1 

BEFORE THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

Sierra Club’s Petition for Rulemaking to Designate ) 

Air Quality Models to use for PSD Permit Applications ) 

with Regard to Ozone and PM2.5 ) 
2 

I. INTRODUCTION 

 Pursuant to the Administrative Procedure Act,1

 the Clean Air Act,2 including 42 

U.S.C. §§ 7475(e)(3)(D), 7607(d), 7410(k)(1)(A) & (k)(5) and Right to Petition the 

Government Clause contained in the First Amendment of the United States Constitution,3

Petitioner Sierra Club file this Petition for Rulemaking with the Administrator. Sierra 

Club respectfully requests her to designate computer models to use to determine if major 

sources of air pollution cause or contribute to violations of the ozone national ambient air 

quality standards and the fine particulate matter national ambient air quality standards 

and increments. 

 This is literally a life or death situation. The United States Environmental 

Protection Agency (EPA) has acknowledged that both ozone and fine particulate matter 

have a variety of adverse impacts including premature mortality. Thus, we hope that you 

treat this petition with the urgency that a life or death matter deserves. 

 Administrator Jackson, upon taking office, promised to uphold three values: 1) 

Science being the backbone of EPA’s work; 2) Respecting the rule of law; and 3) 

Ensuring transparency. The lack of designated models seriously undercuts all three 

 1 5 U.S.C. § 553(e) (1994). 

2 42 U.S.C. § 7401, et seq. (1994).

3 “Congress shall make no law . . . abridging . . . the right of the people . . . to petition 

Government for a redress of grievances.” U.S. Const., amend. I. The right to petition for redress of 

grievances is among the most precious of the liberties safeguarded by the Bill of Rights. United Mine 

Workers of America, Dist. 12 v. Illinois State Bar Association, 389 U.S. 217, 222, 88 S. Ct. 353, 356, 19 L. 

Ed. 2d 426 (1967). It shares the “preferred place” accorded in our system of government to the First 

Amendment freedoms. Thomas v. Collins, 323 U.S. 516, 530, 65 S. Ct. 315, 322, 89 L. Ed. 430 (1945). 

The Supreme Court has recognized that the right to petition is logically implicit in, and fundamental to, the 

very idea of a republican form of government. United States v. Cruikshank, 92 U.S. (2 Otto) 542, 552, 23 L. 

Ed. 588 (1875).
3 

values. Too often, permit applicants and state agencies ignore the current science of 

computer modeling and obtain and issue air pollution permits without an adequate or 

even any analysis of air quality impacts from ozone and fine particulate matter. Science 

provides us with tools, in the form of modern computer models, to adequately analyze air 

quality impacts from ozone and fine particulate matter. It is up to the Administrator to 

promulgate regulations to ensure that this science is used. 

 As to the rule of law, Congress has mandated that the Administrator shall

designate air quality models to determine impacts from major sources of air pollution. 

See 42 U.S.C. § 7475(e)(3)(D). For decades EPA administrators have violated this 

mandate with respect to ozone and fine particulate matter. This disregard for the rule of 

law should come to an end quickly. 

 Finally, “deals” for air pollution permits are very often made between permit 

applicants and state and local agencies or even with EPA regions in meeting without any 

public involvement or input. Also, without designated air quality models, the public is 

not given a clear picture of the impacts a proposed new or modified major source of air 

pollution will have on them. The Administrator can rectify this lack of transparency by 

designating air quality models that will be consistently used by permit applicants and 

agencies and will provide the public with the best assessment of the air quality impacts. 

 Again, we emphasis EPA needs to address this issue quickly. EPA has been 

aware of this issue for a while. Sierra Club has raised it with EPA before. See Sierra 

Club’s Nov. 10, 2008 Comments on Docket ID No. EPA-HQ-OAR-2008-0604, Ninth 

Conference on Air Quality Modeling attached as Ex. 1. EPA personnel have 

acknowledged that this problem long before Sierra Club raised it in the context of the 
4 

Ninth Modeling Conference. See e.g. Ex. 9 at 3rd page (“This issue has been problematic 

ever since I've been working at EPA but it's probably worth discussing...again.”) As far 

back as in 2005, EPA personnel acknowledged that this is a high priority issue. See e.g.

