Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Ohio; Indiana; Redesignation of the Ohio and Indiana Portions of the Cincinnati-Hamilton Area to Attainment for Ozone

摘要

EPA is approving the requests of Ohio and Indiana to redesignate the Ohio and Indiana portions of the Cincinnati-Hamilton, OH-KY-IN 8-hour ozone nonattainment area, "the Cincinnati-Hamilton area," to attainment for that standard, because these requests meet the statutory requirements for redesignation under the Clean Air Act (CAA). The Ohio Environmental Protection Agency (Ohio EPA) and the Indiana Department of Environmental Management (IDEM) submitted these requests on December 14, 2009, and January 21, 2010, respectively. (EPA will address the Kentucky portion of the Cincinnati-Hamilton area in a separate rulemaking action.) These approvals involve several related actions. EPA is making a determination under the CAA that the Cincinnati-Hamilton area has attained the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS). The Cincinnati-Hamilton area includes Butler, Clermont, Clinton, Hamilton, and Warren Counties in Ohio, Lawrenceburg Township in Dearborn County, Indiana, and Boone, Campbell, and Kenton Counties in Kentucky. This determination is based on three years of complete, quality-assured ambient air quality monitoring data for the 2007-2009 ozone seasons that d