Wildfires are reversing America’s progress on ozone pollution

Decades of efforts in the United States to reduce surface ozone pollution, primarily caused by cleaner vehicles, industries, and power sources, have been reversed by increasing wildfire emissions.
Analysis shows that from 2003 to 2024, the gases emitted from wildfires have caused surface ozone levels to turn from declining to increasing after 2015.
Since the mid-2010s, the number of premature deaths due to surface ozone pollution has been rising by about 300 deaths per year.
Ground-level ozone, particularly harmful near the Earth’s surface, can irritate lungs and worsen respiratory diseases, leading to public-health concerns.
Severe wildfires in North America, especially in the western U.S. and Midwest, have transported smoke and gases far from the fire sites, affecting people in areas like the Midwest, Georgia, and New York.
Recent severe wildfire seasons, including record-breaking incidents in Canada in 2023 and 2025, suggest that increased surface ozone levels due to wildfires could rise further with longer and more intense fire seasons.
To mitigate the health impacts of ground-level ozone caused by wildfires, public health efforts should focus on reducing exposure, improving wildfire management, and addressing global warming through reduced fossil fuel usage.
Continuous monitoring and forecasting, along with maintaining air pollution measurement networks, are crucial to identifying and combating ozone pollution.