[Federal Register Volume 59, Number 164 (Thursday, August 25, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-20810]


[[Page Unknown]]

[Federal Register: August 25, 1994]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[ID2-1-5552a; FRL-5012-8]

 

Approval and Promulgation of State Implementation Plans: Idaho

AGENCY: Environmental Protection Agency.

ACTION: Final rule.

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SUMMARY: Environmental Protection Agency (EPA) approves the State 
Implementation Plan (SIP) submitted by the State of Idaho for the 
purpose of bringing about the attainment of the national ambient air 
quality standards (NAAQS) for particulate matter with an aerodynamic 
diameter less than or equal to a nominal 10 micrometers (PM-10). The 
implementation plan was submitted by the State and satisfied certain 
Federal requirements for an acceptable moderate nonattainment area PM-
10 SIP for Pinehurst, Idaho.

DATES: This final rule will be effective on October 24, 1994 unless 
adverse or critical comments are received by September 26, 1994. If the 
effective date is delayed, timely notice will be published in the 
Federal Register.

ADDRESSES: Written comments should be addressed to: Montel Livingston, 
Environmental Protection Agency, 1200 Sixth Avenue, AT-082, Seattle, 
Washington 98101.
    Documents which are incorporated by reference are available for 
inspection during normal business hours at the Air and Radiation Docket 
and Information Center, Environmental Protection Agency, 401 M Street 
SW., Washington, DC 20460. Copies of material submitted to EPA may be 
examined during normal business hours at the following locations: 
Environmental Protection Agency, 1200 Sixth Avenue, Seattle, WA 98101, 
and the State of Idaho Division of Environmental Quality, 1410 N. 
Hilton, Boise, ID 83720.

FOR FURTHER INFORMATION CONTACT: Stephen Fry, Environmental Protection 
Agency, 1200 Sixth Avenue, AT-082, Seattle, Washington 98101, (206) 
553-2575.

SUPPLEMENTARY INFORMATION:

I. Background

    The Shoshone County, Pinehurst, Idaho area was designated 
nonattainment for PM-10 and classified as moderate under sections 
107(d)(4)(B) and 188(a) of the Clean Air Act, upon enactment of the 
Clean Air Act Amendments of 1990\1\ (see 56 FR 56694 (November 6, 1991) 
and 40 CFR 81.313 (codified air quality designation for the Pinehurst 
area)). The air quality planning requirements for moderate PM-10 
nonattainment areas are set out in subparts 1 and 4 of title I of the 
Act.\2\ EPA has issued a ``General Preamble'' describing EPA's 
preliminary views on how EPA intends to review SIP's and SIP revisions 
submitted under title I of the Act, including those State submittals 
containing moderate PM-10 nonattainment area SIP requirements (see 
generally 57 FR 13498 (April 16, 1992) and 57 FR 18070 (April 28, 
1992)). Because EPA is describing its interpretations here only in 
broad terms, the reader should refer to the General Preamble for a more 
detailed discussion of the interpretations of title I advanced in this 
proposal and the supporting rationale. In this rulemaking action on the 
State of Idaho's moderate PM-10 SIP for the Pinehurst nonattainment 
area, EPA is applying its interpretations taking into consideration the 
specific factual issues presented. Additional information supporting 
EPA's action on this particular area is available for inspection at the 
address indicated above.
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    \1\The 1990 Amendments to the Clean Air Act made significant 
changes to the Act. See Public Law No. 101-549, 104 Stat. 2399. 
References herein are to the Clean Air Act, as amended (``the Act'' 
or ``CAA''). The Clean Air Act is codified, as amended, in the U.S. 
Code at 42 U.S.C. 7401, et seq.
    \2\Subpart 1 contains provisions applicable to nonattainment 
areas generally and subpart 4 contains provisions specifically 
applicable to PM-10 nonattainment areas. At times, subpart 1 and 
subpart 4 overlap or conflict. EPA has attempted to clarify the 
relationship among these provisions in the ``General Preamble'' and, 
as appropriate, in today's notice and supporting information.
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    Those states containing initial moderate PM-10 nonattainment areas 
(those areas designated nonattainment under section 107(d)(4)(B)) were 
required to submit, among other things, the following provisions by 
November 15, 1991:
    1. Provisions to assure that reasonably available control measures 
(RACM) (including such reductions in emissions from existing sources in 
the area as may be obtained through the adoption, at a minimum, of 
reasonably available control technology (RACT)) shall be implemented no 
later than December 10, 1993;
    2. Either a demonstration (including air quality modeling) that the 
plan will provide for attainment as expeditiously as practicable but no 
later than December 31, 1994, or a demonstration that attainment by 
that date is impracticable;
    3. Quantitative milestones which are to be achieved every three 
years and which demonstrate reasonable further progress (RFP) toward 
attainment by December 31, 1994; and
    4. Provisions to assure that the control requirements applicable to 
major stationary sources of PM-10 also apply to major stationary 
sources of PM-10 precursors except where the Administrator determines 
that such sources do not contribute significantly to PM-10 levels which 
exceed the NAAQS in the area (see sections 172(c), 188, and 189 of the 
Act).
    States with initial moderate PM-10 nonattainment areas were 
required to submit a permit program for the construction and operation 
of new and modified major stationary sources of PM-10 by June 30, 1992 
(see section 189(a) of the CAA). This permit program element, also 
known as the New Source Review (NSR) program, was submitted by the 
State of Idaho on May 17, 1994. EPA notified Idaho in a June 10, 1994 
letter to the Administrator of the Idaho Division of Environmental 
Quality that the NSR program submittal was complete. EPA is currently 
in the process of reviewing the NSR program to determine if the program 
meets the requirements of the CAA. EPA intends to take action on 
Idaho's NSR program when EPA has completed its review.
    In addition, states containing initial moderate PM-10 nonattainment 
areas were required to submit contingency measures by November 15, 
1993, which become effective without further action by the State or EPA 
upon a determination by EPA that the area has failed to achieve RFP or 
to attain the PM-10 NAAQS by the applicable statutory deadline (see 
section 172(c)(9) and 57 FR 13543-13544). Contingency measures for the 
Pinehurst PM-10 nonattainment area have not yet been submitted by IDEQ. 
A findings letter, dated January 13, 1994, was mailed to the Governor 
of Idaho which informed him that the State had failed to make the 
required PM-10 contingency measures submittal for Pinehurst. The State 
has until July 13, 1995 to correct this deficiency for Pinehurst, or it 
will face Federal highway or offset sanctions (see section 179 of the 
CAA and 58 FR 51270 (October 1, 1993)).
    EPA intends to take action on the contingency measures for the 
Pinehurst PM-10 nonattainment area when this requirement is submitted 
or intends to impose sanctions in the event this deficiency is not 
corrected.

