90 FR 65 pgs. 14939-14954 - Air Plan Approval; Pennsylvania; Redesignation Request and Associated Maintenance Plan for the Liberty-Clairton Area for the 1997 Annual and 2006 24-Hour Fine Particulate Matter Standard and Maintenance Plan for the Allegheny County Area for the 2012 Annual Fine Particulate Matter Standard
Type: PRORULEVolume: 90Number: 65Pages: 14939 - 14954
Pages: 14939, 14940, 14941, 14942, 14943, 14944, 14945, 14946, 14947, 14948, 14949, 14950, 14951, 14952, 14953, 14954Docket number: [EPA-R03-OAR-2024-0586; FRL-10536-01-R3]
FR document: [FR Doc. 2025-05921 Filed 4-4-25; 8:45 am]
Agency: Environmental Protection Agency
Official PDF Version: PDF Version
[top]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 52 and 81
[EPA-R03-OAR-2024-0586; FRL-10536-01-R3]
Air Plan Approval; Pennsylvania; Redesignation Request and Associated Maintenance Plan for the Liberty-Clairton Area for the 1997 Annual and 2006 24-Hour Fine Particulate Matter Standard and Maintenance Plan for the Allegheny County Area for the 2012 Annual Fine Particulate Matter Standard
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
The Environmental Protection Agency (EPA) is proposing to approve a request from the Commonwealth of Pennsylvania to redesignate the Liberty-Clairton, Pennsylvania nonattainment area (Liberty-Clairton Area) to attainment for the 1997 annual and 2006 24-hour fine particulate matter (PM 2.5 ) national ambient air quality standards (NAAQS or standard). The EPA is also proposing to approve, as revisions to the Pennsylvania state implementation plan (SIP), the Commonwealth's plan for maintaining the 1997 annual and 2006 24-hour PM 2.5 NAAQS through 2035 for the Liberty-Clairton Area. Additionally, the EPA is proposing to approve the maintenance plan for the Allegheny County, Pennsylvania nonattainment area (Allegheny County Area) for the 2012 annual PM 2.5 NAAQS through 2035. The maintenance plan includes 2017, 2026, and 2035 mobile vehicle emissions budgets (MVEBs) for mobile sources of PM 2.5 and nitrogen oxides (NO X ) for the Allegheny County Area. The EPA is proposing to find these 2017, 2026, and 2035 MVEBs for PM 2.5 and NO X adequate and to approve these MVEBs into the Pennsylvania SIP for transportation conformity purposes. This action does not redesignate the Allegheny County Area to attainment for the 2012 annual PM 2.5 NAAQS, as Pennsylvania withdrew its redesignation request specific to the Allegheny County Area. The redesignation request and maintenance plan were submitted by the Commonwealth of Pennsylvania Department of Environmental Protection (PADEP or Pennsylvania) on behalf of the Allegheny County Health Department (ACHD). This action is being taken under the CAA.
DATES:
Written comments must be received on or before May 7, 2025.
ADDRESSES:
Submit your comments, identified by Docket ID No. EPA-R03-OAR-2024-0586 at www.regulations.gov, or via email to gordon.mike@epa.gov . For comments submitted at Regulations.gov, follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov . 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 ( i.e., on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the FOR FURTHER INFORMATION CONTACT section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit www.epa.gov/dockets/commenting-epa-dockets .
FOR FURTHER INFORMATION CONTACT:
Ian Neiswinter, 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) 814-2011. Mr. Neiswinter can also be reached via electronic mail at neiswinter.ian@epa.gov .
SUPPLEMENTARY INFORMATION:
Throughout this document, wherever "we," "us," or "our" are used, it is intended to refer to the EPA.
I. What action is the EPA proposing?
[top] On November 30, 2022, the EPA received from PADEP, on behalf of ACHD, a redesignation request for the Liberty-Clairton Area for the 1997 annual and 2006 24-hour PM 2.5 NAAQS and for the Allegheny County Area for
Footnotes:
1 ?The Liberty-Clairton Area is comprised of the following municipalities in Allegheny County, Pennsylvania: the boroughs of Liberty, Lincoln, Port Vue, and Glassport, and the City of Clairton. The Allegheny County Area is comprised of all municipalities within Allegheny County, Pennsylvania, and subsumes the municipalities which comprise the Liberty-Clairton Area. The table listed at 40 Code of Federal Regulations (CFR) 81.339 defines NAAQS area designations within Pennsylvania.
The EPA is proposing to take the following actions for the Liberty-Clairton Area: (1) to redesignate the Liberty-Clairton Area to attainment for the 1997 annual and 2006 24-hour PM 2.5 NAAQS; and (2) to approve into the Pennsylvania SIP the associated maintenance plan for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area. The EPA's proposed approval of the redesignation request and maintenance plan for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area is based upon the EPA's determination that the Liberty-Clairton Area continues to attain both standards, and that all other redesignation criteria have been met for the Liberty-Clairton Area. The EPA is also proposing the following actions for the Allegheny County Area: (1) to approve into the Pennsylvania SIP the maintenance plan for the 2012 annual PM 2.5 NAAQS; and (2) to find the 2017, 2026, and 2035 MVEBs for PM 2.5 and NO X adequate and approve these MVEBs into the Pennsylvania SIP for transportation conformity purposes. The adequacy comment period for these MVEBs will begin upon publication of this notice of proposed rulemaking (NPRM). Please see section IV of this rulemaking for further explanation of the MVEBs and the adequacy process. This action does not redesignate the Allegheny County Area to attainment for the 2012 annual PM 2.5 NAAQS. The EPA may approve a maintenance plan as meeting the requirements under CAA section 175A without redesignating an area to attainment. 2 Notably, all applicable nonattainment area requirements for the Allegheny County Area for the 2012 annual PM 2.5 NAAQS shall remain in place until such time as Pennsylvania submits a request for redesignation pursuant to section 107(d)(3) of the CAA and the EPA determines that the Allegheny County Area meets the CAA requirements for redesignation to attainment and takes action to redesignate the Allegheny County Area for the 2012 annual PM 2.5 NAAQS. These proposed actions are summarized and described in greater detail throughout this proposed rulemaking.
Footnotes:
2 ? See Pg. 7 of "Procedures for Processing Requests to Redesignate Areas to Attainment," Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992.
II. Background
A. The PM 2.5 NAAQS
Fine particulate pollution can be emitted directly from a source (primary PM 2.5 ) or formed secondarily through chemical reactions in the atmosphere involving precursor pollutants emitted from a variety of sources. The main precursors of secondary PM 2.5 are sulfur dioxide (SO 2 ), nitrogen dioxide (NO X ), ammonia (NH 3 ), and volatile organic compounds (VOCs). 3 Sulfates are a type of secondary particulate formed from SO 2 emissions from power plants and industrial facilities. Nitrates, another common type of secondary particulate, are formed from combustion emissions of NO X from power plants, mobile sources, and other combustion sources.
Footnotes:
3 ? See 81 FR 58010 (August 24, 2016).
The first air quality standards for PM 2.5 were established on July 18, 1997 (62 FR 38652). The EPA promulgated an annual standard at a level of 15 micrograms per cubic meter (µg/m 3 ), based on a three-year average of annual mean PM 2.5 concentrations (the 1997 annual PM 2.5 NAAQS). In the same rulemaking action, the EPA promulgated a 24-hour standard of 65 µg/m 3 , based on a three-year average of the 98th percentile of 24-hour concentrations.
On October 17, 2006 (71 FR 61144), the EPA retained the annual PM 2.5 standard at 15 µg/m 3 (2006 annual PM 2.5 NAAQS) but revised the 24-hour standard to 35 µg/m 3 (2006 24-hour PM 2.5 NAAQS), based again on the three-year average of the annual 98th percentile of the 24-hour PM 2.5 concentrations. In response to legal challenges of the 2006 annual PM 2.5 NAAQS, the U.S. Court of Appeals for the District of Columbia Circuit (D.C. Circuit or Court) remanded this standard to the EPA for further consideration. 4 On December 14, 2012, the EPA finalized a rule revising the PM 2.5 annual NAAQS to 12 µg/m 3 (2012 PM 2.5 annual NAAQS) based on current scientific evidence regarding the protection of public health.
Footnotes:
4 ? See American Farm Bureau Federation and National Pork Producers Council, et al. v. EPA, 559 F.3d 512 (D.C. Cir. 2009).
B. Liberty-Clairton Area
On January 5, 2005 (70 FR 944), the EPA published air quality area designations for the 1997 PM 2.5 NAAQS based upon air quality monitoring data for calendar years 2001-2003. In that rulemaking action, the EPA designated the Liberty-Clairton Area as nonattainment for the 1997 annual PM 2.5 and 24-hour PM 2.5 NAAQS. On November 13, 2009 (74 FR 58688), the EPA published designations for the 2006 24-hour PM 2.5 NAAQS based on certified air quality data from 2006-2008, which became effective on December 14, 2009. In that action, the EPA designated the Liberty-Clairton Area as nonattainment for the 2006 24-hour PM 2.5 NAAQS, retaining the same geographical boundaries as for the 1997 annual PM 2.5 NAAQS. In that same action, the EPA clarified that the Liberty-Clairton Area is designated as unclassifiable/attainment for the 1997 24-hour PM 2.5 NAAQS but retained the 1997 annual PM 2.5 NAAQS nonattainment designation.
