Exposure to Traffic Pollution Decreases Brain Function

According to one study published in Environmental Health, brief exposure to diesel exhaust and traffic pollution impairs functional brain connectively in humans in just a matter of hours. Researchers from the Air Pollution Exposure Laboratory at the University of British Columbia the first controlled human exposure study utilizing functional magnetic resonance imaging (fMRI) with an efficient order-randomized double-blind crossover study of diesel exhaust (DE) and control (filtered air; FA).

Chris Carlsten, MD, MPH, senior author of the study remarked in a recent press release, “For many decades, scientists thought the brain may be protected from the harmful effects of air pollution. This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition.”

Twenty-five healthy adults aged between 19 and 45 years were recruited for the study. The study participants were exposed to DE and FA in a controlled laboratory setting. Their brain activity was measured prior to and after the exposures using fMRI. Subsequent analyses were accomplished via mixed effects models.

The researchers noted the short-term declines in default mode network (DMN) functional connectivity due to the exposure to pollution. As each of the participants experienced the DE and FA exposures, fMRI revealed that exposure to DE resulted in a decrease in functional connectivity when compared with exposure to FA.

Regarding the results, the study’s first author, Jodie Gawryluk, PhD, said, “While more research is needed to fully understand the functional impacts of these changes, it’s possible that they may impair people’s thinking or ability to work.”

When asked about steps one could take to protect themselves from traffic-related pollution, Dr. Carlsten offered this advice: “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.”