Traffic pollution may impair cognition

Findings from a new study suggest that exposure to traffic pollution can impair brain function within a few hours.

The study, published in the journal, Environmental Health, was conducted by researchers at the University of British Columbia in Vancouver and University of Victoria in Victoria, British Columbia. Traffic-related air pollution has long been known to cause health problem, according to the study, but the neurological effects are still unclear. For this investigation, researchers aimed to better understand the impact of traffic pollution on the brain.

Included in the study were 25 healthy adults who underwent a brief exposure to diesel exhaust and filtered air at different times. Before and after each exposure the participants’ brain activity was measured using functional magnetic resonance imagining (fMRI). Using the fMRI images, researchers analyzed changes in the brain’s default mode network (DMN), interconnected brain regions that play an in role in memory and internal thought.

Results showed that participants had decreased functional connectivity in many regions of the DMN after being exposed to diesel exhaust.

“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,” said Jodie Gawryluk, PhD, a psychology professor at the University of Victoria and the study’s first author.

Fortunately, the study indicated that the changes in the brain were temporary. However, authors warned that continuous exposure could have longer term effects.

“People may want to think twice the next time they’re stuck in traffic with the windows rolled down,” said senior study author Chris Carlsten, MD, MPH. “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.”