June 18, 2015

VIA ELECTRONIC MAIL George (Tad) Aburn, Director Air & Radiation Management Admin. Maryland Department of the Environment 1800 Washington Blvd. Baltimore, MD 21230 Email: george.aburn@maryland.gov

RE: Implementation of Sulfur Dioxide Consent Decree from Sierra Club v. McCarthy in Maryland

Dear Mr. Aburn:

On behalf of the Sierra Club I write to urge the Department to move forward with its stalled sulfur dioxide (SO 2 ) regulations for coal

- fired power plants in order to avoid non attainment designations in Maryland, which would be required under t he recent consent decree in Sierra Club v. McCarthy 1 if these regulations are not expeditiously finalized and adopted. To aid in this process, as an exhibit to this letter, I am providing the Department with updated steady state and time series mo deling for SO 2 emissions from the C.P. Crane, H.A. Wagner and Brandon Shores plants conducted by Wingra Engineering in adherence with EPA’s most current modeling guidance using the most current versions of U.S. EPA’s AERMOD modeling software. 2 The attached modeling results confirm that, absent enforceable regulatory action by the Department to address actual and allowable short

- term emissions from these fa cilities, Maryland would be required to recommend a nonattainment designation to the U.S. Environmental Protection Agency fo r the area surrounding these plants. In order to avoid this nonattainment designation, the Sierra Club urges the Department to expeditiously finalize its draft sulfur dioxide regulations for the State ’ s coal plants. On June 22, 2010, the U.S. Environmental Protection Agency (EPA) published a new primary National Ambient Air Quality Standard (NAAQS) for SO 2 . This standard

— 75 ppb as a 1

- hour average

— was intended to address adverse health impacts of short

- term exposure to SO 2 . 3

1 Sierra Club v. McCarthy , Case No. 3:13

- cv
- 3953

- SI, Consent Decree (approved Mar. 2, 2015), attached as Exhibit 1. 2 Wingra Engineering, C.P. Crane Generating Station, Chase, Maryland, Brandon Shores & H.A. Wagner Generation Stations, Fort Smallwood Complex, Maryland, Evaluation of Compliance wit h the 1

- hour NAAQS for SO 2 , at 3 Tbl. 1 (May 4, 2015), attached as Exhibit 2

. 3 Exposure to sulfur dioxide (SO2) even in very short time periods

— as short as five minutes

—has been shown to cause significant adverse human health effects. Sulfur dioxide causes decrements in lung function, aggravation of asthma, and respiratory morbidity. See EPA, Integrated Science Assessment for Sulfur Oxides

– Health Criteria, EPA/600/R

- 08/047F, ch. 5 tb ls. 5

- 1, 5

- 2 (2008); Primary National Ambient Air Quality Standard for Sulfur Dioxide Final Rule, 75 Fed. Reg. 35,520, 35,525 (June 22, 2010) (hereinafter ―SO 2 Final Rule‖); see also EPA, Our Nation‘s Air: Status and Trends Through 2008 at 4 (2010) (noting that the health effects of sulfur dioxide exposure include aggravation of asthma and chest tightness) (hereinafter ―Out Nation‘s Air‖), available at http://www.epa.gov/airtrends/2010/report/fullreport.pdf

. Short

- term SO2 exposure is especially risky for children,Mr. George (Tad) Aburn

Page 2 of 4 June 18, 2015 Consistent with the guidance provided in the preamble to EPA’s final rule, which encouraged states to take “early action to address potential violations of the NAAQS before they occur” in order to avoid the need for nonattainment designations, 4 , 5 in October 2013, the Department commenced a stakeholder process to address SO 2 emissions from Maryland’s coal plants. Addressing emissio n s from these facilities is particularly critical because Maryland’s seven coal plants account for over 43% of all SO 2 emissions in the State and comprise nearly all of Maryland’s largest individual SO 2 sources. 6 In January 2014, as part of the ongoing stakeholder process, MDE released a draft regulation for SO 2 emissions from the State’s coal

- fired power plants. The r egulation established 1

- hour SO 2 emission limits in lb/hr for each coal unit in the State that air dispersion modeling demonstrated was necessary to insure the facilities’ emissions do not cause or contribute to violations of the 2010 1

- hour SO 2 NAAQS. Sin ce that date, however, MDE has taken no action to further develop or finalize this regulation. On March 2, 2015, the U.S. District Court for the Northern District of California approved a consent decree 7 requiring the EPA , no later than September 2016, t o finalize designations for undesignated areas containing stationary sources that emitted more than 2,600 tons of SO 2 and had an annual average emission rate of 0.45 lb SO 2 /MMBtu or higher in 2012. Based on data from EPA’s Air Markets Database, the two co al units at the H.A. Wagn er coal plant in Maryland emitted 7,430.0 tons of SO 2 in 2012 with an average emission rate of 1.176 lb SO 2 /MMBtu. 8 Consequently, EPA must finalize its designation for the area containing the Wagner plant no later than September 2 016. Consistent with this designation deadline, the Department is required to submit its designation recommendations to EPA no later than September 2015. In order to avoid a nonattainment designation for the area surrounding the Wagner pla nt , which also contains the Brandon Shores and Crane plants , the Sierra Club urges the Department to submit to EPA as part of its package a final rule establishing modeling

- informed SO 2 limits for

the elderly, and asthmatics. See EPA, Sulfur Dioxide

– Health, available at http://www.epa.gov/air/sulfurdioxide/health.html

. And EPA has determined that SO2 exposure can aggravate existing heart disease, leading to increased hospitalizations and premature deaths. Id. 4 SO 2 Final Rule at 35,576/2. 5 As the Sierra Club has previously identified in correspondence to the Governor and the Department, Maryland has an independent legal obligation to include enforceable emission limits in its Infrastructure State Implementation Plan for the 2010 1

- hour SO 2 NAAQS pursuant to Section 110(a)(2)(A) of the Clean Air Act, 42 U.S.C. § 7410(a)(2)(A). See, e.g. , Ltr. from Joshua Berman, Associate Attorney, Sierra Club, Diana Dascalu

