Air Plan Approval; Pennsylvania; Allegheny County Area Attainment Plan for the 2012 Fine Particulate Matter National Ambient Air Quality Standard

The Environmental Protection Agency (EPA) is proposing to approve elements of a state implementation plan (SIP) revision submitted by the Pennsylvania Department of Environmental Protection (PADEP) on behalf of the Allegheny County Health Department (ACHD) to address Clean Air Act (CAA or "the Act") requirements for the 2012 annual fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standards (NAAQS or "standards") in the Allegheny County Moderate PM<INF>2.5</INF> nonattainment area ("Allegheny County area"). The SIP revision contains the "Attainment Demonstration for the Allegheny County, PA PM<INF>2.5</INF> Nonattainment Area, 2012 NAAQS," submitted on September 30, 2019 (also referred to as "the Allegheny County PM<INF>2.5</INF> Plan" or simply "the plan"). EPA is proposing to fully approve the following elements of the Allegheny County PM<INF>2.5</INF> Plan: The base year emissions inventory, the particulate matter precursor contribution demonstration, the reasonably available control measures/reasonably available control technology (RACM/RACT) demonstration, the attainment demonstration, the air quality modeling demonstration supporting attainment by the attainment deadline, the reasonable further progress (RFP) demonstration, and the a demonstration of interim quantitative milestones to ensure timely attainment. EPA is proposing to conditionally approve the following elements of this Allegheny County PM<INF>2.5</INF> Plan SIP revision: The contingency measures and the motor vehicle emission budget (MVEB) elements of the plan. PADEP commits, on behalf of ACHD, to submit a supplemental SIP revision to remedy those portions of the plan for which EPA is proposing conditional approval within twelve months of EPA's final conditional approval action. This action is being taken under the CAA.