II. This Action

    Section 110(k) of the Act sets out provisions governing EPA's 
review of SIP submittal (see 57 FR 13565-13566). In this action, EPA is 
granting approval of the plan revision submitted to EPA on April 14, 
1992. EPA has determined that the submittal meets the applicable 
requirements of the Act, with respect to moderate area PM-10 submittal.

Analysis of State Submission

1. Procedural Background
    The Act requires states to observe certain procedural requirements 
in developing implementation plans and plan revisions for submission to 
EPA. Section 110(a)(2) of the Act provides that each implementation 
plan submitted by a State must be adopted after reasonable notice and 
public hearing.\3\ Section 110(l) of the Act similarly provides that 
each revision to an implementation plan submitted by a State under the 
Act must be adopted by such State after reasonable notice and public 
hearing.
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    \3\Also Section 172(c)(7) of the Act requires that plan 
provisions for nonattainment areas meet the applicable provisions of 
section 110(a)(2).
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    EPA has also determined whether a submittal is complete and 
therefore warrants further EPA review and action (see section 110(k)(1) 
and 57 FR 13565). EPA's completeness criteria for SIP submittals are 
set out at 40 CFR part 51, appendix V. EPA attempts to make 
completeness determinations within 60 days of receiving a submission. 
However, a submittal is deemed complete by operation of law if a 
completeness determination is not made by EPA six months after receipt 
of the submission.
    The Idaho Division of Environmental Quality (IDEQ) held a public 
hearing on the Pinehurst PM-10 plan on January 22, 1992 in Pinehurst 
and, after IDEQ reviewed the oral testimony, the plan was adopted by 
the IDEQ Administrator on April 7, 1992. The submitted plan was 
received by EPA on April 14, 1992 as a revision to the SIP.
    The SIP revision was reviewed by EPA to determine completeness 
shortly after its submittal, in accordance with the completeness 
criteria set out at 40 CFR part 51, appendix V. A letter dated June 8, 
1992 was forwarded to the Administrator of IDEQ indicating the 
completeness of the submittal and the next steps to be taken in the 
review process. In this action EPA is approving the State of Idaho's 
PM-10 SIP submittal for the Pinehurst PM-10 nonattainment area.
    Since the Pinehurst PM-10 SIP requirements due on November 15, 1991 
were not submitted by that date as required by section 189(a)(2)(A) of 
the CAA, EPA made a finding, pursuant to section 179 of the Act, that 
the State failed to submit the SIP revision and notified the Governor 
in a letter dated December 18, 1991 (see 57 FR 19906 (May 8, 1992)). 
EPA's June 8, 1992 determination that the State had made a complete 
submittal corrected the State's failure to submit the PM-10 SIP 
requirements for Pinehurst due on November 15, 1991 and, therefore, 
terminated the 18-month sanctions clock for that deficiency under 
section 179 of the CAA.
2. Accurate Emissions Inventory
    Section 172(c)(3) of the Act requires that nonattainment plan 
provisions include a comprehensive, accurate, current inventory of 
actual emissions from all sources of relevant pollutants in the 
nonattainment area. The emissions inventory should also include a 
comprehensive, accurate, and current inventory of allowable emissions 
in the area (see section 110(a)(2)(K) of the CAA). Because the 
submission of such inventories is necessary to an area's attainment 
demonstration (or demonstration that the area cannot practicably 
attain), the emissions inventories must be received with the submission 
(see 57 FR 13539).
    The base year emission inventory (1988) developed for the Pinehurst 
nonattainment area identified the major sources of PM-10 concentrations 
during 24-hour worst case winter days as residential wood combustion 
(59%), fugitive dust (38%) and other sources (3%). Annual emissions for 
1988 were residential wood combustion (41%), fugitive dust (38%), 
building construction (18%) and other sources (3%).
    EPA is approving the emissions inventory because it generally 
appears to be accurate and comprehensive, and provides a sufficient 
basis for determining the adequacy of the attainment demonstration for 
this area consistent with the requirements of sections 172(c)(3) and 
110(a)(2)(K) of the Clean Air Act.\4\ For further details see the 
Technical Support Document (TSD).
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    \4\The EPA issued guidance on PM-10 emissions inventories prior 
to the enactment of the Clean Air Act Amendments in the form of the 
1987 PM-10 SIP Development Guideline. The guidance provided in this 
document appears to be consistent with the amended Act; therefore, 
EPA may continue to rely on this guidance (see section 193 of the 
CAA).
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3. RACM (Including RACT)
    As noted, the initial moderate PM-10 nonattainment areas must 
submit provisions to assure that RACM (including RACT) were implemented 
no later than December 10, 1993 (see sections 172(c)(1) and 
189(a)(1)(C)). The General Preamble contains a detailed discussion of 
EPA's interpretation of the RACM (including RACT) requirement (see 57 
