Approval and Promulgation of Implementation Plans and Designation of Areas for Air Quality Planning Purposes; Illinois; Redesignation of the Illinois Portion of the St. Louis, MO-IL Area to Attainment for the 1997 8-Hour Ozone Standard

EPA is proposing to approve a request from Illinois to redesignate the Illinois portion of the St. Louis, MO-IL nonattainment area, "the St. Louis area," to attainment for the 1997 8-hour ozone standard because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA). The St. Louis area includes Jersey, Madison, Monroe, and St. Clair Counties in Illinois and St. Louis City and Franklin, Jefferson, St. Charles and St. Louis Counties in Missouri. The Illinois Environmental Protection Agency (IEPA) submitted this request on May 26, 2010 and supplemented it on September 16, 2011. (EPA will address the Missouri portion of the St. Louis area in a separate rulemaking action.) This proposed approval also involves several related actions. EPA is proposing to approve, as a revision to the Illinois State Implementation Plan (SIP), the State's plan for maintaining the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS) through 2025 in the area. EPA is proposing to approve the 2002 emissions inventory, submitted by IEPA on June 21, 2006, and supplemented on September 16, 2011, as meeting the comprehensive emissions inventory requirement of the CAA for the Illinois portion of the St. Louis area. Finally, EPA finds adequate and is proposing to approve the State's 2008 and 2025 Motor Vehicle Emission Budgets (MVEBs) for the Illinois portion of the St. Louis area.