Air Plan Approval; Indiana; Redesignation of the Indiana Portion of the Chicago-Naperville Area to Attainment of the 2008 Ozone Standard, NOX RACT Waiver, and Serious Plan Elements

The Environmental Protection Agency (EPA) finds that the Indiana portion of the Chicago-Naperville, IL-IN-WI area (Chicago area) is attaining the 2008 ozone National Ambient Air Quality Standard (NAAQS or standard). In addition, in response to a December 6, 2021, request from the Indiana Department of Environmental Management (Indiana or the State), EPA is redesignating the Indiana portion of the Chicago area to attainment for the 2008 ozone NAAQS, because the State has met the statutory requirements for redesignation under the Clean Air Act (CAA). EPA is approving, as a revision to the Indiana State Implementation Plan (SIP), the State's plan for maintaining the 2008 ozone NAAQS through 2035 for the Indiana portion of the Chicago area. EPA is also approving a waiver, for the Indiana portion of the Chicago area, from the oxides of nitrogen (NO<INF>X</INF>) requirements of the CAA. EPA finds adequate and is approving Indiana's 2030 and 2035 volatile organic compound (VOC) and NO<INF>X</INF> motor vehicle emission budgets (budgets) for the Indiana portion of the Chicago area. Finally, EPA is approving the VOC reasonably available control technology (RACT), clean-fuel vehicle programs (CFVP), enhanced monitoring of ozone and ozone precursors (EMP), and enhanced motor vehicle Inspection/Maintenance (I/M) SIP revisions. These SIP revisions satisfy the above requirements for a nonattainment area that is classified as a "Serious area" for the Indiana portion of the Chicago area under the 2008 ozone NAAQS. EPA proposed to approve this action on March 3, 2022, and received adverse comments from one commentor.