FR 13539-13545 and 13560-13561).
    a. Residential Wood Combustion Program. Attainment of the 24-hour 
and annual standards is based on control strategies designed to reduce 
wood smoke. Attainment is demonstrated through the establishment of a 
voluntary residential wood combustion curtailment program, wood stove 
replacement program and home weatherization program. The specific 
control measures are supported and enhanced through an aggressive air 
pollution public awareness program. More details regarding these 
control measures are as follows:
    (1) Episodic Wood Burning Curtailment Program. The IDEQ is in 
charge of declaring episodic voluntary wood burning curtailments in the 
Pinehurst nonattainment area. A voluntary burn ban is declared when 24-
hour PM-10 levels in the nonattainment area, as estimated by 
nephelometer, are measured to exceed 100 g/m3. To keep 
the public informed regarding particulate air quality levels, a 24-hour 
PM-10 prediction is made for the Pinehurst/Silver Valley area after an 
IDEQ meteorologist calculates lower atmospheric stability and evaluates 
nephelometer, upper air temperature sounding, snow cover, surface 
temperature, delta temperature, wind speed, cloud cover, National 
Weather Service and occasionally commercial weather service data.
    Wood burning advisories are made in conjunction with the air 
quality report and are issued weekdays and, as necessary on weekends 
and holidays, by 9 a.m., from November 1 through the end of February. 
The advisory is recorded on a telephone answering machine for both the 
public and media. When a voluntary wood burning curtailment is 
declared, the IDEQ directly contacts the media and conducts radio and 
television interviews to publicize the existence of a burn ban. 
Voluntary curtailment declarations are also carried routinely by the 
local radio station and newspaper.
    IDEQ requests a 25 percent emission reduction credit for its 
voluntary curtailment program in the Pinehurst nonattainment area 
during 24-hour worst case periods. The 25 percent credit is greater 
than the ten percent generally suggested by EPA for voluntary 
curtailment programs. The recommended ten percent credit is viewed by 
EPA as a ``starting point in assessing the effectiveness of residential 
wood combustion control programs.'' However, final judgement of the 
amount of credit to be granted is determined by EPA's regional offices 
based on the program features outlined in EPA's Guidance Document for 
Residential Wood Combustion Emission Control Measures, September 1989, 
(EPA-450/2-89-015). More than ten percent credit may be granted based 
on the program's effectiveness.
    IDEQ cites residential wood heating surveys that were conducted in 
the Ada County/Boise PM-10 nonattainment area, that indicate a 43 
percent effectiveness rate for the voluntary curtailment program in 
that part of Idaho. The State points out in the Pinehurst SIP that the 
Pinehurst City Council adopted a resolution (on November 11, 1991) 
supporting the curtailment program and requesting all Pinehurst 
citizens, except those who must rely on wood burning as their sole 
source of heat, to not burn wood during a curtailment episode. 
Therefore, the features of the Pinehurst curtailment program, the 
effectiveness data obtained from Ada County/Boise coupled with the 
demonstrated local support for the curtailment program by the leaders 
of Pinehurst is the basis for IDEQ's 25 percent emission reduction 
claim. According to IDEQ calculations this 25 percent reduction is 
equivalent to a PM-10 emission reduction of 51.3 lbs/day and a 24-hour 
PM-10 ambient reduction of 20 g/m3.
    Based upon the surveys conducted in Ada County/Boise, the support 
by Pinehurst City officials and the recent success during the 1992-1993 
and 1993-1994 wood burning seasons in preventing PM-10 concentrations 
from exceeding the 24-hour NAAQS, EPA is satisfied that at least a 25 
percent emission reduction is occurring when voluntary episodic wood 
burning curtailments are declared in Pinehurst. Therefore, EPA is 
accepting the 25 percent credit claimed for this control measure. 
Further description of this program and justification for EPA's action 
is set out in the TSD, contained in the public record corresponding 
with this action.
    (2) Public Awareness Program. The wood smoke public awareness 
program for the Pinehurst/Silver Valley area plays a critical role in 
ensuring that the residential wood combustion program is successful. 
Public awareness of the problems associated with wood smoke has a 
significant effect on how well the different components of the wood 
smoke control program are accepted. IDEQ has utilized the following 
methods to promote public awareness about the wood smoke problem in 
Pinehurst: education brochures for each household, utility bill 
inserts, newspaper articles--public service announcements (PSA's), 
educational materials for elementary schools, surveys to determine the 
level of awareness and response to programs, radio interviews, radio 
PSA's, outreach to wood stove dealers and wood/pellet fuel outlets, and 
Speakers Bureau through service clubs and community meetings. IDEQ's 
well-established public awareness program was enhanced in 1991, when 
$14,550 was awarded by the Pacific Northwest and Alaska Bioenergy 
