modification:
    (1) That may have an impact on any integral vista of a mandatory 
Class I Federal area, if it is identified in accordance with Sec. 51.304 
by the Federal Land Manager at least 12 months before submission of a 
complete permit application, except where the Federal Land Manager has 
provided notice and opportunity for public comment on the integral vista 
in which case the review must include impacts on any integral vista 
identified at least 6 months prior to submission of a complete permit 
application, unless the State determines under Sec. 51.304(d) that the 
identification was not in accordance with the identification criteria, 
or
    (2) That proposes to locate in an area classified as nonattainment 
under section 107(d)(1)(A), (B), or (C) of the Clean Air Act that may 
have an impact on visibility in any mandatory Class I Federal area.
    (c) Review of any major stationary source or major modification 
under paragraph (b) of this section, shall be conducted in accordance 
with paragraph (a) of this section, and Sec. 51.166(o), (p)(1) through 
(2), and (q). In conducting such reviews the State must ensure that the 
source's emissions will be consistent with making reasonable progress 
toward the national visibility goal referred to in Sec. 51.300(a). The 
State may take into account the costs of compliance, the time necessary 
for compliance, the energy and nonair quality environmental impacts of 
compliance, and the useful life of the source.
    (d) The State may require monitoring of visibility in any Federal 
Class I area near the proposed new stationary source or major 
modification for such purposes and by such means as

[[Page 252]]

the State deems necessary and appropriate.

[45 FR 80089, Dec. 2, 1980, as amended at 64 FR 35765, 35774, July 1, 
1999]



Sec. 51.308  Regional haze program requirements.

    (a) What is the purpose of this section? This section establishes 
requirements for implementation plans, plan revisions, and periodic 
progress reviews to address regional haze.
    (b) When are the first implementation plans due under the regional 
haze program? Except as provided in paragraph (c) of this section and 
Sec. 51.309(c), each State identified in Sec. 51.300(b)(3) must submit 
an implementation plan for regional haze meeting the requirements of 
paragraphs (d) and (e) of this section by the following dates:
    (1) For any area designated as attainment or unclassifiable for the 
national ambient air quality standard (NAAQS) for fine particulate 
matter (PM2.5), the State must submit a regional haze 
implementation plan to EPA within 12 months after the date of 
designation.
    (2) For any area designated as nonattainment for the 
PM2.5 NAAQS, the State must submit a regional haze 
implementation plan to EPA at the same time that the State's plan for 
implementation of the PM2.5 NAAQS must be submitted under 
section 172 of the CAA, that is, within 3 years after the area is 
designated as nonattainment, but not later than December 31, 2008.
    (c) Options for regional planning. If at the time the SIP for 
regional haze would otherwise be due, a State is working with other 
States to develop a coordinated approach to regional haze by 
participating in a regional planning process, the State may choose to 
defer addressing the core requirements for regional haze in paragraph 
(d) of this section and the requirements for BART in paragraph (e) of 
this section. If a State opts to do this, it must meet the following 
requirements:
    (1) The State must submit an implementation plan by the earliest 
date by which an implementation plan would be due for any area of the 
State under paragraph (b) of this section. This implementation plan must 
contain the following:
    (i) A demonstration of ongoing participation in a regional planning 
process to address regional haze, and an agreement by the State to 
continue participating with one or more other States in such a process 
for the development of this and future implementation plan revisions;
    (ii) A showing, based on available inventory, monitoring, or 
modeling information, that emissions from within the State contribute to 
visibility impairment in a mandatory Class I Federal Area outside the 
State, or that emissions from another State contribute to visibility 
impairment in any mandatory Class I Federal area within the State.
    (iii) A description of the regional planning process, including a 
list of the States which have agreed to work together to address 
regional haze in a region (i.e., the regional planning group), the 
goals, objectives, management, and decisionmaking structure of the 
regional planning group, deadlines for completing significant technical 
analyses and developing emission management strategies, and a schedule 
for State review and adoption of regulations implementing the 
recommendations of the regional group;
    (iv) A commitment by the State to submit an implementation plan 
revision addressing the requirements in paragraphs (d) and (e) of this 
section by the date specified in paragraph (c)(2) of this section. In 
addition, the State must commit to develop its plan revision in 
coordination with the other States participating in the regional 
planning process, and to fully address the recommendations of the 
regional planning group.
    (v) A list of all BART-eligible sources within the State.
    (2) The State must submit an implementation plan revision addressing 
the requirements in paragraphs (d) and (e) of this section by the latest 
date an area within the planning region would be required to submit an 
implementation plan under paragraph (b) of this section, but in any 
event, no later than December 31, 2008.
    (d) What are the core requirements for the implementation plan for 
regional haze? The State must address regional haze in each mandatory 
Class I Federal

[[Page 253]]

area located within the State and in each mandatory Class I Federal area 
located outside the State which may be affected by emissions from within 
the State. To meet the core requirements for regional haze for these 
areas, the State must submit an implementation plan containing the 
following plan elements and supporting documentation for all required 
analyses:
    (1) Reasonable progress goals. For each mandatory Class I Federal 
area located within the State, the State must establish goals (expressed 
in deciviews) that provide for reasonable progress towards achieving 
natural visibility conditions. The reasonable progress goals must 
provide for an improvement in visibility for the most impaired days over 
the period of the implementation plan and ensure no degradation in 
visibility for the least impaired days over the same period.
    (i) In establishing a reasonable progress goal for any mandatory 
Class I Federal area within the State, the State must:
    (A) Consider the costs of compliance, the time necessary for 
compliance, the energy and non-air quality environmental impacts of 
compliance, and the remaining useful life of any potentially affected 
sources, and include a demonstration showing how these factors were 
taken into consideration in selecting the goal.
    (B) Analyze and determine the rate of progress needed to attain 
natural visibility conditions by the year 2064. To calculate this rate 
of progress, the State must compare baseline visibility conditions to 
natural visibility conditions in the mandatory Federal Class I area and 
determine the uniform rate of visibility improvement (measured in 
deciviews) that would need to be maintained during each implementation 
period in order to attain natural visibility conditions by 2064. In 
establishing the reasonable progress goal, the State must consider the 
uniform rate of improvement in visibility and the emission reduction 
measures needed to achieve it for the period covered by the 
implementation plan.
    (ii) For the period of the implementation plan, if the State 
establishes a reasonable progress goal that provides for a slower rate 
of improvement in visibility than the rate that would be needed to 
attain natural conditions by 2064, the State must demonstrate, based on 
the factors in paragraph (d)(1)(i)(A) of this section, that the rate of 
progress for the implementation plan to attain natural conditions by 
2064 is not reasonable; and that the progress goal adopted by the State 
is reasonable. The State must provide to the public for review as part 
of its implementation plan an assessment of the number of years it would 
take to attain natural conditions if visibility improvement continues at 
the rate of progress selected by the State as reasonable.
    (iii) In determining whether the State's goal for visibility 
improvement provides for reasonable progress towards natural visibility 
conditions, the Administrator will evaluate the demonstrations developed 
by the State pursuant to paragraphs (d)(1)(i) and (d)(1)(ii) of this 
section.
    (iv) In developing each reasonable progress goal, the State must 
consult with those States which may reasonably be anticipated to cause 
or contribute to visibility impairment in the mandatory Class I Federal 
area. In any situation in which the State cannot agree with another such 
State or group of States that a goal provides for reasonable progress, 
the State must describe in its submittal the actions taken to resolve 
the disagreement. In reviewing the State's implementation plan 
submittal, the Administrator will take this information into account in 
determining whether the State's goal for visibility improvement provides 
for reasonable progress towards natural visibility conditions.
    (v) The reasonable progress goals established by the State are not 
directly enforceable but will be considered by the Administrator in 
evaluating the adequacy of the measures in the implementation plan to 
achieve the progress goal adopted by the State.
    (vi) The State may not adopt a reasonable progress goal that 
represents less visibility improvement than is expected to result from 
implementation of other requirements of the CAA during the applicable 
planning period.

