ST. LOUIS – As daily air quality forecasting makes its return for the 2025 season, the American Lung Association’s latest “State of the Air” report finds that even after decades of successful efforts to reduce sources of air pollution, 46% of Americans – 156.1 million individuals – are living in places that received failing grades for unhealthy levels of ozone or particle pollution. This is nearly 25 million more people breathing unhealthy air compared to the years covered in last year’s report (2020-2022), and more than in any other “State of the Air” report in the last 10 years. The data reinforces the need to protect our local communities from the continued risks to public health resulting from a combination of factors, including extreme heat, drought, wildfire smoke and more.
Looking back at the “State of the Air” data from almost 30 years ago, when the average number of high ozone days in the St. Louis region approached 50 in the summers of 1996-1998, the drop to just 10.5 high ozone days in the most recent report is a sign of progress. But that progress is tainted by the fact that, for the first time in nine years, the St. Louis region ranked among the top 25 most ozone-polluted U.S. cities, coming in at number 21 on the list for high ozone days out of 228 metropolitan areas. The region also ranked 17th on the list for most polluted cities by annual particle pollution, which is up 13 spots from the previous year. Additionally, St. Louis was reported among the top two cities with the largest change in rank, worsening from 30th to 21st for the topmost ozone-polluted U.S. cities, falling second only to Tulsa, Okla., which moved from 31st on the list to 19th worst overall.
The most up-to-date report findings have added to the extensive evidence that a changing climate is making it harder to protect this hard-fought progress on air quality and human health. Increases in high ozone days and spikes in particle pollution related to extreme heat, drought and wildfires are putting millions of people at risk and adding challenges to the work that states and cities are doing across the nation to clean up air pollution. And after several years of reporting that the worst of the nation’s air quality problems were increasingly concentrated in western states, “State of the Air” 2025 finds the geographic distribution of air pollution shifting back East.
Here’s a look at the latest rankings for ozone pollution across the region for counties in the non-attainment area included in the American Lung Association’s report:
Missouri
Jefferson – F
St. Charles – F
St. Louis County – F
St. Louis City – F
Illinois
Jersey – F
Macoupin – F
Madison – F
St. Clair – F
“For 30 years, the St. Louis Regional Clean Air Partnership has been encouraging voluntary steps to reduce emissions in order to protect lung health, but the latest air quality data makes it clear our region remains a long way from achieving truly healthy air,” said Susannah Fuchs, Director of Healthy Air Solutions for the American Lung Association in Missouri. “As we approach summer when poor air quality becomes more frequent, we urge residents and businesses to renew their commitment to the individual and collective efforts that are essential to improving air quality and protecting public health, especially for children, older adults and those with respiratory conditions who are most at risk. Continued vigilance and community participation are key to ensuring cleaner air and healthier outcomes for everyone in the region.”
According to the 2025 “State of the Air” report, exposure to unhealthy levels of ozone air pollution continues to make breathing difficult for more people living in the U.S. than any other single pollutant. For the three years covered in this year’s report (2021-2023), 37% of the population – some 125.2 million people – were exposed to levels of ozone that put their health at risk. This is an increase of 24.6 million people over last year’s figure, and includes tens of millions of infants and children, people aged 65 or older and others whose conditions make them especially vulnerable to health harm from air pollution. Nationwide, nearly five times as many counties’ ozone levels worsened as improved. Nine states saw the number of unhealthy days for ozone get worse in every one of their counties monitored for this pollutant, including all 23 monitored counties in Illinois and all 17 in Missouri. This encompasses the combined eight counties on both sides of the Mississippi River that fall into the designated non-attainment area in the bi-state region.
Despite the widespread worsening in parts of the country, the list of the worst 25 cities for ozone pollution in “State of the Air” report and their order of ranking remains relatively stable compared with last year’s report. In one other small piece of good news, none of the cities on the list reported a worst-ever average number of days of ozone smog, which is created in part from sources like vehicle exhaust.
“Since transportation remains one of the biggest contributors to air pollution and smog, the ways we choose to travel are some of the simplest and most effective actions to reduce harmful emissions,” Fuchs added. “Small shifts – such as taking public transit, carpooling, combining trips, telecommuting, or walking and biking – can add up to a big difference when it comes to air quality. Beyond commuting, adopting energy-saving habits, reducing waste, and reusing materials are other meaningful steps individuals and businesses can take to protect lung health and the environment.”
As it marks its 30th year, the Clean Air Partnership is renewing its commitment to increasing awareness of regional air quality issues and encouraging activities to reduce air pollution emissions. Area residents can visit CleanAir-StLouis.com to sign up to receive color-coded, daily air quality forecasts via their email inboxes or text through the Environmental Protection Agency’s EnviroFlash air quality alert system to stay informed about ozone pollution levels in the region and how those levels can affect their health. This is especially crucial on orange or red unhealthy air quality days when individuals should plan to alter their outdoor activities to minimize exposure to polluted air. While on the site, people can also access a wealth of air quality information and tips to do their share for cleaner air all summer long.
Additional air quality information and the daily forecast can be accessed by liking the Clean Air Partnership on Facebook, or by following the organization on X (formerly Twitter) @gatewaycleanair. To access the full American Lung Association 2025 “State of the Air” report, visit Lung.org.