Program to provide wood energy education in Idaho's Silver Valley 
(which includes Pinehurst). For the 1993-1994 and 1994-1995 residential 
heating seasons, a wood stove advocate has been hired by IDEQ to serve 
as an information outlet regarding wood stove issues and also track the 
progress of reducing wood stove emissions.
    IDEQ is claiming a five percent credit for the Pinehurst wood smoke 
public awareness program. This credit is based upon the increased 
effectiveness of the public awareness program since 1991, the fact that 
Pinehurst is a small town (population 1,722 in 1990)--which makes it 
relatively easy to keep in contact with the citizens, and the fact that 
IDEQ has hired a Pinehurst wood stove advocate to work on increasing 
the public's awareness of the availability of cleaner-burning 
residential heating devices.
    Considering IDEQ's aforementioned reasons for claiming a five 
percent emission reduction credit (which equals a PM-10 emission 
reduction of 10.8 lbs/day, and a 24-hour PM-10 ambient reduction of 4 
g/m3), EPA is accepting the five percent credit requested 
by the IDEQ.
    (3) Uncertified Wood Stove Change-out Program. IDEQ is in the 
process of replacing 90 uncertified wood stoves in the Pinehurst 
nonattainment area with cleaner heating devices. The uncertified wood 
stoves are replaced as part of a combined Federal assistance grant, and 
State and local loan program. Ninety grants ranging from $500-$1,750 
each will be offered to the residents of Pinehurst as financial 
incentive to replace their uncertified stoves with natural gas 
furnaces, pellet stoves or phase II wood stoves. In addition, 50 of 
these participants will be offered low interest loans, up to a maximum 
amount of $1,500 per homeowner, using Idaho Department of Water 
Resources (IDWR) funds. These loans will cover the additional costs of 
upgrading the qualifying resident's heating system, including the cost 
of installation. IDWR will allow the loans to be paid back over a five-
year period. The combined grant and loan program will be administered 
by the Northern Idaho Community Action Agency (NICAA).
    It is estimated by IDEQ that the combined grant/loan program will 
replace 90 uncertified wood stoves with 40 natural gas furnaces, 25 
pellet stoves and 25 phase II wood stoves. This change is projected to 
result in a PM-10 emission reduction of 43.4 lbs/day (which equals a 17 
g/m3 24-hour PM-10 reduction) in the Pinehurst 
nonattainment area (based upon a 100%, 95% and 55% emission reduction 
credits for replacing uncertified wood stoves with natural gas 
furnaces, pellet stoves and phase II wood stoves, respectively; a 0.56 
lbs/day PM-10 emission rate for a uncertified wood stove in Pinehurst; 
and the determination that a PM-10 emission rate of 393 lbs/day equals 
a 24-hour ambient PM-10 concentration of 150 g/m3 at 
Pinehurst).
    Thus, IDEQ is estimating that the wood stove change-out program 
will reduce PM-10 emissions from residential wood combustion devices in 
Pinehurst by 16.5 percent (or 43.4 lbs of PM-10 reduced/day divided by 
263.8 lbs of PM-10 emitted on the worst case day in 1994). EPA believes 
that the program will reduce PM-10 emissions in the Pinehurst 
nonattainment area because the program is receiving broad based support 
and has secure funding sources. Therefore, EPA is accepting the 16.5 
percent PM-10 emission reduction credit that IDEQ claims will result 
from implementation of the wood stove change-out program.
    (4) Home Weatherization Program. Wood stove emissions can be 
reduced slightly through comprehensive weatherization programs that 
result in a reduction of the amount of fuel utilized. The Idaho 
Economic Opportunity Office offers free weatherization assistance to 
low income families. This assistance takes the form of an energy audit, 
which may result in insulation, weather stripping and heating system 
improvements.
    Home weatherization improvements will be applied to all 90 
households in which wood stove change-outs occur, using loans and grant 
money from Idaho Department of Water Resources, Farmers Home 
Administration, Washington Water Power and North Idaho Community Action 
Agency's Weatherization Division. At least 30 other homes will be 
targeted for weatherization improvements.
    EPA's Guidance Document for Residential Wood Combustion Emission 
Control Measures, September 1989, generally recommends less than a five 
percent credit for home weatherization programs. However, IDEQ is 
claiming an eight percent credit for the Pinehurst home weatherization 
program for the following three reasons: a. Pinehurst has a higher than 
normal percentage of older, uninsulated homes; b. Shoshone County, 
which contains Pinehurst, has a high percentage of low income 
households, who in the past were unable to afford weatherization; and 
c. Pinehurst's cold winter climate results in a high number of heating 
degree days, which enables a home weatherization program to have more 
impact than it would in an area that possesses a warmer winter climate.
    The eight percent reduction claimed from the program is only 
equivalent to a PM-10 decrease of 3.5 lbs/day (which equals a daily 
ambient PM-10 reduction of 1 g/m3). Therefore, this 
program will have only a slight impact on PM-10 levels during worst 
case days. Nonetheless, in light of IDEQ's reasoning that homes in 