- Joffe, Senior General Counsel, Chesapeake Climate Action Network, and Tim Whitehouse, Director, Chesapeake Chapter of the Physicians for Social Responsibility to Governor Martin O’Malley (Aug. 14, 2013). 6 According to EPA’s most current National Emission Inventory, in 2011, the seven coal plants emitted 31,088 tons of SO 2 out of a statewide total from all sources of 71,945 tons. See http://www.epa.gov/ttnchie1/net/2011inventory.html and linked fusion table for SO 2 emissions. 7 Sierra Club v. McCarthy , Case No. 3:13

- cv
- 3953

- SI, Consent Decree (approved Mar. 2, 2015). 8 Total SO 2 (tons) from Wagner coal units in 2012 = Unit 2 SO 2 (tons) + Unit 3 SO 2 (tons) = 2,512.8 + 4,960.2 tons = 7,473.0 tons SO 2 . Average SO 2 (lb/MMBtu) from Wagner coal units in 2 012 = Total SO 2 (tons) * 2000 (lb/ton) / Total Heat Input (MMBtu) = [(2,512.8 + 4,960.2) tons * 2,000 lb/ton] / [(4,438,743 + 8,271,872) MMBtu] = 1.176 lb/MMBtu.Mr. George (Tad) Aburn

Page 3 of 4 June 18, 2015

t hese three plants that are sufficient ly stringent and with an appropriately limited averaging time to ensure that the NAAQS will be attained and maintained in the area around the se plants. Previously, in November 2011, the Sierra Club provided the Department with the results of SO 2 air dispers ion modeling conducted by Gray Sky Solutions using meteorological data from 2006 to 2010 . This modeling was based on steady state emissions at maximum actual and permitted allowable emission rates for the facilities and identified significant exceedances o f the 2010 1

- hour SO 2 NAAQS in the vicinity of the Crane and Wagner plants. I n May 2015 , the Sierra Club retained Wingra Engineering to update the modeling for these facilities by inc orporating the most current (2012

- 2014) meteorological data using the ne west versions of AERMOD, AERMET and AERSURFACE , and including the impacts of Brandon Shores . The updated modeling also includes time series modeling of the Baltimore area coal plants individually and collectively. The updated modeling demonstrates both that the emissions from the Ft. Smallwood (Wagner and Brandon Shores) units individually and the Baltimore units (Wagner, Brandon Shores and Crane) collectively cause exceedances of the SO 2 NAAQS based on actual historical emissions and actual historical m eteorological data from 2012

– 2014. Moreover, the modeling continues to demonstrate that the current permit limits are grossly insufficient, both in emission rate and averaging time, to prevent violations of the 1

- hour SO 2 NAAQS. Instead, the collectiv e emission from the Ft. Smallwood complex must be no higher than 3,737 lb/hr as an hourly rate , and emissions from the three plants collectively must be no higher than 5,466 lb/hr as an hour ly rate to ensure attainment and maintenance of the NAAQS. 9 These results are strongly consistent with the modeling results from MDE’s 2013 modeling and with the emission limits in the January 2014 draft regulation. Given the impending September 2015 deadline for the Department to submit its designation recommendation s to EPA for the Baltimore area, t he Sierra Club urges MDE to move forward expeditiously with finalization of its January 2014 SO 2 regulation to establish enforceable, modeling

- informed 1

- hour SO 2 emission limits for the Baltimore area coal plants in order to ensure that their emissions do not cause or contribute to violations of the NAAQS. By submitting this regulation to EPA as part of Maryland’s designation recommendation, Maryland can avoid the nonattainment designation, which woul d otherwise be required for the area around these plants.

T hank you for your consideration and please do not hesitate to contact me with any questions regarding the updated modeling. Respectfully submitted,

Joshua Berman Staff Attorney

9 May 4, 2015 modeling report at 4, Tbl. 3.Mr. George (Tad) Aburn

Page 4 of 4 June 18, 2015 Sierra Club Environmental Law Program 50 F St. NW, 8 th Floor Washington, DC 20001 Tel: (202) 650

- 6062 Emai l: Josh.Berman@sierraclub.org

C c: Randy Mosier Michael Woodman

# EXHIBIT 1[PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 SAM HIRSCH Acting Assistant Attorney General Environment and Natura l Resources Division MARTHA C. MANN U.S. Department of Justice Environmental Defense Section P.O. Box 7611 Washington, D.C. 20044 Tel: (202) 514-2664 Fax: (202) 514-8865 Email: martha.mann@usdoj.gov Attorneys for Defendant Gina McCarthy, Administrator, United States Environmental Protection Agency [Additional counsel liste d on signature page]

IN THE UNITED STATES DISTRICT COURT FOR THE NORTHERN DISTRICT OF CALIFORNIA SAN FRANCISCO DIVISION

SIERRA CLUB and NATURAL RESOURCES DEFENSE COUNCIL, Plaintiffs,

v. GINA MCCARTHY, in her official capacity as Administrator of the United States Environmental Protection Agency, Defendant. Case No.: 3:13-cv-3953-SI

