Wisconsin air quality targets tightened for first time since 2015 ozone rules took effect

US environmental regulators are approving Wisconsin's plan to meet stricter air quality standards in three regions around Chicago, Milwaukee, and Sheboygan. The state now has to cut car emissions further and inspect vehicle pollution controls more aggressively to hit the 2015 targets.

Wisconsin had been operating under older ozone standards. This approval locks in measurable emissions cuts for specific years, which means factories and car owners in these regions face real compliance deadlines instead of vague targets. The state now has to prove it can hit these numbers or face federal penalties and lost highway funding.