Air Plan Approval; Wisconsin; Milwaukee Second 10-Year 2006 24-Hour PM2.5 Limited Maintenance Plan

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R05-OAR-2022-0369; FRL-11761-01-R5]</DEPDOC> <SUBJECT> Air Plan Approval; Wisconsin; Milwaukee Second 10-Year 2006 24-Hour PM <E T="0735">2.5</E> Limited Maintenance Plan </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) submitted on April 8, 2022, by the Wisconsin Department of Natural Resources (WDNR) for the Milwaukee-Racine maintenance area including Milwaukee, Waukesha, and Racine counties. 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 (PM <E T="52">2.5</E> ). EPA is proposing to approve Wisconsin's LMP submission for Milwaukee-Racine because it provides for the maintenance of the 2006 PM <E T="52">2.5</E> national ambient air quality standard (NAAQS) through the end of the second 10-year portion of the maintenance period. In addition, EPA is initiating the process to find the Milwaukee-Racine PM <E T="52">2.5</E> LMP adequate for transportation conformity purposes. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Comments must be received on or before April 18, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R05-OAR-2022-0369 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">arra.sarah@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, 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, <E T="03">etc.</E> ) 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. 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://www2.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Cecilia Magos, Attainment Planning and Maintenance Section, Air Programs Branch (AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 886-7336, <E T="03">magos.cecilia@epa.gov.</E> The EPA Region 5 office is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Federal holidays and facility closures due to COVID-19. </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. This supplementary information section is arranged as follows: <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP-2">II. The LMP Option</FP> <FP SOURCE="FP-2">III. EPA's Analysis of the State's Submittal</FP> <FP SOURCE="FP-2">IV. What action is EPA taking?</FP> <FP SOURCE="FP-2">V. Environmental Justice Considerations</FP> <FP SOURCE="FP-2">VI. Statutory and Executive Orders Review</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2"> A. The PM <E T="54">2.5</E> NAAQS </HD> PM <E T="52">2.5</E> is one of the criteria pollutants for which a NAAQS is established 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 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 2024, EPA revised the annual primary PM <E T="52">2.5</E> NAAQS to 9.0 μg/m <SU>3</SU> and retained the level of 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 Milwaukee-Racine</HD> On November 13, 2009 (74 FR 58688), EPA designated the Milwaukee-Racine area as a PM <E T="52">2.5</E> nonattainment area due to measured violations of the 2006 PM <E T="52">2.5</E> NAAQS. On June 8, 2012, supplemented on May 30, 2013, WDNR submitted to EPA a request to redesignate the Milwaukee-Racine nonattainment area, to attainment of the 2006 PM <E T="52">2.5</E> NAAQS. The submission included a plan to provide for maintenance of the 2006 PM <E T="52">2.5</E> NAAQS in the area for 10 years. EPA redesignated the Milwaukee-Racine area on April 22, 2014 (79 FR 22415),and approved the associated maintenance plan into the Wisconsin State Implementation Plan (SIP). The purpose of WDNR'S April 8, 2022, LMP submission is to fulfill the second 10-year planning requirement of CAA section 175A(b) to ensure PM <E T="52">2.5</E> NAAQS compliance through 2034. <HD SOURCE="HD1">II. The LMP Option</HD> <HD SOURCE="HD2">A. Demonstration of Maintenance Using the LMP 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.,</E> attainment year inventory). EPA clarified in subsequent guidance memos that certain nonattainment areas could meet the CAA section 175A requirement to provide for maintenance by demonstrating that the area's design value was well below the NAAQS and that the historical stability of the area's air quality levels showed that the area was unlikely to violate the NAAQS in the future. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  Calcagni, John, Director, Air Quality Management Division, EPA Office of Air Quality Planning and Standards, “Procedures for Processing Requests to Redesignate Areas to Attainment,” September 4, 1992 (Calcagni memo). </FTNT> <FTNT> <SU>2</SU>   <E T="03">See</E> “Limited Maintenance Plan Option for Nonclassifiable Ozone Nonattainment Areas” from Sally L. Shaver, Office of Air Quality Planning and Standards (OAQPS), dated November 16, 1994; “Limited Maintenance Plan Option for Nonclassifiable CO Nonattainment Areas” from Joseph Paisie, OAQPS, dated October 6, 1995; and “Limited Maintenance Plan Option for Moderate PM <E T="52">10</E> Nonattainment Areas” (PM <E T="52">10</E> LMP Guidance) from Lydia Wegman, OAQPS, dated August 9, 2001. Copies of these guidance memoranda can be found in the docket for this proposed rulemaking. </FTNT> Most recently, in October 2022, EPA released guidance extending this streamlined option for demonstrating maintenance under CAA section 175A to certain PM <E T="52">2.5</E> areas, titled “Guidance on Limited Maintenance Plan Option for Moderate PM <E T="52">2.5</E> Nonattainment Areas and PM <E T="52">2.5</E> Maintenance Areas” (PM <E T="52">2.5</E> LMP Guidance). <SU>3</SU> <FTREF/> <FTNT> <SU>3</SU>  The guidance document developed by the Office of Air Quality Planning and Standards and the Office of Transportation and Air Quality, within the Office of Air and Radiation, titled “Guidance on the Limited Maintenance Plan Option for Moderate PM <E T="52">2.5</E> Nonattainment Areas and PM <E T="52">2.5</E> Maintenance Areas” can be found at <E T="03">https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1015UL4.pdf.</E> </FTNT> EPA refers to this streamlined demonstration of maintenance as an LMP. EPA has interpreted CAA section 175A as permitting this option because CAA section 175A defines few specific content requirements for maintenance plans and, in EPA's experience implementing the various NAAQS, areas that qualify for an LMP or have approved LMPs have rarely, if ever, experienced subsequent violations of the NAAQS. As noted in the PM <E T="52">2.5</E> LMP guidance, states seeking an LMP should still submit the other maintenance plan elements outlined in the Calcagni memo, including: an attainment emissions inventory, provisions for the continued operation of the amb ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 55k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━