LAX Leader

A recent study conducted by the University of Southern California (USC) involving 8,500 children nationwide has found a connection between a type of air pollution and decreased learning and memory performance in children aged 9 to 10. The pollutant, ammonium nitrate, is a component of fine particle air pollution (PM2.5) and is linked to risks of Alzheimer's and dementia in adults.

Ammonium nitrate forms when ammonia gas from agricultural activities reacts with nitric acid from fossil fuel combustion in the atmosphere. These findings were published in Environmental Health Perspectives.

Senior author Megan Herting, an associate professor at the Keck School of Medicine of USC, stated: "Our study highlights the need for more detailed research on particulate matter sources and chemical components." She emphasized that understanding these elements is vital for shaping air quality regulations and comprehending long-term neurocognitive impacts.

Herting has been analyzing data from the Adolescent Brain Cognitive Development Study (ABCD), America's largest brain study, to investigate PM2.5's effects on the brain.

PM2.5 consists of particles smaller than 2.5 micrometers, including dust, soot, organic compounds, and metals. These particles can penetrate deep into the lungs and enter the bloodstream, posing serious health risks. Major sources include fossil fuel combustion in urban areas as well as wildfires, agriculture, marine aerosols, and chemical reactions.

In previous research conducted in 2020, Herting's team did not find a link between PM2.5 as a whole and children's cognition. However, using advanced statistical methods to examine 15 chemical components within PM2.5 revealed ammonium nitrate as significantly associated with poorer learning outcomes.

"No matter how we examined it...the most robust finding was that ammonium nitrate particles were linked to poorer learning and memory," Herting noted.

The research team plans future studies to explore how different pollutant mixtures relate to individual differences in brain development during childhood and adolescence.

Alongside Herting are co-authors Rima Habre, Kirthana Sukumaran, Katherine Bottenhorn, Jim Gauderman, Carlos Cardenas-Iniguez, Rob McConnell and Hedyeh Ahmadi from Keck School; Daniel A. Hackman from USC Suzanne Dworak-Peck School; Kiros Berhane from Columbia University Mailman School; Shermaine Abad from UC San Diego; Joel Schwartz from Harvard T.H. Chan School.

This study received funding support from grants provided by the National Institutes of Health [NIEHS R01ES032295, R01ES031074,P30ES007048] along with support from the Environmental Protection Agency [RD 83587201,RD83544101].