[top] The EPA's 1997 annual and 2006 24-hour PM 2.5 nonattainment designations for the Liberty-Clairton Area triggered an obligation for Pennsylvania to develop a nonattainment SIP revision addressing certain CAA requirements under title I, part D, subpart 1 (hereinafter "subpart 1") and title I, part D, subpart 4 (hereinafter "subpart 4"). Subpart 1 contains the general requirements for nonattainment areas for criteria pollutants, including requirements to develop a SIP that provides for the implementation of reasonably available control measures (RACM) under section 172(c)(1), reasonable further progress (RFP), base-year and attainment-year emissions inventories, and for the implementation of contingency measures. Subpart 4 contains specific planning and scheduling requirements for coarse particulate matter (PM 10 ) nonattainment areas, including requirements for new
Footnotes:
5 ? See 57 FR 13538 (April 16, 1992).
6 ?In explaining its decision, the Court reasoned that the plain meaning of the CAA requires implementation of the 1997 PM 2.5 NAAQS under subpart 4 because PM 2.5 particles fall within the statutory definition of PM 10 and are thus subject to the same statutory requirements. The EPA finalized its interpretation of subpart 4 requirements as applied to the PM 2.5 NAAQS in its final rule entitled "Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements; Final Rule" (81 FR 58010, August 24, 2016).
On June 2, 2014 (79 FR 31566), the EPA published a rule entitled "Identification of Nonattainment Classification and Deadlines for Submission of State Implementation Plan (SIP) Provisions for the 1997 Fine Particle (PM 2.5 ) National Ambient Air Quality Standard (NAAQS) and 2006 PM 2.5 NAAQS" ("Classification and Deadlines Rule"). In that rule, the Agency responded to the D.C. Circuit's January 2013 decision by identifying all PM 2.5 nonattainment areas for the 1997 and 2006 PM 2.5 NAAQS as "Moderate" nonattainment areas under subpart 4, and by establishing a new SIP submission date of December 31, 2014, for Moderate area attainment plans and for any additional attainment-related or nonattainment new source review plans necessary for areas to comply with the requirements applicable under subpart 4. Id. at 31567-70.
On October 25, 2013 (78 FR 63881) and July 10, 2015 (80 FR 39696), the EPA made determinations that the Liberty-Clairton Area had attained the 1997 annual PM 2.5 NAAQS by the applicable attainment date and has data showing that the Area attained the 2006 24-hour PM 2.5 NAAQS, respectively. Pursuant to 40 CFR 51.1015(a) and based on these determinations, the requirements for the Liberty-Clairton Area to submit an attainment demonstration, RACM, RFP, contingency measures, and other planning SIPs related to the attainment of either the 1997 annual or 2006 24-hour PM 2.5 NAAQS were, and continue to be, suspended until such time as: the Liberty-Clairton Area is redesignated to attainment for each standard, at which time the requirements no longer apply; or the EPA determines that the Liberty-Clairton Area has again violated any of the standards, at which time such plans are required to be submitted. On May 10, 2017 (82 FR 21711), the EPA also determined in accordance with section 179(c) of the CAA, that the Liberty-Clairton Area attained the 2006 24-hour PM 2.5 NAAQS by the applicable attainment date.
The EPA issued a rule entitled "Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements" ("PM 2.5 SIP Requirements Rule"). 7 This rule clarifies how states should meet the statutory SIP requirements that apply to areas designated nonattainment for any PM 2.5 NAAQS under subparts 1 and 4. It does so by establishing regulatory requirements and by providing guidance that is applicable to areas that are currently designated nonattainment for existing PM 2.5 NAAQS and areas that are designated nonattainment for any PM 2.5 NAAQS in the future. In addition, the rule responds to the D.C. Circuit's remand of the 1997 PM 2.5 Implementation Rules. As a result, the requirements of the rule also govern future actions associated with states' ongoing implementation efforts for the PM 2.5 NAAQS. In the PM 2.5 SIP Requirements Rule, the EPA revoked the 1997 primary annual PM 2.5 NAAQS in areas that had always been attainment for that NAAQS, and in areas that had been designated as nonattainment but that were redesignated to attainment before October 24, 2016, the PM 2.5 SIP Requirements Rule effective date. 8
Footnotes:
7 ? See 81 FR 58010 (August 24, 2016). See also 40 CFR 51.1000 through 51.1016.
8 ? Id. See also 40 CFR 50.13(d).
In the August 24, 2016 final rule, the EPA also finalized a provision to revoke the 1997 primary annual PM 2.5 NAAQS in areas redesignated to attainment after October 24, 2016, on the effective date of an area's redesignation. 9 If this redesignation proposal is finalized, the 1997 primary annual PM 2.5 NAAQS will be revoked for the Liberty-Clairton Area on the effective date of the redesignation. Beginning on that date, the Liberty-Clairton Area will no longer be subject to transportation or general conformity requirements for the 1997 annual PM 2.5 NAAQS due to revocation of the primary NAAQS. 10 If redesignated for the 1997 annual PM 2.5 NAAQS, the Liberty-Clairton Area will be required to implement the maintenance plan requirements under section 175A for the 1997 annual PM 2.5 NAAQS, and the prevention of significant deterioration (PSD) program for the 1997 annual PM 2.5 NAAQS. Once approved, the maintenance plan can only be revised if the revision meets the requirements of CAA section 110(l) and, if applicable, CAA section 193. As described in the PM 2.5 SIP Requirements Rule, those 1997 annual PM 2.5 maintenance areas with a revoked NAAQS are no longer required to submit a second 10-year maintenance plan for the 1997 annual PM 2.5 NAAQS. 11
Footnotes:
9 ? See 40 CFR 50.13(d).
10 ? See 81 FR 58009 at 58125-6 (August 24, 2016).
11 ? See 81 FR 58009 at 58144 (August 24, 2016).
Similarly, if this proposal is finalized, the Liberty-Clairton Area will be redesignated to attainment for the 2006 24-hour PM 2.5 NAAQS and be required to implement the maintenance plan requirements under CAA section 175A for the 2006 24-hour PM 2.5 NAAQS, and the PSD program for the 24-hour PM 2.5 NAAQS. Once approved, the maintenance plan can only be revised if the revision meets the requirements of CAA section 110(l) and, if applicable, CAA section 193. Under CAA section 175A, an additional maintenance plan for a subsequent 10-year period following the initial 10-year maintenance period is required for the 2006 24-hour PM 2.5 NAAQS within eight years after redesignation to attainment.
C. Allegheny County Area-2012 Annual PM 2.5 NAAQS
[top] On January 15, 2015 (80 FR 2206), the EPA published air quality designations for the 2012 annual PM 2.5 NAAQS. In that action, the EPA designated all municipalities in Allegheny County, Pennsylvania (Allegheny County Area) as one nonattainment area for the 2012 annual PM 2.5 NAAQS. On March 16, 2022 (87 FR 14799), the EPA determined that the Allegheny County Area had clean data and attained the 2012 annual PM 2.5 NAAQS based on certified air quality data from 2018-2020. That action suspended the requirement for the Allegheny County Area to submit an attainment demonstration, RACM, RFP, and contingency measures related to attainment of the 2012 annual PM 2.5 NAAQS for so long as the Allegheny County Area continued to attain the standard. On May 19, 2023 (88 FR 32117), the EPA determined that the Allegheny County Area had attained the 2012 annual PM 2.5 NAAQS by the applicable attainment date based on certified air quality data from 2019-
III. The EPA's Requirements for Redesignation and Maintenance Plans
A. Criteria for Redesignation to Attainment
The CAA provides the requirements for redesignating a nonattainment area to attainment. Specifically, section 107(d)(3)(E) of the CAA allows for redesignation provided that: (1) the EPA determines that the area has attained the applicable NAAQS; (2) the EPA has fully approved the applicable implementation plan for the area under section 110(k); (3) the EPA determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable SIP and applicable Federal air pollutant control regulations and other permanent and enforceable reductions; (4) the EPA has fully approved a maintenance plan for the area as meeting the requirements of section 175A of the CAA; and (5) the state containing such area has met all requirements applicable to the area under section 110 and part D of the CAA. Each of these requirements are discussed in section IV of this proposed rulemaking action. The EPA provided guidance on redesignations in the "SIPs; General Preamble for the Implementation of title I of the CAA Amendments of 1990," (the General Preamble)? 12 and has provided further guidance on processing redesignation requests in the following documents: (1) "Procedures for Processing Requests to Redesignate Areas to Attainment," Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992 (hereafter referred to as the 1992 Calcagni Memorandum or Calcagni Memo); (2) "SIP Actions Submitted in Response to CAA Deadlines," Memorandum from John Calcagni, Director, Air Quality Management Division, October 28, 1992; and (3) "Part D New Source Review (Part D NSR) Requirements for Areas Requesting Redesignation to Attainment," Memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, October 14, 1994.
Footnotes:
12 ?See 57 FR 13498 (April 16, 1992).
B. Requirements of a Maintenance Plan
Section 175A of the CAA sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after approval of a redesignation of an area to attainment. Eight years after the redesignation, the state must submit a revised maintenance plan demonstrating that attainment will continue to be maintained for the 10 years following the initial 10-year period. 13 To address the possibility of future NAAQS violations, the maintenance plan must contain such contingency measures, with a schedule for implementation, as the EPA deems necessary to assure prompt correction of any future PM 2.5 violations. The 1992 Calcagni Memorandum provides additional guidance on the content of a maintenance plan. The Memorandum states that a maintenance plan should address the following provisions: (1) an attainment emissions inventory; (2) a maintenance demonstration showing maintenance for 10 years; (3) a commitment to maintain an ambient air quality monitoring network in accordance with 40 CFR part 58; (4) verification of continued attainment; and (5) a contingency plan to prevent or correct future violations of the NAAQS. Under the CAA, states are required to submit, at various times, control strategy SIP revisions for nonattainment areas and maintenance plans for areas seeking redesignation to attainment for a given NAAQS. These emission control strategy SIP revisions ( e.g., RFP and attainment demonstration SIP revisions) and maintenance plans also include MVEBs based on onroad mobile source emissions for the relevant criteria pollutants and/or their precursors, where appropriate, to address pollution from onroad transportation sources. The MVEBs are the portions of the total allowable emissions that are allocated to onroad vehicle use that, together with emissions from all other sources in the area, will provide attainment, RFP, or maintenance, as applicable. The budget serves as a ceiling on emissions from an area's planned transportation system. Under 40 CFR part 93, a MVEB for an area seeking a redesignation to attainment is established for the last year of the maintenance plan. The maintenance plan for the Allegheny County Area includes updated PM 2.5 and NO X MVEBs for the years 2017, 2026, and 2035 for transportation conformity purposes. The transportation conformity analysis for the Allegheny County Area and Liberty-Clairton Area is further discussed in section IV.C. of this proposed rulemaking action.
