Ozone is the pollutant that makes a summer afternoon hard to breathe in - the one that keeps children with asthma indoors. Metro Detroit has been formally out of compliance with the federal standard for it.
EPA Region 5 filed a proposal today to change that designation to attainment [1].
The area is seven counties: Livingston, Macomb, Monroe, Oakland, St. Clair, Washtenaw and Wayne. More than 5.3 million people live in them [1].
The measurement that matters is the three-year design value, which is deliberately hard to game - it smooths out a single good summer. Detroit came in at 0.070 parts per million for 2022 through 2024, and again at 0.070 for 2023 through 2025 [1]. At the standard, two consecutive three-year windows.
Region 5 Administrator Anne Vogel signed the proposal. A companion filing would redesignate the Berrien and Muskegon areas the same way [1].
It is a proposal, not a final rule - comments run 30 days from publication. The air quality it describes, though, has already happened. The counting is just catching up.
