Air Plan Approval; Maryland; Determination of Attainment by the Attainment Date for the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality Standard

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R03-OAR-2024-0152; FRL-11858-01-R3]</DEPDOC> <SUBJECT>Air Plan Approval; Maryland; Determination of Attainment by the Attainment Date for the 2010 1-Hour Primary Sulfur Dioxide National Ambient Air Quality 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 determine that the Anne Arundel County and Baltimore County, Maryland sulfur dioxide (SO <E T="52">2</E> ) nonattainment area attained the 2010 1-hour primary SO <E T="52">2</E> national ambient air quality standard (2010 SO <E T="52">2</E> NAAQS) by the applicable attainment date of September 12, 2021. This determination is based on certified ambient air quality data from the 2018-2020 monitoring period, relevant modeling analysis, and additional emissions inventory information. This action, if finalized, will address the EPA's obligation under Clean Air Act (CAA) section 179(c) to determine whether the Anne Arundel and Baltimore County SO <E T="52">2</E> nonattainment area (referred to hereafter as the Anne Arundel-Baltimore County Area, or simply the Area) attained the 2010 SO <E T="52">2</E> NAAQS by the September 12, 2021 attainment date. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before October 7, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R03-OAR-2024-0152 at <E T="03">www.regulations.gov</E> , or via email to <E T="03">talley.david@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">www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Philip McGuire, Planning & Implementation Branch (3AD30), Air & Radiation Division, U.S. Environmental Protection Agency, Region III, 1600 John F Kennedy Boulevard, Philadelphia, Pennsylvania 19103. The telephone number is (215) 814-2251. Mr. McGuire can also be reached via electronic mail at <E T="03">mcguire.philip@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we refer to the EPA. <HD SOURCE="HD1">I. Background</HD> <HD SOURCE="HD2"> A. The 2010 1-Hour Primary SO <E T="54">2</E> NAAQS </HD> Under section 109 of the CAA, the EPA has established primary and secondary NAAQS for certain pervasive air pollutants (referred to as “criteria pollutants”) and conducts periodic reviews of the NAAQS to determine whether they should be revised or whether new NAAQS should be established. The primary NAAQS represent ambient air quality standards that the EPA has determined are requisite to protect the public health, while the secondary NAAQS represent ambient air quality standards that the EPA has determined are requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such an air pollutant in the ambient air. Under the CAA, the EPA must establish a NAAQS for SO <E T="52">2</E> , which is primarily released to the atmosphere through the burning of fossil fuels by power plants and other industrial facilities. The EPA first established primary SO <E T="52">2</E> standards in 1971 at 140 parts per billion (ppb) over a 24-hour averaging period and at 30 ppb over an annual averaging period. <SU>1</SU> <FTREF/> <FTNT> <SU>1</SU>  36 FR 8186, April 30, 1971. </FTNT> On June 22, 2010, the EPA published in the <E T="04">Federal Register</E> a strengthened, primary 1-hour SO <E T="52">2</E> NAAQS, establishing a new standard at a level of 75 ppb, based on the 3-year average of the annual 99th percentile of daily maximum 1-hour average concentrations of SO <E T="52">2</E> . <SU>2</SU> <FTREF/> This revised SO <E T="52">2</E> NAAQS provides increased protection of public health, and provided for revocation of the 1971 primary annual and 24-hour SO <E T="52">2</E> standards for most areas of the country following area designations under the new NAAQS. <FTNT> <SU>2</SU>  75 FR 35520, June 22, 2010. </FTNT> <HD SOURCE="HD2"> B. Designations, Classifications, and Attainment Dates for the 2010 SO <E T="54">2</E> NAAQS </HD> Following promulgation of a new or revised NAAQS, the EPA is required to designate all areas of the country as either “attainment,” “nonattainment,” or “unclassifiable,” pursuant to CAA section 107(d)(1). On August 5, 2013, the EPA finalized its first round of designations for the 2010 1-hour primary SO <E T="52">2</E> NAAQS. <SU>3</SU> <FTREF/> In this 2013 action, the EPA designated 29 areas in 16 states as nonattainment for the 2010 1-hour primary SO <E T="52">2</E> NAAQS. On July 12, 2016, the EPA finalized its second round of initial designations under the 2010 1-hour primary SO <E T="52">2</E> NAAQS, designating an additional four areas as nonattainment, effective September 12, 2016. <SU>4</SU> <FTREF/> Included in this second round of designations was the Anne Arundel-Baltimore County Area. This designation was based on the weight of evidence for the Area, including available air quality modeling and ambient air monitoring data from 2013-2015. Pursuant to section 192(a) of the CAA, the attainment date for the Anne Arundel-Baltimore County Area was no later than five years after the effective date of initial designation, or September 12, 2021. <FTNT> <SU>3</SU>  78 FR 47191, August 5, 2013. </FTNT> <FTNT> <SU>4</SU>  81 FR 45039, July 12, 2016. </FTNT> CAA section 191(a) directs states containing an area designated nonattainment for the 2010 1-hour primary SO <E T="52">2</E> NAAQS to develop and submit a nonattainment area (NAA) state implementation plan (SIP) to the EPA within 18 months of the effective date of an area's designation as nonattainment. For SO <E T="52">2,</E> the NAA SIP (also referred to as an attainment plan) must meet the requirements of subparts l and 5 of part D, of title 1 of the CAA, and provide for attainment of the NAAQS by the applicable statutory attainment date, or no later than five years from the effective date of designation. The Maryland Department of Environment (MDE) submitted an attainment plan SIP for the Anne Arundel-Baltimore County Area on January 31, 2020. When a nonattainment area is attaining the 2010 1-hour primary SO <E T="52">2</E> NAAQS based on the most recent available data, the EPA may issue a Clean Data Determination (CDD), suspending certain NAA planning requirements. The EPA issued a CDD for the Anne Arundel-Baltimore County Area based on modeling and monitoring data for the period 2019-2021 via a final rule published on November 2, 2022, and at the same time, approved certain elements of the submitted attainment plan that are not waived by the EPA's CDD policy. <SU>5</SU> <FTREF/> Notably, a CDD does not alter the Area's nonattainment designation. For the EPA to redesignate an area to attainment, the state must submit, and the EPA must approve a redesignation request for the Area that meets the requirements of CAA section 107(d)(3). To date, Maryland has not requested redesignation of the Area to attainment. <FTNT> <SU>5</SU>  87 FR 66086, November 2, 2022. </FTNT> <HD SOURCE="HD2">C. EPA Determination of Attainment by the Attainment Date</HD> Section 179(c)(1) of the CAA requires the EPA to determine whether a nonattainment area attained an applicable standard by the applicable attainment date based on the area's air quality as of the attainment date. The EPA is required to issue this determination within six months of the attainment date. Thus, the EPA had a mandatory duty to determine by March 12, 2022, under CAA section 179(c) if the Area reached attainment. With this action, the EPA proposes to determine, in accordance with CAA section 179(c), that the Anne Arundel-Baltimore County Area attained the 2010 1-hour primary SO <E T="52">2</E> NAAQS by the September 12, 2021, attainment date. A determination of whether an area's air quality meets applicable standards is generally based upon the most recent three years of complete, quality-assured data gathered at established state and local air monitoring stations (SLAMS) in a nonattainment area and entered into the EPA's Air Quality System (AQS) database. <SU>6</SU> <FTREF/> Data from ambient air monitors operated by state and local agencies in compliance with the EPA monitoring requirements must be submitted to AQS. Monitoring agencies annually certify that these data are accurate to the best of their knowledge. All data are reviewed to determine the area's ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 41k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━