Footnotes:
13 ?As stated previously, a second maintenance is plan is not required for the Liberty-Clairton Area for the 1997 annual PM 2.5 NAAQS because the standard will be revoked upon redesignation to attainment. See 81 FR 58010 (August 24, 2016).
IV. The EPA's Analysis of Pennsylvania's Submittal
The EPA is proposing several rulemaking actions for the Liberty-Clairton Area and Allegheny County Area. For the Liberty-Clairton Area, the EPA is proposing the following actions: (1) to redesignate the Liberty-Clairton Area to attainment for the 1997 annual and 2006 24-hour PM 2.5 NAAQS; and (2) to approve into the Pennsylvania SIP the associated maintenance plan for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area. The EPA's proposed approval of the redesignation request and maintenance plan for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area is based upon the EPA's determination that the Liberty-Clairton Area continues to attain both standards, which the EPA is proposing in this rulemaking action, and that all other redesignation criteria have been met for the Liberty-Clairton Area. For the Allegheny County Area, the EPA is proposing the following actions: (1) to approve into the Pennsylvania SIP the maintenance plan for the 2012 annual PM 2.5 NAAQS; and (2) to find the 2017, 2026, and 2035 MVEBs for PM 2.5 and NO X adequate and to approve these MVEBs into the Pennsylvania SIP for transportation conformity purposes. The following is a description of how Pennsylvania's November 30, 2022, SIP submittal satisfies the requirements of the CAA.
A. Redesignation Request for the Liberty-Clairton Area
1. Attainment
[top] To redesignate an area from nonattainment to attainment, the CAA requires the EPA to determine that the
Footnotes:
14 ?The annual PM 2.5 NAAQS design value is the 3-year average of PM 2.5 annual mean mass concentrations. Three years of valid annual means are required to produce a valid annual PM 2.5 NAAQS design value. A year meets data completeness requirements when at least 75 percent of the scheduled sampling days for each quarter have valid data. See 40 CFR part 50, appendix N.
15 ?The 24-hour PM 2.5 NAAQS design value is the 3-year average of annual PM 2.5 24-hour 98th percentile mass concentrations. Three years of valid annual PM 2.5 98th percentile mass concentrations are required to produce a valid 24-hour PM 2.5 NAAQS design value. A year meets data completeness requirements when at least 75 percent of the scheduled sampling days for each quarter have valid data. See 40 CFR part 50, appendix N.
As referenced previously, on October 25, 2013 (78 FR 63881), the EPA determined that the Liberty-Clairton Area attained the 1997 annual PM 2.5 NAAQS by its applicable attainment date of December 31, 2011, based upon quality-assured and certified ambient air quality monitoring data for 2009-2011 and continued to attain the 1997 annual PM 2.5 NAAQS based on quality-assured and certified ambient air quality monitoring data for 2010-2012. On July 10, 2015 (80 FR 39696) the EPA determined that the Liberty-Clairton Area attained the 2006 24-hour PM 2.5 NAAQS, based on quality-assured and certified ambient air quality monitoring data for 2012-2014. In a separate rulemaking action on May 10, 2017 (82 FR 21711), the EPA also determined that the Liberty-Clairton Area attained the 2006 24-hour PM 2.5 NAAQS by the applicable attainment date of December 31, 2015, based upon quality-assured and certified ambient air quality monitoring data for 2013-2015. The basis and effect of these determinations of attainment for both the 1997 annual and 2006 24-hour PM 2.5 NAAQS were discussed in the notices of the proposed and final rulemakings which determined the Liberty-Clairton Area attained the 1997 annual and 2006 24-hour PM 2.5 NAAQS. 16
Footnotes:
16 ? See notices of the proposed rulemakings at 78 FR 44070 (July 23, 2013), 80 FR 22666 (April 23, 2015), and 81 FR 91088 (December 16, 2016).
The EPA has reviewed the ambient air quality PM 2.5 monitoring data in the Liberty-Clairton Area consistent with the requirements contained in 40 CFR part 50 and recorded in the EPA's AQS, including quality-assured, quality-controlled, and state-certified data for the recent 3-year monitoring periods 2017-2019 through 2021-2023 for the 1997 annual and 2006 24-hour PM 2.5 NAAQS. This data, provided in tables 1 and 2 in this document, shows that the Liberty-Clairton Area continues to attain the 1997 annual and 2006 24-hour PM 2.5 NAAQS. Two ambient PM 2.5 air monitoring sites are located within the Liberty-Clairton Area. For the Liberty-Clairton Area to attain the 1997 annual PM 2.5 NAAQS, the design value at both monitoring sites must be less than or equal to 15.0 µg/m 3 . For the Liberty-Clairton Area to attain the 2006 24-hour PM 2.5 NAAQS, the design value at both monitoring sites must be less than or equal to 35.0 µg/m 3 .
| Monitor ID No. | 2017-2019 | 2018-2020 | 2019-2021 | 2020-2022 | 2021-2023 |
|---|---|---|---|---|---|
| Liberty, 420030064 | 12.4 | 11.1 | 11.2 | 10.9 | 11.6 |
| Clairton, 420033007 | 8.8 | 8.0 | 8.1 | 7.9 | 8.4 |
| Monitor ID No. | 2017-2019 | 2018-2020 | 2019-2021 | 2020-2022 | 2021-2023 |
|---|---|---|---|---|---|
| Liberty, 420030064 | 35 | 32 | 32 | 30 | 33 |
| Clairton, 420033007 | 19 | 19 | 20 | 19 | 21 |
The EPA's review of the monitoring data from 2017 through 2023 supports the EPA's previous determinations that the Liberty-Clairton Area has attained the 1997 annual and 2006 24-hour PM 2.5 NAAQS, and that the Liberty-Clairton Area continues to attain both standards. In addition, as discussed subsequently, with respect to the maintenance plan, Pennsylvania commits to maintain an ambient air quality monitoring network in accordance with 40 CFR part 58. Thus, based upon an analysis of currently available data, the EPA is proposing to determine that the Liberty-Clairton Area continues to attain the 1997 annual and 2006 24-hour PM 2.5 NAAQS.
2. The Area Has Met All Applicable Requirements Under Section 110 and Part D of the CAA and Has a Fully Approved SIP Under Section 110(k)
The SIP revision for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area must be fully approved under section 110(k) and in accordance with section 107(d)(3)(E)(v), all the requirements applicable to the Liberty-Clairton Area under section 110 of the CAA (general SIP requirements) and part D of title I of the CAA (SIP requirements for nonattainment areas) must be met.
a. Section 110 General SIP Requirements
[top] Section 110(a)(2) of title I of the CAA delineates the general requirements for a SIP, which include enforceable emissions limitations and other control measures, means, or techniques, provisions for the establishment and operation of appropriate devices necessary to collect data on ambient air quality, and programs to enforce the limitations. The general SIP elements and requirements set forth in section 110(a)(2), which are commonly referred
Footnotes:
17 ?See, e.g., 81 FR 4420 (July 17, 2006) (final redesignation for the Sullivan County, Tennessee area); 79 FR 43655 (July 28, 2014) (final redesignation for Bellefontaine, Ohio lead nonattainment area); 61 FR 53174-53176 (October 10, 1996) and 62 FR 24826 (May 7 1997) (proposed and final redesignation of Reading, Pennsylvania ozone nonattainment area); 61 FR 20458 (May 7 1996) (final redesignation for Cleveland-Akron Lorain, Ohio ozone nonattainment area); 60 FR 62748 (December 7, 1995) (final redesignation of Tampa, Florida ozone nonattainment area); See also 65 FR 37879, 37890, (June 19, 2000) (discussing this issue in final redesignation of Cincinnati, Ohio 1- hour ozone nonattainment area); and 66 FR 50399 (October 19, 2001) (final redesignation of Pittsburgh, Pennsylvania 1-hour ozone nonattainment area).
The EPA has reviewed the Pennsylvania SIP and has concluded that it meets the general SIP requirements under section 110(a)(2) of the CAA to the extent they are applicable for purposes of redesignation. The EPA has previously approved provisions of Pennsylvania's SIP addressing section 110(a)(2) requirements, including provisions addressing PM 2.5 . 18 These requirements are, however, statewide requirements that are not linked to the PM 2.5 nonattainment status of the Liberty-Clairton Area. Therefore, the EPA proposes to determine that Pennsylvania has met all general SIP requirements for the Liberty-Clairton Area that are applicable for purposes of redesignation under section 110 of the CAA.