Ex. 10 at 3, 5. It is now time for EPA to take action to protect public health and welfare 

from ozone and fine particulate matter. 

II. PETITIONER 

 Petitioner Sierra Club is one of the largest and oldest grassroots environmental 

groups in the nation. Its mission is to explore, enjoy and protect the planet. Towards this 

end, the Sierra Club has been working on ensuring the Clean Air Act is effective even 

before Clean Air Act came into its modern form. Sierra Club was instrumental in 

bringing about the Clean Air Act’s Prevention of Significant Deterioration (PSD) 

program. See e.g. Sierra Club v. Ruckelshaus, 344 F.Supp. 253 (D.D.C.), aff'd, 4 E.R.C. 

1815 (D.C. Cir. 1972), aff'd by an equally divided Court, 412 U.S. 541, 93 S.Ct. 2770, 37 

L.Ed.2d 140 (1973). Sierra Club continues to be very involved in the PSD program. 

 Sierra Club members are adversely affected by air pollution from PSD sources, 

some of which should not have received a permit because they cause or contribute to 

violations of the ozone NAAQS and PM2.5 NAAQS or increments. In addition, Sierra 

Club has to spend considerable time and resources commenting on and litigating PSD 

permits which would never have been issued if the source had to use an appropriate 

computer model to determine whether the source causes or contributes to a violation of 

the Ozone National Ambient Air Quality Standard (NAAQS) and particulate matter less 
5 

than 2.5 microns in diameter (PM2.5) NAAQS. This is because the modeling would 

likely show that the source would cause or contribute to a violation. 

III. REGULATORY STRUCTURE 

 EPA created an initial regulatory Prevention of Significant Deterioration (PSD) 

program as the result of a Sierra Club lawsuit. See 39 Fed. Reg. 31,000 (Aug. 27, 1974). 

Subsequently, in 1977 Congress created the legislative PSD program. The PSD program 

contains a requirement that major source or major modification of a major source of air 

pollution cannot be constructed unless: 

the owner or operator of such facility demonstrates, as required pursuant 

to section 7410(j) of this title, that emissions from construction or 

operation of such facility will not cause, or contribute to, air pollution in 

excess of any (A) maximum allowable increase or maximum allowable 

concentration for any pollutant in any area to which this part applies more 

than one time per year, (B) national ambient air quality standard in any air 

quality control region[.] 

42 U.S.C. § 7475(a)(3). To ensure proper implementation of this critical PSD 

requirement, the Clean Air Act also requires: 

The Administrator shall within six months after August 7, 1977, 

promulgate regulations respecting the analysis required under this 

subsection which regulations-- 

 . . . 

 (D) shall specify with reasonable particularity each air quality 

model or models to be used under specified sets of conditions for 

purposes of this part. 

Any model or models designated under such regulations may be adjusted 

upon a determination, after notice and opportunity for public hearing, 

by the Administrator that such adjustment is necessary to take into 

account unique terrain or meteorological characteristics of an area 

potentially affected by emissions from a source applying for a permit 

required under this part. 

42 U.S.C. § 7475(e)(3). 
6 

 EPA created final regulations to implement the legislative PSD program in 1980. 

These regulations have been amended from time to time. These regulations implement 

42 U.S.C. § 7475(a)(3) by providing: 

 (k) Source impact analysis. 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 reductions (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 [a.k.a. increment] in any area. 

 (l) Air quality models. (1) All estimates of ambient concentrations 

required under this paragraph shall be based on applicable air quality 

models, data bases, and other requirements specified in appendix W of 

part 51 of this chapter (Guideline on Air Quality Models). 

 (2) Where an air quality model specified in appendix W of part 51 of 

this chapter (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 

developed in accordance with paragraph (q) of this section. 

 

40 C.F.R. 52.21(k) & (l)(2008). In other words, to carry out its 42 U.S.C. § 

7475(e)(3)(D) obligations, EPA incorporated by reference its Guideline on Air Quality 

Modeling as Appendix W into its permitting regulations. See 43 Fed. Reg. 26380, 26398 

(June 19, 1978). Thus, despite its name, EPA's Guideline on Air Quality Modeling, 

hereinafter referred to as Appendix W, is a regulation. 