[PROPOSED] CONSENT DECREE Case3:13-cv-03953-SI Document163 Filed03/02/15 Page1 of 102 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 WHEREAS, on August 26, 2013, Plaintiffs Sier ra Club and Natural Resources Defense Council (“Plaintiffs”) filed the complaint (“Co mplaint”) in the above-c aptioned matter against Defendant Regina McCarthy in her official cap acity as Administrator of the United States Environmental Protection Agency (“EPA”) allegi ng that EPA has failed to undertake a certain nondiscretionary duty under the Clean Air Act (“CAA”), 42 U.S.C. §§ 7401-7671q, and that such alleged failure is actionabl e under section 304(a )(2) of the CAA, 42 U. S.C. § 7604(a)(2); WHEREAS, within one year after promulgation of a re vised national ambient air quality standard (“NAAQS”), sectio n 107(d)(1)(A) of the CAA directs states to submit lists of initial designations of all areas, or porti ons thereof, as attainment, nonattainment, or unclassifiable for the revised NAAQS, 42 U.S.C. § 7407(d)(1)(A); WHEREAS, EPA is required to promulgate designations for all areas of the country (including tribal areas and certa in U.S. territories) within tw o years of promulgation of the revised NAAQS, or within three years if EPA ha s insufficient information to promulgate the designations within two years, pursuant to sectio n 107(d)(1)(B) of the CAA, 42 U.S.C. § 7407(d)(1)(B); WHEREAS, EPA is required to publish a noti ce in the Federal Register promulgating designations, pursuant to sect ion 107(d)(2)(A) of the CAA, 42 U.S.C. § 7407(d)(2)(A); WHEREAS, EPA revised the primar y NAAQS for sulfur dioxide (“SO 2 ”) on June 2, 2010, see 75 Fed. Reg. 35,520 (June 22, 2010); WHEREAS, states were direct ed to submit their area designations for the 2010 revised primary SO 2 NAAQS by June 2, 2011, see 75 Fed. Reg. at 35,385/col. 2; WHEREAS, on August 3, 2012, EPA invoked the a dditional year to issue designations,

see 77 Fed. Reg. 46,295 (Aug. 3, 2012); WHEREAS, on August 5, 2013, EPA published designations under the 2010 revised primary SO 2 NAAQS for twenty-nine areas in sixteen states, thus removing such areas from the potential scope of th e above-captioned matter, see 78 Fed. Reg. 47,191 (Aug. 5, 2013); WHEREAS, the Complaint alleges that EPA has a nondiscretionary duty to promulgate and publish the remaining area designa tions for the 2010 revised primary SO 2 NAAQS within Case3:13-cv-03953-SI Document163 Filed03/02/15 Page2 of 103 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 the time lines set forth in section 107(d)(1)(B) of the CAA, 42 U.S.C. § 7407(d)(1)(B), (d)(2)(A); WHEREAS, on October 29, 2013, Pl aintiffs filed a Motion for Summary Judgment on the issue of liability in the above-captioned matte r, reserving for future briefing the issue of remedy; WHEREAS, on November 12, 2013, EPA filed it s response to Plaintiffs’ Motion for Summary Judgment and did not di spute the claim of liability; WHEREAS, on December 6, 2013, the Court granted Plaintiffs’ Motion for Summary Judgment, and directed the parties to meet and confer on the remedy; WHEREAS, the Plaintiffs and EPA have ag reed to a settlement of this action; WHEREAS, the Plaintiffs and EPA, by enteri ng into this Consent Decree, do not waive or limit any claim or defense, on any gr ounds, related to any EPA final action; WHEREAS, the Plaintiffs and EPA consider this Consent D ecree to be an adequate and equitable resolution of all the claims in this matter; WHEREAS, it is in the interest of the pub lic, the Plaintiffs a nd EPA, and judicial economy to resolve this matter withou t unnecessary protracted litigation; WHEREAS, the Administrator has propos ed and anticipates promulgating a rulemaking that would direct states to conduct additional information collection and analyses regarding certain sta tionary sources of SO 2 , for purposes of informing future area designations under the 2010 revised primary SO 2 NAAQS, see 79 Fed. Reg. 27,449 (May 13, 2014); WHEREAS, the Plaintiffs and EPA agree that this Court has jurisdiction over this matter pursuant to the citizen suit prov ision of section 304(a)(2) of the CAA, 42 U.S.C. § 7604(a)(2); WHEREAS, the Court, by entering this Cons ent Decree, finds that the Consent Decree is fair, reasonable, in the public inte rest, and consistent with the CAA; NOW THEREFORE, before the taking of test imony, without trial or determination of any additional issue of fact or law that the Court has not alread y addressed in this matter, and upon consent of the Plaintiffs and EPA, it is hereby ordered, adjudged and decreed, that: Case3:13-cv-03953-SI Document163 Filed03/02/15 Page3 of 104 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1. EPA shall sign for publication in the Federal Register no la ter than sixteen (16) months from the date of this Court’s entry of this Order a notice of EPA’s promulgation of designations for the 2010 revised primary SO 2 NAAQS pursuant to section 107(d) of the CAA, and within ten (10) business days following such signature deliver the notice to the Office of the Federal Register for review and prompt publication, for remaining undesignated areas which: (a) based on air quality monitoring in the th ree (3) full calendar years preceding such deadline have monitored viol ations of the 2010 revised primary SO 2 NAAQS; or (b) contain any stationary source that has not been “announced for retirement” pursuant to subparagraph (c) by the date of this Consent Decree, and that, according to the data in EPA’s Air Markets Database, either (1) emitted more than 16,000 tons of SO 2 in 2012, or (2) emitted more than 2,600 tons of SO 2 and had an annual average emission rate of 0.45 lbs SO 2 /Mmbtu or higher in 2012; where (c) “announced for retirement” means any stat ionary source in the United States with a coal-fired unit that as of January 1, 2010, had a capacity of over five (5) megawatts (MW) and that has announced th at it will cease burning coal at that unit through a company pub lic announcement, public utilities commission filing, consent decree, public legal settle ment, final state or federal permit filing, or other similar means of communication. 2. EPA shall sign for publication in the Federal Register no later than December 31, 2017, a notice of EPA’s promulgation of de signations for the 2010 revised primary SO 2 NAAQS pursuant to section 107(d) of the CAA, and within ten (10) business days following such signature deliver th e notice to the Office of the Federa l Register for review and prompt publication, for remaining undesignated areas in which, by January 1, 2017, states have not installed and begun operating a new SO 2 monitoring network meeting EPA specifications Case3:13-cv-03953-SI Document163 Filed03/02/15 Page4 of 105 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 referenced in EPA’s anticipated rulemaking dir ecting states to collect and analyze additional information regarding SO 2 emissions concentrations. 3. EPA shall sign for publication in the Federal Register no later than December 31, 2020, a notice of EPA’s promulgation of de signations for the 2010 revised primary SO 2 NAAQS pursuant to section 107(d) of the CAA, and within ten (10) business days following such signature deliver the no tice to the Office of the Federal Register for review and publication, for all remaining undesignated areas. 4. After EPA’s obligations under Paragraphs 1 through 3 have been completed, and after the notices required by Paragraphs 1 through 3 have been published in the Federal Register, EPA may move to terminate the Consent Decree. The Plaintiffs shall have fourteen (14) days in which to respond to such motion. 5. Following delivery of the notic es of promulgation of de signations described in Paragraphs 1 through 3 to the Office of the Fe deral Register, EPA sha ll not take any action (other than is necessary to corre ct any typographical errors or othe r errors in form) to delay or otherwise interfere with publicati on of such notices in the Fede ral Register. EPA shall make available to the Plaintiffs c opies of the notices within five (5) business days following signature by the Administrator. 6. The Plaintiffs and EPA may ex tend the deadlines estab lished in Paragraphs 1 through 3 for a period of sixty (60) days or less by written stipulation executed by counsel for the Plaintiffs and EPA and filed with the Cour t. In addition, the deadlines established in Paragraphs 1 through 3 may be extended by the Court upon motion by any party to this Consent Decree for good cause sh own, after consideration of any response by the non-moving party to this Consent Decree. Any party to th is Consent Decree seeking to extend deadlines by motion and without stipulation must provide written notice to all other parties to this Consent Decree of the deadlines the party is seeking to extend at least ten (10) business days prior to filing with the Court such motion. No motion to extend a deadline shall be considered properly filed unless notice pursuant to this Paragraph is provided, or the moving party demonstrates why it could not have provided the advance written notice. Case3:13-cv-03953-SI Document163 Filed03/02/15 Page5 of 106 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 7. Nothing in this Consent D ecree shall be construed to limit or modify the discretion accorded EPA by the CAA and by ge neral principles of administrative law, including the discretion to alter, amend or revi se any response and/or fi nal action contemplated by this Consent Decree. EPA’s ob ligations to take the actions se t forth in Paragraphs 1 through 3 by the dates specified do not constitute limita tions or modifications of EPA’s discretion within the meaning of this paragraph. 8. Nothing in this Consent Decr ee shall be construed to confer upon the District Court jurisdiction to review any final decision made by EPA pursua nt to this Consent Decree. Nothing in this Consent Decree shall be construe d to confer upon the District Court jurisdiction to review any issues that are within the excl usive jurisdiction of the United States Court of Appeals pursuant to section 307( b)(1) of the CAA, 42 U.S.C. § 7607(b)(1). Nothing in the terms of this Consent Decree shall be construed to waive any remedies or defenses the parties may have under CAA section 307(b)(1), 42 U.S.C. § 7607(b)(1). 9. This Court shal l retain jurisdiction to enforce the terms of this Consent Decree and to consider any requests for costs of litigation, including attorneys’ fees. 10. In the event of a disput e between the parties to this Consent Decree concerning the interpretation or implementation of any aspect of this Consent Decree, the disputing party shall provide the other party with a written notice outlining the nature of the dispute and requesting informal negotiations. If the parties cannot reach an agreed-upon resolution within ten (10) business days after re ceipt of notice, any party may move the Court to resolve the dispute. 11. No motion or other proceeding seeking to enforce this Consent Decree shall be considered properly filed, unless the Plainti ffs have followed the procedure set forth in Paragraph 10. 12. The United States, on behalf of EPA, agrees that the Pl aintiffs are entitled to recover their costs of litigati on (including reasonable attorneys’ fees) (“litigation costs”) incurred in this matter pursuant to 42 U.S.C. § 7604(d). The deadline for filing a motion for litigation costs is hereby extended until 120 days after entry of this Consent Decree by the Case3:13-cv-03953-SI Document163 Filed03/02/15 Page6 of 107 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Court. During this time, the Plaintiffs and EPA shall seek to resolve informally any claim for litigation costs, and if they cannot reach a resolution, the Pl aintiffs may seek such litigation costs from the Court. The Court shall retain jurisdiction to resolve any request for litigation

