The U.S. Environmental Protection Agency determined Tuesday that southeast Michigan has successfully met all federal standards for ground-level ozone.
The region has been a designated “non-attainment” area for ozone under the federal Clean Air Act since 2018.
The decision follows a Michigan Department of Great Lakes, Energy, and Environment request that the EPA discount certain air quality data measured on June 24 and 25, 2022, at a monitor on East 7 Mile in Detroit.
EGLE said the higher ozone levels measured at the site were due to western wildfire smoke and should not be considered in evaluating the region’s air quality. EPA rules allow for the exclusion of air quality samples influenced by “exceptional events” that reflect non-local causes not under the reasonable control of local and tribal governments.
By discounting data measured at that location on those days, the region’s overall air quality data measurements across a network of six monitors fell below the National Ambient Air Quality Standards for ozone, paving the way for EPA to grant EGLE’s request.
“Ozone attainment is a significant achievement,” Aaron Keatley, acting EGLE director, said in a statement. “It is a testament to our strides in improving air quality in Michigan’s largest and most industrialized region.”
Ground-level ozone levels have declined nationwide since the 1980s due to improved vehicle emission technology and industrial pollution restrictions under the Clean Air Act. Southeast Michigan’s ozone levels have followed that trend.
But areas near polluting sources and roadways may still face unhealthy ozone levels.
Nick Leonard, who directs the nonprofit advocacy group Great Lakes Environmental Law Center, called the decision “severely disappointing,” saying it prioritizes polluters over some of Detroit’s most vulnerable residents.
“EPA and EGLE have been determined to ignore high levels of ozone pollution on the east side of Detroit to avoid taking regulatory action to require the auto plants to limit pollution,” he told Planet Detroit.
A memo filed by Leonard suggests that the EGLE chose the data it wanted removed to make the region come below the federal air quality standard for ground-level ozone while declining to evaluate potential local emissions sources that could account for the elevated ozone on the days in question.
The decision does not mean state’s work to combat ozone is done, according to EGLE’s statement.
Federal law mandates that states establish maintenance plans to sustain compliance with air quality standards once they come out of a nonattainment designation. EGLE’s redesignation request includes a maintenance plan outlining how it will maintain air quality for the next 20 years, considering any projected growth. The plan will guide actions to address the issue if future monitoring reveals a deviation from ozone criteria.
“Our work is not done,” Keatley said. “EGLE is keenly aware and is working diligently to address neighborhoods where proximity to industry and transportation corridors continues to have a disproportionate impact.”
In its statement, EGLE said the agency will continue to monitor for ozone, partner with and advise community groups on education and monitoring, and conduct inspections and enforcement initiatives focused on environmental justice communities. It also proposes adding an additional air monitor in Hamtramck near the US Ecology site to measure particulate matter and black carbon.
If the region had not been removed from nonattainment status, EPA would have required more stringent polluter restrictions. The region would also have been required to implement vehicle emissions testing.
Using its health-based standards, the American Lung Association gave Wayne County a failing grade for ozone and particulate pollution. Ground-level ozone is a known asthma trigger; the asthma mortality rate in Detroit in 2017-2019 was about three times the rate for Michigan.
“In reality, ozone pollution on the east side of Detroit is above the health-based air quality standard, and the asthma hospitalization rates in that community have worsened in recent years,” Leonard said.
“There is no way to characterize this other than a gross environmental injustice.”