In a new study, conducted by researchers at the University of British Columbia (UBC) and the University of Victoria and published in the journal Environment Health, Canadian researchers have linked automobile exhaust to impairment of brain function.
In a release on Tuesday, UBC noted that it “has shown that common levels of traffic pollution can impair human brain function in only a matter of hours.”
The peer reviewed paper, according to the release, underscored how “just two hours of exposure to diesel exhaust causes a decrease in the brain’s functional connectivity – a measure of how different areas of the brain interact and communicate with each other. The study provides the first evidence in humans, from a controlled experiment, of altered brain network connectivity induced by air pollution.”
Twenty-five adults were exposed to diesel exhaust and filtered air at different times in a laboratory and their brain activity measured before and after each exposure using functional magnetic resonance imaging or fMRI. It was conducted at UBC’s Air Pollution Exposure Laboratory, located at Vancouver General Hospital.
The study sought to address the gap in knowledge of the neurological effect of exposure to traffic-related air pollution or TRAP, even as its adverse effects on the body, particularly the cardiovascular and respiratory systems, have been established.
Senior author of the study, Dr. Chris Carlsten, professor and head of respiratory medicine at UBC, said, “This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition.”
However, the effects of exposure were temporary and participants’ connectivity returned to normal after the exposure. But, Dr. Carlsten “speculated that the effects could be long-lasting where exposure is continuous.”
“People may want to think twice the next time they’re stuck in traffic with the windows rolled down,” he said, adding, “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.”
The researchers analysed changes in the brain’s default mode network (DMN), a set of inter-connected brain regions that play an important role in memory and internal thought.
“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,” Dr. Jodie Gawryluk, psychology professor at the University of Victoria and the study’s first author, said.