The Environmental Protection Agency (EPA) is approving into the Pennsylvania state implementation plan (SIP), a limited maintenance plan (LMP) submitted by the Commonwealth of Pennsylvania's Department of Environmental Protection (PADEP or Commonwealth) on behalf of the Allegheny County Health Department (ACHD). This plan addresses the second 10-year maintenance period after redesignation for coarse particulate matter, particulate matter with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM<INF>10</INF>). A LMP is used to meet the Clean Air Act (CAA or the Act) requirements for formerly designated nonattainment areas that meet certain qualification criteria. EPA has determined that ACHD's second maintenance plan meets applicable CAA requirements.