 As to ozone, Appendix W provides: 

5.2.1.c. Estimating the Impact of Individual Sources. Choice of 

methods used to assess the impact of an individual source depends on 

the nature of the source and its emissions. Thus, model users should 

consult with the Regional Office to determine the most suitable 
7 

approach on a case-by-case basis (subsection 3.2.2). 

40 C.F.R. 52.21 Appx. W, Section 5.2.1.c. Unfortunately, despite the plain language that 

says “model users” in this provision, all too often this provision is cited for the 

proposition that there is no model available. Thus, major sources of ozone precursors 

obtain their PSD permits without demonstrating that they will not cause or contribute to a 

violation of the ozone NAAQS. 

 As to PM2.5, Appendix W says the same thing. It says: 

c. Estimating the Impact of Individual Sources. Choice of 

methods used to assess the impact of an individual source depends on 

the nature of the source and its emissions. Thus, model users should 

consult with the Regional Office to determine the most suitable 

approach on a case-by-case basis (subsection 3.2.2). 

40 C.F.R. 52.21 Appx. W, Section 5.2.2.c. Appendix A to Appendix W is the discussion 

of recommended models. It does not recommend a particular model for ozone or PM2.5 

although it does note that CALPUFF can be used to model PM2.5 including some sulfur 

and nitrogen compound chemistry. 

IV. EPA MUST DESIGNATE CAMx OR ANOTHER PHOTOCHEMICAL 

MODEL TO BE USED TO ASSURE THAT MAJOR SOURCES OR 

MAJOR MODIFICATIONS DO NOT CAUSE OR CONTRIBUTE TO A 

VIOLATION OF THE OZONE NAAQS. 

A. EPA SHOULD DESIGNATE CAMx OR A SIMILAR MODEL AS 

THE APPENDIX W MODEL FOR OZONE FOR PSD 

APPLICATIONS. 

 EPA should amend Appendix W to require all major sources of volatile organic 

compounds (VOCs) and nitrogen oxides (NOx) applying for a PSD permit use the 
8 

Comprehensive Air Quality Model with Extensions (CAMx) or a similar photochemical 

model, such as the Community Multiscale Air Quality modeling system (CMAQ), to 

demonstrate that the proposed source will not cause or contribute to a violation of the 

most current ozone NAAQS. Currently, some PSD applicants are required to or do use a 

computer model such as CAMx to demonstrate they will not cause or contribute to a 

violation. Use of computer models like RPM IV has been going on for a number of years, 

at least by some regions. See e.g. Ex. 9 at 1-2. Other PSD applicants use discredited or 

indefensible screening tools such as the Scheffe “look up tables” or extrapolations from 

modeling exercises in different geographic areas with different sources. See Ex. 14 (Dr. 

Scheffe explaining that Scheffe Lookup Tables are not valid). Still others simply 

provide no analysis on this. This patchwork approach is not scientific, transparent or 

legal. 

 EPA itself has acknowledged that CAMx and similar models can be used to 

determine if a single source causes or contributes to an ozone NAAQS violation. For 

example, EPA acknowledge that using “regional scale ozone models” have been used by 

some EPA Regions since 1999. Ex. 13 at 3. EPA also acknowledged in 2005 that the 

use of regional scale ozone models have some promise. Id. 

 Since then, EPA used and supported the use of “regional scale” models on 

numerous occasions. For example, EPA required this methodology for the proposed 

Desert Rock power plant PSD application. See Ex 2 at 59 – 60 ( ”With respect to the 

Petitioners' request for a source specific impact analysis, this type of analysis was already 

performed using the CAMx model, as part of New Mexico's Early Action Compact 

(“EAC”), which EPA approved into New Mexico's SIP three years ago. See 70 FR 
9 

48,285 (Aug. 17, 2005); 40 C.F.R. § 52.1620(e). This modeling had already been 

accepted as adequate. EPA’s Guideline on Air Quality Models (40 C.F.R. Part 51, App. 

