Air Plan Approval; Connecticut; New Haven and Fairfield Counties Second 10-Year Limited Maintenance Plan for the 2006 24-Hour PM2.5 Standard

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R01-OAR-2024-0117; FRL-12283-01-R1]</DEPDOC> <SUBJECT> Air Plan Approval; Connecticut; New Haven and Fairfield Counties Second 10-Year Limited Maintenance Plan for the 2006 24-Hour PM <E T="0735">2.5</E> Standard </SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve, under the Clean Air Act (CAA), the limited maintenance plan (LMP) for the 2006 PM <E T="52">2.5</E> national ambient air quality standard (NAAQS) for New Haven and Fairfield Counties, which comprise the Connecticut portion of the New York-N. New Jersey-Long Island (NY-NJ-CT) 2006 PM <E T="52">2.5</E> NAAQS maintenance area. This LMP was submitted on May 9, 2023, and supplemented on February 21, 2024, by the Connecticut Department of Energy and Environmental Protection (CT DEEP). The plan addresses the second 10-year maintenance period for particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers, known as PM <E T="52">2.5</E> . EPA is proposing approval of Connecticut's LMP submission because it provides for the maintenance of the 2006 24-hour PM <E T="52">2.5</E> NAAQS through the end of the second 10-year portion of the maintenance period. In addition, EPA is initiating the process to find the Connecticut PM <E T="52">2.5</E> LMP adequate for transportation conformity purposes. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before October 28, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R01-OAR-2024-0117 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">martinelli.ayla@gmail.com.</E> For comments submitted at <E T="03">Regulations.gov,</E> follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">Regulations.gov</E> . For either manner of submission, the EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> Publicly available docket materials are available at <E T="03">https://www.regulations.gov</E> or at the U.S. Environmental Protection Agency, EPA Region 1 Regional Office, Air and Radiation Division, 5 Post Office Square—Suite 100, Boston, MA. EPA requests that, if possible, you contact the contact listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section to schedule your inspection. The Regional Office's official hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m., excluding legal holidays and facility closures due to COVID-19. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Ayla Martinelli, Air Quality Branch, U.S. Environmental Protection Agency, EPA Region 1, 5 Post Office Square—Suite 100, (Mail code 5-MI), Boston, MA 02109-3912, tel. (617) 918-1057, email <E T="03">martinelli.ayla@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background and Purpose</FP> <FP SOURCE="FP1-2"> A. The PM <E T="52">2.5</E> National Ambient Air Quality Standards (NAAQS) </FP> <FP SOURCE="FP1-2">B. Regulatory Actions in New Haven and Fairfield Counties</FP> <FP SOURCE="FP-2">II. The Limited Maintenance Plan Option</FP> <FP SOURCE="FP1-2">A. Demonstration of Maintenance Using the Limited Maintenance Plan Option</FP> <FP SOURCE="FP1-2">B. Transportation Conformity Under Limited Maintenance Plan Option</FP> <FP SOURCE="FP1-2">C. General Conformity Under Limited Maintenance Plan Option</FP> <FP SOURCE="FP-2">III. EPA's Analysis of the State's Submittal</FP> <FP SOURCE="FP1-2">A. Demonstration of Qualification for the Limited Maintenance Plan Option</FP> <FP SOURCE="FP1-2">B. Attainment Inventory</FP> <FP SOURCE="FP1-2">C. Air Quality Monitoring Network</FP> <FP SOURCE="FP1-2">D. Verification of Continued Attainment</FP> <FP SOURCE="FP1-2">E. Contingency Provisions</FP> <FP SOURCE="FP-2">IV. Proposed Action</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background and Purpose</HD> <HD SOURCE="HD2"> A. The PM <E T="54">2.5</E> National Ambient Air Quality Standards (NAAQS) </HD> EPA has established NAAQS for particulate matter with an aerodynamic diameter less than or equal to 2.5 micrometers, known as PM <E T="52">2.5</E> , to protect human health and the environment. In 1997, EPA established the first PM <E T="52">2.5</E> standards based on significant scientific evidence and