Footnotes:
18 ? See 77 FR 58955 (September 25, 2012) (approving infrastructure SIP submittals for 1997 and 2006 PM 2.5 NAAQS).
b. Part D Requirements
Subparts 1 and 4 of part D, title 1 of the CAA contain air quality planning requirements for PM 2.5 nonattainment areas. Subpart 1 contains general requirements for all nonattainment areas of any pollutant, including PM 2.5 , governed by a NAAQS. Subpart 1 requirements include, among other things, provisions for RACM, RFP, emissions inventories, contingency measures, transportation conformity and general conformity. Subpart 4 contains specific planning and scheduling requirements for PM 2.5 nonattainment areas. The requirements in section 189(a), (c), (e) apply specifically to Moderate PM 2.5 nonattainment areas and include an approved permit program for construction of new and modified major stationary sources, provisions for RACM, an attainment demonstration, quantitative milestones demonstrating RFP toward attainment by the applicable attainment date, and provisions to ensure that the control requirements applicable to major stationary sources of PM 2.5 also apply to PM 2.5 precursors, except where the Administrator has determined that such sources do not contribute significantly to PM 2.5 levels that exceed the NAAQS in the area. The applicability of these requirements to this action are addressed in the following sections.
c. Subpart 1 Requirements
Subpart 1 sets forth the basic nonattainment plan requirements applicable to PM 2.5 nonattainment areas. Under section 172, states with nonattainment areas must submit plans providing for timely attainment and must meet a variety of other requirements. The EPA's longstanding interpretation of the nonattainment planning requirements of section 172 is that once an area is attaining the NAAQS, those requirements are not "applicable" for purposes of section 107(d)(3)(E)(ii) and therefore need not be approved into the SIP before the EPA can redesignate the area. In the 1992 General Preamble for Implementation of Title I, the EPA set forth its interpretation of applicable requirements for purposes of evaluating redesignation requests when an area is attaining a standard. 19 The EPA noted that the requirements for RFP and other measures designed to provide for attainment do not apply in evaluating redesignation requests because those nonattainment planning requirements "have no meaning" for an area that has already attained the standard. 20 This interpretation was also set forth in the 1992 Calcagni Memorandum. The EPA's understanding of section 172 also forms the basis of its Clean Data Policy, which was articulated with regard to PM 2.5 in 40 CFR 51.1015(a), and suspends a state's obligation to submit most of the attainment planning requirements that would otherwise apply, including an attainment demonstration and planning SIPs to provide for RFP, RACM, and contingency measures under section 172(c)(9). 21 Courts have upheld the EPA's interpretation of section 172(c)(1)'s "reasonably available" control measures and control technology as meaning only those controls that advance attainment, which precludes the need to require additional measures where an area is already attaining. 22
Footnotes:
19 ? See 57 FR 13498, 13564 (April 16, 1992).
20 ? Id.
21 ?This regulation was promulgated as part of the 1997 PM 2.5 NAAQS implementation rule that was subsequently challenged and remanded in NRDC v. EPA, 706 F.3d 428 (D.C. Cir. 2013), as discussed in section II.B of this rulemaking. However, the Clean Data Policy portion of the implementation rule was not at issue in that case.
22 ? See NRDC v. EPA, 571 F.3d 1245, 1252 (D.C. Cir. 2009); Sierra Club v. EPA, 294 F.3d 155, 162 (D.C. Cir. 2002); Sierra Club v. EPA, 314 F.3d 735, 744 (5th Cir. 2002).
[top] Therefore, because attainment has been reached for the 1997 annual and
Footnotes:
23 ? See October 25, 2013 (78 FR 63881) and July 10, 2015 (80 FR 39696).
The requirement under section 172(c)(3) of the CAA was not suspended by the EPA's clean data determination for the 1997 annual and 2006 24-hour PM 2.5 NAAQS. Section 172(c)(3) of the CAA requires submission and approval of a comprehensive, accurate, and current inventory of actual emissions. For purposes of the PM 2.5 NAAQS, this emissions inventory should address not only direct emissions of PM 2.5 , but also emissions of all precursors with the potential to participate in PM 2.5 formation, i.e., SO 2 , NO X , VOC and NH 3 . To satisfy the 172(c)(3) requirement, on January 2, 2014 (79 FR 00054) and October 2, 2015 (80 FR 59615), the EPA approved the 2002 base year emissions inventory for the 1997 annual PM 2.5 NAAQS and the 2007 base year emissions inventory for the 2006 24-hour PM 2.5 NAAQS, respectively, for the Liberty-Clairton Area.
Section 172(c)(4) of the CAA requires the identification and quantification of allowable emissions for major new and modified stationary sources in an area, and section 172(c)(5) requires source permits for the construction and operation of new and modified major stationary sources anywhere in the nonattainment area. The EPA has determined that, since PSD requirements will apply after redesignation, areas being redesignated need not comply with the requirement that a nonattainment NSR program be approved prior to redesignation, provided that the area demonstrates maintenance of the NAAQS without a nonattainment NSR program. A more detailed rationale for this view is described in a memorandum from Mary Nichols, Assistant Administrator for Air and Radiation, dated October 14, 1994, entitled, "Part D New Source Review Requirements for Areas Requesting Redesignation to Attainment." Nevertheless, Pennsylvania currently has an approved NSR program codified in Pennsylvania's regulations at 25 Pa. Code Chapter 127.201, et seq . 24 Pennsylvania's regulations were incorporated by reference into ACHD's nonattainment new source review regulations for Allegheny County on March 30, 2015 (80 FR 16568). However, ACHD's PSD program in Section 2102.07 of Article XXI of Allegheny County Health Department's Rules and Regulations for Air Pollution Control for PM 2.5 will become effective in the Liberty-Clairton Area upon redesignation to attainment. Section 2102.07 of Article XXI adopted in its entirety, and incorporated by reference, the PSD requirements of 40 CFR part 52.
Footnotes:
24 ? See 77 FR 41276 (July 13, 2012) (approving NSR program into the SIP).
Section 172(c)(7) of the CAA requires the SIP to meet the applicable provisions of section 110(a)(2). As noted previously, the EPA believes the Pennsylvania SIP meets the requirements of section 110(a)(2) that are applicable for purposes of redesignation, which have been identified as sections 172(c)(3) through (5).
Section 175A requires a state seeking redesignation to attainment to submit a SIP revision to provide for the maintenance of the NAAQS in the area "for at least 10 years after the redesignation." In conjunction with its request to redesignate the Liberty-Clairton Area to attainment status, Pennsylvania submitted, on behalf of ACHD, a SIP revision on November 30, 2022, to provide for maintenance of the 1997 annual and 2006 24-hour PM 2.5 NAAQS in the Liberty-Clairton Area for at least 10 years after redesignation, throughout 2035. ACHD is requesting that the EPA approve the maintenance plan to meet the requirement of section 175A of the CAA for both NAAQS for the Liberty-Clairton Area. Once approved, the maintenance plan for the Liberty-Clairton Area will ensure that the SIP for Pennsylvania meets the requirements of the CAA regarding maintenance of the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area. ACHD is also requesting that the EPA approve the maintenance plan for the Allegheny County Area for the 2012 annual PM 2.5 NAAQS as meeting the requirements of section 175A of the CAA without redesignating the Allegheny County Area to attainment of the 2012 annual PM 2.5 NAAQS. The EPA's analysis of the maintenance plan is provided in section IV.B of this proposed rulemaking action.
Section 176(c) of the CAA requires states to establish criteria and procedures to ensure that federally supported or funded projects conform to the air quality planning goals in the applicable SIP. The requirement to determine conformity applies to transportation plans, programs, and projects that are developed, funded, or approved under title 23 of the United States Code (U.S.C.) and the Federal Transit Act (transportation conformity) as well as to all other federally supported or funded projects (general conformity). State transportation conformity SIP revisions must be consistent with Federal conformity regulations relating to consultation, enforcement, and enforceability which the EPA promulgated pursuant to its authority under the CAA. The EPA interprets the conformity SIP requirements as not applying for purposes of evaluating a redesignation request under CAA section 107(d) because state conformity rules are still required after redesignation, and Federal conformity rules apply where state rules have not been approved. 25 Nonetheless, the EPA approved Pennsylvania's transportation conformity SIP requirements on April 29, 2009 (74 FR 19451).
Footnotes:
25 ? See Wall v. EPA, 265 F. 3d 426 (6th Cir. 2001) (upholding this interpretation) and 60 FR 62748 (December 7, 1995) (discussing Tampa, Florida).
d. Subpart 4 Requirements
As discussed in section II of this document, in NRDC v. EPA, the D.C. Circuit held that the EPA should have implemented the 1997 PM 2.5 annual NAAQS pursuant to the particulate matter-specific provisions of subpart 4. On remand, the EPA identified all areas designated nonattainment for either the 1997 or the 2006 PM 2.5 NAAQS, including the Liberty-Clairton Area, as
[top]
Footnotes:
26 ? See 79 FR 31566 (June 2, 2014) and 40 CFR 81.339.
With respect to the specific attainment planning requirements under subpart 4, the EPA applies the same interpretation that it applies to attainment planning requirements under subpart 1 or any other pollutant-specific subparts. That is, under its longstanding interpretation of the CAA, where an area is already attaining the standard, the EPA does not consider those attainment planning requirements to be applicable for purposes of evaluating a request for redesignation, that is, CAA section 107(d)(3)(E)(ii) or (v), because requirements that are designed to help an area achieve attainment no longer have meaning where an area is already meeting the standard. The EPA is therefore proposing to determine that the specific attainment planning requirements under subpart 4 are not applicable for evaluating ACHD's redesignation request.
