Traffic Fumes Impair Brain Function, Research Finds

Air pollution is a health concern for anyone living in a crowded city, near industrial pollutants, and in proximity to wildfires—pretty much all of us. It can wreak havoc on your skin, hair, airways, and overall health. And now, research reveals what it does to your brain.

This study involved the brain scans of 25 healthy adults taken before and after exposure to traffic fumes. Alarmingly, researchers found that exposure to the fumes had immediate effects on the brain, decreasing connectivity between brain networks and dimming overall cognitive function.

While the effects of pollution on humans have long been studied, this study is the first to look specifically at its acute effects on brain activity.

Chris Carlsten, M.D., a senior author of the study, said in a statement, "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."

One significant limitation of the study was that it compared filtered air with air contaminated with diesel fuel, and diesel vehicles are less common than gasoline in vehicles on American roads and highways. Additional studies that include more types of traffic fumes will help us understand the global implication of these findings.

It will also be interesting to see what long-term studies find in addition to these acute, adverse effects.

The latest findings regarding cognitive decline are another reason to avoid breathing polluted air whenever possible (and push your local legislatures to help incentivize the transition to EVs). Seeking cleaner air is easier said than done, especially for racial minorities and lower-income groups that bear the brunt of air pollution in the U.S.2

"Air pollution is now recognized as the largest environmental threat to human health, and we are increasingly seeing the impacts across all major organ systems," says Carlsten. "I expect we would see similar impacts on the brain from exposure to other air pollutants, like forest fire smoke. With the increasing incidence of neurocognitive disorders, it's an important consideration for public health officials and policymakers."

While many people don't have the luxury of moving their home farther from main roads or cutting out their morning commute entirely, there are some takeaways from the study that can help you set yourself up to avoid the worst effects of pollution exposure.

Carlsten recommends driving with your windows rolled up and making sure your car's air filter is in working order, meaning it should be of high quality and replaced regularly.

If you walk, bike, or take public transport, you're already part of the solution, but you still may fall victim to pollution. Carlsten recommends rerouting to avoid the busiest driving streets.