The exposure to diesel exhaust for just two hours reduces the brain's functional connectivity.
People living in metropolitan cities have been battling pollution for a very long time. Long-term exposure to air pollution, particularly dust from building activities in severe weather, affects the respiratory system in addition to causing heart and neurological issues such cardiac arrests, strokes and stomach issues. Now, a recent study by researchers at the University of British Columbia and the University of Victoria found that even moderate traffic pollution can impair brain function within hours.
The study was published in the journal Environmental Health and reveals that exposure to diesel exhaust for just two hours reduces the brain's functional connectivity. It offers the first scientific proof of altered brain network connectivity brought on by air pollution in humans in a controlled experiment.
The researchers conducted the study by briefly exposing 25 healthy adults to diesel exhaust and filtered air at different times in a laboratory setting. Using functional magnetic resonance imaging, brain activity was recorded before and after each exposure for all adults.
The brain's default mode network (DMN), a set of interconnected brain regions that are crucial for memory and internal thought, was the focus of the researchers' analysis. After exposure to diesel exhaust as compared to filtered air, the results showed that subjects had less functional connectivity in many areas of the DMN.
Dr Jodie Gawryluk, a psychology professor at the University of Victoria and the study's first author stated, "We know that altered functional connectivity in the DMN has been associated with reduced cognitive performance and symptoms of depression, so it's concerning to see traffic pollution interrupting these same networks." He said that more research is needed to fully understand the functional impacts of these changes. However, "it's possible that they may impair people's thinking or ability to work."
However, the changes in the brain were only temporary and people's connectivity went back to normal after the exposure. The researchers speculated that where exposure is continuous, the effects could be long lasting.
Senior study author and Head of Respiratory Medicine at the University of British Columbia, Dr Chris Carlsten said, "People may want to think twice the next time they're stuck in traffic with the windows rolled down. It's important to ensure that your car's air filter is in good working order, and if you're walking or biking down a busy street, consider diverting to a less busy route."