CAA section 189(e) provides that control requirements for major stationary sources of direct PM 10 (including PM 2.5 ) shall also apply to particulate matter precursors from those sources, except where the EPA determines that major stationary sources of such precursors do not contribute significantly to PM 10 levels that exceed the standard in the area. The CAA does not explicitly address whether it would be appropriate to include a potential exemption from precursor controls for all source categories under certain circumstances. In implementing subpart 4 with regard to controlling PM 10 , the EPA permitted states to determine that a precursor was "insignificant" where the state could show in its attainment plan that it would expeditiously attain without adoption of emission reduction measures aimed at that precursor. This approach was upheld in the Association of Irritated Residents v. EPA, 423 F.3d 989 (9th Cir. 2005) and extended to PM 2.5 implementation in the PM 2.5 SIP Requirements Rule. A state may develop its attainment plan and adopt RACM that target only those precursors that are necessary to control for purposes of timely attainment. 27 For the Liberty-Clairton Area, a precursor exemption analysis under section 189(e) and the EPA's implementing regulations is not an applicable requirement that needs to be fully approved in the context of a redesignation under CAA section 107(d)(3)(E)(ii). As discussed previously in this document, for areas that are attaining the standard, the EPA does not interpret attainment planning requirements of subparts 1 and 4 to be applicable requirements for purposes of redesignating an area to attainment. On October 25, 2013 (78 FR 63881) and May 10, 2017 (82 FR 21711), the EPA determined that the Liberty-Clairton Area had attained the 1997 annual and 24-hour PM 2.5 NAAQS by the respective statutory attainment dates. Having attained and maintained the NAAQS, the Liberty-Clairton Area needs no additional controls of any pollutant, including any PM 2.5 precursor, to bring it into attainment with the 1997 annual and 2006 24-hour PM 2.5 NAAQS. In section IV.A.1 of this document, the EPA made a finding that the Liberty-Clairton Area continues to attain both NAAQS, and in section IV.A.3 of this document, the EPA has determined that the Liberty-Clairton Area has attained the standards due to permanent and enforceable emissions reductions. Further, as set forth in section IV.B of this document, the EPA is proposing to find that the Liberty-Clairton Area maintenance plan demonstrates continued maintenance of the 1997 annual and 2006 24-hour PM 2.5 NAAQS standard through 2035, which also demonstrates that the PM 2.5 precursors are insignificant. Taken together, these factors support our conclusion that PM 2.5 precursors are adequately controllable.
Footnotes:
27 ? See 81 FR 58010 (August 24, 2016).
For these reasons, the EPA proposes to find that ACHD has satisfied all applicable requirements for purposes of redesignation of the Liberty-Clairton Area under section 110 and part D of the CAA.
e. The Liberty-Clairton Area Has a Fully Approved Applicable SIP Under Section 110(k) of the CAA
At various times, ACHD and PADEP have submitted, and the EPA has approved, provisions addressing the various SIP elements applicable for the 1997 annual and 2006 24-hour PM 2.5 NAAQS. As discussed above, the EPA has fully approved all applicable requirements of Pennsylvania's SIP for the Liberty-Clairton Area for purposes of redesignation to attainment for the 1997 annual and 2006 24-hour PM 2.5 NAAQS in accordance with section 110(k) of the CAA. The EPA has determined that there are no outstanding SIP elements required for the Liberty-Clairton Area for purposes of redesignation to attainment for the 1997 annual and 2006 24-hour PM 2.5 NAAQS. Indicated above, the EPA believes that the section 110 elements not connected with nonattainment plan submissions and not linked to an area's nonattainment status are not applicable requirements for purposes of redesignation. The EPA may rely on prior SIP approvals in approving a redesignation request ( see the Calcagni Memo at page 3; Southwestern Pennsylvania Growth Alliance v. Browner, 144 F.3d 984, 989-990 (6th Cir. 1998); Wall v. EPA, 265 F.3d 426), plus any additional measures it may approve in conjunction with a redesignation action (see 68 FR 25426 (May 12, 2003) and citations therein).
3. Permanent and Enforceable Reductions in Emissions
[top] For redesignating a nonattainment area to attainment, section 107(d)(3)(E)(iii) requires the EPA to determine that the air quality improvement in the area is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP and applicable Federal air pollution control regulations and other permanent and enforceable reductions. For the 1997 annual PM 2.5 NAAQS, ACHD has calculated the change in emissions between the 2002 base year and a 2011 control year, the year for which the Liberty-Clairton Area monitored attainment for the 1997 annual PM 2.5 NAAQS. For the 2006 24-hour PM 2.5 NAAQS, ACHD calculated the change in emissions between the 2007 base year and a 2014 control year, the year for which the Liberty-Clairton Area monitored attainment for the 2006 24-hour PM 2.5 NAAQS. ACHD took emissions from the NEI for both the 2011 and 2014 control years. Point source emissions were for sources within the Liberty-Clairton Area, and area and mobile source emissions were scaled from the county level to the area-level based on population percentage of the Liberty-Clairton area. A summary of the emissions reductions in tons per year (tpy) of PM 2.5 , NO X , SO 2 , VOC, and NH 3 from the base year to the control year in the Liberty-Clairton Area, provided by ACHD, is shown in tables 3 and 4, in this document, for the 1997
Footnotes:
28 ? See Appendix B of ACHD's submission for further information regarding the emission inventory methodology and emission data by category totals for the Liberty-Clairton Area.
| Liberty-Clairton totals (1997 annual PM 2.5 NAAQS) | PM 2.5 | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| 2002 Base Year | 2,266 | 2,933 | 1,469 | 6,377 | 1,089 | 321 |
| 2011 Control Year | 644 | 841 | 1,492 | 3,456 | 776 | 138 |
| Reduction, Base to Control Year | -1,622 | -2,092 | 23 | -2,921 | -313 | -183 |
| Percent Change | -72% | -71% | 2% | -46% | -29% | -57% |
| Liberty-Clairton totals (2006 24-hour PM 2.5 NAAQS) | PM 2.5 | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| 2007 Base Year | 998 | 1,214 | 1,811 | 5,593 | 1,106 | 28 |
| 2014 Control Year | 739 | 1,003 | 1,520 | 4,177 | 751 | 156 |
| Reduction, Base to Control Year | -259 | -211 | -291 | -1,416 | -355 | 128 |
| Percent Change | -26% | -17% | -16% | -25% | -32% | 457% |
From the 2002 base year to the 2011 control year for the 1997 annual PM 2.5 NAAQS, overall PM 2.5 emissions were reduced by 72%. SO 2 increased nominally by 2%; however, all other PM 2.5 precursors measured reductions. From the 2007 base year to the 2014 control year for the 2006 24-hour PM 2.5 NAAQS, NH 3 was the only pollutant that did not show a reduction in the area. However, NH 3 was found to be an insignificant precursor for attainment in Allegheny County, including the Liberty-Clairton Area. 29 The reduction in emissions and the corresponding improvement in air quality in the Liberty-Clairton Area from 2002 to 2011 for the 1997 annual PM 2.5 NAAQs, and 2007 to 2014 for the 2006 24-hour PM 2.5 NAAQs, can be attributed to a number of control measures that have been implemented in the Liberty-Clairton Area and contributing areas in recent years.
Footnotes:
29 ? See EPA's proposed approval of certain elements of Allegheny County's 2012 PM 2.5 attainment plan, including the precursor demonstration discussion, at 85 FR 35852 (May 14, 2021).
ACHD identified implemented source controls at the United States Steel Corporation (USS) Mon Valley Works (MVW) Clairton Plant (USS Clairton Plant) that have contributed to reductions of PM 2.5 levels in the Liberty-Clairton Area. Some of these controls were required by consent order and agreements entered into between ACHD and USS in 2007 and in 2008 (later amended in 2010 and 2011). The USS Clairton Plant requires permits to operate (operating permit) and to install new equipment or expand operations (installation permits). These consent order and agreements were incorporated by reference into installation permits for the C Coke Battery (IP #0052-I011) and Quench Towers 5A and 7A (IP #0052-I014a). The USS Clairton Plant's title V operating permit (OP #0052) incorporates conditions from the installation permits and other applicable regulations. These permits are federally enforceable under 40 CFR 52.2020. Controls specific to the USS Clairton Plant that contributed to reduction in PM 2.5 levels for the 1997 annual and 2006 24-hour PM 2.5 NAAQS are as follows:
• An enhanced maintenance refractory repair plan for Coke Battery 15 was completed in 2008.
• Coke Batteries 7-9 and associated processes were permanently shut down in 2009.
• All heating walls for B Coke Battery were replaced in 2010.
• 25 heating walls for Coke Battery 19 were replaced in 2012.
• The title V permit (OP #0052) issued in 2012 included baffle washing and maintenance requirements at all quench towers. 30
Footnotes:
30 ?These source control requirements were also approved into the SIP as part of source specific RACT controls for the 2008 8-hour ozone NAAQS (86 FR 58223, October 21, 2021), which requires quench towers at the USS Clairton Plant to comply with the quench tower work practice standards, and operation and maintenance requirements of NESHAP 40 CFR 63, subpart CCCCC, including daily baffle washing.
• New low-emission Quench Towers 5A and 7A were installed for Coke Batteries 13-15 and 19-20, respectively, in 2013.
• A new Screening Station #4 was installed as a replacement to Screening Station #3 in 2013.
[top] In addition, ACHD provided an analysis to demonstrate that the improvement in air quality for the Liberty-Clairton Area was not due to unusually favorable meteorology. The analysis was based on 20 years of meteorological data collected at the Liberty monitor (ID #420030064) and included frequency of temperature inversions, average temperature, and total precipitation. The Liberty site has historically been the highest-concentration PM 2.5 site within the Liberty-Clairton area, and Allegheny County as a whole. ACHD identified that, in particular, temperature inversions correlate with monitored PM 2.5 concentrations at the Liberty monitor, and that a higher frequency of temperature inversions coincide with relatively higher measured PM 2.5 concentrations. While variations in PM 2.5 concentrations from year-to-year correlate with the frequency of temperature inversions, ACHD points out that both annual weighted mean and 24-hour 98th percentile concentrations at the Liberty monitor have declined throughout the timeframe while the average frequency of inversions remained similar throughout the period, indicating that the reductions are due to emissions control and not unusually favorable meteorology.