[[Page 254]]

    (2) Calculations of baseline and natural visibility conditions. For 
each mandatory Class I Federal area located within the State, the State 
must determine the following visibility conditions (expressed in 
deciviews):
    (i) Baseline visibility conditions for the most impaired and least 
impaired days. The period for establishing baseline visibility 
conditions is 2000 to 2004. Baseline visibility conditions must be 
calculated, using available monitoring data, by establishing the average 
degree of visibility impairment for the most and least impaired days for 
each calendar year from 2000 to 2004. The baseline visibility conditions 
are the average of these annual values. For mandatory Class I Federal 
areas without onsite monitoring data for 2000-2004, the State must 
establish baseline values using the most representative available 
monitoring data for 2000-2004, in consultation with the Administrator or 
his or her designee;
    (ii) For an implementation plan that is submitted by 2003, the 
period for establishing baseline visibility conditions for the period of 
the first long-term strategy is the most recent 5-year period for which 
visibility monitoring data are available for the mandatory Class I 
Federal areas addressed by the plan. For mandatory Class I Federal areas 
without onsite monitoring data, the State must establish baseline values 
using the most representative available monitoring data, in consultation 
with the Administrator or his or her designee;
    (iii) Natural visibility conditions for the most impaired and least 
impaired days. Natural visibility conditions must be calculated by 
estimating the degree of visibility impairment existing under natural 
conditions for the most impaired and least impaired days, based on 
available monitoring information and appropriate data analysis 
techniques; and
    (iv)(A) For the first implementation plan addressing the 
requirements of paragraphs (d) and (e) of this section, the number of 
deciviews by which baseline conditions exceed natural visibility 
conditions for the most impaired and least impaired days; or
    (B) For all future implementation plan revisions, the number of 
deciviews by which current conditions, as calculated under paragraph 
(f)(1) of this section, exceed natural visibility conditions for the 
most impaired and least impaired days.
    (3) Long-term strategy for regional haze. Each State listed in 
Sec. 51.300(b)(3) must submit a long-term strategy that addresses 
regional haze visibility impairment for each mandatory Class I Federal 
area within the State and for each mandatory Class I Federal area 
located outside the State which may be affected by emissions from the 
State. The long-term strategy must include enforceable emissions 
limitations, compliance schedules, and other measures as necessary to 
achieve the reasonable progress goals established by States having 
mandatory Class I Federal areas. In establishing its long-term strategy 
for regional haze, the State must meet the following requirements:
    (i) Where the State has emissions that are reasonably anticipated to 
contribute to visibility impairment in any mandatory Class I Federal 
area located in another State or States, the State must consult with the 
other State(s) in order to develop coordinated emission management 
strategies. The State must consult with any other State having emissions 
that are reasonably anticipated to contribute to visibility impairment 
in any mandatory Class I Federal area within the State.
    (ii) Where other States cause or contribute to impairment in a 
mandatory Class I Federal area, the State must demonstrate that it has 
included in its implementation plan all measures necessary to obtain its 
share of the emission reductions needed to meet the progress goal for 
the area. If the State has participated in a regional planning process, 
the State must ensure it has included all measures needed to achieve its 
apportionment of emission reduction obligations agreed upon through that 
process.
    (iii) The State must document the technical basis, including 
modeling, monitoring and emissions information, on which the State is 
relying to determine its apportionment of emission reduction obligations 
necessary for achieving reasonable progress in each

[[Page 255]]

mandatory Class I Federal area it affects. The State may meet this 
requirement by relying on technical analyses developed by the regional 
planning organization and approved by all State participants. The State 
must identify the baseline emissions inventory on which its strategies 
are based. The baseline emissions inventory year is presumed to be the 
most recent year of the consolidate periodic emissions inventory.
    (iv) The State must identify all anthropogenic sources of visibility 
impairment considered by the State in developing its long-term strategy. 
The State should consider major and minor stationary sources, mobile 
sources, and area sources.
    (v) The State must consider, at a minimum, the following factors in 
developing its long-term strategy:
    (A) Emission reductions due to ongoing air pollution control 
programs, including measures to address reasonably attributable 
visibility impairment;
    (B) Measures to mitigate the impacts of construction activities;
    (C) Emissions limitations and schedules for compliance to achieve 
the reasonable progress goal;
    (D) Source retirement and replacement schedules;
    (E) Smoke management techniques for agricultural and forestry 
management purposes including plans as currently exist within the State 
for these purposes;
    (F) Enforceability of emissions limitations and control measures; 
and
    (G) The anticipated net effect on visibility due to projected 
changes in point, area, and mobile source emissions over the period 
addressed by the long-term strategy.
    (4) Monitoring strategy and other implementation plan requirements. 
The State must submit with the implementation plan a monitoring strategy 
for measuring, characterizing, and reporting of regional haze visibility 
impairment that is representative of all mandatory Class I Federal areas 
within the State. This monitoring strategy must be coordinated with the 
monitoring strategy required in Sec. 51.305 for reasonably attributable 
visibility impairment. Compliance with this requirement may be met 
through participation in the Interagency Monitoring of Protected Visual 
Environments network. The implementation plan must also provide for the 
following:
    (i) The establishment of any additional monitoring sites or 
equipment needed to assess whether reasonable progress goals to address 
regional haze for all mandatory Class I Federal areas within the State 
are being achieved.
    (ii) Procedures by which monitoring data and other information are 
used in determining the contribution of emissions from within the State 
to regional haze visibility impairment at mandatory Class I Federal 
areas both within and outside the State.
    (iii) For a State with no mandatory Class I Federal areas, 
procedures by which monitoring data and other information are used in 
determining the contribution of emissions from within the State to 
regional haze visibility impairment at mandatory Class I Federal areas 
in other States.
    (iv) The implementation plan must provide for the reporting of all 
visibility monitoring data to the Administrator at least annually for 
each mandatory Class I Federal area in the State. To the extent 
possible, the State should report visibility monitoring data 
electronically.
    (v) A statewide inventory of emissions of pollutants that are 
reasonably anticipated to cause or contribute to visibility impairment 
in any mandatory Class I Federal area. The inventory must include 
emissions for a baseline year, emissions for the most recent year for 
which data are available, and estimates of future projected emissions. 
The State must also include a commitment to update the inventory 
periodically.
    (vi) Other elements, including reporting, recordkeeping, and other 
measures, necessary to assess and report on visibility.
    (e) Best Available Retrofit Technology (BART) requirements for 
regional haze visibility impairment. The State must submit an 
implementation plan containing emission limitations representing BART 
and schedules for compliance with BART for each BART-eligible source 
that may reasonably be anticipated to cause or contribute to any 
impairment of visibility in any

[[Page 256]]

mandatory Class I Federal area, unless the State demonstrates that an 
emissions trading program or other alternative will achieve greater 
reasonable progress toward natural visibility conditions.
    (1) To address the requirements for BART, the State must submit an 
implementation plan containing the following plan elements and include 
documentation for all required analyses:
    (i) A list of all BART-eligible sources within the State.
    (ii) A determination of BART for each BART-eligible source in the 
State that emits any air pollutant which may reasonably be anticipated 
to cause or contribute to any impairment of visibility in any mandatory 
Class I Federal area. All such sources are subject to BART. This 
determination must be based on the following analyses:
    (A) An analysis of the best system of continuous emission control 
technology available and associated emission reductions achievable for 
each BART-eligible source within the State subject to BART. In this 
analysis, the State must take into consideration the technology 
available, the costs of compliance, the energy and nonair quality 
environmental impacts of compliance, any pollution control equipment in 
use at the source, and the remaining useful life of the source; and
    (B) An analysis of the degree of visibility improvement that would 
be achieved in each mandatory Class I Federal area as a result of the 
emission reductions achievable from all sources subject to BART located 
within the region that contributes to visibility impairment in the Class 
I area, based on the analysis conducted under paragraph (e)(1)(ii)(A) of 
this section.
    (iii) If the State determines in establishing BART that 
technological or economic limitations on the applicability of 
measurement methodology to a particular source would make the imposition 
of an emission standard infeasible, it may instead prescribe a design, 
equipment, work practice, or other operational standard, or combination 
thereof, to require the application of BART. Such standard, to the 
degree possible, is to set forth the emission reduction to be achieved 
by implementation of such design, equipment, work practice or operation, 
and must provide for compliance by means which achieve equivalent 
results.
    (iv) A requirement that each source subject to BART be required to 
install and operate BART as expeditiously as practicable, but in no 
event later than 5 years after approval of the implementation plan 
revision.
    (v) A requirement that each source subject to BART maintain the 
control equipment required by this subpart and establish procedures to 
ensure such equipment is properly operated and maintained.
    (2) A State may opt to implement an emissions trading program or 
other alternative measure rather than to require sources subject to BART 
to install, operate, and maintain BART. To do so, the State must 
demonstrate that this emissions trading program or other alternative 
measure will achieve greater reasonable progress than would be achieved 
through the installation and operation of BART. To make this 
demonstration, the State must submit an implementation plan containing 
the following plan elements and include documentation for all required 
analyses:
    (i) A demonstration that the emissions trading program or other 
alternative measure will achieve greater reasonable progress than would 
have resulted from the installation and operation of BART at all sources 
subject to BART in the State. This demonstration must be based on the 
following:
    (A) A list of all BART-eligible sources within the State.
    (B) An analysis of the best system of continuous emission control 
technology available and associated emission reductions achievable for 
each source within the State subject to BART. In this analysis, the 
State must take into consideration the technology available, the costs 
of compliance, the energy and nonair quality environmental impacts of 
compliance, any pollution control equipment in use at the source, and 
the remaining useful life of the source. The best system of continuous 
emission control technology and the above factors may be determined on a 
source category basis. The State

