The world’s first study suggests that even brief exposure to air pollution has a rapid impact on the brain

The world’s first study suggests that even brief exposure to air pollution has a rapid impact on the brain

A new study by researchers at the University of British Columbia and the University of Victoria has shown that ordinary levels of traffic pollution can affect human brain function within hours.

The peer-reviewed findings, published in the journal Enviromental healthshow that just two hours of exposure to diesel exhaust causes a decrease in functional brain connectivity, a measure of how The study provides the first human evidence, from a controlled experiment, of altered network connectivity brain induced by air pollution.

“For many decades, scientists thought that the brain might be protected from the deleterious effects of air pollution,” said study lead author Dr. Chris Carlsten, professor and director of respiratory medicine and Canada’s chair of research. in occupational and environmental lung diseases at UBC. “This study, which is the first of its kind in the world, provides new evidence supporting a connection between air pollution and cognition.”

For the study, the researchers briefly exposed 25 healthy adults to diesel exhaust and filtered air at different times in a laboratory setting. Brain activity was measured before and after each exposure using functional magnetic resonance imaging (fMRI).

The researchers analyzed changes in the brain’s default mode network (DMN), a set of interconnected brain regions that play an important role in memory and internal thinking. The fMRI revealed that the participants had decreased functional connectivity over large regions of the DMN after exposure to diesel exhaust, compared to filtered air.

“We know that impaired functional connectivity in the DMN has been associated with reduced cognitive performance and symptoms of depression, so it is concerning to see traffic pollution disrupt these very networks,” said Dr. Jodie Gawryluk, professor of psychology. at the University of Victoria and the first author of the study. “While more research is needed to fully understand the functional impacts of these changes, it is possible that they could affect people’s thinking or ability to work.”

Take steps to protect yourself

Notably, the changes in the brain were temporary, and the participants’ connectivity returned to normal after exposure. Dr. Carlsten speculated that the effects could be long lasting when the exposure is continuous. 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 may want to think twice the next time they’re stuck in traffic with their windows down,” Dr. Carlsten said. “It’s important to make sure your car’s air filter is in good working order, and if you’re walking or biking down a busy street, consider detouring to a less crowded route.”

While the current study only looked at the cognitive impacts of traffic pollution, Dr. Carlsten said other combustion products are likely to be a concern.

“Air pollution is now recognized as the biggest environmental threat to human health and we are increasingly seeing the impacts on all major organ systems,” says Dr. Carlsten. “I expect we will see similar impacts on the brain from exposure to other air pollutants, such as smoke from wildfires. With the increasing incidence of neurocognitive disorders, it is an important consideration for public health officials and policymakers.” .

The study was conducted at the UBC Air Pollution Exposure Laboratory, located at Vancouver General Hospital, which is equipped with a state-of-the-art exposure booth that can mimic what it is like to breathe in a variety of air pollutants. . In this study, which was carefully designed and approved for safety, the researchers used newly generated exhaust gases that were diluted and aged to reflect real-world conditions.

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