Approval and Promulgation of Air Quality Implementation Plan; Kentucky; Disapproval of Interstate Transport Submission for the 2006 24-hour PM2.5 Standards

EPA is taking final action to disapprove the portion of Kentucky's September 8, 2009, submission which was intended to meet the requirement to address interstate transport for the 2006 24-hour fine particulate matter (PM<INF>2.5</INF>) national ambient air quality standards (NAAQS). Additionally, EPA is responding to comments received on EPA's January 26, 2011, proposed disapproval of the aforementioned portion of Kentucky's September 8, 2009, submission. On September 8, 2009, the Commonwealth of Kentucky, through the Kentucky Division for Air Quality (KDAQ), provided a letter to EPA with certification that Kentucky's state implementation plan (SIP) meets the interstate transport requirements with regard to the 2006 24-hour PM<INF>2.5</INF> NAAQS. Specifically, the interstate transport requirements under the Clean Air Act (CAA or Act) prohibit a state's emissions from significantly contributing to nonattainment or interfering with the maintenance of the NAAQS in any other state. The effect of today's action will be the promulgation of a Federal Implementation Plan (FIP) for Kentucky no later than two years from the date of disapproval. The proposed Transport Rule, when final, is the FIP that EPA intends to implement for Kentucky.