EPA Approves Wisconsin Ozone Plans for Three Metro Areas
Kenosha, Milwaukee and Sheboygan County win federal sign-off on their 2015 ozone attainment plans after no adverse public comment.
The EPA is approving key pieces of Wisconsin's plan to bring the Wisconsin portion of the Chicago area (Kenosha County), the Milwaukee area, and Sheboygan County into compliance with the 2015 ozone air quality standard. The approval covers the state's reasonable further progress demonstration, the motor vehicle emissions budgets tied to it for 2023, the vehicle inspection and maintenance program, and the nonattainment new source review program that governs permitting for new pollution sources in these areas.
The agency is also approving the base-year emissions inventory as satisfying earlier requirements tied to the areas' prior marginal nonattainment status, and it is separately finding the 2023 motor vehicle emissions budgets adequate. Those budgets set the ceiling on vehicle-related pollution that state and federal transportation plans in the affected counties must not exceed.
Wisconsin submitted the plan elements on April 2, 2025, and the EPA proposed approval on April 2, 2026, opening a public comment period that closed May 4, 2026, with no adverse comments received. The absence of adverse comments allowed the agency to finalize the approval as proposed.
The rule takes effect September 21, 2026. For Kenosha County, Milwaukee, and Sheboygan County, the action locks in the emissions accounting and vehicle inspection and permitting programs that underpin their path toward meeting the 2015 ozone standard, closing out one round of federal review for these three Wisconsin nonattainment areas.
— Source: Federal Register, EPA final rule, 'Air Plan Approval; Wisconsin; Moderate Attainment Plan Elements for Wisconsin's 2015 Ozone Standard Areas,' published August 20, 2026.