Pinehurst are in need of weatherization, and that weatherizing 120 
homes will result in lower fuel consumption and correspondingly less 
PM-10 emissions in the Pinehurst nonattainment area, EPA is accepting 
the eight percent credit claimed by IDEQ.
    b. Other Sources. RACM (including RACT) does not require the 
imposition of controls on emissions from sources that are insignificant 
(i.e. de minimis) and does not require the implementation of all 
available control measures where an area demonstrates timely attainment 
and the implementation of additional controls would not expedite 
attainment (see 57 FR 13540-44).
    IDEQ has determined, through its emission inventory analysis of the 
nonattainment area, that road dust contributed 38 percent of the PM-10 
concentration on the worst case days in base year 1988. IDEQ 
demonstrated timely attainment of the 24-hour PM-10 NAAQS by 
controlling wood smoke. Therefore, RACM does not require road dust 
control measures. Furthermore, RACM does not require the implementation 
of controls for prescribed silvicultural and agricultural burning for 
the Pinehurst nonattainment area, because the area is not significantly 
impacted by those activities on worst case days, according to the 
emission inventory analysis.
    Similarly, RACT does not require the implementation of control 
technology for sources of PM-10 in the nonattainment area, because the 
area is primarily characterized by residential and commercial uses 
which are not subject to RACT requirements. There are no major 
stationary sources operating in the Pinehurst PM-10 nonattainment area.
    A more detailed discussion of the control measures contained in the 
SIP and an explanation as to why certain available control measures 
were not implemented, can be found in IDEQ's submittal and in the TSD. 
EPA has reviewed IDEQ's submittal and associated documentation and 
concluded that they adequately justify the control measures to be 
implemented. The implementation of the Pinehurst, Idaho PM-10 
nonattainment plan control strategy will result in the attainment of 
the PM-10 NAAQS as expeditiously as practicable--by December 31, 1994. 
By this notice, EPA is approving IDEQ's control strategy as satisfying 
the RACM (including RACT) requirement.
4. Demonstration
    Moderate PM-10 nonattainment areas must submit a demonstration 
(including air quality modeling) showing that the plan will provide for 
attainment as expeditiously as practicable but no later than December 
31, 1994 (see section 189(a)(1)(B) of the Act). The General Preamble 
sets out EPA's guidance on the use of modeling for moderate area 
attainment demonstrations (57 FR 13539). Alternatively, the State must 
show attainment by December 31, 1994, is impracticable. The 24-hour PM-
10 NAAQS is 150 micrograms/cubic meter (g/m3), and the 
standard is attained when the expected number of days per calendar year 
with a 24-hour average concentration above 150 g/m3 is 
equal to or less than one (see 40 CFR 50.6). The annual PM-10 NAAQS is 
50 g/m3, and the standard is attained when the expected 
annual arithmetic mean concentration is less than or equal to 50 
g/m3 (id.).
    IDEQ utilized an attainment demonstration for Pinehurst based upon 
proportional rollback modeling supported by a complete emission 
inventory, receptor modeling and WYNDvalley, a non-guideline dispersion 
model.
    The receptor modeling consisted of using the Chemical Mass Balance 
(CMB) version 7.0 air quality model to analyze for days during 1988-
1990 when 24-hour PM-10 concentrations were either elevated or exceeded 
the NAAQS. CMB results from ten PM-10 filters showed that on the 
average residential wood smoke and fugitive dust were responsible for 
77 and 18 percent, respectively, of the PM-10 on high concentration 
days. The CMB percentages for residential wood smoke and fugitive dust 
are greater and lower, respectively, than those that were determined 
from the emission inventory, but the CMB analysis still confirms that 
residential wood combustion is the major source of PM-10 on worst case 
days in the Pinehurst nonattainment area. Therefore, these results 
support IDEQ's reliance on wood smoke control strategies to attain the 
PM-10 standard.
    The IDEQ used version 3.06 of the WYNDvalley dispersion model to 
simulate PM-10 concentrations in Pinehurst during a wintertime 
stagnation episode. WYNDvalley was chosen because of the model's 
ability to handle both the light wind conditions and complex terrain 
that significantly help trap PM-10 air pollution in the Pinehurst PM-10 
nonattainment area. Also, the WYNDvalley dispersion model was used 
because Pinehurst is dominated by area sources (wood smoke and fugitive 
road dust) and lacks any major point source impacts. The modeled 
stagnation event began on January 20, 1988 and continued through 
January 30, 1988. Pinehurst's design value exceedance of 183 
g/m3 was measured on January 28, during this stagnant 
period. The WYNDvalley model showed that the maximum PM-10 values 
occurred at or near the Pinehurst school, agreeing with results found 
in the January-March 1989 CMB/saturation study. Therefore, the model 
helped verify that the Pinehurst PM-10 monitor is situated in the area 
of maximum PM-10 impact.
    The attainment demonstration indicates that Pinehurst will attain 
