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Wildfire smoke and pollution: A primer on Michigan’s attainment status and efforts to protect residents

Courtesy of Canadian wildfire smoke, it’s been a busy summer for Air Quality Action Days in Michigan. The result of the smoke periodically blanketing Michigan and many other states has been an unprecedented number of action days called for both fine particulate and ozone. This year, high levels of particulate in the smoke caused Michigan to issue the first-ever statewide alert, and the first one for the Upper Peninsula.

EGLE air monitor in Allen Park, Michigan.

EGLE air monitor in Allen Park, Mich.


Wildfire smoke elevates the amount of fine particulate in the air. It also can mix with sunlight, creating ground level ozone. Two areas in Michigan have a history of unhealthy air caused by ozone pollution – west Michigan and southeast Michigan.

Impacts from this year’s wildfire smoke come on the heels of a success story for southeast Michigan. This spring, the US Environmental Protection Agency (EPA) determined that the region is in attainment with the national air quality standards for ozone following several decades of air quality improvements. More protective standards, cleaner emissions, reduction technologies, and the retirement of polluting coal burning power plants helped the area reach attainment.  This allowed southeast Michigan to avoid federal requirements like mandatory vehicle emissions testing that could have been implemented if the area remained in a non-attainment status.

The unprecedented wildfire related pollution has people wanting to know how it might affect southeast Michigan’s status, and what the state is doing to protect residents. The following helps explain the complex process of determining ozone attainment and Michigan’s role in protecting residents from excessive ozone pollution.

What happened this spring?

EPA confirmed that the 7-county southeast Michigan region met all federal air quality standards for ozone pollution. The agency redesignated the region from “out of attainment” with federal ground-level ozone standards to “in attainment”.

As part of the decision-making process, EPA agreed that Michigan should discount two days of 2022 data from one air monitor due to influence by Canadian wildfire smoke. As a result of the smoke, the one monitor slightly exceeded ozone standards. The data was excluded under a process spelled out in federal regulations called an “Exceptional Events Demonstration” – in which EPA agreed that pollutants from the smoke both caused the high ozone readings and was not an event that could be controlled by regulators.

And what’s happening this summer?

This summer southeast Michigan and the rest of the state has seen unprecedented levels of Canadian wildfire smoke drifting across Michigan and much of the rest of the country. In addition to pollutants like fine particulate matter carried in the smoke, there are gasses containing the chemicals that – when combined with sunlight – form ground-level ozone. These chemical reactions contribute to the ozone levels we have seen in both west and southeast Michigan numerous times this summer.

Will the State of Michigan ask the EPA to exclude additional data due to the wildfire events this year?

That remains to be seen. Certain data will be flagged for potential additional evaluation based on the wildfire smoke. Air monitoring data is submitted quarterly to EPA. Once all data from this year’s ozone season has been collected, validated, and submitted, Michigan will analyze the results. To pursue an exception for any data, the action must have regulatory significance – that is, the exclusion of the data must be likely to change regulatory determinations. A decision on whether to pursue an Exceptional Events Demonstration will be decided later this year following analysis of all the data collected during the ozone season.

Will EPA change any rules or guidance because of the 2023 wildfire season’s effect on air quality in Michigan and many other states?

EGLE will be watching closely to see if any regulatory changes on the federal level impact Michigan.

Will “contingency” measures take effect in southeast Michigan if Michigan’s 2023 data shows ozone exceedances?

A portion of EPA’s approval of the southeast Michigan redesignation included the acceptance of contingency measures that would go into effect if air quality declined over time.  Whether contingency measures in southeast Michigan are warranted and appropriate in the future will be determined following the 2023 ozone season and after the data has been reviewed and validated.  Any other regulatory considerations must also be evaluated. Michigan has 18 months following the close of the ozone season to implement any necessary contingency measures.

Could the wildfire pollution contributing to increased ozone levels put southeast Michigan back out of attainment?

The region’s previous “out of attainment” designation was based on the EPA’s 2015 ozone standard. Michigan will not formally be designated as out of attainment for that standard (although contingency measures could be required). When EPA issues an updated standard the data will again be evaluated to determine compliance.

What about the rest of Michigan? 

The wildfire smoke this summer impacted the entire state, affecting fine particulate and ozone concentrations.  Many areas of the state that don’t typically see higher pollution levels did this summer due to the wildfires.  Michigan’s Upper Peninsula experienced several days with high fine particulate concentrations.

In west Michigan there are areas, particularly along the lakeshore, that historically have high ozone concentrations primarily because of pollution transported from other states to the south and west.  This summer, west Michigan has again seen high ozone concentrations which have been further exacerbated due to the wildfire smoke. 

Just like in southeast Michigan, all collected data will be quality assured and validated. The validated data will then be evaluated for any regulatory significance and exceptional event demonstrations will be considered if appropriate. 

What is Michigan doing about the Canadian wildfire pollution?

There is nothing the state can do to reduce the pollutants from the fires drifting over from Canada. However, state agencies, including EGLE, Health and Human Services, Natural Resources and Agriculture and Rural Development are working together to give Michiganders the latest information on how to be informed and protect yourself and your loved ones when air quality may be harmful.

How can the public find out more and get notifications?

Many online resources exist to help Michigan residents.