Air Plan Approval; Illinois; Moderate Attainment Plan Elements for the Chicago and Metro East Areas for the 2015 Ozone Standard

The Environmental Protection Agency (EPA) is approving portions of Illinois' 2015 ozone National Ambient Air Quality Standard (NAAQS or standard) Moderate nonattainment area State Implementation Plan (SIP) submittal for the Chicago and the Metro East St. Louis areas. The portions being approved are the reasonable further progress (RFP) demonstration, including the associated motor vehicle emissions budgets for 2023; the motor vehicle inspection and maintenance (I/M) program; the nonattainment new source review (NNSR) program; and the updated 2017 base year emissions inventories. The EPA is approving these portions of the State's SIP submittal pursuant to section 110 and part D of the Clean Air Act (CAA), and the EPA's regulations. The EPA is also finding adequate and approving the 2023 motor vehicle emissions budgets (budgets) for the Chicago and Metro East St. Louis Moderate ozone nonattainment RFP demonstration included in this SIP submittal. The EPA proposed to approve this action on February 12, 2026, and received no adverse comments.