Michigan air quality today

The highest ozone readings in Michigan usually come from monitors within a few miles of Lake Michigan rather than from the interior. Precursor emissions from the urban corridor at the lake’s southern end drift out over water that stays colder than the land, sit in a shallow stable layer, react through the morning, and then the afternoon lake breeze carries the product back onshore in a narrow band. The gradient is steep: a concentration that trips an alert at the shoreline can fall off sharply a short distance inland. Multi-agency field work, including the 2017 Lake Michigan Ozone Study, was organized around that pattern specifically. Berrien County and parts of Allegan and Muskegon counties hold ozone nonattainment designations on that basis, all three reclassified to Serious in January 2025, so the worst ozone afternoon of a Michigan summer can be measured well away from the state’s industrial core. EPA proposed returning Berrien and Muskegon to attainment in July 2026.

Detroit runs on different pollutants. The Detroit sulfur dioxide nonattainment area was drawn around the coke, steel and power generation along the lower Rouge and Detroit rivers; after reductions at those plants, EPA’s redesignation of the area to attainment took effect on April 2, 2026. The same corridor, plus the truck traffic feeding the international crossings, keeps diesel and industrial particulate in the same neighborhoods year-round.

The Air Quality Division of the Michigan Department of Environment, Great Lakes, and Energy forecasts daily and issues air quality advisories. Smoke arriving from Canadian fires is a third pattern that answers to neither the lake nor the river.