Connecticut Department of

ENERGY &



### ~ r ENVI RONMENTAL


### ~ PROTECTION 79 Elm Street • Hartford, CT 06106-5127 www.ct.gov/deep Affirmative Action/Equal Opportunity Employer

August 5, 2015 David B. Conroy, Chief Air Programs Branch EPA New England, Region 1 5 Post Office Square — Suite 100 Boston, MA 02109-3912 

### Re: Supplement to Infrastructure State Implementation Plan (SIP) Revisions Dear Mr. Conroy: The letter addresses a question, a point of information and a request that Region 1 of the U.S. Environmental Protection Agency (EPA) presented to the Connecticut Department of Energy and Environmental Protection (DEEP) concerning its air quality regulatory programs as set out in several infrastructure SIP revisions. Regarding the question, Region 1 asked whether Connecticut requires that the condensable portion PM 10 and PM 2.5 be considered for the purposes of major new source review permitting applicability determinations and for establishing source-specific emissions limits in new source review permits. Region 1 has raised this question because Connecticut's definitions of "PM 10" and "PM2.5" in section 22a-174-1 of the Regulations of Connecticut State Agencies (RCSA) 1 do not include explicit references to condensable portions of PM10 and PM2.5. DEEP responds in the affirmative as DEEP does currently require consideration of the condensable portion of the pollutants PM10 and PM2.5 to determine applicability for major new source review and to establish permit limits. DEEP interprets the definitions of the terms "PM 10" and "PM 2.5" in RCSA section 22a-174-1 to include the condensable portion of the pollutants PM 10 and PM 2.5 even though the word "condensable" is not used in those definitions. The pollutants are defined in terms of the how each pollutant is measured in ambient

From RCSA section 22a-174-1: (87) "PM 2.5" means particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers as measured by a reference method set forth in 40 CFR 50, Appendix L, and designated as a reference method in accordance with 40 CFR 53 or by an equivalent method approved by the Administrator in accordance with 40 CFR 53. (88) "PM 10" means particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers as measured by a reference method set forth in 40 CFR 50, Appendix J, and designated as a reference method in accordance with 40 CFR 53 or by an equivalent method approved by the Administrator in accordance with 40 CFR 53.David B. Conroy

Page 2 5 August 2015
monitoring, which, as a technical matter, necessarily includes the condensable portions of PM 10 and PM 2.5. Regarding the point of information, Connecticut does have a state statute, Section 22a-7 of the Connecticut General Statutes, which provides the Commissioner with emergency powers similar to those provided to the Administrator by Section 303 of the Clean Air Act. Regarding EPA Region 1's request, it is for a commitment to make regulatory revisions related. to Connecticut's prevention of significant deterioration (PSD) and new source review (NSR) permitting requirements. The request is for revision of four provisions that EPA Region 1 has identified as potentially producing permitting determinations that are not consistent with determinations made under the federal requirements, as modified by EPA in the Phase 2 ozone implementation rule (70 Fed. Reg. 71612; November 29, 2005). The provisions include the definitions of "maj or stationary source," "maj or modification," and "minor source baseline date" 2 in RCSA section 22a-174-1; and the PSD applicability provision in RCSA section 22a174-3a(k)(1)(A). DEEP understands the reason for EPA Region 1's request and is committing to pursue the adoption of appropriate revisions to RCSA sections 22a-174-1 and 22a-174-3a to conform to the intent of EPA's PSD and NSR program requirements as modified in 2005 and in subsequent revisions so that DEEP's infrastructure SIPs may be approved. As DEEP's NSR program does not duplicate the federal requirements precisely, DEEP will consider the regulatory drafting options available to achieve the intended result and will keep Region 1 informed of the chosen approach. DEEP commits to seek completion of the necessary regulatory revisions as outlined above. DEEP understands that EPA intends to provide for an automatic disapproval if the requested PSD program revisions are not submitted within the time period designated by EPA in the notice (i. e., one year from the publication of the conditional approval). Feel free to get in touch with me or Jaimeson Sinclair (860-424-3408) if you have any questions concerning this letter. Sincerely yours,



# . ✓

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# - _ Anne R. Gobin, Chief Bureau of Air Management

The minor source baseline date for PM2.5 is September 24, 2014.