the 24-hour PM-10 NAAQS by December 31, 1994, with the maximum 24-hour 
concentration predicted to be 143 g/m3 (which is the 
result of the proposed control measures reducing the projected 1994 
maximum PM-10 emissions from 484.8 to 375.9 lbs/day).
    According to EPA's review, which identified incomplete quarterly 
data in 1986 and corrected for the use of non-reference PM-10 data in 
1986 and 1987 (i.e. Hi-Vol SA321A gravimetric PM-10 sampler), Pinehurst 
has never violated the annual arithmetic mean PM-10 standard. The 
highest valid three-year annual average at Pinehurst is 46 g/
m3, during 1987-1989, while the lowest three-year average is 36 
g/m3, during 1990-1992. Therefore, IDEQ and EPA believe 
that because the annual PM-10 standard has never been violated at 
Pinehurst, and the 24-hour PM-10 controls have helped reduce annual 
concentrations (as evidenced in the downward trend in the annual 
average concentrations), it is reasonable to predict that the area will 
continue to meet the annual standard and the standard will not be 
violated in 1994.
    EPA is finding that the modeling analysis is adequate to 
demonstrate timely attainment of the PM-10 NAAQS in Pinehurst. The 
control strategies used to achieve attainment are summarized in the 
section titled ``RACM (including RACT).'' A more detailed description 
of the attainment demonstration is contained in the TSD accompanying 
this notice.
    It should be noted that the 1997 maintenance demonstration, 
supplied by IDEQ, shows that Pinehurst will remain in attainment for 
both the 24-hour and annual PM-10 NAAQS through 1997. According to 
IDEQ's calculations, which were partially based on a 1994 Washington 
Water Power residential heating survey for the Pinehurst area, the 
maximum 24-hour PM-10 concentration in 1997 will be 127 g/
m3. This 1997 24-hour value is equivalent to a PM-10 emission rate 
of 332 lbs/day. Furthermore, the annual arithmetic standard will be 
maintained from 1994-2000, with the maximum annual average value of 
47.2 g/m3 (occurring in the year 2000). This 
aforementioned concentration is equivalent to a PM-10 emission rate of 
47.0 tons/year. This 1997 maintenance demonstration satisfies part of 
the quantitative milestones/reasonable further progress requirement 
(see CAA section 189(c)).
5. Quantitative Milestones and Reasonable Further Progress (RFP)
    The PM-10 nonattainment area plan revisions demonstrating 
attainment must contain quantitative milestones which are to be 
achieved every three years until the area is redesignated attainment 
and which demonstrate RFP, as defined in section 171(1), toward 
attainment by December 31, 1994 (see section 189(c) of the CAA).
    While section 189(c) plainly provides that quantitative milestones 
are to be achieved until an area is redesignated attainment, it is 
silent in indicating the starting point for counting the first three-
year period or how many milestones must be initially addressed. In the 
General Preamble, EPA addressed the statutory gap in the starting point 
for counting the three-year milestones, indicating that it would begin 
from the due date for the applicable implementation plan revision 
containing the control measures for the area (i.e., November 15, 1991 
for initial moderate PM-10 nonattainment areas) (see 57 FR 13539).
    As to the number of milestones, EPA believes that at least two 
milestones must be initially addressed. Thus, submittal to address the 
SIP revisions due on November 15, 1991 for the initial moderate PM-10 
nonattainment areas must demonstrate that two milestones will be 
achieved (First milestone: November 15, 1991 through November 15, 1994; 
Second milestone: November 15, 1994 through November 15, 1997).
    For the initial PM-10 nonattainment areas that demonstrate 
attainment, the emissions reduction progress made between the SIP 
submittal (due date of November 15, 1991) and the attainment date of 
December 31, 1994 (46 days beyond the November 15, 1994 milestone date) 
will satisfy the first quantitative milestone. The de minimis timing 
differential makes it administratively impracticable to require 
separate milestone and attainment demonstrations (see 57 FR 13539). For 
such areas that demonstrate timely attainment of the PM-10 NAAQS, the 
second milestone should, at a minimum, provide for continued 
maintenance of the standards.\5\
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    \5\ Section 189(c) of the Act provides that quantitative 
milestones are to be achieved ``until the area is redesignated 
attainment.'' However, this endpoint for quantitative milestones is 
speculative because redesignation of an area as attainment is 
contingent upon several factors and future events. Therefore, EPA 
believes it is reasonable for States to initially address at least 
the first two milestones. Addressing two milestones will ensure that 
the State continues to maintain the NAAQS beyond the attainment date 
for at least some period during which an area could be redesignated 
attainment. However, in all instances, additional milestones must be 
addressed if an area is not redesignated attainment.
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    This SIP demonstrates attainment by December 31, 1994 and 
maintenance through December 31, 1997, satisfying two milestones. 
Therefore, the submittal satisfies the quantitative milestones 
