Approval and Promulgation of Implementation Plans; Kentucky: Kentucky Portion of Cincinnati-Hamilton, Revision to the Motor Vehicle Emissions Budgets

EPA is taking direct final action to approve a revision to the Kentucky State Implementation Plan (SIP), submitted to EPA on August 9, 2012, by the Commonwealth of Kentucky, through the Kentucky Energy and Environment Cabinet, Division for Air Quality (DAQ). Kentucky's August 9, 2012, SIP revision includes changes to the maintenance plan for the Kentucky portion of the Cincinnati-Hamilton, OH-KY-IN, maintenance area for the 1997 8-hour ozone national ambient air quality standards (NAAQS). The Cincinnati-Hamilton, OH-KY-IN, maintenance area for the 1997 8-hour ozone NAAQS includes the counties of Boone, Campbell and Kenton in Kentucky (hereafter also referred to as Northern Kentucky); a portion of Dearborn County, Indiana; and the entire counties of Butler, Clermont, Clinton, Hamilton and Warren in Ohio. Kentucky's August 9, 2012, SIP revision proposes to update the motor vehicle emissions budget using an updated mobile emissions model, the Motor Vehicle Emissions Simulator (also known as MOVES2010a), and to increase the safety margin allocated to motor vehicle emissions budgets (MVEBs or budgets) for nitrogen oxides (NO<INF>X</INF>) and volatile organic compounds (VOC) for Northern Kentucky to account for changes in the emissions model and vehicle miles traveled (VMT) projection model. EPA is approving this SIP revision and deeming the MVEB adequate for transportation conformity purposes, because the Commonwealth has demonstrated that it is consistent with the Clean Air Act (CAA or Act).