W) allows Region 9 the flexibility to apply this modeling for a PSD permit ozone impact 

analysis.”); at 63 ( “In this modeling, New Mexico developed a “base case” and 

demonstrated that the CAMx model performed adequately compared to monitored 

ambient data for then-current conditions (2002, in this case). Projected future emissions 

were then supplied to the model to predict future ambient concentrations, and finally, an 

additional “sensitivity” model run simulated emissions from two power plants that have 

yet to be built, including the DREF (called “STEAG” at the time).”) Despite all the 

caveats and exceptions EPA Region 9 included in its legal brief, the fact is that EPA 

relied on CAMx modeling to determine whether a single PSD applicant caused or 

contributed to an ozone NAAQS violation. 

 More recently, EPA Region 6 has commented that photochemical modeling was 

needed to demonstrate that a proposed major source, the White Stallion proposed power 

plant in Texas, would not cause or contribute to a violation of the ozone NAAQS. Ex. 11 

at Enclosure, first page. In this instance, EPA Region 6 recommended CMAQ or CAMx. 

Id. Region 6 explained that Texas CEQ as well as other permitting agencies and permit 

applicants have worked with EPA Region 6 to develop modeling protocols to determine 

if a major source causes or contributes to a violation of the ozone NAAQS. Id. 

 EPA has also performed ozone modeling to assess the impacts of individual 

proposed major sources on behalf of states. For example almost a decade ago, “U.S. 

EPA’s Atmospheric Modeling Development Branch (AMD), at the request of Kentucky, 

performed a series of model simulations with the Community Multi-Scale Air Quality 
10 

(CMAQ) modeling system to examine the potential air impacts of adding new electrical 

generating units in Kentucky.” Ex. 3 at 29. This modeling demonstrated individual 

sources that were particularly problematic in contributing to ozone violation. See e.g. Id. 

at 33. Note that the Cash Creek facility identified in this report recently received its PSD 

permit from Kentucky without any ozone modeling in support of its application. 

 Similarly, EPA has accepted ozone modeling performed by states to support PSD 

applications for individual sources. For example, Illinois was a PSD delegated state 

when it issued the PSD permit for the Prairie State Generating Station. The Illinois 

Environmental Protection Agency (IEPA) used the Urban Airshed Model, Version 1.24 

(UAM-V) modeling exercise that supported a previous ozone attainment demonstration 

to determine that the Prairie State Generating Station and several other proposed sources 

will not cause or contribute to a violation of the ozone NAAQS. See Ex. 6 at 2, 3, 12-13. 

 EPA has also used modeling to determine the impacts from individual sources in 

PSD enforcement actions. For example, EPA presented data from a CMAQ modeling 

exercise to predict the impacts that Cinergy’s Wabash River Power Station will have on 

ambient ozone levels. See Ex. 5 at 1, 3. EPA’s use of this information in federal court 

means that EPA and the U.S. Department of Justice determined that this methodology of 

determining a single stationary source’s impact on ambient ozone levels was 

scientifically credible. See generally Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 

U.S. 579, (1993). 

 Other examples of using a “regional model” to determine impacts from individual 

or a few point sources include: 
11 

*Oklahoma –For a number of natural gas fired turbine EGUs, other large point 

sources using DFW modeling. 

•Missouri DNR –Multiple sources (mostly cement kilns) using old 1995-96 

OTAG modeling episodes 

•San Antonio –For multiple facilities as they were developing their Early Action 

Compact 8-hr ozone demonstration (8-day episode) 

•Dallas-Fort Worth –Evaluated impacts from single county (Ellis) to aid in 

determining if the county should be included in 8-hr nonattainment area. 

•Dallas-Fort Worth –Evaluated impacts from groups of power plants in 

Oklahoma, Arkansas, Louisiana, and also looked at individual Louisiana power plants 

and their impacts on areas in Texas for 3 episodes (two 8-day episodes in 1999 and a 15 

day Episode in 2000) 

Ex. 13 at 9. 

 EPA has explained that there are tools available, even 5 years ago, to assist in 

evaluating individual sources with a CMAQ or CAMx type model. These include: 

•Source apportionment techniques: APCA, APCA2, OSAT, PSAT, DDM, etc. 

(Utilizes an accounting procedure for 

generation and destruction of ozone 

based on the source of pre-cursors). 

