USC study finds connection from pollution to decreased memory in kids

A recent study by the University of Southern California revealed that exposure to air pollution can harm children's learning and memory. 

Ammonium nitrate, a specific component of fine particle air pollution primarily produced by agricultural emissions, is associated with decreased learning and memory performance in children aged 9 and 10. The comprehensive research analyzed data from 8,500 children nationwide, suggesting potential long-term implications for cognitive development.

The study, published in Environmental Health Perspectives, examined the effects of PM2.5, a mixture of microscopic particles measuring less than 2.5 micrometers in diameter. These particles can penetrate deep into the lungs and enter the bloodstream, potentially crossing the blood-brain barrier.

"Our study highlights the need for more detailed research on particulate matter sources and chemical components," said Megan Herting, associate professor of population and public health sciences at USC's Keck School of Medicine and senior author of the study. "It suggests that understanding these nuances is crucial for informing air quality regulations and understanding long-term neurocognitive effects."

The research team utilized data from the Adolescent Brain Cognitive Development Study, the largest brain study conducted across America. Unlike their 2020 research that found no significant relationship between overall PM2.5 and childhood cognition, this new analysis focused on 15 specific chemical components within PM2.5.

Ammonium nitrate, formed when ammonia gas from agricultural activities combines with nitric acid from fossil fuel combustion in the atmosphere, emerged as the primary concern. The same pollutant has been previously linked to increased risk of Alzheimer's disease and dementia in adults, indicating potential neurocognitive impacts throughout different life stages.

The researchers employed advanced statistical methods to isolate the effects of various PM2.5 components. "No matter how we examined it, on its own or with other pollutants, the most robust finding was that ammonium nitrate particles were linked to poorer learning and memory," Herting noted.

While fossil fuel combustion remains a major source of PM2.5 in urban areas, the study emphasizes the significant role of agricultural emissions in air quality concerns. Other contributing factors include wildfires, marine aerosols, and various chemical reactions in the atmosphere.

The research team plans to now investigate how these pollution mixtures correlate with individual differences in brain development during childhood and adolescence. 

The study involved collaboration among researchers from USC's Keck School of Medicine, the USC Suzanne Dworak-Peck School of Social Work, Columbia University Mailman School of Public Health, University of California, San Diego, and the Harvard T.H. Chan School of Public Health.