Based upon the previously listed actions by ACHD in the submitted maintenance plan, the EPA finds that the improvement in air quality in the Liberty-Clairton Area is the result of permanent and enforceable emissions reductions, satisfying CAA section 107(d)(3)(E)(iii).
B. Maintenance Plan for the Liberty-Clairton Area and Allegheny County Area
On November 30, 2022, PADEP submitted, on behalf of ACHD, a combined maintenance plan for the Liberty-Clairton Area for the 1997 annual and 2006 24-hour PM 2.5 NAAQS and for the Allegheny County Area for the 2012 annual PM 2.5 NAAQS. As stated previously in this action, the EPA is proposing to approve the maintenance plan as satisfying section 175A of the CAA. The EPA's analysis for proposing approval of the maintenance plan for both areas is provided in this section.
Section 175A of the CAA sets forth the elements of a maintenance plan for areas seeking redesignation from nonattainment to attainment. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after the Administrator approves a redesignation to attainment. Because the 1997 annual PM 2.5 NAAQS will be revoked for the Liberty-Clairton Area if redesignated to attainment, Pennsylvania is not required to submit a second 10-year maintenance plan for the Liberty-Clairton Area for the 1997 annual PM 2.5 NAAQS. 31 Pennsylvania will be required to submit a second 10-year maintenance plan for the Liberty-Clairton Area for the 2006 24-hour PM 2.5 NAAQS, and because Pennsylvania has withdrawn the redesignation request for the Allegheny County Area for the 2012 annual PM 2.5 NAAQS, a second 10-year maintenance plan beyond 2035 is not a requirement for the Allegheny County Area at this time. As stated previously, this action does not redesignate the Allegheny County Area to attainment for the 2012 annual PM 2.5 NAAQS.
Footnotes:
31 ? See 81 FR 58010 (August 24, 2016).
To address the possibility of future NAAQS violations, the maintenance plan must contain such contingency measures, as the EPA deems necessary, to assure prompt correction of any future NAAQS violations. The Calcagni Memo provides further guidance on the content of a maintenance plan, explaining that a maintenance plan should address five requirements: The attainment emissions inventory, maintenance demonstration, monitoring, verification of continued attainment, and a contingency plan. As discussed below, the EPA finds that ACHD's maintenance plan includes all the necessary components and is thus proposing to approve it as a revision to the Pennsylvania SIP.
1. Attainment Emissions Inventory
As discussed previously, the EPA is proposing to determine that the Liberty-Clairton Area is continuing to attain the 1997 annual and 2006 24-hour PM 2.5 NAAQS based on monitoring data for the monitoring time period from 2017-2023. The EPA has also previously determined that the Allegheny County Area attained the 2012 annual PM 2.5 NAAQS based on certified air quality data from 2018-2020. 32 For all three NAAQS, Pennsylvania selected 2017 as the attainment emission inventory year. The attainment inventory identifies the level of emissions in an area that is sufficient to attain the NAAQS. While occuring later than the design value periods that originally achieved attainment for the 1997 annual and 2006 24-hour PM 2.5 NAAQS, Pennsylvania determined that year 2017 is an appropriate attainment year for the Liberty-Clairton Area and Allegheny County Area for the following reasons:
Footnotes:
32 ? See 87 FR 14799 (March 16, 2022).
• For the 2012 annual PM 2.5 NAAQS for the Allegheny County Area, 2017 is the most recent NEI with emissions compiled for all data categories. The next NEI year would be 2020, which was not finalized at the time ACHD developed this maintenance plan. For these reasons, among others identified in Section 6 of ACHD's maintenance plan, 2017 is the most appropriate attainment year for the Allegheny County Area.
• For the 1997 annual PM 2.5 NAAQS, the 2011 control year used for the emission reduction calculation in section III.A.3 of this action could be a viable attainment year; however, the 10-year maintenance timeframe has already passed. Also, since the 2012 annual PM 2.5 NAAQS has replaced the 1997 annual PM 2.5 NAAQS, and the Liberty-Clairton Area is within the Allegheny County Area, it is reasonable for the two areas to have the same attainment year, for which 2017 is the most appropriate year for the Allegheny County Area.
• For the 2006 24-hour PM 2.5 NAAQS, the 2014 control year used for the emission reduction calculation in section III.A.3 of this action could be a viable attainment year; however, 2017 is the next national emission inventory (NEI) year and would allow for consistency with the Allegheny County Area. As mentioned previously, the Liberty-Clairton Area is located within the Allegheny County Area, and projected emissions for the Liberty-Clairton Area would inherently be included in projected emissions for the Allegheny County Area.
• To demonstrate maintenance, future case emissions projections must be lower than the attainment year inventory. The 2017 NEI for the Liberty-Clairton Area shows lower emissions than the 2011 and 2014 NEIs, which would result in stricter maintenance tests.
The projected inventory included with the maintenance plan estimates emissions from 2017 to 2035, which satisfies the 10-year interval required in section 175A of the CAA. The emissions inventories are composed of the following sources: point, area, on-road mobile, non-road mobile, fire, and biogenic. The attainment and future year emissions inventories were developed/projected by ACHD as follows:
• Point and area source emissions were obtained from the 2017 NEI, with corrections to which are detailed in Appendix B of ACHD's submittal, included in this docket. 33 Projected point and area source emissions were calculated using growth factors developed by the Mid-Atlantic Regional Air Management Association, Inc. (MARAMA). Additional resources that ACHD used to project future emissions can be found in Section 6 and Appendix C of ACHD's submittal, included in this docket.
Footnotes:
33 ?The projections for the 2026 and 2035 inventories included the permitted plantwide emission limits for a proposed new major source facility-the Invenergy Allegheny Energy Center (Installation Permit No. 0959-I001a). However, the installation permit for this facility was terminated on November 9, 2023. See Allegheny County Energy Center Termination Letter, available in the docket for this action.
• Onroad and nonroad mobile emissions were estimated using the latest version of the EPA's MOVES3 model. PADEP performed the nonroad modeling and engaged a contractor to perform the onroad modeling. Additional details on the onroad and nonroad mobile emissions can be found in Section 6 and Appendix D of ACHD's submission, included in this docket.
• Fire and biogenic sources were held constant from 2017 through the 2026 and 2035 projection years, because their emissions can be dependent on meteorology.
[top] The EPA has reviewed the documentation provided by ACHD for developing the 2017, 2026, and 2035 emissions inventories for the Liberty-
Footnotes:
34 ? See Appendix B of ACHD's submittal or detailed emissions by process/facility or source section/description, located within this docket.
35 ? See Appendix C of ACHD's submittal for detailed emissions by process/facility or source section/description, located within this docket.
36 ? Id.
37 ? See Appendix B of ACHD's submittal for detailed emissions by process/facility or source section/description, located within this docket.
| Liberty-Clairton Area (2017) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 680 | 878 | 1,130 | 2,626 | 184 | 119 |
| Area | 38 | 62 | 3 | 91 | 185 | 10 |
| Nonroad Mobile | 4 | 4 | 0 | 39 | 36 | 0 |
| Onroad Mobile | 4 | 9 | 1 | 121 | 52 | 4 |
| Fires | 0 | 0 | 0 | 0 | 0 | 0 |
| Biogenics | 0 | 0 | 0 | 3 | 85 | 0 |
| Total | 726 | 953 | 1,134 | 2,880 | 543 | 133 |
| Liberty-Clairton Area (2026) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 537 | 682 | 999 | 2,142 | 158 | 104 |
| Area | 39 | 63 | 4 | 93 | 200 | 10 |
| Nonroad Mobile | 3 | 3 | 0 | 27 | 34 | 0 |
| Onroad Mobile | 2 | 9 | 0 | 56 | 29 | 3 |
| Fires | 0 | 0 | 0 | 0 | 0 | 0 |
| Biogenics | 0 | 0 | 0 | 3 | 85 | 0 |
| Total | 580 | 756 | 1,003 | 2,322 | 505 | 118 |
| Liberty-Clairton Area (2035) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 510 | 646 | 982 | 2,154 | 148 | 97 |
| Area | 40 | 65 | 4 | 91 | 203 | 10 |
| Nonroad Mobile | 2 | 3 | 0 | 26 | 35 | 0 |
| Onroad Mobile | 2 | 9 | 0 | 40 | 23 | 3 |
| Fires | 0 | 0 | 0 | 0 | 0 | 0 |
| Biogenics | 0 | 0 | 0 | 3 | 85 | 0 |
| Total | 554 | 722 | 986 | 2,313 | 495 | 111 |
[top]
| Allegheny County Area (2017) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 1,351 | 1,752 | 4,758 | 6,336 | 1,493 | 305 |
| Area | 2,564 | 4,113 | 224 | 6,059 | 12,360 | 657 |
| Nonroad Mobile | 264 | 278 | 4 | 2,616 | 2,370 | 6 |
| Onroad Mobile | 257 | 584 | 47 | 8,046 | 3,469 | 271 |
| Fires | 0 | 0 | 0 | 0 | 1 | 0 |
| Biogenics | 0 | 0 | 0 | 216 | 5,690 | 0 |
| Total | 4,437 | 6,728 | 5,033 | 23,273 | 25,383 | 1,238 |
| Allegheny County Area (2026) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 1,184 | 1,481 | 2,732 | 5,144 | 1,563 | 334 |
| Area | 2,568 | 4,181 | 267 | 6,175 | 13,313 | 687 |
| Nonroad Mobile | 182 | 194 | 3 | 1,811 | 2,287 | 7 |
| Onroad Mobile | 161 | 605 | 25 | 3,748 | 1,906 | 229 |
| Fires | 0 | 0 | 0 | 0 | 1 | 0 |
| Biogenics | 0 | 0 | 0 | 216 | 5,690 | 0 |
| Total | 4,095 | 6,462 | 3,027 | 17,094 | 24,760 | 1,257 |
| Allegheny County Area (2035) | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 |
|---|---|---|---|---|---|---|
| Point | 1,160 | 1,471 | 2,710 | 5,258 | 1,601 | 357 |
| Area | 2,648 | 4,319 | 273 | 6,039 | 13,533 | 684 |
| Nonroad Mobile | 158 | 169 | 4 | 1,709 | 2,347 | 8 |
| Onroad Mobile | 128 | 591 | 22 | 2,638 | 1,556 | 222 |
| Fires | 0 | 0 | 0 | 0 | 1 | 0 |
| Biogenics | 0 | 0 | 0 | 216 | 5,690 | 0 |
| Total | 4,095 | 6,551 | 3,009 | 15,861 | 24,728 | 1,271 |
2. Maintenance Demonstration
Footnotes:
38 ? See Appendix C of ACHD's submittal or detailed emissions by process/facility or source section/description, located within this docket.