•Zero-out modeling -Analyses were conducted in which specific point source(s) 

 emissions were removed from the model in separate sensitivity runs and 

 compared with runs with the source(s) included. 

Ex. 13 at 10. 

 It seems like the main reason why PSD applicants are not currently required to 

conduct modeling to demonstrate they will not cause or contribute to a violation of the 

ozone NAAQS is the perception that it would cost the PSD applicants too much money to 

conduct the modeling exercise. See e.g. Ex. 8 at first page. However, EPA has already 

set de minimis thresholds for which sources must comply with PSD. 42 U.S.C. §§ 

7475(e)(3)(D) imposes a mandatory duty on the Administrator to designate the model to 

be used to demonstrate that PSD applicants will not cause or contribute to a violation of 

the NAAQS. 
12 

 In any event, the cost of this modeling has to be taken in context. Many PSD 

sources cost a billion or more dollars. Thus, though the cost for the modeling exercise is 

not trivial, it is going to be modest in the relative sense. 

 Furthermore, PSD applicants can use existing modeling exercises with the 

addition of nested grids to lessen the cost. For example, EPA’s expert used a CMAQ 

modeling exercise from VISTAS, a regional planning organization of Southeastern states 

that was formed to address air pollution problems, to model secondary PM2.5 impacts 

from the Wabash plant in the Cinergy NSR enforcement case. See U.S. v. Cinergy, 99-

cv-1693 May 29, 2009 Slip Op. at 14-15. The Court found this evidence credible, further 

finding that “CMAQ is one of the most peer-reviewed air quality models and reflects 

years of scientific testing, experiments, and comparisons of the model’s predictions to 

measured air pollution by air quality monitors.” Id. EPA also used, or actually re-used, 

CAMx modeling that had been prepared for another purpose. Id. at 16. Some modeling 

exercises include a whole year of modeling. See e.g. Ex. 15 at 6, 7. 

 Another option is for EPA to maintain and run the photochemical models and 

have PSD applicants send their input data to EPA for EPA to use. While this has not 

been the approach used in recent years, not allowing major sources of air pollution to 

“test themselves” would actually go a long way to gaining public trust. 
13 

B. EPA SHOULD CLARIFY THAT THERE IS NO SIGNIFICANT 

IMPACT LEVEL FOR CONTRIBUTION TO OZONE NAAQS 

VIOLATIONS. 

 In addition to designating a model, EPA should make clear that a proposed major 

source of NOx or VOCs may not cause or contribute to any violation of the ozone 

NAAQS. In other words, EPA should clarify that there is no significant impact level for 

ozone. EPA has acknowledged that this is an unpleasant issue for EPA. See e.g. Ex. 13 

at 4 (significance level is “third rail” of PSD). However, Administrator Jackson’s three 

guiding principles of science, law and transparency do not afford EPA the opportunity to 

shy away from uncomfortable issues. 

 EPA’s regulatory language should end this issue. 40 C.F.R. 52.21(k) refers to 

proposed sources or modifications that cause or contribute, not significantly cause or 

contribute, to a violation. Moreover, if the air is unsafe to breathe because there is a 

NAAQS violation, it is simply irresponsible to permit additional pollution to be added to 

the situation.4

 

V. EPA MUST DESIGNATE CAMx, CALPUFF OR ANOTHER PUFF 

MODEL TO BE USED TO ASSURE THAT MAJOR SOURCES OR 

MAJOR MODIFICATIONS, INCLUDING EMISSIONS OF PRECURSOR 

CHEMICALS, DO NOT CAUSE OR CONTRIBUTE TO A VIOLATION 

OF THE PM2.5 NAAQS OR INCREMENT 

 EPA should also amend Appendix W to designate a specific model that PSD 

permit applicants must use to demonstrate that they will not cause or contribute to a 

 

4

 In the alternative, if EPA insists on setting a significance level, it should be no more than 0.30 parts per 

billion. See Ex. 13 at 4. 
14 

violation of the PM2.5 NAAQS or increments.5

 The designated model must be able to 

consider ambient impacts caused by secondary PM2.5. Failure to consider secondary 

