Approval and Promulgation of Air Quality Implementation Plans, and Designation of Areas for Air Quality Planning Purposes; Indiana

EPA is taking final action to approve an ozone maintenance plan submitted as a State Implementation Plan (SIP) revision request and a redesignation request submitted by the State of Indiana for the purpose of redesignating Vanderburgh County (Evansville) from marginal nonattainment to attainment of the one-hour ozone national ambient air quality standard. Besides being based on information contained in the State's redesignation request, the approval of this redesignation request is also based on review of the ozone data for this area over the three most recent years, 1995 through 1997. EPA finds the State's maintenance plan and redesignation request to be acceptable and notes that, based on the most recent three years of ozone data, the area is currently attaining the one-hour ozone standard. This action does not address the area's attainment of the recently promulgated eight-hour ozone standard, which will be addressed in future rulemaking.