39 ? Id.
The maintenance plan for the Liberty-Clairton Area and Allegheny County Area includes a maintenance demonstration that: (1) shows compliance with and maintenance of both area's respective PM 2.5 standard by providing information to support the demonstration that current and future emissions of PM 2.5 and precursors remain at or below 2017 emissions levels, (2) uses 2017 as the attainment year for both areas and includes future emission inventory projections for 2026 interim and 2035 maintenance years, (3) identifies an "out year" at least 10 years after the EPA review and potential approval of the maintenance plan, 40 and (4) provides, as shown in tables 5 through 10 in this document, the 2017 attainment year, 2026 interim, and 2035 maintenance year emissions inventories, in tpy, for the Liberty-Clairton Area and Allegheny County Area, for PM 2.5 , NO X , SO 2 , VOC, and NH 3 .
Footnotes:
40 ?Per 40 CFR part 93, NO X and PM 2.5 MVEBs were established for the last year (2035) of the maintenance plan for the Allegheny County Area. On October 2, 2015 (80 FR 59615), the EPA approved an insignificance finding for the mobile source contribution of PM 2.5 and NO X for the Liberty-Clairton Area for both the 1997 annual and 2006 24-hour PM 2.5 NAAQS (see section IV.C of this action).
Where the emissions inventory method of showing maintenance is used, its purpose is to show that emissions during the maintenance period will not increase over the attainment year inventory. 41 For a demonstration of maintenance, emissions inventories are required to be projected to future dates to assess the influence of future growth and controls; however, the demonstration need not be based on modeling. 42 ACHD developed projection inventories for an interim year of 2026 and a maintenance plan end year of 2035 to show that future emissions of PM 2.5 , NO X , SO 2 , VOC, and NH 3 will remain at or below the 2017 attainment year for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area, and for the 2012 annual PM 2.5 NAAQS for the Allegheny County Area, through the year 2035. Tables 11 and 12, in this document, provide summaries of the PM 2.5 , NO X , SO 2 , VOC, and NH 3 emissions inventories, in tpy, for the Liberty-Clairton Area and the Allegheny County Area, respectively, for the 2017 attainment year as compared to the projected inventories for the 2026 interim year and the 2035 maintenance year. ACHD calculated "total PM 2.5 " as the sum of PM 2.5 and precursors for each inventory, with PM 10 excluded. Reductions of the projected year emissions from the attainment year emissions are shown as negative values.
Footnotes:
41 ? See 1992 Calcagni Memorandum, pages 9-10.
42 ? See Wall v. EPA, supra; Sierra Club v. EPA, supra. See also 66 FR 53099-53100 (October 19, 2001) and 68 FR 25430-32 (May 12, 2003).
[top]
| Liberty-Clairton Area | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 | Total PM 2.5 |
|---|---|---|---|---|---|---|---|
| 2017 Attainment Year | 726 | 953 | 1,134 | 2,880 | 543 | 133 | 5,416 |
| 2026 Interim Year | 580 | 756 | 1,003 | 2,322 | 505 | 118 | 4,529 |
| 2035 Maintenance Year | 554 | 722 | 986 | 2,313 | 495 | 111 | 4,460 |
| Reduction, Attainment to Interim Year | -146 | -196 | -131 | -559 | -37 | -15 | -887 |
| Reduction, Attainment to Maintenance Year | -172 | -231 | -148 | -567 | -48 | -22 | -956 |
| Allegheny County Area | PM 2.5 (filterable and condensable) | PM 10 | SO 2 | NO X | VOC | NH 3 | Total PM 2.5 |
|---|---|---|---|---|---|---|---|
| 2017 Attainment Year | 4,437 | 6,728 | 5,033 | 23,273 | 25,383 | 1,238 | 59,364 |
| 2026 Interim Year | 4,095 | 6,462 | 3,027 | 17,094 | 24,760 | 1,257 | 50,233 |
| 2035 Maintenance Year | 4,095 | 6,551 | 3,009 | 15,861 | 24,728 | 1,271 | 48,963 |
| Reduction, Attainment to Interim Year | -343 | -266 | -2,066 | -6,179 | -623 | 18 | -9,132 |
| Reduction, Attainment to Maintenance Year | -343 | -177 | -2,024 | -7,413 | -655 | 33 | -10,401 |
For the Liberty-Clairton Area, the 2026 interim year and 2035 maintenance year projected emissions for total PM 2.5 and all precursors are lower than the 2017 attainment year. For the Allegheny County Area, total PM 2.5 and most precursors show lower emissions in the projected years compared to the attainment year. Although NH 3 emissions are projected to increase for the Allegheny County Area, the emissions increase is relatively small (33 tpy from 2017 to 2035) and the decrease in emissions of the other precursors more than offset the projected increase. Also, as noted in footnote 29 of this document, NH 3 was found to be an insignificant precursor for attainment in the Allegheny County Area. Thus, ACHD has adequately demonstrated that the Liberty-Clairton Area will continue to maintain the 1997 annual and the 2006 24-hour PM 2.5 NAAQS, and that the Allegheny County Area will continue to maintain the 2012 annual PM 2.5 NAAQS, through 2035.
3. Monitoring Network
ACHD's maintenance plan includes a commitment to operate its EPA-approved monitoring network, as necessary to demonstrate ongoing compliance with the NAAQS. ACHD currently operates two PM 2.5 monitors in the Liberty-Clairton Area and eight PM 2.5 monitors in the Allegheny County Area. In its November 30, 2022 submittal, ACHD stated that it will consult with the EPA prior to making any necessary changes to the network and will continue to operate the monitoring network in accordance with the requirements of 40 CFR part 58.
4. Verification of Continued Attainment
As noted in the previous section, ACHD has stated that it will continue to operate its monitoring system in accordance with 40 CFR part 58 and remains obligated to quality assure monitoring data and enter all data into the AQS in accordance with Federal requirements. ACHD has stated that air monitoring will be the primary mechanism for verification of continued attainment. Also, to provide additional tracking of the emission levels in the Liberty-Clairton Area and Allegheny County Area, ACHD will: (1) continue to evaluate the periodic emissions inventory, prepared annually by ACHD for point sources and every three years by PADEP for area and mobile sources, to determine whether there is an exceedance of the 2017 attainment inventory for each area, and (2) if there is an exceedance of the attainment inventory, conduct a study to determine if the emissions increases led to increased monitored emissions. ACHD will use this data in considering whether additional control measures are necessary to assure continued attainment in the areas.
5. Contingency Measures
The maintenance plan should identify the events that would "trigger" the adoption and implementation of a contingency measure(s), the contingency measure(s) that would be adopted and implemented, and the schedule indicating the time frame by which the state would adopt and implement the measure(s). 43 The contingency plan provisions included in ACHD's maintenance plan are designed to promptly correct any violation of the 2006 24-hour PM 2.5 NAAQS that occur in the Liberty-Clairton Area after redesignation, and/or for the 2012 PM 2.5 NAAQS for the Allegheny County Area. Triggers for the 2012 annual PM 2.5 NAAQS for the Allegheny County Area are inherently applicable to the 1997 annual PM 2.5 NAAQS for the Liberty-Clairton Area since the Allegheny County Area encompasses the Liberty-Clairton Area. There are no specific triggers for the 1997 annual PM 2.5 NAAQS for the Liberty-Clairton Area because it has been superseded by the 2012 annual PM 2.5 NAAQS.
Footnotes:
43 ? See 1992 Calcagni Memorandum, page 12.
[top] Section 175A of the CAA requires that a maintenance plan include such contingency measures as the EPA deems necessary to ensure that a state will promptly correct a violation of the NAAQS occurring after redesignation. ACHD's maintenance plan describes the procedures for the adoption and implementation of contingency measures to reduce emissions should a violation occur. ACHD's contingency measures include a first level warning response, a second level warning response, and an action response. A first level response is triggered if the 98th percentile 24-hour PM 2.5 concentration exceeds 35.5 µg/m 3 at any monitor site in a single calendar year within the Liberty-Clairton Area, and/or the annual weighted mean PM 2.5 concentration
Footnotes:
44 ?See Section 6.5.2 of ACHD's Maintenance Plan for the detailed implementation schedule, which is included in the docket of this action.
