The Environmental Protection Agency (EPA) is taking final action to redesignate the nonattainment area in Muscatine County, Iowa to attainment for the 2010 1-hour sulfur dioxide (SO<INF>2</INF>) National Ambient Air Quality Standard (NAAQS). The EPA is also approving Iowa's maintenance plan for the 2010 1-hour SO<INF>2</INF> NAAQS for the Muscatine nonattainment area and approving modifications to source-specific permits in the Iowa State Implementation Plan (SIP). The EPA is taking this action in accordance with the requirements of the Clean Air Act (CAA).