costs. 13. The obligations imposed upon EPA by this Consent Decree may only be undertaken using appropriated funds. No pr ovisions of this Cons ent Decree shall be interpreted as or constitute a commitment or requirement that EPA obligate or pay funds in contravention of the Anti-Defic iency Act, 31 U.S.C. § 1341, or any other applicable federal law. 14. The parties recognize that the possibility exists that a lapse in the appropriations that fund EPA could delay complia nce with the timetable s contained in this Consent Decree. Should a delay occur due to a lapse in appropria tions, any deadlines occurring within ninety (90) days of the termin ation of the delay shall be extended one day for each day of the delay. EPA will provide Plaintiffs with notice as soon as is reasonably possible under the circumstances in the event that EPA invokes this Paragraph of the Consent Decree and will provide Plaintiffs with an explanation of EPA's basis for invoking this Paragraph. Plaintiffs may challenge the invocation of this Paragraph of the Consent Decree under the dispute resolution terms of this Consent Decree, and EPA shall bear the burden of justifying its invocation of this Paragraph. 15. The Plaintiffs and EPA shall not challenge the terms of this Consent Decree or this Court’s jurisdiction to enter this Consent Decree. 16. The Plaintiffs and EPA agr ee and acknowledge that before this Consent Decree is entered by the Court, EP A must provide notice of this Consent Decree in the Federal Register and provide an opport unity for public comment pursuan t to section 113(g) of the CAA, 42 U.S.C. § 7413(g). After this Consent Decree has undergone notice and comment, the Administrator and/or the Attorney General, as appropriate, shall promp tly consider any such written comments in determining whether to with draw or withhold their consent to the Consent Decree, in accordance with se ction 113(g) of the CAA. If the Administrator and/or the Case3:13-cv-03953-SI Document163 Filed03/02/15 Page7 of 108 [PROPOSED] CONSENT DECREE C ASE N O .: 3:13-cv-3953-SI 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Attorney General do not el ect to withdraw and w ithhold their consent, EPA shall promptly file a motion that requests the Court to enter this Consent Decree. 17. Any notices required or prov ided by this Consent Decree shall be made in writing, via facsimile, e-mail, or other means, and sent to the following: For Plaintiffs: Nicholas Morales David S. Baron Earthjustice 1625 Massachusetts Ave., STE 702 Washington, DC 20036 nmorales@earthjustice.org dbaron@earthjustice.org Fax: 202-667-2356 Zachary M. Fabish The Sierra Club 50 F Street, NW – 8th Floor Washington, DC 20001 zachary.fabish@sierraclub.org Fax: 202-547-6009 Emily K. Davis Natural Resources Defense Council 1152 15th Street, NW, Suite 300 Washington, DC 20005 edavis@nrdc.org Fax: 202-289-1060