ACHD's candidate contingency measures include both countywide measures as well as measures specific to USS Mon Valley Works. Countywide measures include the following: (1) new woodstove changeout, fireplace conversion, or other wood burning-related programs; (2) voluntary diesel projects such as diesel retrofit for public or private local onroad or offroad fleets, idling reduction technologies or strategies for locomotives, trucks, warehouse, and other freight-handling activities, and replacement of select diesel terminal trucks with electric alternatives; (3) a new clean vehicle rebate program, applicable to the purchase of zero-emission passenger motor vehicles; (4) enhancement of the Air Quality Action Day program; (5) paving of certain unpaved roads and/or parking lots within the county; (6) promotion of accelerated turnover of lawn and garden equipment, with emphasis on commercial equipment; (7) promotion of alternative fuels for fleets, home heating, and agricultural use; and (8) adoption of an ordinance to restrict sale and use of heavy fuel oil and/or waste derived liquid fuel (WDLF) within Allegheny County. Measures specific to USS Mon Valley Works and associated sources include: (1) paving of select unpaved road and/or parking lots at USS Mon Valley Works facilities; (2) repowering or replacement of tugboats and/or locomotives used by the Mon Valley Works plants or the McKeesport switchyard with cleaner-burning equipment or electric alternatives; (3) increased times for the hood of the Pushing Emission Control (PEC) system to be held in place during the pushing process at one or more of the coke batteries at the USS Clairton Plant; (4) increased air flow to the baghouses of the PEC system of one or more of the coke batteries at the USS Clairton Plan to increase capture efficiencies; and (5) increase baffle washing for one or more of the USS Clairton Plant quench towers. ACHD will adopt and implement these contingency measures according to the implementation schedule in the maintenance plan. For all of the reasons discussed in this section, the EPA is proposing to approve ACHD's maintenance plan as meeting the requirements of section 175A of the CAA for the 1997 annual and 2006 24-hour PM 2.5 NAAQS for the Liberty-Clairton Area and for the 2012 annual PM 2.5 NAAQS for the Allegheny County Area.
C. Motor Vehicle Emissions Budgets
Under the CAA, maintenance plans identify and establish MVEBs for certain criteria pollutants and/or their precursors to address pollution from on-road mobile sources. In the maintenance plan, the MVEBs are termed "on road-mobile source emission budgets." Pursuant to 40 CFR part 93 and section 51.112, MVEBs must be established in a PM 2.5 maintenance plan.
Motor vehicle budgets are the projected levels of controlled emissions from the transportation sector (mobile sources) that are estimated in the SIP to provide for maintenance of the NAAQS. When reviewing submitted maintenance plans containing MVEBs, the EPA must affirmatively find the MVEBs contained therein "adequate" for use in determining transportation conformity. After the EPA affirmatively finds that the submitted MVEBs are adequate for transportation conformity purposes, the MVEBs can be used by state and Federal agencies in determining whether proposed transportation projects "conform" to the SIP as required by section 176(c) of the CAA. The EPA's substantive criteria for determining "adequacy" of a MVEB are set out in 40 CFR 93.118(e)(4).
For the Liberty-Clairton Area for the 1997 annual and 2006 24-hour PM 2.5 NAAQS, a finding of insignificance of motor vehicle emission contributions was determined for the Liberty-Clairton Area (October 2, 2015, 80 FR 59615). The Liberty-Clairton Area continues to demonstrate that motor vehicle emissions constitute a low percentage of the total SIP inventory. As a result, transportation conformity for SIP purposes is not required; however, the Liberty-Clairton Area must continue to follow procedures such as interagency consultation, as described in the transportation conformity rule (40 CFR part 93, subpart A).
[top] The maintenance plan submitted for the Allegheny County Area identifies the NO X and PM 2.5 MVEBs for transportation conformity purposes for the years 2017, 2026, and 2035. These MVEBs (including safety margins) are the modeled emissions for the on-road mobile sources plus any portion of the safety margin allocated to the MVEBs (safety margin allocation for 2026 and 2035 only). A "safety margin," as defined in the transportation conformity rule (40 CFR part 93, subpart A), is the amount by which the total projected emissions from all sources of a given pollutant are less than the total emissions that would satisfy the applicable requirement for reasonable further progress, attainment, or maintenance. The safety margins were created by setting aside a portion of the difference between attainment year and maintenance year emissions of PM 2.5 and NO X to accommodate unanticipated growth in highway vehicles. Table 13, in this document, shows the MOVES3 modeled results for years 2017, 2026, and 2035 for PM 2.5 and NO X onroad mobile source emissions. The proposed MVEB for the Allegheny County Area are based on the modeled emissions for 2017, 2026, and 2035, plus the addition
| VMT/emissions | 2017 | 2026 | 2035 |
|---|---|---|---|
| Annual VMT | 8,266,734,599 | 8,659,512,983 | 9,018,014,459 |
| PM 2.5 (Modeled) | 257 | 161 | 128 |
| PM 2.5 Safety Margin (10%) | 16 | 13 | |
| Proposed PM 2.5 MVEB | 257 | 177 | 141 |
| NO X (Modeled) | 8,046 | 3,748 | 2,638 |
| NO X Safety Margin (10%) | 375 | 264 | |
| Proposed NO X MVEB | 8,046 | 4,123 | 2,902 |
The 2017, 2026, and 2035 MVEBs for the Allegheny County Area are approvable because the MVEBs for NO X and PM 2.5 continue to maintain the total emissions at or below the attainment year inventory levels as required by the transportation conformity regulations. The EPA is concurrently processing the action on the maintenance plan and the adequacy process for the Allegheny County Area MVEBs contained therein. In this proposed rule, the EPA is proposing to find the MVEBs adequate and proposing to approve the MVEBs as part of the maintenance plan. The MVEBs cannot be used for transportation conformity until the maintenance plan and associated MVEBs are approved in a final Federal Register publication, or the EPA otherwise finds the budgets adequate in a separate action following the comment period.
If the EPA receives adverse written comments with respect to the proposed approval of the Allegheny County Area MVEBs, or any other aspect of the proposed approval of this maintenance plan, the EPA will respond to the comments on the MVEBs in the final rulemaking notice or proceed with the adequacy process as a separate action. The EPA's analyses of the MVEBs for the Allegheny County Area can be found in the EPA's MVEB TSD prepared for this action, available online at www.regulations.gov, Docket ID: EPA-R03-OAR-2024-0586.
V. Proposed Actions
The EPA is proposing to approve Pennsylvania's request to redesignate the Liberty-Clairton Area from nonattainment to attainment for the 1997 annual and the 2006 24-hour PM 2.5 NAAQS. The EPA has evaluated Pennsylvania's redesignation request and determined that the Liberty-Clairton Area has met the redesignation criteria set forth in section 107(d)(3)(E) of the CAA. The monitoring data demonstrates that the Liberty-Clairton Area attained, as determined by the EPA in a prior rulemaking, and for reasons discussed herein, continues to attain both NAAQS. Final approval of this redesignation request would change the designation of the Liberty-Clairton Area from nonattainment to attainment for the 1997 annual and the 2006 24-hour PM 2.5 NAAQS. In addition, if finalized, according to the Fine Particulate Matter National Ambient Air Quality Standards: State Implementation Plan Requirements (81 FR 58010, August 24, 2016), "for an area that is redesignated to attainment after the effective date of this final rule, the 1997 primary annual PM 2.5 NAAQS will be revoked in such an area on the effective date of its redesignation to attainment for that NAAQS. After revocation of the 1997 primary annual PM 2.5 NAAQS in a given area, the designation for that standard is no longer in effect." The EPA is also proposing to approve the maintenance plan for the Liberty-Clairton Area for the 1997 annual and 2006 24-hour PM 2.5 NAAQS and for the Allegheny County Area for the 2012 annual PM 2.5 NAAQS as a revision to the Pennsylvania SIP because it meets the requirements of section 175A of the CAA as described previously in this proposed rulemaking. Furthermore, the EPA is proposing to find the 2017, 2026, and 2035 PM 2.5 and NO X MVEBs contained in the maintenance plan for the Allegheny County Area adequate and is also proposing to approve these MVEBs into the Pennsylvania SIP for transportation conformity purposes. The EPA is soliciting public comments on the issues discussed in this document. These comments will be considered before taking final action.
VI. Statutory and Executive Order Reviews
Under the CAA, the redesignation of an area to attainment and the accompanying approval of the maintenance plan under CAA section 107(d)(3)(E) are actions that affect the status of geographical area and do not impose any additional regulatory requirements on sources beyond those required by state law. A redesignation to attainment does not in and of itself impose any new requirements, but rather results in the application of requirements contained in the CAA for areas that have been redesignated to attainment. Moreover, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:
• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 12866 (58 FR 51735, October 4, 1993);
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );
• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );
• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
[top] • Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and
• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act;
In addition, this proposed redesignation of the Liberty-Clairton Area to attainment of the 1997 annual and 2006 24-hour NAAQS and approval of the associated maintenance plan for the Liberty-Clairton Area and Allegheny County Area does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP is not approved to apply in Indian country located in the State, and the EPA notes that it will not impose substantial direct costs on tribal governments or preempt tribal law.
List of Subjects
40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by reference, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, Volatile organic compounds.
40 CFR Part 81
Environmental protection, Air pollution control, Carbon monoxide, Intergovernmental relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements, Sulfur oxides, Volatile organic compounds.
Catherine A. Libertz,
Acting Regional Administrator, Region III.
[FR Doc. 2025-05921 Filed 4-4-25; 8:45 am]
BILLING CODE 6560-50-P