[[Page 257]]

may elect to consider both source-specific and category-wide 
information, as appropriate, in conducting its analysis.
    (C) An analysis of the degree of visibility improvement that would 
be achieved in each mandatory Class I Federal area as a result of the 
emission reductions achievable from all such sources subject to BART 
located within the region that contributes to visibility impairment in 
the Class I area, based on the analysis conducted under paragraph 
(e)(2)(i)(B) of this section.
    (ii) A demonstration that the emissions trading program or 
alternative measure will apply, at a minimum, to all BART-eligible 
sources in the State. Those sources having a federally enforceable 
emission limitation determined by the State and approved by EPA as 
meeting BART in accordance with Sec. 51.302(c) or paragraph (e)(1) of 
this section do not need to meet the requirements of the emissions 
trading program or alternative measure, but may choose to participate if 
they meet the requirements of the emissions trading program or 
alternative measure.
    (iii) A requirement that all necessary emission reductions take 
place during the period of the first long-term strategy for regional 
haze. To meet this requirement, the State must provide a detailed 
description of the emissions trading program or other alternative 
measure, including schedules for implementation, the emission reductions 
required by the program, all necessary administrative and technical 
procedures for implementing the program, rules for accounting and 
monitoring emissions, and procedures for enforcement.
    (iv) A demonstration that the emission reductions resulting from the 
emissions trading program or other alternative measure will be surplus 
to those reductions resulting from measures adopted to meet requirements 
of the CAA as of the baseline date of the SIP.
    (v) At the State's option, a provision that the emissions trading 
program or other alternative measure may include a geographic 
enhancement to the program to address the requirement under 
Sec. 51.302(c) related to BART for reasonably attributable impairment 
from the pollutants covered under the emissions trading program or other 
alternative measure.
    (3) After a State has met the requirements for BART or implemented 
emissions trading program or other alternative measure that achieve more 
reasonable progress than the installation and operation of BART, BART-
eligible sources will be subject to the requirements of paragraph (d) of 
this section in the same manner as other sources.
    (4) Any BART-eligible facility subject to the requirement under 
paragraph (e) of this section to install, operate, and maintain BART may 
apply to the Administrator for an exemption from that requirement. An 
application for an exemption will be subject to the requirements of 
Sec. 51.303 (a)(2) through (h).
    (f) Requirements for comprehensive periodic revisions of 
implementation plans for regional haze. Each State identified in 
Sec. 51.300(b)(3) must revise and submit its regional haze 
implementation plan revision to EPA by July 31, 2018 and every ten years 
thereafter. In each plan revision, the State must evaluate and reassess 
all of the elements required in paragraph (d) of this section, taking 
into account improvements in monitoring data collection and analysis 
techniques, control technologies, and other relevant factors. In 
evaluating and reassessing these elements, the State must address the 
following:
    (1) Current visibility conditions for the most impaired and least 
impaired days, and actual progress made towards natural conditions 
during the previous implementation period. The period for calculating 
current visibility conditions is the most recent five year period 
preceding the required date of the implementation plan submittal for 
which data are available. Current visibility conditions must be 
calculated based on the annual average level of visibility impairment 
for the most and least impaired days for each of these five years. 
Current visibility conditions are the average of these annual values.
    (2) The effectiveness of the long-term strategy for achieving 
reasonable progress goals over the prior implementation period(s); and
    (3) Affirmation of, or revision to, the reasonable progress goal in 
accordance

[[Page 258]]

with the procedures set forth in paragraph (d)(1) of this section. If 
the State established a reasonable progress goal for the prior period 
which provided a slower rate of progress than that needed to attain 
natural conditions by the year 2064, the State must evaluate and 
determine the reasonableness, based on the factors in paragraph 
(d)(1)(i)(A) of this section, of additional measures that could be 
adopted to achieve the degree of visibility improvement projected by the 
analysis contained in the first implementation plan described in 
paragraph (d)(1)(i)(B) of this section.
    (g) Requirements for periodic reports describing progress towards 
the reasonable progress goals. Each State identified in 
Sec. 51.300(b)(3) must submit a report to the Administrator every 5 
years evaluating progress towards the reasonable progress goal for each 
mandatory Class I Federal area located within the State and in each 
mandatory Class I Federal area located outside the State which may be 
affected by emissions from within the State. The first progress report 
is due 5 years from submittal of the initial implementation plan 
addressing paragraphs (d) and (e) of this section. The progress reports 
must be in the form of implementation plan revisions that comply with 
the procedural requirements of Sec. 51.102 and Sec. 51.103. Periodic 
progress reports must contain at a minimum the following elements:
    (1) A description of the status of implementation of all measures 
included in the implementation plan for achieving reasonable progress 
goals for mandatory Class I Federal areas both within and outside the 
State.
    (2) A summary of the emissions reductions achieved throughout the 
State through implementation of the measures described in paragraph 
(g)(1) of this section.
    (3) For each mandatory Class I Federal area within the State, the 
State must assess the following visibility conditions and changes, with 
values for most impaired and least impaired days expressed in terms of 
5-year averages of these annual values.
    (i) The current visibility conditions for the most impaired and 
least impaired days;
    (ii) The difference between current visibility conditions for the 
most impaired and least impaired days and baseline visibility 
conditions;
    (iii) The change in visibility impairment for the most impaired and 
least impaired days over the past 5 years;
    (4) An analysis tracking the change over the past 5 years in 
emissions of pollutants contributing to visibility impairment from all 
sources and activities within the State. Emissions changes should be 
identified by type of source or activity. The analysis must be based on 
the most recent updated emissions inventory, with estimates projected 
forward as necessary and appropriate, to account for emissions changes 
during the applicable 5-year period.
    (5) An assessment of any significant changes in anthropogenic 
emissions within or outside the State that have occurred over the past 5 
years that have limited or impeded progress in reducing pollutant 
emissions and improving visibility.
    (6) An assessment of whether the current implementation plan 
elements and strategies are sufficient to enable the State, or other 
States with mandatory Federal Class I areas affected by emissions from 
the State, to meet all established reasonable progress goals.
    (7) A review of the State's visibility monitoring strategy and any 
modifications to the strategy as necessary.
    (h) Determination of the adequacy of existing implementation plan. 
At the same time the State is required to submit any 5-year progress 
report to EPA in accordance with paragraph (g) of this section, the 
State must also take one of the following actions based upon the 
information presented in the progress report:
    (1) If the State determines that the existing implementation plan 
requires no further substantive revision at this time in order to 
achieve established goals for visibility improvement and emissions 
reductions, the State must provide to the Administrator a negative 
declaration that further revision of the existing implementation plan is 
not needed at this time.
    (2) If the State determines that the implementation plan is or may 
be inadequate to ensure reasonable progress

[[Page 259]]

due to emissions from sources in another State(s) which participated in 
a regional planning process, the State must provide notification to the 
Administrator and to the other State(s) which participated in the 
regional planning process with the States. The State must also 
collaborate with the other State(s) through the regional planning 
process for the purpose of developing additional strategies to address 
the plan's deficiencies.
    (3) Where the State determines that the implementation plan is or 
may be inadequate to ensure reasonable progress due to emissions from 
sources in another country, the State shall provide notification, along 
with available information, to the Administrator.
    (4) Where the State determines that the implementation plan is or 
may be inadequate to ensure reasonable progress due to emissions from 
sources within the State, the State shall revise its implementation plan 
to address the plan's deficiencies within one year.
    (i) What are the requirements for State and Federal Land Manager 
coordination?
    (1) By November 29, 1999, the State must identify in writing to the 
Federal Land Managers the title of the official to which the Federal 
Land Manager of any mandatory Class I Federal area can submit any 
recommendations on the implementation of this subpart including, but not 
limited to:
    (i) Identification of impairment of visibility in any mandatory 
Class I Federal area(s); and
    (ii) Identification of elements for inclusion in the visibility 
monitoring strategy required by Sec. 51.305 and this section.
    (2) The State must provide the Federal Land Manager with an 
opportunity for consultation, in person and at least 60 days prior to 
holding any public hearing on an implementation plan (or plan revision) 
for regional haze required by this subpart. This consultation must 
include the opportunity for the affected Federal Land Managers to 
discuss their:
    (i) Assessment of impairment of visibility in any mandatory Class I 
Federal area; and
    (ii) Recommendations on the development of the reasonable progress 
goal and on the development and implementation of strategies to address 
visibility impairment.
    (3) In developing any implementation plan (or plan revision), the 
State must include a description of how it addressed any comments 
provided by the Federal Land Managers.
    (4) The plan (or plan revision) must provide procedures for 
continuing consultation between the State and Federal Land Manager on 
the implementation of the visibility protection program required by this 
subpart, including development and review of implementation plan 
revisions and 5-year progress reports, and on the implementation of 
other programs having the potential to contribute to impairment of 
visibility in mandatory Class I Federal areas.

[64 FR 35765, July 1, 1999]



Sec. 51.309  Requirements related to the Grand Canyon Visibility Transport 
Commission.

