Missouri’s air quality worsened from 2021 to 2023, with wildfires, warmer temperatures and dangerous air pollutants fouling the air Missourians breathe.
The American Lung Association’s 2025 State of the Air report found that the St. Louis and Kansas City areas both had poorer outcomes for some measures of air quality compared to previous years.
St. Louis was ranked 21st worst city across the country for its ozone levels this year, after being ranked 30th last year. Kansas City was ranked 34th worst for its ozone levels, compared to 48th for 2024’s report.
In Missouri, 19 of the state’s 114 counties have official air quality monitors that feed data back to the Environmental Protection Agency for monitoring.
In all 19 monitored counties, ozone levels worsened in the years spanning the report, said Laura Turner, the director of advocacy at the Missouri chapter of the American Lung Association.
“That was something that really stood out to me,” Turner said. “We know asthma can really be influenced by air quality, and ozone is particularly problematic for people with asthma, especially kids with asthma.”
Air quality monitoring infrastructure is mostly concentrated near Missouri’s urban areas, such as counties surrounding Kansas City, St. Louis, Columbia and Springfield. But some monitors are scattered across rural counties as well.
In urban areas, things like high vehicle traffic and concentrations of industrial output can worsen air quality and be associated with higher rates of lung diseases and other chronic conditions. In more rural parts of the state, manufacturing, mining and agriculture all contribute to poorer air quality.
Plus, high-pollutant industries tend to be concentrated in lower-income areas, where residents are predisposed to other forms of chronic health conditions, said Caitlin Stiltner, a staff attorney at Great Rivers Environmental Law Center in St. Louis, which works for free to represent clients in environmental cases.
“When issuing air permits under the Clean Air Act to some of these industries, they’re disproportionately located near low-income and communities of color,” Stiltner said. “You’re seeing higher levels of asthma and lung cancers in those areas.”
The report found that people of color make up 41.2% of the overall population nationwide, but account for 50.2% of the people living in counties with at least one failing metric in the report.
From 2021 to 2023, 125.2 million Americans were exposed to potentially unsafe ozone levels, an increase of 24.6 million people from last year’s report. Unsafe ozone has been linked with worsening symptoms for those with asthma and COPD and higher risk of respiratory infections.
“One thing that does contribute to ozone across the board is increased temperatures,” Turner said. “When you have higher temperatures, you’re going to see more ozone formation. …That’s just a pretty direct correlation.”
There were improvements in year-round particle pollution, which come from things like factories, power plants and diesel and gasoline vehicles that generate things like nitrogen or sulfur oxides. Increases in long-term particle pollution have been linked with higher likelihood of childhood asthma and lung cancer.
The report found that 85 million people were exposed to year-round levels of particle pollution that don’t meet air quality standards, compared to 90.7 million for 2024’s report.
How urban areas bear the brunt of monitored air pollution
Areas concentrated around Kansas City and St. Louis had the poorest grades in the lung association’s 2025 report.
In the Kansas City area, Clay and Clinton counties received an F for high ozone days, while Cass County received a C. Jackson County did not collect data covered in the report. St. Louis city and St. Louis, St. Genevieve, St. Charles, Lincoln and Jefferson counties all received an F for higher ozone days.
People living in poverty are more likely to live close to sources of pollution and have fewer resources to relocate out of a potentially unhealthy area.
Out of Jackson County’s nearly 720,000 residents, for example, nearly 85,000 live in poverty and are considered an at-risk group, the report found. More than 13,000 kids are statistically at risk because of pediatric asthma rates, and another more than 55,000 asthmatic adults are at risk. Another 44,500 are statistically more at risk due to COPD.
Stiltner pointed to a mapping tool that can track facilities with air permits under the Clean Air Act and compare them with rates of asthma, cancer and other diseases.
“We can see the permitted facilities and then overlay it with rates of asthma, rates of lung cancer and other types of cancer, cardiovascular disease, everything,” Stiltner said. “And there’s higher rates near these facilities. These communities are experiencing a cumulative impact from every facility that’s feeding air permits in these areas.”
Both Great Rivers and the American Lung Association are advocating to increase the number of air quality monitors placed throughout the state. But they aren’t holding out hope, given cuts to the Environmental Protection Agency at the federal level.
“There’s simply not enough air monitors for us to do enforcement on some of these facilities,” Stiltner said. “If they’re not complying with their air permits, proving that the facility is a source of (pollutants) is difficult when there are only a few air monitors near the city.”
Other organizations, including community groups and researchers, run their own air quality monitoring programs, but those reports are not considered official data sources when it comes to enforcement of the Clean Air Act.
Rural Missouri’s lack of air quality monitors and what it means for health
Andrew, Buchanan, Callaway, Cedar, Jasper, Monroe and Perry counties are the rural parts of the state that have EPA-certified air quality monitors.
All of the counties — besides Buchanan, which does not collect the data — received C or F scores for the number of high ozone days in the report. Many do not collect back high particle pollution figures, the report found.
In rural areas, industries like manufacturing, mining and agriculture all contribute to poorer air quality.
“There are so many gaps between these monitors and the rural communities where there is no monitor there yet,” said Bruce Morrison, who serves as general counsel at Great Rivers. “Whether it’s a factory, a new quarry or some kind of operation that generates air pollutants, it’s something that is not even being monitored. Those health effects are going to be real for the people that live there.”
A lack of monitoring does not equate to a lack of pollution, the lung association said in its report. The group urges Missouri to invest in research programs to gather data, use other forms of technology to track pollutants and to use data for public health protection.
Emissions from many industries are unavoidable, said Frank Mitloehner, a professor and air quality specialist at the University of California-Davis department of animal science. He studies pollutants that come from large-scale animal farming operations, such as dairy and poultry farms.
Ammonia is one agricultural output that can contribute to higher levels of PM 2.5, a pollutant that is measured when assessing air quality. If concentrations are too high, it can be dangerous for neighboring communities and those who work on farms.
“What I can assure you is nobody is sitting back and not worrying about these things,” Mitloehner said. “Farmers do not want to have issues with neighboring communities.”
Mitloehner said that while farmers are working to reduce their emissions, it’s difficult to do so without larger profit margins.
“Some have a low profit margin, and they will do things if they are forced to, but it has no production advantage to them,” he said. “If nobody pays for it, then the question is, ‘Who foots the bill?’ You can only be green if you’re in the green.”
And as the Trump administration rolls back regulation, environmental standards are caught in the fray.
The EPA has been operating under a provision called the endangerment finding, which concludes that climate change threatens public health. The measure has led to new standards on how much pollution is released into the air.
Under the Trump administration, the federal agency is exploring ways to roll back at least 31 air, water and emissions regulations related to the endangerment finding, and experts say the rollbacks could harm public health.
Now, if states want to uphold the standards that may be stripped away, the responsibility will fall on their shoulders. The lawyers at Great Rivers don’t expect Missouri to step in to enforce defunct regulations.
Earlier this month, utility company Ameren asked the Trump administration for exemptions for two coal plants in the St. Louis region, giving the company two additional years to limit emissions and unsafe air pollutants.
“Without the EPA making those rules,” Morrison said, “then there’s nothing really holding states and industries from having stronger controls on pollution.”
This story was originally published by The Beacon, a fellow member of the KC Media Collective.
