Air Pollution Can Impair Brain Activity In Just 2 Hours: Study

Air quality in Delhi has been in the severe category for several days and a thick toxic smog has engulfed the entire city resulting in poor visibility. Scientists have warned of a spike in pollution levels in Delhi-NCR over the next two weeks. This is concerning as the Air Quality Index (AQI) in many areas has already breached the 400 mark. Many people are facing respiratory issues while health experts have detailed the hazardous impact of air pollution on the overall health of the human body. The government has barred trucks from entering Delhi unless they are carrying essential goods, providing essential services, or are powered by LNG, CNG, or electricity. Meanwhile, the Centre has put the Graded Response Action Plan (GRAP), a set of anti-pollution measures, into effect at its highest level in the city and surrounding cities to fight the worsening air quality. Now, a 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 results of the study, which were published in the journal Environmental Health, show that even two hours of exposure to diesel pollution decreases the functional connectivity of the brain. 
It provides the first scientific proof of altered brain network connectivity in people as a result of air pollution, in a carefully monitored experiment

Twenty-five healthy adults were briefly exposed to filtered air and diesel exhaust at various intervals in a laboratory setting as part of the study. The brain activity of every adult was observed both before and following each exposure using functional magnetic resonance imaging.

“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,” senior study author Dr Chris Carlsten said.

As per the study, the brain’s network of linked areas known as the default mode network (DMN) is triggered when internal mental state functions including memory recall take place. After being exposed to diesel exhaust, the researchers found that there was a decline in functional connectivity in the DMN through analysis of the brain scans.

Dr Jodie Gawryluk added, “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. 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.”

However, the changes in the brain were only temporary and the brain connectivity went back to normal after the exposure. The researchers believed that if there is ongoing exposure, the effects might 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.” 

He added that air pollution is the “largest environmental threat to human health” and he expects that they could witness “similar impacts on the brain from exposure to other air pollutants, like forest fire smoke”.