Air pollution has already been linked to respiratory and cardiac problems, and researchers form the University of Southern California recently identified a new risk: poor learning and memory in children.
Their new study, published this week in the Environmental Health Perspectives journal, included 8,500 children from across the country. It found that air pollution, mostly the product of agricultural emissions, was associated with learning and memory outcomes in 9-year-olds and 10-year-olds.
“Our study highlights the need for more detailed research on particulate matter sources and chemical components,” said senior author Megan Herting, associate professor of population and public health sciences at the Keck School of Medicine of USC. “It suggests that understanding these nuances is crucial for informing air quality regulations and understanding long-term neurocognitive effects.”
Previous research found that overall fine particle air pollution, known as PM2.5, was implicated in an increased risk of Alzheimer’s disease and dementia in adults. However, Herting and her team published a paper in 2020 that did not find a relationship between PM2.5 as a whole and its potential impact on cognition in children.
They have been researching the impact of PM2.5 on the brain for years through the Adolescent Brain Cognitive Development Study, or ABCD.
PM2.5 is comprised of dust, soot, organic compounds and metals under 2.5 micrometers in diameter, caused by a fossil fuel combustion, agriculture, wildfires and other sources. USC explained that it can travel deep into the lungs and even pass into the bloodstream, bypassing the blood-brain barrier, causing serious health problems.
For the recent study, Herting and her colleagues focused on 15 specific fine particles found in PM2.5. Among these ammonium nitrate, a particle forms when ammonia gas and nitric acid react in the atmosphere, stood out as a “prime suspect,” according to USC.
“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 explained. “That suggests that overall PM2.5 is one thing, but for cognition, it’s a mixture effect of what you’re exposed to.”
Going forward, Herting and her team plan to look at how these mixtures are related to “individual differences in brain phenotypes during child and adolescent development,” USC added.
Ammonium nitrate isn’t the only suspect linked with adverse health outcomes in children by USC researchers recently. Another study found that dust from the Salton Sea, California’s largest lake is linked to health issues in children who live nearby, including asthma, coughing, wheezing and disrupted sleep, USC research shows.
That “sea” was created by an accident in 1905 and it is sustained mostly by irrigation runoff from adjacent farmland. It is 50% saltier than the actual sea, which contributes to water quality issues. Problems associated with the body of water are expected to get worse in a hotter climate.