In 2024, over 50 million Americans resided in counties where there was no air-quality monitoring, a new study released in the Proceedings of the National Academy of Sciences reports. Researchers at Penn State University caution that the gap leaves millions without the benefit of real-time data about whether or not the air they breathe is safe.
Rural Communities Most Affected
The study reveals that 58% of U.S. counties, 1,848 in total, lack an active air-quality monitoring site. The absence is particularly prominent in rural areas, especially in the Midwest and South.
“Air pollution affects everyone’s health, so it is important for everyone in the nation to have access to accurate information about the quality of the air they breathe,” said Nelson Roque, lead author and assistant professor at Penn State.
Why Monitoring Matters
Air-quality monitoring is an essential part of public health. Air-pollution exposure has been attributed to many severe conditions, such as cancer, heart disease, respiratory disease, and immune dysfunction.
“If we are not measuring air quality in large regions of the country, then we do not know how significant air pollution problems are,” said Alexis Santos, co-author and associate professor of demography and human development. “If there’s a wildfire in a county without a monitoring site, how will people know if it’s even safe to stay in their homes?”
Demographics Behind the Data
Using data from the EPA and the American Community Survey, the researchers found that counties without monitoring sites tend to have:
- Higher poverty rates
- Lower high school completion rates
- Larger Black and Hispanic populations
These findings underscore concerns about environmental justice, where vulnerable communities are disproportionately left in the dark about health risks.
Infrastructure in Need of Modernization
The study also found that the country had 4,821 active monitoring stations at the time of analysis. But these stations are often outdated and frequently go offline.
“Stations are in flux all the time,” Roque said. “Some have been operating since the 1950s, and others disappear due to funding or maintenance issues.”
Between 1957 and September 2024, a total of 20,815 stations have been active at some point, but many no longer function.
Time for Federal Investment?
The researchers argue that the lack of consistent air monitoring is a public health failure, and a fixable one. They’re calling for national investment to modernize and expand the country’s air-quality tracking system.
“As a society, we need to invest in air-quality monitoring if we want to keep people safe and save on the long-term costs of pollution exposure,” Santos added.
The research team includes Hailey Andrews, a human research technologist at Penn State’s Center for Healthy Aging.
