A growing body of research suggests that air pollution affects our brains. Lifetime exposure to poor air quality has been associated with disorders including Alzheimer’s disease, Parkinson’s disease and multiple sclerosis. A new study finds even short-term exposure to polluted air can cause challenges for cognitive functioning, including selective attention and emotional regulation.
Specifically, researchers wanted to examine the effects of short-term exposure to the most common form of air pollution, PM2.5, particulate matter several times finer than human hair that’s found in vehicle exhaust, industrial processing and wildfire smoke.
Researchers conducted a cognitive test on 26 healthy adults. Half the participants were exposed to clean air, and the other half were put in a closed room in which two candles were recently extinguished, exposing them to candle smoke, which contains PM2.5. The participants remained in each room for one hour, then waited four hours, after which they took a series of tests.
The people exposed to the candle smoke scored poorly on tests that evaluated ability to stay focused on a task and had a reduced ability to detect and interpret emotions. Previous studies have also linked poor air quality to the inability to focus, a core symptom of ADHD, and reduced ability to identify emotions, a core symptom of autism.
The new study only looked at adults. However, Tom Faherty, the study’s lead author and a research fellow at the University of Birmingham, U.K., told Mongabay by phone, “It really does stand to reason that if we see those effects here, children’s brains who are currently developing might be more vulnerable to the effects of air pollution.”
Previous studies have found a significant link between air pollution and brain development in children.
In the new study, participants waited four hours between exposure and testing to allow for brain inflammation, which the authors suspect affects cognitive function.
Faherty said delayed inflammation is significant because “during high exposure episodes, when people are commuting to work, you might get this big burst of PM2.5,” from vehicle exhaust.
“And then four hours later, you’re at work, and you’ve become irritable and less productive in your job, because you’ve had that initial hit during your commute,” he added.
This study “adds to the growing body of literature indicating that particulate air pollution can have negative impacts on brain function,” Dr. Philip Landrigan, a pediatrician and epidemiologist at Boston College, U.S., not involved with the study, said in an email to Mongabay.
Dr. Landrigan recently published a related study that found, each microgram increase in PM 2.5 pollution level results in the loss of about 0.4 IQ points. That may not sound like much, but “in heavily polluted countries like India, the cumulative impact is so large that it could undercut national prospects for economic development,” he added.
Banner image: Air pollution from vehicle exhaust by MPCA Photos via Flickr (CC BY-NC 2.0).
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