| | Description: | On April 15, 2004, the United States Environmental Protection Agency (U.S. EPA) designated portions of the Chicago metropolitan area as nonattainment for the 8-hour ozone National Ambient Air Quality Standard (NAAQS) promulgated in 1997. The Chicago nonattainment area (NAA) includes Cook, DuPage, Kane, Lake, McHenry, and Will counties, and Aux Sable and Goose Lake Townships in Grundy County, and Oswego Township in Kendall County. This designation became effective on June 15, 2004. In the Lake Michigan region, portions of eastern Wisconsin, northwestern Indiana and western Michigan were also designated as nonattainment for the 8-hour ozone standard. As a result of the designation of these counties to nonattainment, the State of Illinois is required by the Clean Air Act (CAA) to develop a plan to attain the NAAQS by a specified deadline. For 8-hour ozone, the attainment plan was due by June 15, 2007 and attainment of the NAAQS is to be achieved by June 15, 2010. | |