health studies demonstrating the serious health effects associated with exposure to PM <E T="52">2.5</E> . EPA set an annual standard of 15.0 micrograms per cubic meter (μg/m <SU>3</SU> ) and a 24-hour (or daily) standard of 65 μg/m <SU>3</SU> . In 2006, EPA strengthened the 24-hour PM <E T="52">2.5</E> NAAQS by revising it to 35 μg/m <SU>3</SU> and retained the level of the annual PM <E T="52">2.5</E> standard at 15.0 μg/m <SU>3</SU> . Subsequently, in 2012, EPA established an annual primary PM <E T="52">2.5</E> NAAQS at 12.0 μg/m <SU>3</SU> and retained the 2006 24-hour PM <E T="52">2.5</E> NAAQS at 35 μg/m <SU>3</SU> . In early 2024, EPA strengthened the level of the annual primary PM <E T="52">2.5</E> standard to 9.0 μg/m <SU>3</SU> and retained the 2006 24-hour PM <E T="52">2.5</E> NAAQS at 35 μg/m <SU>3</SU> . <HD SOURCE="HD2">B. Regulatory Actions in New Haven and Fairfield Counties</HD> Hereafter, “New Haven-Fairfield” means the Connecticut portion of the NY-NJ-CT maintenance area which is comprised of New Haven and Fairfield Counties. EPA promulgated the designations for New Haven-Fairfield as a PM <E T="52">2.5</E> nonattainment area for the 1997 annual PM <E T="52">2.5</E> NAAQS on January 5, 2005 (70 FR 944) and the 2006 24-hour PM <E T="52">2.5</E> NAAQS (74 FR 58688) on November 13, 2009, due to measured violations of the standards. These designations became effective on April 5, 2005, and December 14, 2009, respectively. On June 22, 2012, CT DEEP submitted a request to EPA to redesignate the New Haven- Fairfield nonattainment area to attainment of both the 1997 annual and 2006 24-hour PM <E T="52">2.5</E> NAAQS. This submittal included a maintenance plan to provide for maintenance of the PM <E T="52">2.5</E> NAAQS in the area for 10 years. EPA redesignated New Haven-Fairfield to attainment for the 1997 and 2006 PM <E T="52">2.5</E> NAAQS on October 24, 2013 (78 FR 58467) and approved the associated maintenance plan into the Connecticut State Implementation Plan (SIP). The purpose of CT DEEP's May 9, 2023 (supplemented on February 21, 2024) LMP submission is to fulfill the second 10-year planning requirement of CAA section 175A(b), thus ensuring PM <E T="52">2.5</E> NAAQS compliance through the end of the maintenance period. In the LMP submittal, CT DEEP indicates that it is seeking approval of the LMP for both the 2006 24-hour standard as well as the 1997 annual standard. However, as explained in the PM <E T="52">2.5</E> SIP Requirements Rule (81 FR 58009), a second 10-year maintenance plan for the revoked 1997 annual PM <E T="52">2.5</E> NAAQS is not required. Therefore, CT DEEP clarified via email that it incorrectly sought approval of the plan for the revoked 1997 annual standard and asked that EPA ignore the request for approval of the plan for this standard. The email, sent on July 7, 2023, can be found in the docket of this action. Thus, EPA will only proceed with proposing approval of the LMP for the 2006 24-hour PM <E T="52">2.5</E> NAAQS. <HD SOURCE="HD1">II. The Limited Maintenance Plan Option</HD> <HD SOURCE="HD2">A. Demonstration of Maintenance Using the Limited Maintenance Plan Option</HD> Section 175A of the CAA sets forth the elements of a maintenance plan. Under section 175A, a state must submit a revision to the SIP that provides for maintenance of the applicable NAAQS for at least 10 years after an area is redesignated to attainment. Section 175A also requires that eight years into the first maintenance period, the state must submit a second maintenance plan demonstrating that the area will continue to attain for the following 10-year period. EPA has published long-standing guidance for states on developing maintenance plans. <SU>1</SU> <FTREF/> The Calcagni memo provides that states may generally demonstrate maintenance by either performing air quality modeling to show that the future mix of sources and emission rates will not cause a violation of the NAAQS or by showing that future emissions of a pollutant and its precursors will not exceed the level of emissions during a year when the area was attaining the NAAQS ( <E T="03">i.e ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 42k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━