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 Admini strative 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 com puter 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 desi gnated models seriousl y 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. Cons t., amend. I. The right to petition for redress of grievances is among the most precious of the libertie s 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 (196 7). 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 app licants and state agencies i gnore 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 particulat e matter. It is up to the Administrator to promulgate regulations to ensure that this science is used. As to the rule of law, Congress ha s mandated that the Administrator shall designate air quality models to determine im pacts from major source s of air pollution.
See 42 U.S.C. § 7475(e)(3)(D). For decades EP A administrators have violated this mandate with respect to ozone and fine particul ate 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 qu ality models, the public is not given a clear picture of the impacts a pr oposed 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 us ed by permit applicants and agencies and will provide the public with the be st assessment of the air quality impacts. Again, we emphasis EPA needs to addre ss 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 atta ched as Ex. 1. EPA personnel have acknowledged that this problem long before Si erra Club raised it in the context of the4 Ninth Modeling Conference. See e.g. Ex. 9 at 3 rd 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 larg est and oldest grassroots environmental groups in the nation. Its mission is to explore, enj oy and protect the planet. Towards this end, the Sierra Club has been working on ensu ring 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 Preven tion of Significant De terioration (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 aff ected by air pollution from PSD sources, some of which should not have received a pe rmit because they cause or contribute to violations of the ozone NAAQS and PM2.5 NAA QS 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 sour ce causes or contribute s to a violation of the Ozone National Ambient Air Quality Sta ndard (NAAQS) and particulate matter less5 than 2.5 microns in diameter (PM2.5) NAAQS . This is because the modeling would likely show that the source would caus e or contribute to a violation.

III. REGULATORY STRUCTURE EPA created an initial regulatory Prev ention 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 le gislative 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, th at emissions from construction or operation of such facility will not cause, or contribute to, air pollution in excess of any (A) maximum allowabl e increase or maximum allowable concentration for any pollutant in any area to which this part applies more than one time per year, (B) national am bient air quality standard in any air quality control region[.] 42 U.S.C. § 7475(a)(3). To ensure prope r 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 an d opportunity for public hearing, by the Administrator that such adjustment is necessary to take into account unique terrain or meteorolog ical characteristics of an area potentially affected by emissions fr om a source applying for a permit required under this part. 42 U.S.C. § 7475(e)(3).6 EPA created final regulations to impl ement 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 owne r or operator of the proposed source or modification shall demons trate that allowable emission increases from the proposed source or modification, in conjunction with all other applicable emissions in creases or reductions (including secondary emissions), would not cause or contribute to air pollution in violation of: (1) Any national ambient air qua lity 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 (Guide line on Air Quality Models). (2) Where an air quality model sp ecified in appendix W of part 51 of this chapter (Guideline on Air Qual ity Models) is inappropriate, the model may be modified or another m odel substituted. Such a modification or substitution of a mode l 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 opp ortunity 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, EP A'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 suitable7 approach on a case-by-case basis (subsection 3.2.2).

40 C.F.R. 52.21 Appx. W, Section 5.2.1.c. Unfort unately, despite the plain language that says “model users” in this provision, all t oo often this provisio n 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 I ndividual 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. Appe ndix A to Appendix W is the discussion of recommended models. It does not recommen d a particular model for ozone or PM2.5 although it does note that CALPUFF can be us ed to model PM2.5 including some sulfur and nitrogen compound chemistry.

IV. EPA MUST DESIGNATE CAMx OR ANOTHER PHOTOCHEMICAL MODEL TO BE USED TO ASS URE 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 the8 Comprehensive Air Quality Model with Exte nsions (CAMx) or a similar photochemical model, such as the Community Multiscale Air Quality modeling system (CMAQ), to demonstrate that the proposed source will no t 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 demonstrat e 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 a pplicants use discredited or indefensible screening tools such as the Sc heffe “look up tables” or extrapolations from modeling exercises in different geogra phic 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 contri butes to an ozone NAA QS violation. For example, EPA acknowledge that using “regiona l 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 th e 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 FR9 48,285 (Aug. 17, 2005); 40 C.F.R. § 52.1620(e). Th is 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 perfor med 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 fu ture ambient concentrations, and finally, an additional “sensitivity” model run simulated em issions from two power plants that have yet to be built, including the DREF (called “STEAG” at th e 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 wh ether a single PSD applicant caused or contributed to an oz one NAAQS violation. More recently, EPA Region 6 has comme nted 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 th e 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 Bran ch (AMD), at the request of Kentucky, performed a series of model simulations w ith the Community Multi-Scale Air Quality10 (CMAQ) modeling system to examine the poten tial air impacts of adding new electrical generating units in Kentucky.” Ex. 3 at 29. This modeling demonstrated individual sources that were particul arly problematic in contri buting to ozone violation. See e.g. Id

