Research from the Keck School of Medicine shows that exposure to certain pollutants, even at levels considered acceptable by the Environmental Protection Agency (EPA), may cause alterations in children’s brain function over time. The investigation, which analyzed brain scans of over 9,000 young people, found that pollutant exposure could change the connectivity among different brain regions, potentially elevating the risk of future cognitive and emotional challenges.
One of the pioneering longitudinal studies of this kind, conducted by scientists from the Keck School of Medicine at the University of Southern California, found that consistent exposure to air pollution could influence the pattern of brain development in adolescents.
There’s a widespread understanding that air pollution can cause illnesses, which has led organizations like the EPA to regulate emission limits. However, new evidence suggests that even pollution levels deemed ‘safe’ could pose a threat to health, including brain health.
In a study conducted by the Keck School of Medicine of USC, funded by the National Institutes of Health and the EPA, it was revealed that even EPA-approved levels of some pollutants are associated with alterations in brain functionality over time.
Recently published in Environment International, the study utilized brain scan data from more than 9,000 participants of the Adolescent Brain Cognitive Development (ABCD) study, the largest-ever nationwide study of adolescent brain health. Children exposed to a higher amount of pollutants displayed changes in the connectivity of various brain regions. In some instances, the connections were more numerous than normal, whereas, in other areas, there were fewer.
According to Devyn L. Cotter, MSc, a neuroscience doctoral candidate at the Keck School of Medicine and the study’s primary author, “Any deviation, either towards over-connectivity or under-connectivity, from the normal brain development trajectory, could potentially lead to future harm.”
The communication between different brain regions allows us to process our environment and influences how we think and feel. A substantial number of these crucial connections develop between the ages of 9 and 12, impacting whether children undergo typical or unusual cognitive and emotional development.
Megan M. Herting, Ph.D., associate professor of population and public health sciences at the Keck School of Medicine, and the study’s senior author, said, “The EPA’s ‘safe’ air quality standards across the U.S. are contributing to changes in brain networks during this pivotal period, which may serve as an early indicator of increased risk for future cognitive and emotional issues.”
Investigating the Connection between Air Pollution and Brain Development
To examine the connection between air pollution and brain development, Herting, Cotter, and their team analyzed functional MRI scans from 9,497 participants of the ABCD study. Initial brain scans were taken from children aged 9 to 10, and follow-up scans were collected from a subset of the participants two years later. This allowed the researchers to observe changes in brain connectivity over time.
They focused on specific brain networks, the amygdala and the hippocampus — areas involved in emotion, learning, memory, and other complex functions. The research team used EPA data, among other sources, to map the air quality at each child’s residence. They tracked levels of fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ground-level ozone (O3) and used advanced statistical tools to study the correlation between air pollution levels and changes in brain connectivity over time.
Exposure to higher PM2.5 levels was associated with an increase in functional connectivity between regions, while increased NO2 exposure corresponded with decreases in connectedness. More exposure to O3 was linked to more connections within the brain’s cortex, but fewer connections between the cortex and other regions such as the amygdala and hippocampus.
The researchers controlled for several factors that could impact brain development, such as gender, race/ethnicity, parental education level, household income, location (urban or rural), and seasonal variations, as pollution levels can fluctuate between summer and winter.
Adjusting Air Quality Guidelines
These findings might urge regulatory authorities to take brain health into consideration, along with lung and cardiometabolic health, when setting or adjusting air quality standards. Although the EPA suggested strengthening PM2.5 standards earlier this year, the guidelines for annual NO2 levels have remained unchanged since their inception in 1971.
“Despite relatively low air pollution levels in the U.S., we’re observing notable effects on the brain,” said Cotter. “Policy makers should consider this evidence when evaluating the need to adjust the current standards.”
Cotter, Herting, and their team plan to investigate the chemical composition of pollutants further to understand their potential harmful impact on the brain. This could help refine regulations. They also intend to continue analyzing brain health over time using data from the ABCD study.
Herting questioned, “In the long term, could this exposure increase the risk for mental disorders during mid-to-late adolescence? And how does it affect people’s trajectory of mental health?”
Reference: “Effects of ambient fine particulates, nitrogen dioxide, and ozone on maturation of functional brain networks across early adolescence” by Devyn L. Cotter, Claire E. Campbell, Kirthana Sukumaran, Rob McConnell, Kiros Berhane, Joel Schwartz, Daniel A. Hackman, Hedyeh Ahmadi, Jiu-Chiuan Chen, and Megan M. Herting, 1 June 2023, Environment International. DOI: 10.1016/j.envint.2023.108001
The research was funded by the National Institute of Environmental Health Sciences and the Environmental Protection Agency.
Table of Contents
Frequently Asked Questions (FAQs) about Air Pollution Impact on Brain Development
What was the primary finding of the Keck School of Medicine’s study?
The study found that even exposure to certain pollutants at levels considered safe by the Environmental Protection Agency (EPA) can lead to changes in brain function over time in children.
Who funded the research?
The research was funded by the National Institutes of Health and the Environmental Protection Agency.
What data did the researchers use in their study?
The researchers used brain scan data from over 9,000 participants of the Adolescent Brain Cognitive Development (ABCD) study and mapped the air quality at each child’s residence using EPA and other data sources.
How might these findings impact air quality regulations?
These findings could urge regulatory authorities to consider brain health in addition to lung and cardiometabolic health when setting or adjusting air quality standards.
What are the future research plans of the study team?
The researchers plan to investigate the chemical composition of pollutants further to understand their potential harmful impact on the brain and to continue analyzing brain health over time using data from the ABCD study.
More about Air Pollution Impact on Brain Development
- Keck School of Medicine at USC
- Adolescent Brain Cognitive Development (ABCD) Study
- The Environmental Protection Agency (EPA)
- National Institute of Environmental Health Sciences
- Research Paper: Effects of ambient fine particulates, nitrogen dioxide, and ozone on maturation of functional brain networks across early adolescence
5 comments
just another reason to move to the countryside i guess. cities aint safe with all that pollution.
we need to keep pushing for stricter standards and renewable energy! Our health and our planet are at stake here!
Wow, this is pretty scary. you think the air’s safe, but no. what else aren’t they telling us??
Am i reading this right? Even “safe” air can harm our kids’ brains?? Thats messed up.
Gosh, this is worrying. We really need to take better care of our environment. For our children’s sake…