    (a) What is the purpose of this section? This section establishes 
the requirements for the first regional haze implementation plan to 
address regional haze visibility impairment in the 16 Class I areas 
covered by the Grand Canyon Visibility Transport Commission Report. For 
the years 2003 to 2018, certain States (defined in paragraph (b) of this 
section as Transport Region States) may choose to implement the 
Commission's recommendations within the framework of the national 
regional haze program and applicable requirements of the Act by 
complying with the provisions of this section, as supplemented by an 
approvable Annex to the Commission Report as required by paragraph (f) 
of this section. If a transport region State submits an implementation 
plan which is approved by EPA as meeting the requirements of this 
section, it will be deemed to comply with the requirements for 
reasonable progress for the period from approval of the plan to 2018.
    (b) Definitions. For the purposes of this section:
    (1) 16 Class I areas means the following mandatory Class I Federal 
areas on the Colorado Plateau: Grand Canyon National Park, Sycamore 
Canyon Wilderness, Petrified Forest National

[[Page 260]]

Park, Mount Baldy Wilderness, San Pedro Parks Wilderness, Mesa Verde 
National Park, Weminuche Wilderness, Black Canyon of the Gunnison 
Wilderness, West Elk Wilderness, Maroon Bells Wilderness, Flat Tops 
Wilderness, Arches National Park, Canyonlands National Park, Capital 
Reef National Park, Bryce Canyon National Park, and Zion National Park.
    (2) Transport Region State means one of the States that is included 
within the Transport Region addressed by the Grand Canyon Visibility 
Transport Commission (Arizona, California, Colorado, Idaho, Nevada, New 
Mexico, Oregon, Utah, and Wyoming).
    (3) Commission Report means the report of the Grand Canyon 
Visibility Transport Commission entitled ``Recommendations for Improving 
Western Vistas,'' dated June 10, 1996.
    (4) Fire means wildfire, wildland fire (including prescribed natural 
fire), prescribed fire, and agricultural burning conducted and occurring 
on Federal, State, and private wildlands and farmlands.
    (5) Milestone means an average percentage reduction in emissions, 
expressed in tons per year, for a given year or for a period of up to 5 
years ending in that year, compared to a 1990 actual emissions baseline.
    (6) Mobile Source Emission Budget means the lowest level of VOC, 
NOX, SO2 elemental and organic carbon, and fine 
particles which are projected to occur in any area within the transport 
region from which mobile source emissions are determined to contribute 
significantly to visibility impairment in any of the 16 Class I areas.
    (7) Geographic enhancement means a method, procedure, or process to 
allow a broad regional strategy, such as a milestone or backstop market 
trading program designed to achieve greater reasonable progress than 
BART for regional haze, to accommodate BART for reasonably attributable 
impairment.
    (c) Implementation Plan Schedule. Each Transport Region State may 
meet the requirements of Sec. 51.308(b) through (e) by electing to 
submit an implementation plan that complies with the requirements of 
this section. Each Transport Region State must submit an implementation 
plan addressing regional haze visibility impairment in the 16 Class I 
areas no later than December 31, 2003. A Transport Region State that 
elects not to submit an implementation plan that complies with the 
requirements of this section (or whose plan does not comply with all of 
the requirements of this section) is subject to the requirements of 
Sec. 51.308 in the same manner and to the same extent as any State not 
included within the Transport Region.
    (d) Requirements of the first implementation plan for States 
electing to adopt all of the recommendations of the Commission Report. 
Except as provided for in paragraph (e) of this section, each Transport 
Region State must submit an implementation plan that meets the following 
requirements:
    (1) Time period covered. The implementation plan must be effective 
for the entire time period between December 31, 2003 and December 31, 
2018.
    (2) Projection of visibility improvement. For each of the 16 
mandatory Class I areas located within the Transport Region State, the 
plan must include a projection of the improvement in visibility 
conditions (expressed in deciviews, and in any additional ambient 
visibility metrics deemed appropriate by the State) expected through the 
year 2018 for the most impaired and least impaired days, based on the 
implementation of all measures as required in the Commission report and 
the provisions in this section. The projection must be made in 
consultation with other Transport Region States with sources which may 
be reasonably anticipated to contribute to visibility impairment in the 
relevant Class I area. The projection may be based on a satisfactory 
regional analysis.
    (3) Treatment of clean-air corridors. The plan must describe and 
provide for implementation of comprehensive emission tracking strategies 
for clean-air corridors to ensure that the visibility does not degrade 
on the least-impaired days at any of the 16 Class I areas. The strategy 
must include:
    (i) An identification of clean-air corridors. The EPA will evaluate 
the State's identification of such corridors based upon the reports of 
the Commission's Meteorology Subcommittee and

[[Page 261]]

any future updates by a successor organization;
    (ii) Within areas that are clean-air corridors, an identification of 
patterns of growth or specific sites of growth that could cause, or are 
causing, significant emissions increases that could have, or are having, 
visibility impairment at one or more of the 16 Class I areas.
    (iii) In areas outside of clean-air corridors, an identification of 
significant emissions growth that could begin, or is beginning, to 
impair the quality of air in the corridor and thereby lead to visibility 
degradation for the least-impaired days in one or more of the 16 Class I 
areas.
    (iv) If impairment of air quality in clean air corridors is 
identified pursuant to paragraphs (d)(3)(ii) and (iii) of this section, 
an analysis of the effects of increased emissions, including provisions 
for the identification of the need for additional emission reductions 
measures, and implementation of the additional measures where necessary.
    (v) A determination of whether other clean air corridors exist for 
any of the 16 Class I areas. For any such clean air corridors, an 
identification of the necessary measures to protect against future 
degradation of air quality in any of the 16 Class I areas.
    (4) Implementation of stationary source reductions. The first 
implementation plan submission must include:
    (i) Monitoring and reporting of sulfur dioxide emissions. The plan 
submission must include provisions requiring the monitoring and 
reporting of actual stationary source sulfur dioxide emissions within 
the State. The monitoring and reporting data must be sufficient to 
determine whether a 13 percent reduction in actual stationary source 
sulfur dioxide emissions has occurred between the years 1990 and 2000, 
and whether milestones required by paragraph (f)(1)(i) of this section 
have been achieved for the transport region. The plan submission must 
provide for reporting of these data by the State to the Administrator. 
Where procedures developed under paragraph (f)(1)(ii) of this section 
and agreed upon by the State include reporting to a regional planning 
organization, the plan submission must provide for reporting to the 
regional planning body in addition to the Administrator.
    (ii) Criteria and procedures for a market trading program. The plan 
must include the criteria and procedures for activating a market trading 
program or other program consistent with paragraph (f)(1)(i) of this 
section if an applicable regional milestone is exceeded, procedures for 
operation of the program, and implementation plan assessments and 
provisions for implementation plan assessments of the program in the 
years 2008, 2013, and 2018.
    (iii) Provisions for activating a market trading program. Provisions 
to activate the market trading program or other program within 12 months 
after the emissions for the region are determined to exceed the 
applicable emission reduction milestone, and to assure that all affected 
sources are in compliance with allocation and other requirements within 
5 years after the emissions for the region are determined to exceed the 
applicable emission reduction milestone.
    (iv) Provisions for market trading program compliance reporting. If 
the market trading program has been activated, the plan submission must 
include provisions requiring the State to provide annual reports 
assuring that all sources are in compliance with applicable requirements 
of the market trading program.
    (v) Provisions for stationary source NOX and PM. The plan 
submission must include a report which assesses emissions control 
strategies for stationary source NOX and PM, and the degree 
of visibility improvement that would result from such strategies. In the 
report, the State must evaluate and discuss the need to establish 
emission milestones for NOX and PM to avoid any net increase 
in these pollutants from stationary sources within the transport region, 
and to support potential future development and implementation of a 
multipollutant and possibly multisource market-based program. The plan 
submission must provide for an implementation plan revision, containing 
any necessary long-term strategies and BART requirements for stationary 
source PM and NOX (including enforceable limitations,

[[Page 262]]

compliance schedules, and other measures) by no later than December 31, 
2008.
    (5) Mobile sources. The plan submission must provide for:
    (i) Statewide inventories of current annual emissions and projected 
future annual emissions of VOc, NOX, 
SO2, elemental carbon, organic carbon, and fine particles 
from mobile sources for the years 2003 to 2018. The future year 
inventories must include projections for the year 2005, or an 
alternative year that is determined by the State to represent the year 
during which mobile source emissions will be at their lowest levels 
within the State.
    (ii) A determination whether mobile source emissions in any areas of 
the State contribute significantly to visibility impairment in any of 
the 16 Class I Areas, based on the statewide inventory of current and 
projected mobile source emissions.
    (iii) For States with areas in which mobile source emissions are 
found to contribute significantly to visibility impairment in any of the 
16 Class I areas:
    (A) The establishment and documentation of a mobile source emissions 
budget for any such area, including provisions requiring the State to 
restrict the annual VOC, NOX, SO2, elemental and 
organic carbon, and/or fine particle mobile source emissions to their 
projected lowest levels, to implement measures to achieve the budget or 
cap, and to demonstrate compliance with the budget.
    (B) An emission tracking system providing for reporting of annual 
mobile source emissions from the State in the periodic implementation 
plan revisions required by paragraph (d)(10) of this section. The 
emission tracking system must be sufficient to determine the States' 
contribution toward the Commission's objective of reducing emissions 
from mobile sources by 2005 or an alternate year that is determined by 
the State to represent the year during which mobile source emissions 
will be at their lowest levels within the State, and to ensure that 
mobile source emissions do not increase thereafter.
    (iv) Interim reports to EPA and the public in years 2003, 2008, 
2013, and 2018 on the implementation status of the regional and local 
strategies recommended by the Commission Report to address mobile source 
emissions.
    (6) Programs related to fire. The plan must provide for:
    (i) Documentation that all Federal, State, and private prescribed 
fire programs within the State evaluate and address the degree 
visibility impairment from smoke in their planning and application. In 
addition the plan must include smoke management programs that include 
all necessary components including, but not limited to, actions to 
minimize emissions, evaluation of smoke dispersion, alternatives to 
fire, public notification, air quality monitoring, surveillance and 
enforcement, and program evaluation.
    (ii) A statewide inventory and emissions tracking system (spatial 
and temporal) of VOC, NOX, elemental and organic carbon, and 
fine particle emissions from fire. In reporting and tracking emissions 
from fire from within the State, States may use information from 
regional data-gathering and tracking initiatives.
    (iii) Identification and removal wherever feasible of any 
administrative barriers to the use of alternatives to burning in 
Federal, State, and private prescribed fire programs within the State.
    (iv) Enhanced smoke management programs for fire that consider 
visibility effects, not only health and nuisance objectives, and that 
are based on the criteria of efficiency, economics, law, emission 
reduction opportunities, land management objectives, and reduction of 
visibility impact.
    (v) Establishment of annual emission goals for fire, excluding 
wildfire, that will minimize emission increases from fire to the maximum 
extent feasible and that are established in cooperation with States, 
tribes, Federal land management agencies, and private entities.
    (7) Area sources of dust emissions from paved and unpaved roads. The 
plan must include an assessment of the impact of dust emissions from 
paved and unpaved roads on visibility conditions in the 16 Class I 
Areas. If such dust emissions are determined to be a significant 
contributor to visibility impairment in the 16 Class I areas, the