. at 33. Note that the Cash Creek facility identifi ed in this report rece ntly received its PSD permit from Kentucky without any ozone m odeling in support of its application. Similarly, EPA has accepted ozone modeli ng performed by states to support PSD applications for individual sources. For example, Illi nois was a PSD delegated state when it issued the PSD permit for the Prai rie State Generating Station. The Illinois Environmental Protection Agency (IEPA) us ed 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 se veral 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 determin e the impacts from individual sources in PSD enforcement actions. For example, EPA presented data from a CMAQ modeling exercise to predict the impacts that Ciner gy’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 mode l” 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 demons tration (8-day episode) •Dallas-Fort Worth –Evaluated impact s from single county (Ellis) to aid in determining if the county should be included in 8-hr nonattainment area. •Dallas-Fort Worth –Evaluated impact s from groups of power plants in Oklahoma, Arkansas, Louisiana, and also look ed 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 ther e 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: AP CA, 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 conducte d 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 a pplicants are not cu rrently 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 co st 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 wi ll not cause or contri bute to a violation of the NAAQS.12 In any event, the cost of this modelin g 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 m odest in the relative sense. Furthermore, PSD applicants can us e 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 organizati on 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 C ourt 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, a nd 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 pr epared 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 CONTRI BUTION 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 c ontribute to any violation of the ozone NAAQS. In other words, EPA should clarify that there is no signi ficant 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 “t hird rail” of PSD). However, Administrator Jackson’s three guiding principles of science, law and transp arency 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 th e air is unsafe to breat he 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 ASS URE 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 c ontribute 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 thevarious 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, nevert heless, excused consideration of secondary PM2.5 because it claimed there were technical and informa tional 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 th e technical difficulties were resolved. Id. at 2. It is now 13 years later. The technica l 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 th e proposed PM2.5 increments.15 Under the current system, PSD sources ar e not consistently taking into account secondarily formed fine particles. Thus, according to EPA, the PSD program is failing. As with ozone, currently, PSD permit a pplicants’ “demonstration” of PM2.5 air quality impact varies for actual demonstra tions 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 requireme nt to actually demons trate that proposed major sources will not cause or contribut e 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. Howeve r, 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 s econdary 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 PM 2.5 (among other pollutants) on air quality related values (AQRV) ( e.g. , visibility impairment) at Class I areas under modeling guidelines issued by desi gnated Federal Land Managers. See U.S. EPA, “Interagency Workgroup on Air Quality Rela ted 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 asse ssing applicability of Best Available Retrofit Technology (BART) regulations spec ified the CALPUFF modeling system to determine whether PM2.5 concentrations attr ibutable to eligible sources cause or16 contribute to visibility impa irment 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 PM 2.5 concentrations, these guidelines do not apply fo r 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 PM 2.5 . In addition, EPA should take action to improve the atmospheric chem istry.” 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 i ndividual sources imp acts to PM2.5 NAAQS violations. For example, EPA has used m odels 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 th e vast majority of Coshocton County's contribution to PM2.5 violations in th e 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 suffi cient monitoring data to verify and validate protocol modeling results.

EPA recently explained that at “that time, the statement above referred to the MODELS-3
d evelopment 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 im pacts 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 determini ng a single stationary source’s impact on ambient PM2.5 levels is scie ntifically credible. We are encouraged by EPA’s recent statem ent that it is evaluating using regional scale models with the ability to track primar y 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 “reg ional 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 de termine if their proposed source or modification, including its emissions of precurs or 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 pr otect 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 C439-0119 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