PM2.5 ignores the current science which shows that secondary PM2.5 is often times the 

majority of PM2.5. Thus, major sources that ignore secondary PM2.5 impacts have not 

demonstrated that they will not cause or contribute to a violation of the PM2.5 NAAQS 

or increments. EPA has acknowledged that secondary PM2.5 impacts have potentially 

significant contributions to NAAQS and increment violations. See Ex. 7 at 5. EPA has 

also acknowledged that failure to consider secondary PM2.5 underestimates the ambient 

impacts of proposed sources. 75 Fed. Reg. 6827, 6833 (Feb. 11, 2010). EPA has also 

stated in 1997: 

Any comprehensive system for regulating PM2.5 must take into account not 

only the fine particles emitted directly by stationary sources but also the 

various precursors, emitted by certain sources, which result in secondarilyformed fine particles through chemical reactions in the atmosphere. Recent 

studies suggest that secondary particulate matter may account for over half of 

total ambient PM2.5 nationwide.

Ex. 12 at 1 (emphasis added). EPA, nevertheless, excused consideration of secondary 

PM2.5 because it claimed there were technical and informational deficiencies. EPA 

stated in 1997 that it would take 3-5 years to address these technical and information 

deficiencies. Id. at 2. EPA promised the American public that it would amend its 

regulations to address this issue when the technical difficulties were resolved. Id. at 2. 

 It is now 13 years later. The technical and informational deficiencies, to the 

extent they ever even existed, are resolved. EPA simply needs to address the failure to 

comprehensively regulated PM2.5 by amending Appendix W to designate a model that 

will consider secondary PM2.5 for PSD sources. 

 

5

 EPA also needs to finalize the proposed PM2.5 increments. 
15 

 Under the current system, PSD sources are not consistently taking into account 

secondarily formed fine particles. Thus, according to EPA, the PSD program is failing. 

 As with ozone, currently, PSD permit applicants’ “demonstration” of PM2.5 air 

quality impact varies for actual demonstrations using modeling to predict primary and 

secondary impacts to completely ignoring the issue. EPA must mandate the use of a 

specific model to ensure a uniform requirement to actually demonstrate that proposed 

major sources will not cause or contribute to NAAQS or increment violations. 

 The best choice would be for EPA to require the use of CAMx or a similar 

comprehensive model such as CMAQ. However, another, less desirable option is to 

designate CALPUFF or another PUFF model that is capable of modeling the “chemistry” 

of the transformation of precursors into secondary PM2.5. The advantage to designating 

CALPUFF is it is already a guideline model for PSD applicants for Class 1 area impacts 

which includes modeling PM2.5 impacts in the visibility analysis. 

 Within the past decade, PSD permit applicants have commonly used the 

CALPUFF modeling system to estimate impacts of PM2.5 (among other pollutants) on air 

quality related values (AQRV) (e.g., visibility impairment) at Class I areas under 

modeling guidelines issued by designated Federal Land Managers. See U.S. EPA, 

“Interagency Workgroup on Air Quality Related Values, Phase 2 Summary Report and 

Recommendations for Modeling Long Range Transport Impacts,” December 1998. 

CALPUFF was used in support of the Plum Point PSD application in Arkansas. 

 More recently, U.S. EPA guidance for assessing applicability of Best Available 

Retrofit Technology (BART) regulations specified the CALPUFF modeling system to 

determine whether PM2.5 concentrations attributable to eligible sources cause or 
16 

contribute to visibility impairment at Class I areas. See “Regional Haze Regulations and 

Guideline for Best Available Retrofit Technology (BART) Determinations,” Federal 

Register Volume 70, No. 128, July 6, 2005. 

 Although these guidelines recommend the use of CALPUFF for modeling PM2.5 

concentrations, these guidelines do not apply for PSD air quality analyses as specified at 

40 CFR §52.21(k) – Source Impact Analysis. 40 C.F.R. §52.21(l) – Air Quality Models 

refers to the Guideline, which currently recommends CALPUFF only for dispersion 

estimates in short-range complex winds situations and long-range transport.

