Public health data hangs in the air

Air quality across the country has greatly improved over the decades, as shown in official reports from the Environmental Protection Agency. These improvements are good news overall, but lingering effects of past air pollution still cause health concerns for many people.

University of Tennessee, Knoxville researchers Alex Bentley and Larisa Ozeryansky co-authored a paper, published in September in Scientific Reports, exploring the robust association between statistics of fine-particulate air pollution (called PM 2.5) in the United States and the prevalence of attention-deficit/hyperactivity disorder (ADHD) in children years later.

“This is the first study to identify a significant association between long-term air pollution exposure and childhood ADHD prevalence across US counties over a generational timescale,” said Bentley, professor in the Department of Anthropology and director of the Center for the Dynamics of Social Complexity. 

Bentley and Ozeryansky both teach public health topics in their respective colleges—Ozeryansky is a teaching assistant professor in the Department of Nutrition and Public Health Sciences of the College of Education, Health, and Human Sciences.

Their study made use of new county-level ADHD-prevalence estimates published in 2023, combined with what is now a detailed record of air pollution and other contextual variables at the county level going back years, offering an unprecedented opportunity to examine the long-term relationship between air pollution exposure and the prevalence of childhood ADHD years later.

“We have annual, county-scale air-pollution data going back to the early 2000s and county-scale ADHD rate data, published in 2023 for the first time,” said Bentley. “Controlling for a range of other factors like income, demography, education, and living in different states, we found a significant association between ADHD diagnoses and PM 2.5 air pollution over the years.”

Their study reveals an impact that is not shown by a single pollution reading taken today: what a community has breathed over the past 10 or 20 years.

“US air is about half as dirty as it was in 2000, yet the counties that were dirtiest over 2005–2015 still have more kids diagnosed with ADHD in recent years,” said Ozeryansky. “Conditions like this seem to carry the weight of years of exposure, not a single snapshot. We have to think about history and be honest about its gaps: what was never measured finely enough, what gets averaged away at the county level, and where the data is thinnest.”

The long-term impact is also not spread evenly across demographics. Communities facing greater socioeconomic disadvantage have consistently breathed more pollution, so the places with the longest exposure histories are often the ones less studied.

“Lower-income communities may experience greater exposure to pollution, while conditions such as ADHD can themselves have long-term consequences for education, employment, income and access to health care,” said Bentley. “These factors can potentially reinforce one another over time.”

These findings could add vitally beneficial statistics for ongoing community health studies. Current cleaner-air policies are justified mainly by lower rates in deaths stemming from heart and lung diseases. Taking children’s brain development into consideration would strengthen the case for stricter limits.

“Air quality should be judged on the cumulative exposure of what people have breathed over the years, not just today’s annual National Ambient Air Quality Standards (NAAQS),” said Ozeryansky. “Children’s health in historically polluted places deserves continued tracking.”

Bentley and Ozeryansky’s combined efforts speak to UT’s ongoing focus on health improvements for all Tennesseans.

“The findings have important policy implications and suggest a direct means of reducing future ADHD in Tennessee,” said Bentley. “It also demonstrates what can now be done through the college’s interdisciplinary computational social sciences program.”