For Defendant:

Martha C. Mann United States Department of Justice Environmental Defense Section P.O. Box 7611 Washington, DC 20044 martha.mann@usdoj.gov Fax: 202-514-8865 Case3:13-cv-03953-SI Document163 Filed03/02/15 Page8 of 10Case3:13-cv-03953-SI Document163 Filed03/02/15 Page9 of 101

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 COUNSEL FOR DEFENDANT:
Dated: ~) us~- ~ ~'LQ~~

~~~

SO ORDERED on this day of SAM HIRSCH Acting Assistant Attorney General Environment &Natural Resources Division
MARTHA C. MANN United States Department of Justice Environment &Natural Resources Division P.O. Box 7611 Washington, D.C. 20044 Tel: (202) 514-2664 E-mail: martha.mann(a~usdoj~ov_

Counsel for Defendant EPA

2014

SUSAN ILLSTON United States District Judge

10 [PROPOSED] CONSENT DECREE CASE No.: 3:13-cv-3953-SI Case3:13-cv-03953-SI Document163 Filed03/02/15 Page10 of 10

# EXHIBIT 2

## C.P. Crane Generating Station Chase, Maryland

Brandon Shores & H.A. Wag ner Generating Stations Fort Smallwood Complex, Maryland

Evaluation of Compliance wi th the 1-hour NAAQS for SO 2 

## May 4, 2015

Conducted by: Steven Klafka, P.E., BCEE

Wingra Engineering, S.C. Madison, WisconsinEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 2

1. Introduction Wingra Engineering, S.C. was hi red by the Sierra Club to conduc t an air modeling impact analysis to help USEPA, state and local air a gencies identify facilities th at are likely causing exceedences of the 1-hour sulfur dioxide (SO 2 ) national ambient air qualit y standard (NAAQS). This document describes the results and pro cedures for an evaluation conducte d for three Maryland generating stations located near Baltimore , Maryland. These three stations include C.P. Crane Generating Station in Chase, Maryland and B randon Shores & H.A. Wagner Gen erating Stations at the Fort Smallwood Complex in Maryland. This analysis updates the 2011 report prepared by Gray Sky Solutions by incorporating emissions from the most recent three years (2012-2014), incorporating the emissions from the Bra ndon Shores facility, and using the m ost current version of EPA’s AERMOD and related software. 1
The dispersion modeling analysis predicted ambient air concentr ations for comparison with the 1- hour SO 2 NAAQS. The modeling was performe d using the most recent versi on of AERMOD, AERMET, and AERMINUTE, with data provided to the Sierra Club by regulatory air agencies and through other publicly-available so urces as documented below. The analysis was conducted in adherence to all available USEP A guidance for evaluating source impacts on attainment of the 1- hour SO 2 NAAQS via aerial dispersion mode ling, including the AERMOD Imp lementation Guide; USEPA's Applicability of Appendi x W Modeling Guidance for the 1 -hour SO 2 National Ambient Air Quality Standard, August 23, 2010; modeling guidance promul gated by USEPA in Appendix W to 40 CFR Part 51; USEPA’s Ma rch 2011 Modeling Guidance for SO 2 NAAQS Designations; 2 and, USEPA’s December 2013 SO2 NAAQS Des ignations Technical Assistan ce Document. 3

2. Compliance with the 1-hour SO 2 NAAQS

2.1 1-hour SO 2 NAAQS

The 1-hour SO 2 NAAQS takes the form of a t hree-year average of the 99 th -percentile of the annual distribution of daily maximum 1- hour concentrations, which cann ot exceed 75 ppb. 4 Compliance with this standard w as verified using USEPA’s AERMOD air disper sion model, which produces air concentrations in units of μg/m 3 . The 1-hour SO 2 NAAQS of 75 ppb equals 196.2 μg/m 3 , and this is the value used for determining whether modeled impacts exceed t he NAAQS. 5 The 99 th -percentile

1 Gray Sky Solutions, Modeling the Short-term SO 2 Impacts Due to Wagner and Cr ane Power Plant Emissions, September 2011. 2 http://www.epa.gov/scram001/ so2_modeling_guidance.htm 3 http://www.epa.gov/oaqps001/sulfurdioxide/pdfs/SO2ModelingTAD. pdf 4 USEPA, Applicability of Appendix W Modeling Guidance for the 1- hour SO 2 National Ambient Air Quality Standard, August 23, 2010. 5 The ppb to μg/m 3 conversion is found in the source code to AERMOD v. 14134, sub routine Modules. The conversion calculation is 75/0.3823 = 196.2 μg/m 3

.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 3

of the annual distri bution of daily maximum 1-hour concentratio ns corresponds to the fourth-highest value at each receptor for a given year. 2.2 Modeling Results Modeling results for the three Maryland generating stations are summarized in Table 1. It was determined that based on either current allowable emissions, pe ak maximum emissions, or measured actual emissions, the three Mary land generating stations are es timated to create downwind SO 2 concentrations which e xceed the 1-hour NAAQS. More specifically, the modeling results presented in Table 1, s how exceedences of the NAAQS by the plant’s allowable, maximum and actual emissions. “Allowabl e” is the peak emission rate from each unit as approved by the curre nt air quality operation perm it for the facility. “Maximum” is the peak hourly emissions which at each location between January 1, 2012 and December 31, 2014 as taken from USEPA Air Markets Program Data

. 6 “Actual” represents the emissions which occurred during each hour during the between January 1, 2012 and Decembe r 31, 2014 period. Air quality impacts in Maryl and are based on a background conce ntration of 26.2 μg/m 3 . This is the 2011-13 design value for Prince Geor ge's, Maryland - the lowest measured background concentration in the state. This is the most recently availabl e design value. See S ection 5 for further discussion of the background concen trations used for this analy sis.

Table 1 - SO 2 Modeling Results for the Three Maryland Generating Stations

Power Plant(s) Emission Rates 99th Percentile 1-hour Daily Maximum (μg/m3) NAAQS Meets NAAQS? Impact Background Total (μg/m3) (μg/m3) All Allowable 1,261.2 26.2 1,287.4 196.2 No Crane Allowable 826.7 26.2 852.9 196.2 No Brandon/Wagner Allowable 1,250.9 26.2 1,277.1 196.2 No All Maximum 561.0 26.2 587.2 196.2 No Crane Maximum 478.0 26.2 504.2 196.2 No Brandon/Wagner Maximum 468.4 26.2 494.6 196.2 No All Actual 267.7 26.2 293.9 196.2 No Crane Actual 103.9 26.2 130.1 196.2 Yes Brandon/Wagner Actual 265.3 26.2 291.5 196.2 No

