February 3, 2023
CHICAGO (February 3, 2023) – Today, U.S. Environmental Protection Agency began a 31-day public comment period on a determination that the Detroit metropolitan area has attained the health-based air quality standard for ground level ozone, or smog. This determination is based on an analysis from the Michigan Department of Environment, Great Lakes and Energy (EGLE) that high ozone values in June 2022 were caused by wildfires. EPA is also taking comment on the state’s analysis.
EGLE’s analysis relies on meteorological data, modeling of air mass trajectories, comparisons to historical data, and measurements of brown carbon and black carbon, or soot. Considered together, the analysis concludes that high smog values measured at an air monitor in Wayne County on June 24 and 25, 2022, were caused by Canadian wildfires. Under EPA rules, wildfire impacts may be excluded when calculating attainment of the smog standard.
The air quality data now show that the Detroit area meets the federal smog standard. Air quality that shows attainment of the standard is one of the requirements for areas to receive formal air quality “attainment” status under the Clean Air Act.
Comments may be submitted at Regulations.gov (search for docket number EPA-R05-OAR-2023-0058) or via email to [email protected] until March 6. For comments submitted at Regulations.gov, follow the online instructions for submitting comments.
Additional information about the proposal can be found on EPA’s website.