Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Michigan; Redesignation of Flint, Grand Rapids, Kalamazoo-Battle Creek, Lansing-East Lansing, Muskegon, Benton Harbor, Benzie County, Cass County, Huron County, and Mason County 8-Hour Ozone Nonattainment Areas to Attainment for Ozone

EPA is making determinations under the Clean Air Act (CAA) that the nonattainment areas of Flint (Genesee and Lapeer Counties), Grand Rapids (Kent and Ottawa Counties), Kalamazoo-Battle Creek (Calhoun, Kalamazoo, and Van Buren Counties), Lansing-East Lansing (Clinton, Eaton, and Ingham Counties), Muskegon (Muskegon County), Benton Harbor (Berrien County), Benzie County, Cass County, Huron County, and Mason County have attained the 8-hour ozone National Ambient Air Quality Standard (NAAQS). For the Grand Rapids, Kalamazoo- Battle Creek, Lansing-East Lansing, Benzie County, Huron County, and Mason County areas, these determinations are based on two overlapping three-year periods of complete, quality-assured ambient air quality monitoring data for the 2002-2004 seasons and the 2003-2005 seasons that demonstrate that the 8-hour ozone NAAQS has been attained in the areas. Quality assured monitoring data for 2006 show that the areas continue to attain the standard. For the Flint, Muskegon, Benton Harbor, and Cass County areas, these determinations are based on three years of complete quality-assured ambient air quality monitoring data for the 2004-2006 seasons that demonstrate that the 8-hour ozone NAAQS has been attained in the areas. In addition, quality- assured data for 2003-2005 also demonstrate that the 8-hour NAAQS was attained during this period. EPA is approving requests from the State of Michigan to redesignate the Flint, Grand Rapids, Kalamazoo-Battle Creek, Lansing-East Lansing, Muskegon, Benton Harbor, Benzie County, Cass County, Huron County, and Mason County areas to attainment of the 8-hour ozone NAAQS. The Michigan Department of Environmental Quality (MDEQ) submitted these requests on May 9, 2006 and June 13, 2006, and supplemented them on May 26, 2006, August 25, 2006, and November 30, 2006. In approving these requests, EPA is also approving, as revisions to the Michigan State Implementation Plan (SIP), the State's plans for maintaining the 8-hour ozone