6 http://ampd.epa.gov/ampd/Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 4

The emissions used for the mode ling analysis are summarized in Table 2.

Table 2 - Modeled SO 2 Emissions from the Three Maryland Generating Stations 7

Power Plant (s) Unit Heat Input (mmbtu/hr) Allowable Emissions (Averaging Period) Allowable Emissions (lbs/mmbtu) Allowable Emissions

(lbs/hr) Maximum Emissions

(lbs/hr)

Crane C01 1,865 24-hours 3.5 6,527.5 2,966.7 C02 1,865 24-hours 3.5 6,527.5 4,574.1 All Units 3,730 13,055.0 7,540.8

Brandon Shores & Wagner B01 7,128 1.0% Coal Sulfur 1.5 10,692.0 2,112.1 B02 7,128 1.0% Coal Sulfur 1.5 10,692.0 1,511.1 W02 1,337 1.0% Coal Sulfur 1.5 2,005.5 2,445.4 W03 2,740 1.0% Coal Sulfur 1.5 4,110.0 3,205.2 All Units 18,333 27,499.5 9,273.8 All Power Plants All Un its 22,063 40,555 16,815

Based on the modeling results, Table 3 provides the necessary e mission reductions from current allowable rates necessary to ach ieve compliance with the 1-hour NAAQS. Table 3 - Required Emission Reduc tions for Compliance with the 1-hour NAAQS for SO 2
Power Plant (s) Acceptable Impact (μg/m 3 ) Required Reduction (%) Required Emissions

(lbs/hr) Required Emissions (lbs/mmbtu) All 170.0 86.5% 5,466.4 0.25 Crane 170.0 79.4% 2,684.6 0.72 Brandon / Wagner 170.0 86.4% 3,737.2 0.20 Predicted exceedences of the 1-hour NAAQS for SO 2 based on allowable emissions extend throughout the region to a maxim um distance of the modeling dom ain of 25 kilometers. Figures 1 through 5 show the extent of predicted exceedences of the 1-hour NAAQS for SO2 based on the allowable emissions from all three plants, the C.P. Cran e Generating Station by itself, and the Brandon Shores and H.A. Wagner Gene rating Stations by themselve s.

7 Allowable emissions for Crane are based on Maryland Department of Natural Resources, Part 70 Operating Permit No. 24-005-00079, March 1, 2009. Allowable emissions for Brandon Sh ores and Wagner are based on Maryland Department of Natural Resources, Part 70 Operating Permit No. 24-003-00468 , May 1, 2011.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 5
2.3 Conservative Modeling Assumptions A dispersion modeling analysis requires the selection of numero us parameters which affect the predicted concentrations. For the enclosed analysis, several pa rameters were selected which underpredict facility impacts. Assumptions used in this modeli ng analysis which likely under-e stimate concentrations include the following:

 Allowable emissions are base d on a limitation with an averaging period which is greater than the 1-hour average used for the SO 2 air quality standard. Emissions and impacts during any 1-hour period may be higher than assumed for the modeling analy sis.

 No consideration of facility operation at less than 100% load. Stack parameters such as exit flow rate and temperature are typically lower at less than full load, reducing pollutant dispersion and increasing predic ted air quality impacts.

 No consideration of building or s tructure downwash. These downw ash effects typically increase predicted concentr ations near the facility.

 No evaluation has been conducted t o determine if the stack heig ht exceeds Good Engineering Practice or GEP height. If the st ack height exceeds GEP, the pr edicted concentrations will increase.

 No consideration of off-site sources. These other sources of SO 2 will increase the predicted impacts.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 6

Figure 1 - Regional View of Impacts Due to Allowable Emissions from All Three PlantsEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 7

Figure 2 - Regional View of Impacts Due to Allowable Emissions from C.P. CraneEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 8

Figure 3 - Local View of Impacts Due to Allowable Emissions from C.P. CraneEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 9

Figure 4 - Regional View of Impacts Due to Allowable Emissions from Brandon Shores & WagnerEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 10

Figure 5 - Local View of Impacts Due to Allowable Emissions from Brandon Shores & WagnerEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 11

3. Modeling Methodology 3.1 Air Dispersion Model The modeling analysis used U SEPA’s AERMOD program, v. 14134. A ERMOD, as available from the Support Center for Regulator y Atmospheric Modeling (SCRAM) website, was used in conjunction with a third-par ty modeling software program, AERMOD View , sold by Lakes Environmental Software. 3.2 Control Options

The AERMOD model was run with t he following control options:

 1-hour average air concentrations

 Regulatory defaults

 Flagpole receptors To reflect a representative i nhalation level, a flagpole height of 1.5 meters was used for all modeled receptors. This parameter was added to the receptor file when running AERMAP, as described in Section 4.4.

An evaluation was conducted to det ermine if the modeled facilit ies are located in a rural or urban setting using USEPA’s methodology outlined in Section 7.2.3 of the Guideline on Air Quality Models. 8 For urban sources, the URBANOPT option is used in conjunction with the urban population from an appropriate ne arby city and a default surfac e roughness of 1.0 meter. Methods described in Section 4.1 were used t o determine whether rural o r urban dispersion coefficients were appropriate for the modeling analysis.

3.3 Output Options The AERMOD analysis was based on three years of recent meteorol ogical data. The modeling analyses used one run with three ye ars of sequential meteorolog ical data from 2012-2014. Consistent with USEPA’s Modeling Guidance for SO 2 NAAQS Designations, AER MOD provided a table of fourth-high 1-hour SO 2 impacts concentrations consiste nt with the form of the 1-hour SO 2 NAAQS. 9
