Full Breakdown
Michigan Requests EPA Exemption for Wildfire-Linked Ozone Spikes
12/17/2025, 11:25:15 AM
Overview of the Situation
Michigan regulators are seeking the U.S. Environmental Protection Agency's (EPA) approval to exclude certain high ozone days attributed to wildfire smoke from Canadian wildfires in 2023 and 2025. The Michigan Department of Environment, Great Lakes and Energy (EGLE) has submitted multiple “exceptional event” demonstrations, arguing that these natural events artificially inflated ozone readings at monitoring sites in Berrien and Muskegon counties. If the EPA grants this request, it could lead to a re-designation of these areas as meeting federal ozone standards, alleviating the need for stricter air quality controls.
Context of the Request
In January, the EPA reclassified Berrien and parts of Muskegon and Allegan counties as being in “serious” nonattainment due to their failure to meet ozone improvement deadlines under the Clean Air Act. This classification necessitates a detailed state implementation plan that outlines additional pollution controls. However, EGLE contends that the high ozone levels recorded during specific days in June and July 2023 were primarily due to dense smoke from Canadian wildfires, which coincided with elevated ozone readings. For instance, the Coloma monitor in Berrien County recorded some of its highest ozone levels during these smoke episodes.
Implications of the Request
If the EPA accepts the exceptional event requests, Berrien and Muskegon counties would no longer be subject to the stringent requirements associated with a “serious” nonattainment designation. This would relieve local authorities from implementing costly pollution controls, which EGLE air quality evaluation manager Tom Shanley noted may not significantly impact ozone concentrations in the region. Conversely, Allegan County would remain under stricter regulations, as state officials assert it does not meet the ozone standard even when accounting for wildfire smoke.
Broader Ozone Issues
EGLE's analysis indicates that West Michigan's ozone problems are largely influenced by pollutants from upwind states, particularly from the Chicago metropolitan area and the industrial Midwest. Shanley explained that on hot, sunny days, nitrogen oxides and volatile organic compounds react chemically as air masses move eastward, contributing to ground-level ozone formation. This poses health risks, especially for vulnerable populations such as individuals with lung diseases, children, and older adults.
Official Statements & Responses
EGLE has also submitted a separate request concerning ozone spikes in southeast Michigan, specifically in Wayne County, during periods of heavy wildfire smoke in June 2023. This request aims to protect the region's maintenance plan and prevent wildfire-driven spikes from triggering enforcement thresholds. Public comments on the re-designation requests and exceptional event demonstrations concluded recently, with the EPA expected to make decisions within the next few months.
Conflicting Reports & Gaps
While EGLE argues for the exclusion of wildfire smoke days from ozone calculations, the agency acknowledges that Allegan County does not meet the ozone standard even when considering these impacts. This discrepancy highlights the complexity of air quality management in the region and the challenges posed by external pollution sources.
Verbatim Quotes
“Shanley said imposing additional local controls required under a serious nonattainment classification “can be costly, but it doesn’t necessarily move the needle for ozone concentrations in West Michigan,” he said.” — Tom Shanley, EGLE Air Quality Evaluation Manager
“the data does not support re-designation, even if we were to consider wildfire smoke impacts,” — Tom Shanley, EGLE Air Quality Evaluation Manager
