Approval and Promulgation of Air Quality Implementation Plans; Illinois; Indiana; Michigan; Minnesota; Ohio; Wisconsin; Infrastructure SIP Requirements for the 1997 8-Hour Ozone and PM2.5 National Ambient Air Quality Standards

EPA is taking final action to approve elements of submissions by Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin regarding the infrastructure requirements of sections 110(a)(1) and (2) of the Clean Air Act (CAA) for the 1997 eight-hour ground level ozone national ambient air quality standards (1997 8-hour ozone NAAQS) and 1997 fine particle national ambient air quality standards (1997 PM<INF>2.5</INF> NAAQS). The infrastructure requirements are designed to ensure that the structural components of each state's air quality management program are adequate to meet the state's responsibilities under the CAA. The proposed rulemaking was published on April 28, 2011. During the comment period, which ended on May 31, 2011, EPA received three comment letters raising a number of concerns, which will be addressed in this final action.