The largest long-term study of brain development and child health in the United States found that even air pollution levels considered “safe” by federal regulators are impairing cognitive and emotional development in adolescents.
Published this month in Environment International, the research by the Keck School of Medicine at the University of Southern California and funded by the National Institutes of Health and the U.S. Environmental Protection Agency concluded mounting evidence shows even pollution levels long regarded as safe increase the risk of health problems, including in the brain.
What the research shows
The “ABCD” study used brain data collected from MRI scans from more than 9,000 participants at 21 research sites, including Utah. The University of Utah’s ABCD research team used brain imaging performed at the diagnostic imaging lab at the Huntsman Mental Health Institute in Salt Lake City. Teams collected baseline brain scans and revisited them two years later in a subset of participants to look at potential changes in connectivity for the Adolescent Brain Cognitive Development study.
The study found them after digging down into site-specific air quality data at each child’s residence, looking at levels of PM2.5, or fine particulate matter, nitrogen dioxide and ground level ozone to observe how brain connectivity changed over time.
“Air quality across America, even though ‘safe’ by EPA standards, is contributing to changes in brain networks during this critical time, which may reflect an early biomarker for increased risk for cognitive and emotional problems later in life,” said Megan M. Herting, associate professor of population and public health sciences at the Keck School of Medicine and the study’s senior author.

Why the research is important
Communication between regions of the brain, according to a release on the study, helps us navigate practically every moment of the day — from everything to the way information is processed to feelings. Many of those “connections” develop between the ages of 9 and 12.
“A deviation in any direction from a normal trajectory of brain development — whether brain networks are too connected or not connected enough — could be harmful down the line,” said Devyn L. Cotter, a doctoral candidate in neuroscience at the Keck School of Medicine and first author of the study.
The results do not surprise advocates in the clean energy arena pushing for fewer emissions.
“We’ve known for a while that, just like smoking, even low amounts of air pollution cause severe health and economic impacts, and this study provides another robust piece of evidence. As we deploy more clean energy technologies like EVs and all electric homes our air quality will improve, and so will our health outcomes and our quality of life,” said Logan Mitchell, climate scientist and energy analyst with Utah Clean Energy.
Researchers said the findings of the ABCD study could prompt federal regulators to consider brain health, in addition to lung and cardio health, when it comes to the review and potential adjustment of clean air standards.
“On average, air pollution levels are fairly low in the U.S., but we’re still seeing significant effects on the brain,” Cotter said. “That’s something policymakers should take into account when they’re thinking about whether to tighten the current standards.”
The EPA proposed cutting allowable PM2.5 emissions earlier this year, dropping the standard from an annual average of 12 micrograms per cubic meter to a range of 9 to 10 micrograms per cubic meter. It would be the first revision to the standard since it was set in 2012.
Utah Attorney General Sean Reyes is among 19 state attorney generals who objected to the proposal in a letter to the EPA, arguing the federal agency is not using sound science and is rewriting the Clean Air Act to breach its authority to ultimately wreck economies.

The study continues
Cotter, Herting and their colleagues aim to look more closely at the chemical makeup of pollutants to determine how and why they cause harm in the brain, which could help further refine regulations. They also plan to continue using information from the ABCD study to analyze brain health over time.
Mitchell said studies like these should provide pathways of opportunity for improving public health.
“Utahns have been working on improving our air quality for over a century and today we finally have the clean energy technology available to make dramatic improvements,” he said. “We should leverage conservative leadership to find innovative solutions that are right for Utah that find the nexus of environmental stewardship and sustainable economic prosperity.”