We tend to think of air pollution as harmful to our lungs, but recent research suggests it also could be damaging our brains.
That’s what University of Pennsylvania researchers concluded after inspecting more than 600 autopsied brains of older people for signs of neurological damage and comparing their findings to air-quality measurements — especially the presence of fine particulate matter called PM2.5 — in the neighborhoods where they lived. Their findings were published last fall in JAMA Neurology.
PM2.5 is among the smallest particulates emitted by power plants, factories, motor vehicles, and wildfires. When inhaled, these molecules can travel from the nose to the brain.
Researchers determined that the brains of those who lived in areas with high levels of PM2.5 were about 20 percent more likely than the brains of those residing in less-polluted neighborhoods to exhibit the tau tangles and amyloid plaques that are characteristic of severe Alzheimer’s disease.
“The quality of the air you live in affects your cognition,” lead study author Edward Lee, MD, PhD, tells The New York Times.
Lee, a neuropathologist who leads the Penn Medicine Brain Bank, notes that the study confirms earlier research relying primarily on epidemiological evidence.
“We’re linking what we actually see in the brain with exposure to pollutants,” he explains. “We’re able to do a deeper dive.”
These findings suggest that recent governmental efforts to curtail clean-energy projects and loosen air-quality regulations in favor of boosting fossil-fuel production may be shortsighted. “People argue that air quality is expensive,” Lee notes. “So is dementia care.”
This article originally appeared in the May/June 2026 issue of Experience Life as “The Cognitive Dangers of Dirty Air.”
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