 Others familiar with the issue have recommended CALPUFF. For example, 

NESCAUM recommended “EPA should allow the use of the current chemistry algorithm 

in CALPUFF as a screening tool for sulfate and nitrate formation in Class I and Class II 

increment analyses, SILs, and NAAQS analyses for PM2.5. In addition, EPA should take 

action to improve the atmospheric chemistry.” NESCAUM, Comments on EPA’s 

Proposed Rule – PSD for PM2.5, December 13, 2007. 

 Any claim that individual sources cannot be modeled would be false because EPA 

itself has used modeling to determine individual sources impacts to PM2.5 NAAQS 

violations. For example, EPA has used models in evaluating individual sources in 

making designations for the 1997 PM2.5 NAAQS. Catawba County v EPA, 571 F.3d 20, 

42 (D.C. Cir. 2009) (“EPA used air quality modeling to determine that the power plant in 

Franklin Township was responsible for the vast majority of Coshocton County's 

contribution to PM2.5 violations in the Columbus Metropolitan Area.”). 

 John S. Seitz's October 23, 1997 memorandum regarding Interim Implementation 

of New Source Review Requirements for PM2.5: 
17 

The EPA is in the process of developing a comprehensive modeling 

system which will be designed to include precursor emissions and account 

for secondary particle formation. The modeling system will also 

incorporate a method for nesting small local impacts from individual point 

sources within a greater modeling domain. Before this can be completed, 

it will be necessary to collect sufficient monitoring data to verify and 

validate protocol modeling results. 

EPA recently explained that at “that time, the statement above referred to the MODELS-3 

development efforts of EPA's Office of Research and Development (ORD). These efforts 

resulted in the completion of the Community Multi-scale Air Quality (CMAQ) model which 

is a sophisticated photochemical air quality model distributed to the public[.]” Ex. 4 at First 

Page. Thus, EPA’s 13 year old claim that it is working on a model to use for PM2.5 PSD 

determination has borne fruit. It is time for EPA to adopt this fruit into its regulations. 

EPA has also used modeling to determine the impacts from individual sources in 

PSD enforcement actions. For example, EPA presented data from a CMAQ and 

CALPUFF modeling exercise to predict the impacts that Cinergy’s Wabash River Power 

Station will have on ambient PM2.5 levels. See Ex. 5 at 1, 3. EPA’s use of this 

information in federal court means that EPA and the U.S. Department of Justice 

determined that this methodology of determining a single stationary source’s impact on 

ambient PM2.5 levels is scientifically credible. 

 We are encouraged by EPA’s recent statement that it is evaluating using regional 

scale models with the ability to track primary and secondary PM2.5 from individual sources 

for PSD compliance purposes. See 75 Fed. Reg. at 6833. However, it has been 13 years 

since EPA promulgated the PM2.5 NAAQS. The time to act is now because as explained 

above, EPA has already demonstrated that “regional scale models” can reliable be used 

for individual source determinations. 
18 

VI. CONCLUSION 

 Therefore, for the reasons explained above, EPA should very quickly modify 

Appendix W to design a specific model for PSD applicants to use to determine if their 

proposed source or modification will cause or contribute to a violation of the ozone 

NAAQS and a specific model to use to determine if their proposed source or 

modification, including its emissions of precursor chemicals, will cause or contribute to a 

violation of the PM2.5 NAAQS or increments. If you have any questions or wish to 

discuss this petition, please do not hesitate to contact the undersigned. Otherwise, we 

look forward to your rapid action to help protect the public health and welfare of the 

United States from the grave threat posed by ozone and PM2.5 air pollution. 

 Respectfully submitted, 

 

 Robert Ukeiley 

 Law Office of Robert Ukeiley 

 435R Chestnut Street, Suite 1 

 Berea, KY 40403 

 Tel: 859-986-5402 

 Fax: 866-618-1017 

 rukeiley@igc.org

 Counsel for Sierra Club 

Dated: July 28, 2010 

Cc: Tyler Fox 

 Group Lead 

 Air Quality Modeling Group 

 US EPA 

 Mail Drop C439-01 
19 

 Research Triangle Park, North Carolina 27711 

Raj Rao 

Group Leader 

New Source Review Group 

US EPA 

Mail Drop C504-03 

Research Triangle Park, North Carolina 27711 

Paul Miller 

NESCAUM 

89 South Street, Suite 602 

Boston, MA 02111