[[Page 263]]

State must implement emissions management strategies to address the 
impact as necessary and appropriate.
    (8) Pollution prevention. The plan must provide for:
    (i) An initial summary of all pollution prevention programs 
currently in place, an inventory of all renewable energy generation 
capacity and production in use, or planned as of the year 2002 
(expressed in megawatts and megawatt-hours), the total energy generation 
capacity and production for the State, the percent of the total that is 
renewable energy, and the State's anticipated contribution toward the 
renewable energy goals for 2005 and 2015, as provided in paragraph 
(d)(8)(vi) of this section.
    (ii) Programs to provide incentives that reward efforts that go 
beyond compliance and/or achieve early compliance with air-pollution 
related requirements.
    (iii) Programs to preserve and expand energy conservation efforts.
    (iv) The identification of specific areas where renewable energy has 
the potential to supply power where it is now lacking and where 
renewable energy is most cost-effective.
    (v) Projections of the short- and long-term emissions reductions, 
visibility improvements, cost savings, and secondary benefits associated 
with the renewable energy goals, energy efficiency and pollution 
prevention activities.
    (vi) A description of the programs relied on to achieve the State's 
contribution toward the Commission's goal that renewable energy will 
comprise 10 percent of the regional power needs by 2005 and 20 percent 
by 2015, and a demonstration of the progress toward achievement of the 
renewable energy goals in the years 2003, 2008, 2013, and 2018. This 
description must include documentation of the potential for renewable 
energy resources, the percentage of renewable energy associated with new 
power generation projects implemented or planned, and the renewable 
energy generation capacity and production in use and planned in the 
State. To the extent that it is not feasible for a State to meet its 
contribution to the regional renewable energy goals, the State must 
identify in the progress reports the measures implemented to achieve its 
contribution and explain why meeting the State's contribution was not 
feasible.
    (9) Implementation of additional recommendations. The plan must 
provide for implementation of all other recommendations in the 
Commission report that can be practicably included as enforceable 
emission limits, schedules of compliance, or other enforceable measures 
(including economic incentives) to make reasonable progress toward 
remedying existing and preventing future regional haze in the 16 Class I 
areas. The State must provide a report to EPA and the public in 2003, 
2008, 2013, and 2018 on the progress toward developing and implementing 
policy or strategy options recommended in the Commission Report.
    (10) Periodic implementation plan revisions. Each Transport Region 
State must submit to the Administrator periodic reports in the years 
2008, 2013, and 2018. The progress reports must be in the form of 
implementation plan revisions that comply with the procedural 
requirements of Sec. 51.102 and Sec. 51.103.
    (i) The report will assess the area for reasonable progress as 
provided in this section for mandatory Class I Federal area(s) located 
within the State and for mandatory Class I Federal area(s) located 
outside the State which may be affected by emissions from within the 
State. This demonstration may be based on assessments conducted by the 
States and/or a regional planning body. The progress reports must 
contain at a minimum the following elements:
    (A) A description of the status of implementation of all measures 
included in the implementation plan for achieving reasonable progress 
goals for mandatory Class I Federal areas both within and outside the 
State.
    (B) A summary of the emissions reductions achieved throughout the 
State through implementation of the measures described in paragraph 
(d)(10)(i)(A) of this section.
    (C) For each mandatory Class I Federal area within the State, an 
assessment of the following: the current visibility conditions for the 
most impaired and least impaired days; the difference between current 
visibility conditions

[[Page 264]]

for the most impaired and least impaired days and baseline visibility 
conditions; the change in visibility impairment for the most impaired 
and least impaired days over the past 5 years.
    (D) An analysis tracking the change over the past 5 years in 
emissions of pollutants contributing to visibility impairment from all 
sources and activities within the State. Emissions changes should be 
identified by type of source or activity. The analysis must be based on 
the most recent updated emissions inventory, with estimates projected 
forward as necessary and appropriate, to account for emissions changes 
during the applicable 5-year period.
    (E) An assessment of any significant changes in anthropogenic 
emissions within or outside the State that have occurred over the past 5 
years that have limited or impeded progress in reducing pollutant 
emissions and improving visibility.
    (F) An assessment of whether the current implementation plan 
elements and strategies are sufficient to enable the State, or other 
States with mandatory Federal Class I areas affected by emissions from 
the State, to meet all established reasonable progress goals.
    (G) A review of the State's visibility monitoring strategy and any 
modifications to the strategy as necessary.
    (ii) At the same time the State is required to submit any 5-year 
progress report to EPA in accordance with paragaph (d)(10)(i) of this 
section, the State must also take one of the following actions based 
upon the information presented in the progress report:
    (A) If the State determines that the existing implementation plan 
requires no further substantive revision at this time in order to 
achieve established goals for visibility improvement and emissions 
reductions, the State must provide to the Administrator a negative 
declaration that further revision of the existing implementation plan is 
not needed at this time.
    (B) If the State determines that the implementation plan is or may 
be inadequate to ensure reasonable progress due to emissions from 
sources in another State(s) which participated in a regional planning 
process, the State must provide notification to the Administrator and to 
the other State(s) which participated in the regional planning process 
with the States. The State must also collaborate with the other State(s) 
through the regional planning process for the purpose of developing 
additional strategies to address the plan's deficiencies.
    (C) Where the State determines that the implementation plan is or 
may be inadequate to ensure reasonable progress due to emissions from 
sources in another country, the State shall provide notification, along 
with available information, to the Administrator.
    (D) Where the State determines that the implementation plan is or 
may be inadequate to ensure reasonable progress due to emissions from 
within the State, the State shall develop additional strategies to 
address the plan deficiencies and revise the implementation plan no 
later than one year from the date that the progress report was due.
    (11) State planning and interstate coordination. In complying with 
the requirements of this section, States may include emission reductions 
strategies that are based on coordinated implementation with other 
States. Examples of these strategies include economic incentive programs 
and transboundary emissions trading programs. The implementation plan 
must include documentation of the technical and policy basis for the 
individual State apportionment (or the procedures for apportionment 
throughout the trans-boundary region), the contribution addressed by the 
State's plan, how it coordinates with other State plans, and compliance 
with any other appropriate implementation plan approvability criteria. 
States may rely on the relevant technical, policy and other analyses 
developed by a regional entity (such as the Western Regional Air 
Partnership) in providing such documentation. Conversely, States may 
elect to develop their own programs without relying on work products 
from a regional entity.
    (12) Tribal implementation. Consistent with 40 CFR Part 49, tribes 
within the Transport Region may implement the required visibility 
programs for the 16 Class I areas, in the same manner as States, 
regardless of whether such

[[Page 265]]

