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EGLE statement on Southeast Michigan meeting ozone standards

The U.S. Environmental Protection Agency (EPA) has confirmed that southeast Michigan has met all federal standards for the national health-based standard for ozone. Ground-level ozone, one of the most monitored pollutants in Michigan, has shown steady improvements in the greater Detroit area since the 1990s, culminating in the region now being designated as “in attainment” with the EPA’s national ambient air quality standards.

This determination was made following a request from the Michigan Department of Environment, Great Lakes, and Energy (EGLE) in 2022 asking for confirmation that the region is meeting the ozone standard. In the request, EGLE provided the necessary long-term data showing the region was meeting all federal requirements. The EPA informed EGLE that their determination will go into effect later this month when the EPA publishes its findings in the Federal Register.

The attainment designation reflects cleaner air for the entire region and is the most recent chapter in a success story spanning decades. High amounts of ground-level ozone can cause coughing, shortness of breath, worsen asthma or bronchitis symptoms, and irritate or damage airways. The federal standards for ozone are health-based standards designed to be protective of sensitive populations which have been lowered by the EPA several times in recent decades to be even more protective. Factors driving ozone levels down include more protective vehicle emissions standards, better pollution control technology in industrial and commercial facilities, and the closure of coal plants among others.

“Ozone attainment is a significant achievement,” said Aaron Keatley, acting EGLE director. “It is a testament to the strides we have made in improving air quality in Michigan’s largest and most industrialized region.”

Meeting the national ozone standard does not mean that the work to reduce ozone in the area stops. When an area is designated back to attainment, federal law requires states to establish a maintenance plan that shows how it will continue to meet the standard. EGLE’s redesignation request (Section 4) includes Michigan’s maintenance plan detailing how air quality will be maintained considering projected growth for a period of 20 years. If future monitoring shows that ozone levels are no longer meeting the criteria, the maintenance plan helps determine the ways the problem will be addressed.

While the region is meeting the federal ozone standards, effects from other air pollutants continue to be a concern in some neighborhoods, particularly those in heavily industrialized areas, which are often in low-income communities of color.

“Our work is not done,” said Keatley.  “EGLE is keenly aware and is working diligently to address neighborhoods where proximity to industry and transportation corridors continues to have disproportionate impact. EGLE is committed to expanding our ozone success in similar ways to further reduce sulfur dioxide emissions, particulate emissions, and air toxics.”

EGLE’s ongoing air quality work in Southeast Michigan includes:

  • Continuing to monitor for ozone. EGLE currently has 26 monitoring stations for ozone in the state with eight in southeast Michigan. Monitoring data is available to the public on EGLE’s Air Monitoring webpage
  • Making improvements to the air monitoring network. The draft network review is currently out for comment and includes proposals for a new site around Northeast Detroit near GM Hamtramck and US Ecology-North to measure fine particulate matter (PM10 and PM5) and black carbon. It is anticipated to be functional in the fall of 2023 or spring of 2024. A new site is also being proposed with a continuous fine particulate (PM2.5) sampler in an enclosure at a location in Marquette, and new continuous fine particulate matter (PM2.5) samplers for the Oak Park, E. 7 Mile, Little River Band of Ottawa Indians tribal site in Manistee. 
  • Continuing to collaborate with the city of Detroit in an advisory role and remaining available to provide guidance upon request for the successful deployment and operation of their citywide particulate monitoring program. 
  • Working to develop a strategy for deployment of air sensors in different areas around the state and in collaborative projects with local partner organizations and communities. Some are already available through EGLE’s environmental lending station
  • Conducting inspection and enforcement initiatives focused on environmental justice communities, like the ones done in partnership with the EPA in North Detroit and Flint over the last year. 
  • Partnering with community and advocacy groups, as well as state and federal agencies on education around air quality concerns and health.

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