currently due. Accordingly, EPA is approving the SIP for Pinehurst 
relative to the quantitative milestone requirement.
    Finally, once a milestone has passed, the State will have to 
demonstrate that the milestone was, in fact, achieved for the Pinehurst 
area as provided in section 189(c)(2) of the Act.
6. PM-10 Precursors
    The control requirements which are applicable to major stationary 
sources of PM-10, also apply to major stationary sources of PM-10 
precursors unless EPA determines such sources do not contribute 
significantly to PM-10 levels in excess of the NAAQS in that area (see 
section 189(e) of the Act). The General Preamble contains guidance 
addressing how EPA intends to implement section 189(e) (see 57 FR 
13539-13540 and 13541-13542).
    The filter analyses (chemical mass balance) indicated that, on 
average, less than 4 percent of the PM-10 mass was comprised of 
secondary particulate on high concentration days. EPA believes that 
this is an insignificant portion and, therefore, is proposing to grant 
the exclusion from control requirements authorized under section 189(e) 
for major stationary sources of PM-10 precursors.
    Note that while EPA is making a general finding for this area about 
precursor contribution to PM-10 NAAQS exceedances, this finding is 
based on the current character of the area including, for example, the 
existing mix of sources in the area. It is possible, therefore, that 
future growth could change the significance of precursors in the area.
7. Enforceability Issues
    All measures and other elements in the SIP must be enforceable by 
IDEQ and EPA (see sections 172(c)(6), 110(a)(2)(A) of the CAA and 57 FR 
13556). EPA criteria addressing the enforceability of SIP's and SIP 
revisions are set forth in a September 23, 1987 memorandum (with 
attachments) from J. Craig Potter, Assistant Administrator for Air and 
Radiation, et. al. (see 57 FR 13541). Nonattainment area plan 
provisions must also contain a program that provides for enforcement of 
the control measures and other elements in the SIP (see section 
110(a)(2)(C) of the CAA).
    The particular control measures contained in the SIP are addressed 
above under the section headed ``RACM (including RACT).'' These control 
measures apply to residential wood combustion activities. The SIP 
provides that the control measures for the affected activities apply 
throughout the entire nonattainment area.
    The SIP provided that all affected activities would be in full 
compliance with the implementation of applicable control measures by 
December 10, 1993. However, funding problems has delayed implementation 
of the wood stove change-out and home weatherization programs until the 
summer of 1994.
    IDEQ is responsible for running the voluntary episodic wood burning 
curtailment and public awareness programs. The curtailment program for 
Pinehurst is part of a statewide program that evaluates air quality and 
meteorological parameters in the PM-10 nonattainment areas on a daily 
basis, during November 1 through the end of February, and declares 
burning bans as necessary. The public awareness program is a broad-
based strategy designed for the entire Silver Valley (which includes 
the Pinehurst NAA). IDEQ, through the Pinehurst Particulate (PM-10) Air 
Quality Improvement Plan and supporting documentation, commits to 
carrying out the curtailment and public awareness programs in 
Pinehurst. If either of these two measures are discontinued without EPA 
and public approval, then the State of Idaho would be subject to a 
findings letter for non-implementation of an approved part of the plan 
(see section 179(a)(4) of the CAA). This in turn could result in 
Federal sanctions imposed against the State and the loss of State base 
grant funds.
    IDEQ's submittal and the TSD contain further information on 
enforceable requirements. The TSD also contains a discussion of the 
personnel and funding intended to support effective implementation of 
the control measures.
8. Contingency Measures
    As provided in section 172(c)(9) of the Act, all moderate 
nonattainment area SIP's that demonstrate attainment must include 
contingency measures (see generally 57 FR 13543-13544). These measures 
were required to be submitted by November 15, 1993 for the initial 
moderate nonattainment areas. Contingency measures should consist of 
other available measures that are not part of the area's control 
strategy. These measures must take effect without further action by the 
State or EPA, upon a determination by EPA that the area has failed to 
make RFP or attain the PM-10 NAAQS by the applicable statutory 
deadline.
    Contingency measures for the Pinehurst PM-10 nonattainment area 
have not yet been submitted by IDEQ. A findings letter, dated January 
13, 1994, was mailed to the Governor of Idaho which informed him that 
the State had failed to make the required PM-10 contingency measures 
submittal for Pinehurst. The State has until July 13, 1995 to correct 
this deficiency for Pinehurst, or it will face federal highway or 
offset sanctions (see section 179 of the CAA).
    EPA intends to take action on the contingency measures for the 
Pinehurst PM-10 nonattainment area when the requirement is submitted, 
or intends to impose sanctions in the event this deficiency is not 
corrected.