tribes have participated as members of a visibility transport 
commission.
    (e) States electing not to implement the commission recommendations. 
Any Transport Region State may elect not to implement the Commission 
recommendations set forth in paragraph (d) of this section. Such States 
are required to comply with the timelines and requirements of 
Sec. 51.308. Any Transport Region State electing not to implement the 
Commission recommendations must advise the other States in the Transport 
Region of the nature of the program and the effect of the program on 
visibility-impairing emissions, so that other States can take this 
information into account in developing programs under this section.
    (f) Annex to the Commission Report. (1) A Transport Region State may 
choose to comply with the provisions of this section and by doing so 
shall satisfy the requirements of Sec. 51.308(b) through (e) only if the 
Grand Canyon Visibility Transport Commission (or a regional planning 
body formed to implement the Commission recommendations) submits a 
satisfactory annex to the Commission Report no later than October 1, 
2000. To be satisfactory, the Annex must contain the following elements:
    (i) The annex must contain quantitative emission reduction 
milestones for stationary source sulfur dioxide emissions for the 
reporting years 2003, 2008, 2013 and 2018. The milestones must provide 
for steady and continuing emission reductions for the 2003-2018 time 
period consistent with the Commission's definition of reasonable 
progress, its goal of 50 to 70 percent reduction in sulfur dioxide 
emissions from 1990 actual emission levels by 2040, applicable 
requirements under the CAA, and the timing of implementation plan 
assessments of progress and identification of deficiencies which will be 
due in the years 2008, 2013, and 2018. The emission reduction milestones 
must be shown to provide for greater reasonable progress than would be 
achieved by application of best available retrofit technology (BART) 
pursuant to Sec. 51.308(e)(2) and would be approvable in lieu of BART.
    (ii) The annex must contain documentation of the market trading 
program or other programs to be implemented pursuant to paragraph (d)(4) 
of this section if current programs and voluntary measures are not 
sufficient to meet the required emission reduction milestones. This 
documentation must include model rules, memoranda of understanding, and 
other documentation describing in detail how emission reduction progress 
will be monitored, what conditions will require the market trading 
program to be activated, how allocations will be performed, and how the 
program will operate.
    (2) The Commission may elect, at the same time it submits the annex, 
to make recommendations intended to demonstrate reasonable progress for 
other mandatory Class I areas (beyond the original 16) within the 
Transport Region States, including the technical and policy 
justification for these additional mandatory Class I Federal areas in 
accordance with the provisions of paragraph (g) of this section.
    (3) The EPA will publish the annex upon receipt. If EPA finds that 
the annex meets the requirements of paragraph (f)(1) of this section and 
assures reasonable progress, then, after public notice and comment, will 
amend the requirements of paragraph (d)(4) of this section to 
incorporate the provisions of the annex within 1 year after EPA receives 
the annex. If EPA finds that the annex does not meet the requirements of 
paragraph (f)(1) of this section, or does not assure reasonable 
progress, or if EPA finds that the annex is not received, then each 
Transport Region State must submit an implementation plan for regional 
haze meeting all of the requirements of Sec. 51.308.
    (4) In accordance with the provisions under paragraph (f)(1) of this 
section, the annex may include a geographic enhancement to the program 
provided for in paragraph (d)(4) of this section to address the 
requirement under Sec. 51.302(c) related to Best Available Retrofit 
Technology for reasonably attributable impairment from the pollutants 
covered by the milestones or the backstop market trading program. The 
geographic enhancement program may include an appropriate level of 
reasonably attributable impairment which

[[Page 266]]

may require additional emission reductions over and above those achieved 
under the milestones defines in paragraph (f)(1)(i) of this section.
    (g) Additional Class I areas. The following submittals must be made 
by Transport Region States implementing the provisions of this section 
as the basis for demonstrating reasonable progress for additional Class 
I areas in the Transport Region States. If a Transport Region State 
submits an implementation plan which is approved by EPA as meeting the 
requirements of this section, it will be deemed to comply with the 
requirements for reasonable progress for the period from approval of the 
plan to 2018.
    (1) In the plan submitted for the 16 Class I areas no later than 
December 31, 2003, a declaration indicating whether other Class I areas 
will be addressed under Sec. 51.308 or paragraphs (g)(2) and (3) of this 
section.
    (2) In a plan submitted no later than December 31, 2008, provide a 
demonstration of expected visibility conditions for the most impaired 
and least impaired days at the additional mandatory Class I Federal 
area(s) based on emissions projections from the long-term strategies in 
the implementation plan. This demonstration may be based on assessments 
conducted by the States and/or a regional planning body.
    (3) In a plan submitted no later than December 31, 2008, provide 
revisions to the plan submitted under paragraph (c) of this section, 
including provisions to establish reasonable progress goals and 
implement any additional measures necessary to demonstrate reasonable 
progress for the additional mandatory Federal Class I areas. These 
revisions must comply with the provisions of Sec. 51.308(d)(1) through 
(4).
    (4) The following provisions apply for Transport Region States 
establishing reasonable progress goals and adopting any additional 
measures for Class I areas other than the 16 Class I areas under 
paragraphs (g)(2) and (3) of this section.
    (i) In developing long-term strategies pursuant to 
Sec. 51.308(d)(3), the State may build upon the strategies implemented 
under paragraph (d) of this section, and take full credit for the 
visibility improvement achieved through these strategies.
    (ii) The requirement under Sec. 51.308(e) related to Best Available 
Retrofit Technology for regional haze is deemed to be satisfied for 
pollutants addressed by the milestones and backstop trading program if, 
in establishing the emission reductions milestones under paragraph (f) 
of this section, it is shown that greater reasonable progress will be 
achieved for these Class I areas than would be achieved through the 
application of source-specific BART emission limitations under 
Sec. 51.308(e)(1).
    (iii) The Transport Region State may consider whether any strategies 
necessary to achieve the reasonable progress goals required by paragraph 
(g)(3) of this section are incompatible with the strategies implemented 
under paragraph (d) of this section to the extent the State adequately 
demonstrates that the incompatibility is related to the costs of the 
compliance, the time necessary for compliance, the energy and no air 
quality environmental impacts of compliance, or the remaining useful 
life of any existing source subject to such requirements.

[64 FR 35769, July 1, 1999]

    Effective Date Note: At 68 FR 33784, June 5, 2003, Sec. 51.309 was 
amended by revising paragraphs (b)(5), (c), (d)(4) through (d)(4)(iv), 
(f)(1), and (f)(3), and by adding paragraphs (b)(8) through (b)(13), and 
(h), effective Aug. 4, 2003. For the convenience of the user, the 
revised and added text is set forth as follows:

Sec. 51.309  Requirements related to the Grand Canyon Visibility 
          Transport Commission.

                                * * * * *

    (b) * * *
    (5) Milestone means the maximum level of annual regional sulfur 
dioxide emissions for a given year, assessed annually consistent with 
paragraph (h)(2) of this section beginning in the year 2003.

                                * * * * *

    (8) Base year means the year, generally a year between 1996 and 
1998, for which data for a source included within the program were used 
by the WRAP to calculate base year emissions as a starting point for 
development of the Annex required by paragraph (f) of this section.

[[Page 267]]

    (9) Forecast means the process used by the WRAP to predict future 
emissions for purposes of developing the milestones required by 
paragraph (f) of this section.
    (10) Reforecast means a corrected forecast, based upon reapplication 
of the forecasting process after correction of base year emissions 
estimates.
    (11) BHP San Manuel means:
    (i) The copper smelter located in San Manuel, Arizona which operated 
during 1990, but whose operations were suspended during the year 2000,
    (ii) The same smelter in the event of a change of name or ownership.
    (12) Phelps Dodge Hidalgo means:
    (i) The copper smelter located in Hidalgo, New Mexico which operated 
during 1990, but whose operations were suspended during the year 2000,
    (ii) The same smelter in the event of a change of name or ownership.
    (13) Eligible renewable energy resource, for purposes of 40 CFR 
51.309, means electricity generated by non-nuclear and non-fossil low or 
no air emission technologies.
    (c) Implementation Plan Schedule. Each Transport Region State may 
meet the requirements of Sec. 51.308(b) through (e) by submitting an 
implementation plan that complies with the requirements of this section. 
Each Transport Region State must submit an implementation plan 
addressing regional haze visibility impairment in the 16 Class I areas 
no later than December 31, 2003. Indian Tribes may submit implementation 
plans after the December 31, 2003 deadline. A Transport Region State 
that does not submit an implementation plan that complies with the 
requirements of this section (or whose plan does not comply with all of 
the requirements of this section) is subject to the requirements of 
Sec. 51.308 in the same manner and to the same extent as any State not 
included within the Transport Region.

                                * * * * *

    (d) * * *
    (4) * * *
    (i) Sulfur dioxide milestones consistent with paragraph (h)(1) of 
this section.
    (ii) Monitoring and reporting of sulfur dioxide emissions. The plan 
submission must include provisions requiring the annual monitoring and 
reporting of actual stationary source sulfur dioxide emissions within 
the State. The monitoring and reporting data must be sufficient to 
determine whether a 13 percent reduction in actual emissions has 
occurred between the years 1990 and 2000, and for determining annually 
whether the milestone for each year between 2003 and 2018 is exceeded, 
consistent with paragraph (h) (2) of this section. The plan submission 
must provide for reporting of these data by the State to the 
Administrator and to the regional planning organization consistent with 
paragraph (h)(2) of this section.
    (iii) Criteria and Procedures for a Market Trading Program. The plan 
must include the criteria and procedures for activating a market trading 
program consistent with paragraphs (h)(3) and (h)(4) of this section. 
The plan must also provide for implementation plan assessments of the 
program in the years 2008, 2013, and 2018.
    (iv) Provisions for market trading program compliance reporting 
consistent with paragraph (h)(4) of this section.

                                * * * * *

    (f) * * *
    (1) * * *
    (i) The annex must contain quantitative emissions milestones for 
stationary source sulfur dioxide emissions for the reporting years 2003, 
2008, 2013 and 2018. The milestones must provide for steady and 
continuing emissions reductions for the 2003-2018 time period consistent 
with the Commission's definition of reasonable progress, its goal of 50 
to 70 percent reduction in sulfur dioxide emissions from 1990 actual 
emission levels by 2040, applicable requirements under the CAA, and the 
timing of implementation plan assessments of progress and identification 
of deficiencies which will be due in the years 2008, 2013, and 2018. The 
milestones must be shown to provide for greater reasonable progress than 
would be achieved by application of best available retrofit technology 
(BART) pursuant to Sec. 51.308(e)(2) and would be approvable in lieu of 
BART.
    (2) * * *

[[Page 268]]

    (3) The EPA will publish the annex upon receipt. If EPA finds that 
the annex meets the requirements of paragraph (f)(1) of this section and 
assures reasonable progress, then, after public notice and comment, EPA 
will amend the requirements of this section to incorporate the 
provisions of the annex. If EPA finds that the annex does not meet the 
requirements of paragraph (f)(1) of this section, or does not assure 
reasonable progress, or if EPA finds that the annex is not received, 
then each Transport Region State must submit an implementation plan for 
regional haze meeting all of the requirements of Sec. 51.308.