Please refer to Table 1 for the modeling results.

8 USEPA, Revision to the Guidelin e on Air Quality Models: Adopti on of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, November 9, 2005. 9 USEPA, Area Designations for the 2010 Revised Primary Sulfur Di oxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, pp. 24-26.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 12

4. Model Inputs 4.1 Geographical Inputs The “ground floor” of all air dis persion modeling analyses is e stablishing a coordinate system for identifying the geographical loc ation of emission sources and r eceptors. These geographical locations are used to determine local characteristics (such as land use and elevation), and also to ascertain source to receptor di stances and relationships.

The Universal Transverse Merca tor (UTM) NAD83 coordinate system was used for identifying the easting (x) and northing (y) coordi nates of the modeled sources and receptors. Stac k locations were obtained from facility permits and prior modeling files provide d by the state regulatory agency. The stack locations were then veri fied using aerial photographs. The facility was evaluated to de termine if it should be modeled using the rural o r urban dispersion coefficient option in AERMOD. A GIS was used to determine whet her rural or urban dispersion coefficients apply to a site. L and use within a three-kilomete r radius circle surr ounding the facility was considered. USEPA guidance st ates that urban dispersion coe fficients are used if more than 50% of the area within 3 kilometers has urban land uses. Otherwise, rural dispersion coefficients are appropriate. 10

USEPA’s AERSURFACE v. 13016 was use d to develop the meteorologi cal data for the modeling analysis. This model was also us ed to evaluate surrounding land use within 3 kilometers. Based on the output from the AERSURFAC E, approximately 2.6% of the land surrounding the C.P. Crane Generating Station and 13.4% of the land surrounding the Brando n Shores and H.A. Wagner Generating Stations were of ur ban land use types including Type 21 – Low Intensity Residential, Type 22 – High Intensity Residen tial and Type 23 – Commercial / Industrial / Transportation.

This is less than the 50% value c onsidered appropriate for the use of urban dispersion coefficients. Based on the AERSURFACE analysis, i t was concluded that the rur al option would be used for the modeling summarized in this re port. Please refer to Section 4. 5.3 for a discussion of the AERSURFACE analysis.

10 USEPA, Revision to the Guidelin e on Air Quality Models: Adopti on of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, No vember 9, 2005, Section 7.2.3.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 13

4.2 Emission Rates and Source Parameters The modeling analyses only considered SO 2 emissions from the facilit y. Off-site sources were not considered. Concentrations were predicted for the following sce narios: 1) allowable emissions based on t he current permit issued by th e regulatory agency, 2) maximum emissions occurring d uring any hour between January 1, 2012 and December 31, 2014 as taken from USEPA Air Markets Program Data

. 11 For the Brandon Shores and Wagner plants, this hour was ba sed on the total emissions for e ach hour from all units at their location, and, 2) actual hourly emissions m easured during each hour of the Jan uary 1, 2012 and December 31, 2014 period. Stack parameters and emissions use d for the modeling analysis a re summarized in Table 4. Table 4 – Facility Stack Parameters and Emissions 12

Stack B01 B02 C01 C02 W02 W03 Generating Station Brandon Brandon Crane Crane Wagner Wagner Boiler/Unit Unit 1 Unit 2 Unit 1 Unit 2 Unit 2 Unit 3 X Coord. [m] 366970.5 366980.5 382293.8 382335.7 368092 368050 Y Coord. [m] 4338117.53 4338120.09 4353574.5 4353566.3 4337574 4337602 Base Elevation [m] 10 9.92 1.27 1.27 3.85 4.1 Release Height [m] 121.92 121.92 107.59 107.59 87.48 105.46 Gas Exit Temperature [°K] 326.483 326.483 427.594 427.594 409.8 17 418.706

Gas Exit Velocity [m/s] 13.023 11 .96 29.942 29.071 22.692 28.73 3

Inside Diameter [m] 9.51 9.51 3.322 3.322 3.109 4.206 Allowable Emission Rate [g/s] 1347 1347 822.5 822.5 252.7 517.9 Maximum Emission Rate [g/s] 266.1 190.4 373.8 576.3 308.1 403.8

Actual Emission Rate [g/s] - - - - - - The above stack parameters and emissions were obtained from reg ulatory agency documents and databases identified in Secti on 2.2. The analysis was conducted based on 100% operating load using maximum exhaust flow rates and t emperatures. Operation at less than full capacity loads was not considered. This assumption te nds to under-predict impacts sinc e stack parameters such as exit flow rate and temperature are typically lower at less than full load , reducing pollutant dispersion and

11 http://ampd.epa.gov/ampd/ 12 U.S. Energy Information Agency, Form EIA-860 detailed data, 201 3, http://www.eia.gov/electricity/data/eia860/xls/eia8602013.zipEvaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 14

increasing predicted air qualit y impacts. Stack location, heigh t and diameter were verified using aerial photographs, and flue gas fl ow rate and temperature were verified using combustion calculations. 4.3 Building Dimensions and GEP No building dimensions or prior dow nwash evaluations were avail able. Therefore this modeling analysis did not address the e ffects of downwash and this may u nder-predict impacts. 4.4 Receptors For the three Maryland generati ng stations, two receptor grids were employed:

