Air Plan Approval; Connecticut; 2014 and 2017 Periodic Emissions Inventory for 2008 8-Hour Ozone NAAQS

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R01-OAR-2025-0240; FRL-12861-01-R1]</DEPDOC> <SUBJECT>Air Plan Approval; Connecticut; 2014 and 2017 Periodic Emissions Inventory for 2008 8-Hour Ozone NAAQS</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 State Implementation Plan (SIP) revisions submitted by the State of Connecticut. These SIP revisions relate to the 2008 8-Hour ozone National Ambient Air Quality Standards (NAAQS). The SIP revisions consist of the following: 2014 and 2017 calendar year periodic emissions inventories. This action is being taken under the Clean Air Act. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before August 6, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-0240 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">lillis.patrick@epa.gov.</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 at all possible, you contact the contact listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section to schedule your inspection. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Patrick Lillis, Air and Radiation Division (Mail Code 5-MI), U.S. Environmental Protection Agency—Region 1, 5 Post Office Square, Suite 100, Boston, Massachusetts 02109-3912; tel. (617) 918-1067, or by email at <E T="03">lillis.patrick@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</FP> <FP SOURCE="FP1-2">A. The 2008 Ozone NAAQS</FP> <FP SOURCE="FP1-2">B. Statutory and Regulatory Emission Inventory Requirements</FP> <FP SOURCE="FP-2">II. State's Submittal</FP> <FP SOURCE="FP-2">III. EPA's Evaluation</FP> <FP SOURCE="FP1-2">A. 2014 Periodic Emissions Inventory</FP> <FP SOURCE="FP1-2">B. 2017 Periodic Emissions Inventory</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</HD> Ozone is a gas that is formed by the reaction of Volatile Organic Compounds (VOC) and Oxides of Nitrogen (NO <E T="52">X</E> ) in the atmosphere in the presence of sunlight. Therefore, an emission inventory for ozone focuses on the emissions of VOC and NO <E T="52">X</E> , referred to as ozone precursors. These precursors (VOC and NO <E T="52">X</E> ) are emitted by many types of pollution sources, including point sources such as power plants and industrial emissions sources; on-road and off-road mobile sources (motor vehicles and engines); and smaller residential and commercial sources, such as dry cleaners, auto body shops, and household paints, collectively referred to as nonpoint sources (also called area sources). An emission inventory of ozone is an estimation of actual emissions of air pollutants that contribute to the formation of ozone in an area. The emissions inventory provides emissions data for a variety of air quality planning tasks, including establishing baseline emission levels for calculating emission reduction targets needed to attain the NAAQS, determining emission inputs for ozone air quality modeling analyses, and tracking emissions over time to determine progress toward meeting Reasonable Further Progress (RFP) requirements. <HD SOURCE="HD2">A. The 2008 Ozone NAAQS</HD> On March 12, 2008, the EPA revised both the primary and secondary NAAQS  <SU>1</SU> <FTREF/> for ozone to a level of 0.075 parts per million (ppm) to provide increased protection of public health and the environment. ( <E T="03">See</E> 73 FR 16436, March 27, 2008). The 2008 ozone NAAQS retains the same general form and averaging time as the 0.08 ppm NAAQS set in 1997 but is set at a more protective level. Under the EPA's regulations, the 2008 8-hour ozone NAAQS is attained when the 3-year average of the annual fourth highest daily maximum 8-hour average ambient air quality ozone concentrations is less than or equal to 0.075 ppm. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  The primary ozone standards provide protection for children, older adults, and people with asthma or other lung diseases, and other at-risk populations against an array of adverse health effects that include reduced lung function, increased respiratory symptoms and pulmonary inflammation; effects that contribute to emergency department visits or hospital admissions; and mortality. The secondary ozone standards protect against adverse effects to the public welfare, including those related to impacts on sensitive vegetation and forested ecosystems. </FTNT> <FTNT> <SU>2</SU>  For a detailed explanation of the calculation of the 3-year 8-hour average, <E T="03">see</E> 40 CFR part 50, appendix P. </FTNT> Effective July 20, 2012, the EPA designated as nonattainment any area that was violating the 2008 8-hour ozone NAAQS based on the three most recent years (2008-2010) of air monitoring data. <SU>3</SU> <FTREF/> With that rulemaking, the Greater Connecticut and the Connecticut portion of the New York-Northern New Jersey-Long Island, NY-NJ-CT areas were designated as marginal ozone nonattainment areas. Areas that were designated as marginal nonattainment were required to attain the 2008 8-hour ozone NAAQS no later than July 20, 2015, based on 2012-2014 monitoring data. Any state in which a marginal nonattainment area is located is required to submit certain SIP elements to the EPA in accordance with section 182(a) of the CAA. <FTNT> <SU>3</SU>   <E T="03">See</E> 77 FR 30088, May 21, 2012. </FTNT> <HD SOURCE="HD2">B. Statutory and Regulatory Emission Inventory Requirements</HD> CAA sections 182(a)(1) and 182(a)(3)(A) require submission of base year and periodic emissions inventories, respectively, for each ozone nonattainment area. <SU>4</SU> <FTREF/> States are required to submit a periodic inventory of emissions sources in the nonattainment areas to meet the requirements of CAA § 182(a)(3)(A), as specified in the Air Emissions Reporting Requirements (AERR) at 40 CFR part 51, subpart A. Each periodic inventory shall be submitted no later than the end of each 3-year period after the required submission of the base year inventory for the nonattainment area and this requirement shall apply until the area is redesignated to attainment. <SU>5</SU> <FTREF/> The emissions value included in the inventories shall be actual ozone season day emissions as defined by § 51.1100(cc). <SU>6</SU> <FTREF/> These requirements allow the EPA, based on the states' progress in reducing emissions, to reassess its policies and air quality standards periodically and revise them as necessary. Most important, these inventories will be used to develop and assess new control strategies that states may use in attainment demonstration SIPs for ozone or other pollutants. The inventory may also serve as part of statewide inventories for purposes of regional modeling in transport areas, where the inventory plays an important role in modeling demonstrations for areas classified as nonattainment and outside transport regions. <FTNT> <SU>4</SU>  “For each nonattainment area, the state shall submit a base year inventory as defined by § 51.1100(bb) to meet the emissions inventory requirement of CAA section 182(a)(1). This inventory shall be submitted no later than 24 months after the effective date of designation. The inventory year shall be selected consistent with the baseline year for the RFP plan as required by § 51.1110(b).” (40 CFR 51.115(a)). </FTNT> <FTNT> <SU>5</SU>  CAA § 182(a)(3)(A); 40 CFR 51.1115(b). </FTNT> <FTNT> <SU>6</SU>  40 CFR 51.1115(c); <E T="03">see also</E> Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements, 80 FR 12264 (March 6, 2015). </FTNT> <HD SOURCE="HD1">II. State's Submittal</HD> CAA Sections 182(a)(3) and 172(c)(3) require the periodic submission of emissions inventories for the SIP planning process to address SIP requirements applicable to ozone nonattainment areas in each classification category. The Greate ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 32k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━