Air Plan Approval; Ohio; Redesignation of the Ohio Portion of the Cincinnati-Hamilton, OH-IN-KY Area to Attainment of the 1997 Annual Standard for Fine Particulate Matter

The Environmental Protection Agency (EPA) is redesignating the Ohio portion of the Cincinnati-Hamilton, OH-IN-KY, nonattainment area (hereafter, "the Cincinnati-Hamilton area") to attainment for the 1997 fine particulate matter (PM<INF>2.5</INF>) annual national ambient air quality standards (NAAQS or standard). The Ohio portion of the Cincinnati-Hamilton area includes Butler, Clermont, Hamilton, and Warren Counties. Because EPA has determined that the Cincinnati- Hamilton area is attaining the annual PM<INF>2.5</INF> standard, EPA is redesignating the area to attainment and also approving several additional related actions. EPA is approving the Reasonably Available Control Measures (RACM)--Reasonably Available Control Technology (RACT) portion of Ohio's Cincinnati-Hamilton area attainment plan state implementation plan (SIP) revision as providing adequate RACM/RACT. EPA is also approving an update to the Ohio SIP, by updating the state's approved plan for maintaining the 1997 annual PM<INF>2.5</INF> NAAQS through 2027. EPA previously approved the base year emissions inventory for the Cincinnati-Hamilton area, and is approving Ohio's updated emission inventory which includes emission inventories for volatile organic compounds (VOCs) and ammonia. Ohio's approved maintenance plan submission includes a budget for the mobile source contribution of PM<INF>2.5</INF> and nitrogen oxides (NO<INF>X</INF>) to the Cincinnati-Hamilton area for transportation conformity purposes, which EPA is approving. EPA is taking these actions in accordance with the Clean Air Act (CAA) and EPA's implementation rule regarding the 1997 PM<INF>2.5</INF> NAAQS.