World’s first study suggests even brief exposure to air pollution has rapid effects on the brain – Zoo House News
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- January 25, 2023
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A new study by researchers from the University of British Columbia and the University of Victoria has shown that general traffic pollution can impair human brain function in a matter of hours.
The peer-reviewed findings, published in the journal Environmental Health, show that just two hours of exposure to diesel exhaust leads to a decrease in the brain’s functional connectivity — a measure of how the study provides the first evidence in humans from a controlled experiment provides , the altered brain network connectivity induced by air pollution.
“For decades, scientists thought the brain might be protected from the harmful effects of air pollution,” said lead study author Dr. Chris Carlsten, Professor and Head of Respiratory Medicine and Canadian Research Chair in Occupational and Environmental Lung Diseases at UBC. “This study, the first of its kind in the world, provides new evidence linking air pollution and cognition.”
For the study, the researchers briefly exposed 25 healthy adults to diesel exhaust and filtered air in a laboratory setting at different times. Brain activity was measured before and after each exposure using functional magnetic resonance imaging (fMRI).
Researchers analyzed changes in the brain’s default mode network (DMN), a series of interconnected brain regions that play important roles in memory and internal thinking. The fMRI showed that after exposure to diesel exhaust, participants had reduced functional connectivity over large areas of the DMN compared to filtered air.
“We know that altered functional connectivity in the DMN has been associated with decreased cognitive performance and symptoms of depression, so it’s worrying to see traffic congestion disrupting the same networks,” said Dr. Jodie Gawryluk, a psychology professor at the University of Victoria and the study’s first author. “While more research is needed to fully understand the functional implications of these changes, it is possible that they affect people’s thinking or ability to work.”
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Remarkably, the changes in the brain were transient and the participants’ connectivity returned to normal after exposure. dr Carlsten speculated that the effects could be long-lasting with continued exposure. He said people should be mindful of the air they breathe and take appropriate steps to minimize their exposure to potentially harmful air pollutants, such as car exhaust.
“People might want to think twice the next time they’re stuck in traffic with their windows down,” said Dr. Carlsten. “It’s important to make sure your car’s air filter is in good condition, and if you’re going to walk or bike on a busy street, consider taking a less-travelled route.”
While the current study only looked at the cognitive effects of traffic-related pollution, Dr. Carlsten that other combustion products are likely to be a problem.
“Air pollution is recognized as the number one environmental threat to human health today, and we are increasingly seeing the impact on all major organ systems,” says Dr. Carlsten. “I assume we would see similar effects on the brain from exposure to other air pollutants such as wildfire smoke. With the increasing prevalence of neurocognitive disorders, this is an important consideration for public health officials and policy makers.”
The study was conducted at UBC’s Air Pollution Exposure Laboratory at Vancouver General Hospital, which is equipped with a state-of-the-art exposure booth that can mimic what it’s like to breathe in a variety of air pollutants. In this study, carefully designed and approved for safety reasons, researchers used freshly generated exhaust gases that were diluted and aged to reflect real-world conditions.