Disapproval, Approval and Promulgation of Air Quality Implementation Plan Revisions; Infrastructure Requirements for the 1997 and 2006 PM2.5 National Ambient Air Quality Standards; Prevention of Significant Deterioration; Wyoming

EPA is partially approving and partially disapproving the State Implementation Plan (SIP) submissions from the State of Wyoming to demonstrate that the SIP meets the infrastructure requirements of the Clean Air Act (CAA) for the National Ambient Air Quality Standards (NAAQS) promulgated for fine particulate matter (PM<INF>2.5</INF>) on July 18, 1997 and on October 17, 2006. The CAA requires that each state, after a new or revised NAAQS is promulgated, review their SIPs to ensure that they meet infrastructure requirements. The State of Wyoming provided infrastructure submissions for the 1997 and 2006 PM<INF>2.5</INF> NAAQS on March 26, 2008 and August 19, 2011, respectively. EPA is also approving revisions to Wyoming's Prevention of Significant Deterioration (PSD) program that incorporate necessary provisions from EPA's 2010 PM<INF>2.5</INF> Increment Rule.