                                * * * * *

    (h) Emissions Reduction Program for Major Industrial Sources of 
Sulfur Dioxide. The first implementation plan submission must include a 
stationary source emissions reductions program for major industrial 
sources of sulfur dioxide that meets the following requirements:
    (1) Regional sulfur dioxide milestones. The plan must include the 
milestones in Table 1, and provide for the adjustments in paragraphs 
(h)(1)(i) through (iv) of this section. Table 1 follows:

[[Page 269]]



                                  Table 1.--Sulfur Dioxide Emissions Milestones
----------------------------------------------------------------------------------------------------------------
               Column 1                        Column 2                 Column 3                 Column 4
----------------------------------------------------------------------------------------------------------------
                                       . . . if BHP San Manuel    . . . if neither BHP    . . . and the emission
                                           and Phelps Dodge      San Manuel nor Phelps    inventories for these
                                            Hidalgo resume       Dodge Hidalgo resumes     years will determine
          For the year . . .            operation, the maximum   operation, the minimum   whether emissions are
                                       regional sulfur dioxide  regional sulfur dioxide    greater than or less
                                          milestone is . . .       milestone is . . .      than the milestone:
----------------------------------------------------------------------------------------------------------------
2003.................................  720,000 tons...........  682,000 tons...........  2003.
2004.................................  720,000 tons...........  682,000 tons...........  Average of 2003 and
                                                                                          2004.
2005.................................  720,000 tons...........  682,000 tons...........  Average of 2003, 2004
                                                                                          and 2005.
2006.................................  720,000 tons...........  682,000 tons...........  Average of 2004, 2005
                                                                                          and 2006.
2007.................................  720,000 tons...........  682,000 tons...........  Average of 2005, 2006
                                                                                          and 2007.
2008.................................  718,333 tons...........  680,333 tons...........  Average of 2006, 2007
                                                                                          and 2008.
2009.................................  716,667 tons...........  678,667 tons...........  Average of 2007, 2008
                                                                                          and 2009.
2010.................................  715,000 tons...........  677,000 tons...........  Average of 2008, 2009
                                                                                          and 2010.
2011.................................  715,000 tons...........  677,000 tons...........  Average of 2009, 2010
                                                                                          and 2011.
2012.................................  715,000 tons...........  677,000 tons...........  Average of 2010, 2011
                                                                                          and 2012.
2013.................................  695,000 tons...........  659,667 tons...........  Average of 2011, 2012
                                                                                          and 2013.
2014.................................  675,000 tons...........  642,333 tons...........  Average of 2012, 2013
                                                                                          and 2014.
2015.................................  655,000 tons...........  625,000 tons...........  Average of 2013, 2014
                                                                                          and 2015.
2016.................................  655,000 tons...........  625,000 tons...........  Average of 2014, 2015
                                                                                          and 2016.
2017.................................  655,000 tons...........  625,000 tons...........  Average of 2015, 2016
                                                                                          and 2017.
2018.................................  510,000 tons...........  480,000 tons...........  Year 2018 only.
Each year after 2018.................  no more than 510,000     no more than 480,000     3-year average of the
                                        tons unless the          tons unless the          year and the two
                                        milestones are           milestones are           previous years, or any
                                        replaced with a          replaced with a          alternative provided
                                        different program that   different program that   in any future plan
                                        meets any BART and       meets any BART and       revisions under Sec.
                                        reasonable progress      reasonable progress      51.308(f).
                                        requirements             requirements
                                        established in Sec.      established in Sec.
                                        51.309.                  51.309.
----------------------------------------------------------------------------------------------------------------


[[Page 270]]

    (i) Adjustment for States and Tribes Which Choose Not to Participate 
in the Program, and for Tribes that opt into the program after the 2003 
deadline. If a State or Tribe chooses not to submit an implementation 
plan under the option provided in Sec. 51.309, or if EPA has not 
approved a State or Tribe's implementation plan by the date of the draft 
determination required by Sec. 51.309(h)(3)(ii), the amounts for that 
State or Tribe which are listed in Table 2 must be subtracted from the 
milestones that are included in the implementation plans for the 
remaining States and Tribes. For Tribes that opt into the program after 
2003, the amounts in Table 2 or 4 will be automatically added to the 
milestones that are included in the implementation plans for the 
participating States and Tribes, beginning with the first year after the 
tribal implementation plan implementing Sec. 51.309 is approved by the 
Administrator. The amounts listed in Table 2 are for purposes of 
adjusting the milestones only, and they do not represent amounts that 
must be allocated under any future trading program. Table 2 follows:

[[Page 271]]



            Table 2.--Amounts Subtracted From the Milestones for States and Tribes Which Do Not Exercise the Option Provided by Sec.  51.309
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 State or tribe                       2003         2004         2005         2006         2007         2008         2009         2010
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Arizona......................................      117,372      117,372      117,372      117,372      117,372      117,941      118,511      119,080
2. California...................................       37,343       37,343       37,343       37,784       37,343       36,363       35,382       34,402
3. Colorado.....................................       98,897       98,897       98,897       98,897       98,897       98,443       97,991       97,537
4. Idaho........................................       18,016       18,016       18,016       18,016       18,016       17,482       16,948       16,414
5. Nevada.......................................       20,187       20,187       20,187       20,187       20,187       20,282       20,379       20,474
6. New Mexico...................................       84,624       84,624       84,624       84,624       84,624       84,143       83,663       83,182
7. Oregon.......................................       26,268       26,268       26,268       26,268       26,268       26,284       26,300       26,316
8. Utah.........................................       42,782       42,782       42,782       42,782       42,782       42,795       42,806       42,819
9. Wyoming......................................      155,858      155,858      155,858      155,858      155,858      155,851      155,843      155,836
10. Navajo Nation...............................       53,147       53,147       53,147       53,147       53,147       53,240       53,334       53,427
11. Shoshone-Bannock Tribe of the Fort Hall             4,994        4,994        4,994        4,994        4,994        4,994        4,994        4,994
 Reservation....................................
12. Ute Indian Tribe of the Uintahand Ouray             1,129        1,129        1,129        1,129        1,129        1,131        1,133        1,135
 Reservation....................................
13. Wind River Reservation......................        1,384        1,384        1,384        1,384        1,384        1,384        1,384        1,384


--------------------------------------------------------------------------------------------------------------------------------------------------------
                 State or tribe                       2011         2012         2013         2014         2015         2016         2017         2018
--------------------------------------------------------------------------------------------------------------------------------------------------------
1. Arizona......................................      119,080      119,080      116,053      113,025      109,998      109,998      109,998       82,302
2. California...................................       34,402       34,402       33,265       32,128       30,991       30,991       30,991       27,491
3. Colorado.....................................       97,537       97,537       94,456       91,375       88,294       88,294       88,294       57,675
4. Idaho........................................       16,414       16,414       15,805       15,197       14,588       14,588       14,588       13,227
5. Nevada.......................................       20,474       20,474       20,466       20,457       20,449       20,449       20,449       20,232
6. New Mexico...................................       83,182       83,182       81,682       80,182       78,682       78,682       78,682       70,000
7. Oregon.......................................       26,316       26,316       24,796       23,277       21,757       21,757       21,757        8,281
8. Utah.........................................       42,819       42,819       41,692       40,563       39,436       39,436       39,436       30,746
9. Wyoming......................................      155,836      155,836      151,232      146,629      142,025      142,025      142,025       97,758
10. Navajo Nation...............................       53,427       53,427       52,707       51,986       51,266       51,266       51,266       44,772
11. Shoshone-Bannock Tribe of the Fort Hall             4,994        4,994        4,994        4,994        4,994        4,994        4,994        4,994
 Reservation....................................
12. Ute Indian Tribe of the Uintahand Ouray             1,135        1,135        1,135        1,135        1,135        1,135        1,135        1,135
 Reservation....................................
13. Northern Arapaho and Shoshone Tribes of the         1,384        1,384        1,384        1,384        1,384        1,384        1,384        1,384
 Wind River Reservation.........................
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 272]]

    (ii) Adjustment for Future Operation of Copper Smelters. (A) The 
plan must provide for adjustments to the milestones in the event that 
Phelps Dodge Hidalgo and/or BHP San Manuel resume operations or that 
other smelters increase their operations.
    (B) The plan must provide for adjustments to the milestones 
according to Tables 3a and 3b except that if either the Hidalgo or San 
Manuel smelters resumes operation and is required to obtain a permit 
under 40 CFR 52.21 or 40 CFR 51.166, the adjustment to the milestone 
must be based upon the levels allowed by the permit. In no instance may 
the adjustment to the milestone be greater than 22,000 tons for the 
Phelps Dodge Hidalgo, greater than 16,000 tons for BHP San Manuel, or 
more than 30,000 tons for the combination of the Phelps Dodge Hidalgo 
and BHP San Manuel smelters for the years 2013 through 2018. Tables 3a 
and 3b follow:

