How Clean Air Action Days are Forecasted

The Michigan Department of Environmental Quality (MDEQ) coordinates with the states of Illinois, Indiana, and Wisconsin to prepare Clean Air Action Day forecasts. Throughout the year, meteorologists from each state work together through a conference call to develop a regional air quality forecast. In order to have a Clean Air Action Day called in Michigan, the forecast must predict ozone levels above 70 ppb over an eight-hour period or fine particle levels above 35 ug/m3 over a 24-hour period.

Forecasting Schedule

  • 8:00-11:30 a.m. EDT: Meteorologists from each state individually prepare both a detailed forecast for the next day and a general extended forecast.
  • 11:30 a.m. EDT: The meteorologists and the Lake Air Directors Consortium (LADCo) convene a conference call and discuss the forecasts. A consensus is then reached regarding the outlook for elevated pollution levels for the next day. If weather conditions are not conducive for the formation of elevated pollution levels for the extended forecasts, the participants then determine when the next conference call will take place.
  • By 1:00 p.m. EDT: The MDEQ meteorologists write a brief meteorological summary stating whether or not elevated pollution levels are expected and whether or not the following day has been designated as a Clean Air Action Day. The meteorological summary is then e-mailed to a primary contact person at the Grand Valley Metro Council, the West Michigan Shoreline Regional Development Commission, and the Macatawa Area Coordinating Council. These organizations coordinate the Clean Air Action programs for Kent, Muskegon, Ottawa, and Kalamazoo counties.