Approval and Promulgation of Air Quality Implementation Plans; Indiana; Redesignation of Lake and Porter Counties to Attainment of the Fine Particulate Matter Standard

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In an April 3, 2008, submittal, supplemented on March 6, 2009, May 26, 2011, and July 20, 2011, the Indiana Department of Environmental Management (IDEM) requested redesignation of the Lake and Porter Counties, Indiana portion (Lake and Porter Counties) of the Chicago-Gary-Lake County, Illinos-Indiana (IL-IN) nonattainment area (Greater Chicago nonattainment area) to attainment of the 1997 annual fine particulate matter (PM 2.5 ) National Ambient Air Quality Standard (NAAQS or standard). EPA is proposing to approve the redesignation request for Lake and Porter Counties, along with related Indiana State Implementation Plan (SIP) revisions, including the State's plan for maintaining attainment of the PM 2.5 standard in this area through 2025, because the request meets the statutory requirements for redesignation under the Clean Air Act (CAA). EPA is also proposing to approve Indiana's 2025 Nitrogen Oxides (NO X ) and PM 2.5 Motor Vehicle Emission Budgets (MVEBs) for Lake and Porter Counties, as well as the 2005 PM 2.5 -related emissions inventories for this area.