III. Implications of This Action

    EPA is approving the plan revision submitted to EPA on April 14, 
1992 for the Pinehurst nonattainment area. Among other things, IDEQ has 
demonstrated that the Pinehurst moderate PM-10 nonattainment area will 
attain the PM-10 NAAQS by December 31, 1994.

IV. Administrative Review

    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA 
must prepare a regulatory flexibility analysis assessing the impact of 
any proposed or final rule on small entities. 5 U.S.C. 603 and 604. 
Alternatively, EPA may certify that the rule will not have a 
significant impact on a substantial number of small entities. Small 
entities include small businesses, small not-for-profit enterprises, 
and government entities with jurisdiction over populations of less than 
50,000.
    SIP approvals under section 110 and subchapter I, part D of the CAA 
do not create any new requirements, but simply approve requirements 
that the state is already imposing. Therefore, because the federal SIP-
approval does not impose any new requirements, I certify that it does 
not have a significant impact on any small entities affected. Moreover, 
due to the nature of the federal-state relationship under the CAA, 
preparation of a regulatory flexibility analysis would constitute 
federal inquiry into the economic reasonableness of state action. The 
CAA forbids EPA to base its actions concerning SIPs on such grounds. 
Union Electric Co. v. U.S.E.P.A., 427 U.S. 246, 256-66 (S.Ct. 1976); 42 
U.S.C. 7410(a)(2).
    The EPA is publishing this action without prior proposal because 
the Agency views this as a noncontroversial amendment and anticipates 
no adverse comments. However, in a separate document in this Federal 
Register publication, the EPA is proposing to approve the SIP revision 
should adverse or critical comments be filed. This action will be 
effective October 24, 1994 unless, by September 26, 1994 adverse or 
critical comments are received.
    If the EPA receives such comments, this action will be withdrawn 
before the effective date by publishing a subsequent document that will 
withdraw the final action. All public comments received will be 
addressed in a subsequent final rule based on this action serving as a 
proposed rule. The EPA will not institute a second comment period on 
this action. Any parties interested in commenting on this action should 
do so at this time. If no such comments are received, the public is 
advised that this action will be effective October 24, 1994.
    The EPA has reviewed this request for revision of the federally 
approved SIP for conformance with the provisions of the 1990 Clean Air 
Act Amendments enacted on November 15, 1990. The EPA has determined 
that this action conforms with those requirements.
    Nothing in this action should be construed as permitting or 
allowing or establishing a precedent for any future request for 
revision to any SIP. Each request for revision to the SIP shall be 
considered separately in light of specific technical, economic and 
environmental factors and in relation to relevant statutory and 
regulatory requirements.
    This action has been classified as a Table 2 action by the Regional 
Administrator under the procedures published in the Federal Register on 
January 19, 1989 (54 FR 2214-2225), as revised by an October 4, 1993 
memorandum from Michael H. Shapiro, Acting Assistant Administrator for 
Air and Radiation. The OMB has exempted this regulatory action from 
E.O. 12866 review.
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by October 24, 1994. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this rule for the purposes of judicial 
review nor does it extend the time within which a petition for judicial 
review may be filed and shall not postpone the effectiveness of such 
rule or action. This action may not be challenged later in proceedings 
to enforce its requirements. (See section 307(b)(2), 42 U.S.C. 
7607(b)(2)).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Particulate matter.

    Dated: July 5, 1994.
Gerald A. Emison,
Acting Regional Administrator.

    Part 52, chapter I, title 40 of the Code of Federal Regulations is 
amended as follows:

PART 52--[AMENDED]

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

Subpart N--Idaho

    2. Section 52.670 is amended by adding paragraph (c)(28) to read as 
follows:


Sec. 52.670  Identification of plan.

* * * * *
    (c) * * *
    (28) On April 14, 1992, the State of Idaho submitted a revision to 
the SIP for Pinehurst, ID, for the purpose of bringing about the 
attainment of the national ambient air quality standards for 
particulate matter with an aerodynamic diameter less than or equal to a 
nominal 10 micrometers.
    (i) Incorporation by reference.
    (A) April 7, 1992 letter from Idaho Department of Health and 
Welfare to EPA Region 10 submitting the Pinehurst Particulate Air 
Quality Improvement Plan as a revision to the Implementation Plan for 
the Control of Air Pollution in the State of Idaho. The plan has been 
adopted in accordance with the authorities and requirements of the 
Federal Clean Air Act and the Idaho Environmental Protection and Health 
Act (Idaho Code section 39-10/et seq).
    (B) SIP revision for Pinehurst Particulate Air Quality Improvement 
Plan, February 5, 1992 (adopted on April 7, 1992).

[FR Doc. 94-20810 Filed 8-24-94; 8:45 am]
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