On Oct. 31, 2024, a University of Southern California (USC) study involving 8,500 children from across the country has revealed that a form of air pollution, largely the product of agricultural emissions, is linked to poor learning and memory performance in 9- and 10-year-olds.

The specific component of fine particle air pollution (PM2.5), ammonium nitrate, is also implicated in Alzheimer’s and dementia risk in adults, suggesting that PM2.5 may cause neurocognitive harm across the lifespan. Ammonium nitrate forms when ammonia gas and nitric acid, produced by agricultural activities and fossil fuel combustion, respectively, react in the atmosphere.

PM2.5, a key indicator of air quality, is a mixture of dust, soot, organic compounds and metals that come in a range of particle sizes less than 2.5 micrometers in diameter. PM2.5 can travel deep into the lungs, where these particles can pass into the bloodstream, and bypass the blood-brain barrier, causing serious health problems. The findings appeared in Environmental Health Perspectives.