1. A 100-meter Cartesian receptor grid centered on the three Maryl and generating stations and extending out 15 kilometers. 2. A 500-meter Cartesian receptor grid centered on the three Maryl and generating stations and extending out 25 kilometers. A flagpole height of 1.5 meters w as used for all these receptor s. Elevations from stacks and recep tors were obtained from Nationa l Elevation Dataset (NED) GeoTiff data. GeoTiff is a binary file tha t includes data descriptors a nd geo-referencing information necessary for extract ing terrain elevations. These elevations w ere extracted from 1 arc-second (30 meter) resolution NED files. The U SEPA software program AERMAP v. 11103 is used for these tasks. 4.5 Meteorological Data To improve the accuracy of the modeling analysis, recent meteor ological data for the 2012-2014 period were prepared using the U SEPA’s program AERMET which cre ates the model-ready surface and profile data files requir ed by AERMOD. Required data inpu ts to AERMET included surface meteorological measurements, t wice-daily soundings of upper air measurements, and the micrometeorological parameters surface roughness, albedo, and B owen ratio. One-minute ASOS data were available so USEPA met hods were used to reduce calm a nd missing hours. 13 The USEPA software program AERMINUTE v. 14237 is used for these tasks.

This section discusses how the meteorological data was prepared for use in the 1-hour SO 2 NAAQS modeling analyses. The USEPA software program AERMET v. 14134 is used for these tasks.

13 USEPA, Area Designations for the 2010 Revised Primary Sulfur D ioxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, p. 19.Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 15

4.5.1 Surface Meteorology Surface meteorology was obtained for Baltimore Washington Inter national Airport located near the the three Maryland generating stations. Integrated Surface Hour ly (ISH) data for the 2012-2014 period were obtained from the Natio nal Climatic Data Center (NC DC). The ISH surface data was processed through AERMET Stage 1, which performs data extractio n and quality control checks. 4.5.2 Upper Air Data Upper-air data are collected by a “ weather balloon” that is rel eased twice per day at selected locations. As the balloon is rel eased, it rises through the at mosphere, and radios the data back to the surface. The measuring and transmitting device is known as eit her a radiosonde, or rawindsonde. Data collected and radioed back i nclude: air pressure, height, temperature, dew point, wind speed, and wind direction. The upper air data were processed through AERMET Stage 1, which performs data extraction and quality control checks. For the three Maryland genera ting stations, the concurrent 2012 -2014 upper air data from twicedaily radiosonde measurements obtai ned at the most representati ve location were used. This location was the Ster ling, Virgina measurement station. These d ata are in Forecast Systems Laboratory (FSL) format and were downloaded in ASCII text forma t from NOAA’s FSL website. 14 All reporting levels were downl oaded and processed with AERMET.

4.5.3 AERSURFACE AERSURFACE is a program that ex tracts surface roughness, albedo , and daytime Bowen ratio for an area surrounding a given locatio n. AERSURFACE uses land use and land cover (LULC) data in the U.S. Geological Survey’s 1992 National Land Cover Dataset t o extract the necessary micrometeorological data. LULC data was used for processing me teorological data sets used as input to AERMOD.

AERSURFACE v. 13016 was used to deve lop surface roughness, albe do, and daytime Bowen ratio values in a region surrounding the meteorological data collecti on site. AERSURFACE was used to develop surface roughness in a one kilometer radius surrounding the data collection site. Bowen ratio and albedo was developed for a 10 kilometer by 10 kilomet er area centered on the meteorological data collection si te. These micrometeorological data were processed for seasonal periods using 30-degree sectors . Seasonal moisture conditions w ere considered ave rage with winter months having continuous snow cover.

14 Available at: http://esrl.noaa.gov/raobs/Evaluation of Compliance with the 1-hour NAAQS for SO 2 May 4, 2015 Page 16

4.5.4 Data Review Missing meteorological data were not filled as the data file me t USEPA’s 90% data completeness requirement. 15 The AERMOD output file shows th ere were 0.2% missing data. To confirm the representativene ss of the airport meteorological data, the surface characteristics of the airport data collection s ite and the modeled source locatio n were compared. Since the Baltimore Washington International Airpor t is located close to the three Maryland generating stations, this meteorological data set was consid ered appropriate for this mod eling analysis. 16 Additionally, this weather station provided high quality surface measurements for the most recent 3-year time, and had similar land use, surface charac teristics, terrain features and climate. 5. Background SO 2 Concentrations Background concentrations were determined consistent with USEPA ’s Modeling Guidance for SO 2 NAAQS Designations. 17 To preserve the form of the 1-hour SO 2 standard, based on the 99 th percentile of the annual distri bution of daily maximum 1-hour c oncentrations averaged across the number of years modeled, the b ackground fourth-highest daily ma ximum 1-hour SO 2 concentration was added to the modeled fourth-h ighest daily maximum 1-hour SO 2 concentration. 18 Background concentrations were based on the 2011-13 design value measured by the ambient monitors located in Maryland. 19
6. Reporting All files from the programs used for this modeling analysis are available to regulatory agencies. These include analyses prepared w ith AERSURFACE, AERMET, AERMAP , and AERMOD.

15 USEPA, Meteorological Monitoring Guidance for Regulatory Modeli ng Applications, EPA-454/R-99-05, February 2000, Section 5.3.2, pp. 5-4 to 5-5. 16 USEPA, AERMOD Implementation Guide, March 19, 2009, pp. 3-4. 17 USEPA, Area Designations for the 2010 Revised Primary Sulfur D ioxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, pp. 20-23. 18 USEPA, Applicability of Appendix W Modeling Guidance for the 1- hour SO 2 National Ambient Air Quality Standard, August 23, 2010, p. 3. 19 http://www.epa.gov/airtrends/values.html