Approval of Air Quality Implementation Plans; Indiana; Approval of “Infrastructure” SIP With Respect to Source Impact Analysis Provisions for the 2006 24-Hour PM2.5 NAAQS

Pursuant to its authority under the Clean Air Act (CAA), EPA is taking final action to approve portions of submissions made by the Indiana Department of Environmental Management (IDEM) to address the section 110(a)(1) and (2) requirements of the CAA, often referred to as the "infrastructure" state implementation plan (SIP). Specifically, we are finalizing the approval of portions of IDEM's submissions intended to meet certain requirements of sections 110(a)(2)(C), 110(a)(2)(D)(i)(II), and 110(a)(2)(J) of the CAA with respect to the 2006 24-hour PM<INF>2.5</INF> national ambient air quality standards (2006 PM<INF>2.5</INF> NAAQS). Among other provisions, these sections of the CAA require states to perform source impact analyses as part of their prevention of significant deterioration (PSD) programs. EPA is finalizing approval of Indiana's submissions intended to satisfy this requirement. The proposed rule associated with this final action was published on August 2, 2012.