Proposed rule · 2025-05921

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

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<INF>2.5</INF>) 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<INF>2.5</INF> 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<INF>2.5</INF> NAAQS through 2035. The maintenance plan includes 2017, 2026, and 2035 mobile vehicle emissions budgets (MVEBs) for mobile sources of PM<INF>2.5</INF> and nitrogen oxides (NO<INF>X</INF>) for the Allegheny County Area. The EPA is proposing to find these 2017, 2026, and 2035 MVEBs for PM<INF>2.5</INF> and NO<INF>X</INF> 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<INF>2.5</INF> 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.