Table 3a.--Adjustments to the Milestones for Future Operations of Copper
                                Smelters
------------------------------------------------------------------------
                                                          . . . then you
                                                          calculate the
                                                           milestone by
      Scenario        If this happens  and this happens    adding this
                           . . .             . . .        amount to the
                                                         value in column
                                                           3 of Table 1
------------------------------------------------------------------------
1..................  Phelps Dodge      Phelps Dodge      A. Beginning
                      Hidalgo resumes   Hidalgo resumes   with the year
                      operation, but    production        that
                      BHP San Manuel    consistent with   production
                      does not.         past operations   resumes, and
                                        and emissions.    for each year
                                                          up to the year
                                                          2012, the
                                                          milestone
                                                          increases by:
                                                         (1) 22,000 tons
                                                          PLUS
                                                         (2) Any amounts
                                                          identified in
                                                          Table 3b.
                                                         B. For the
                                                          years 2013
                                                          through 2018,
                                                          the milestone
                                                          increases by
                                                          this amount or
                                                          by 30,000
                                                          tons,
                                                          whichever is
                                                          less.
2..................  Phelps Dodge      Phelps Dodge      A. Beginning
                      Hidalgo resumes   Hidalgo resumes   with the year
                      operation, but    operation in a    that
                      BHP San Manuel    substantially     production
                      does not.         different         resumes, and
                                        manner such       for each year
                                        that emissions    up to the year
                                        will be less      2012, the
                                        than for past     milestone
                                        operations (an    increases by:
                                        example would    (1) Expected
                                        be running only   emissions for
                                        one portion of    Phelps Dodge
                                        the plant to      Hidalgo (not
                                        produce sulfur    to exceed
                                        acid only).       22,000 tons),
                                                          PLUS
                                                         (2) Any amounts
                                                          identified in
                                                          Table 3b.
                                                         B. For the
                                                          years 2013
                                                          through 2018,
                                                          the milestone
                                                          increases by
                                                          this amount or
                                                          by 30,000
                                                          tons,
                                                          whichever is
                                                          less.
3..................  BHP San Manuel    BHP San Manuel    A. 16,000 tons
                      Manuel resumes    resumes           PLUS
                      operation, but    production       B. Any amounts
                      Phelps Dodge      consistent with   identified in
                      Hidalgo does      past operations   Table 3b.
                      not.              and emissions.
4..................  BHP San Manuel    BHP San Manuel    A. Expected
                      resumes           resumes           emissions for
                      operation, but    operations in a   BHP (not to
                      Phelps Dodge      substantially     exceed 16,000
                      Hidalgo does      different         tons) PLUS
                      not.              manner such      B. Any amounts
                                        that emissions    identified in
                                        will be less      Table 3b.
                                        than for past
                                        operations (an
                                        example would
                                        be running only
                                        one portion of
                                        the plant to
                                        produce sulfur
                                        acid only).
5..................  Both Phelps       Both smelters     A. Beginning
                      Dodge Hidalgo     resume            with the year
                      and BHP San       production        that
                      Manuel resume     consistent with   production
                      operations.       past operations   resumes, and
                                        and emissions.    for each year
                                                          up to the year
                                                          2012, the
                                                          milestone
                                                          increase by
                                                          38,000 tons.
                                                         B. For the
                                                          years 2013
                                                          through 2018,
                                                          the milestone
                                                          increases by
                                                          30,000 tons.
6..................  Both Phelps       Phelps Dodge      A. For the year
                      Dodge Hidalgo     Hidalgo resumes   that
                      and BHP San       production        production
                      Manuel resume     consistent with   resumes, and
                      operations.       past operations   for each year
                                        and emissions,    up to the year
                                        but BHP San       2012, the
                                        Manuel resumes    milestone
                                        operations in a   increases by:
                                        substantially    (1) 22,000 PLUS
                                        different        (2) Expected
                                        manner such       emissions for
                                        that emissions    San Manuel
                                        will be less      (not to exceed
                                        than for past     16,000 tons).
                                        operations (an   B. For the
                                        example would     years 2013
                                        be running only   though 2018,
                                        one portion of    the milestone
                                        the plant to      increases by
                                        produce sulfur    this same
                                        acid only).       amount, or by
                                                          30,000 tons,
                                                          whichever is
                                                          less.

[[Page 273]]

 
7..................  Both Phelps       BHP San Manuel    A. For the year
                      Dodge Hidalgo     resume            that
                      and BHP San       production        production
                      Manuel resumes    consistent with   resumes, and
                      operations.       the past          for each year
                                        operations and    up to the year
                                        emissions, but    2012,
                                        Phelps Dodge      milestone
                                        Hidalgo resumes   increases by:
                                        operations in a  (1) 16,000 PLUS
                                        substantially    (2) Expected
                                        different         Hidalgo
                                        manner such       emissions (not
                                        that emissions    to exceed
                                        will be less      22,000 tons).
                                        than for past    B. For the
                                        operations (an    years 2013
                                        example would     though 2018,
                                        be running only   the milestone
                                        one portion of    increases by
                                        the plant to      this same
                                        produce sulfur    amount, or by
                                        acid only).       30,000 tons,
                                                          whichever is
                                                          less.
8..................  Both Phelps       ................  A. Any amounts
                      Dodge Hidalgo                       identified in
                      and BHP San                         Table 3b.
                      Manuel do not
                      resume
                      operations.
------------------------------------------------------------------------


 Table 3b.--Adjustments for Certain Copper Smelters Which Operate Above
                             Baseline Levels
                                [In tons]
------------------------------------------------------------------------
                                                             . . . the
                                           complies with     milestone
                                             existing      increases by
                                            permits but   the difference
                                            has actual    between actual
  Where it applies in table 3a, if the        annual       emissions and
         following smelter . . .          emissions that   the baseline
                                            exceed the     level, or the
                                             following       following
                                          baseline level      amount,
                                               . . .       whichever is
                                                               less
------------------------------------------------------------------------
Asarco Hayden...........................          23,000           3,000
BHP San Manuel..........................          16,000           1,500
Kennecott Salt Lake.....................           1,000             100
Phelps Dodge Chino......................          16,000           3,000
Phelps Dodge Hidalgo....................          22,000           4,000
Phelps Dodge Miami......................           8,000           2,000
------------------------------------------------------------------------

    (iii) Adjustments for changes in emission monitoring or calculation 
methods. The plan must provide for adjustments to the milestones to 
reflect changes in sulfur dioxide emission monitoring or measurement 
methods for a source that is included in the program, including changes 
identified under paragraph (h)(2)(iii)(D) of this section. Any such 
adjustment based upon changes to emissions monitoring or measurement 
methods must be made in the form of an implementation plan revision that 
complies with the procedural requirements of Sec. 51.102 and 
Sec. 51.103. The implementation plan revision must be submitted to the 
Administrator no later than the first due date for a periodic report 
under paragraph (d)(10) of this section following the change in emission 
monitoring or measurement method.
    (iv) Adjustments for changes in flow rate measurement methods for 
affected sources under 40 CFR 72.1. For the years between 2003 and 2017, 
the implementation plan must provide for adjustments to the milestones 
for sources using the methods contained in 40 CFR part 60, appendix A, 
Methods 2F, 2G, and 2H. For any year for which such an adjustment has 
not yet been made to the milestone, the implementation plan must provide 
for an adjustment to the emissions reporting to ensure consistency. The 
implementation plan must provide for adjustments to the milestones by no 
later than the date of the periodic plan revision required under 
Sec. 51.309(d)(10).
    (v) Adjustments due to enforcement actions arising from settlements. 
The implementation plan must provide for adjustments to the milestones, 
as specified in paragraph (h)(1)(vii) and (viii) of this section, if:
    (A) An agreement to settle an action, arising from allegations of a 
failure of an owner or operator of an emissions unit at a source in the 
program to comply with applicable regulations which were in effect 
during the base year, is reached between the parties to the action;

[[Page 274]]

    (B) The alleged failure to comply with applicable regulations 
affects the assumptions that were used in calculating the source's base 
year and forecasted sulfur dioxide emissions; and
    (C) The settlement includes or recommends an adjustment to the 
milestones.
    (vi) Adjustments due to enforcement actions arising from 
administrative or judicial orders. The implementation plan must also 
provide for adjustments to the milestones as directed by any final 
administrative or judicial order, as specified in paragraph (h)(1)(vii) 
and (viii) of this section. Where the final administrative or judicial 
order does not include a reforecast of the source's baseline, the State 
or Tribe shall evaluate whether a reforecast of the source's baseline 
emissions is appropriate.
    (vii) Adjustments for enforcement actions. The plan must provide 
that, based on paragraph (h)(1)(v) and (vi) of this section, the 
milestone must be decreased by an appropriate amount based on a 
reforecast of the source's decreased sulfur dioxide emissions. The 
adjustments do not become effective until after the source has reduced 
its sulfur dioxide emissions as required in the settlement agreement, or 
administrative or judicial order. All adjustments based upon enforcement 
actions must be made in the form of an implementation plan revision that 
complies with the procedural requirements of Secs. 51.102 and 51.103.
    (viii) Documentation of adjustments for enforcement actions. In the 
periodic plan revision required under 51.309(d)(10), the State or Tribe 
shall include the following documentation of any adjustment due to an 
enforcement action:
    (A) Identification of each source under the State or Tribe