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COMMENTS AND RESPONSES

State Implementation Plan Revision:

Section 110(a)(2)(d)(i) for the Eight-Hour Ozone and PM2.5 National Ambient Air 

Quality Standards

The public comment period began on September 15, 2007 and closed on October 16, 

2007. A public hearing was held on October 16, 2007. Proof of publication is attached. 

COMMENTATORS:

1. Anne R. Gobin, Chief

Bureau of Air Management

Connecticut Department of Environmental Protection

79 Elm Street

Hartford, CT 06106-5127

COMMENTS: 

COMMENT: Pennsylvania has taken sincere efforts to support regional solutions to 

the ozone problem with its involvement in the Ozone Transport Commission and we are 

grateful to have your commitment to work with us to address gaps left by CAIR. We 

remain concerned that the emission reductions that will result from the Clean Air 

Interstate Rule (CAIR) will not satisfy the Clean Air Action Section 110(a)(D)(i) that 

states upwind from Connecticut, such as Pennsylvania, prohibit emissions in amounts 

that contribute significantly to nonattainment of the eight-hour ozone standard in other 

states. EPA concluded that most of the 2010 projected peak ozone levels would be 

transported from upwind states.

The regional summer season NOx emission reductions from CAIR provide very little 

ambient peak ozone improvement in Connecticut. Levels of transport after CAIR 

implementation remain large enough that attainment may be difficult to achieve in 

Connecticut by June 2010, regardless of the level of in-state emission controls. This

creates uncertainty about Connecticut’s ability to attain the ozone standard by the 

required June 2010 deadline. EPA’s Phase 2 CAIR reductions in 2015 are inadequate to 

ensure healthy air quality in Connecticut. 

EPA’s CAIR data also indicate that a NOx budget more stringent than CAIR can be 

achieved at a reasonable cost compared to many control measures that are being 

pursued by Connecticut and other states. Additional cost effective reductions may also 

be realized by targeting emissions that occur on peak electric demand days in the 

summer months. (1)
2

RESPONSE: The Department appreciates the commentator’s support of its efforts to 

reduce transported ozone precursors. The Department believes the Commonwealth is 

meeting its obligations under section 110(a)(2)(D)(i) of the Clean Air Act (CAA) to 

include in its State Implementation Plan (SIP) adequate provisions prohibiting sources 

and other emissions activities in the Commonwealth from emitting any air pollutant in 

amounts that will “contribute significantly” to nonattainment in downwind states, like 

Connecticut. Beginning with the 2009 control period, EGUs in the Commonwealth will 

be subject to the federal Clean Air Interstate Rule (CAIR) Federal Implementation Plan 

(FIP). In the meantime, electric generating units (EGU)s and certain non-EGUs are 

subject to the Commonwealth’s NOx Budget Trading Program, and the Department plans 

to present its final CAIR rulemaking to the Commonwealth’s Environmental Quality

Board for approval in December, 2007. If the necessary approvals are timely obtained, 

the final CAIR regulation should be published and effective early in 2008, at which time 

it will be submitted to EPA for inclusion in the Commonwealth’s SIP.

On April 25, 2005, EPA published national findings that States had failed to 

submit SIPs required under section 110(a)(2)(D) to address interstate transport with 

respect to the eight-hour ozone and PM2.5 NAAQS. 70 Fed. Reg. 21147. On May 12, 

2005, EPA published the CAIR, which established emission reduction requirements for 

affected upwind States under section 110(a)(2)(D)(i). 70 Fed. Reg. 25162. On April 28, 

2006, EPA denied North Carolina’s Section 126 petition with respect to sources in States 

having an approved SIP meeting the CAIR emissions reductions requirements, and with 

respect to sources in States for which EPA promulgated a Federal Implementation Plan 

(FIP) with those same emission reductions requirements. In either case, EPA reasoned, 

there would no longer be a violation of the prohibition in section 110(a)(2)(D)(i). Since a 

violation of that prohibition is a condition precedent for granting a section 126 petition, 

EPA necessarily denied the petition. 71 Fed. Reg. 25334-5.

In addition, EPA interprets “significant contribution” under section 110(a)(2)(D) 

in the CAIR “to include both an emission component and a feasibility/cost-effectiveness 

component, so that what is prohibited are specific levels of emissions which can feasibly

be reduced in a highly cost-effective manner.” 71 Fed. Reg. 25335. EPA states in its 

preamble to the CAIR FIPs that “adoption of a CAIR SIP (or EPA adopting a CAIR FIP) 

fully addresses” the section 110(a)(2)(D)(i) prohibition against significant contribution. 

Id.

Recognizing that the Connecticut Department of Environmental Protection asserts 

that implementing CAIR is inadequate to satisfy 110(a)(2)(D)(i), we note the other 

measures listed in Pennsylvania’s proposed section 110(a)(2)(D)(i) SIP that will also 

reduce downwind transport of ozone precursors.