Study suggests traffic pollution impairs brain function

A world-first study by researchers at the University of British Columbia and University of Victoria has discovered that pollution caused by vehicle traffic can impair brain function in as little as a few hours.

The findings, published in the Environmental Health journal, showed that adults exposed to just two hours of diesel emissions decreased their brain’s functional connectivity – how different parts of the brain communicate with each other.

It was originally thought that air pollution had no effect on the brain until this study was conducted according to Dr. Chris Carlsten, professor and head of respiratory medicine and the Canada Research Chair in occupational and environmental lung disease at UBC.

“This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition,” Dr. Carlsten said.

It was conducted by exposing 25 adults (11 females and 14 males) with an average age of 27 to diesel fumes and clean air at different times in a laboratory setting. Brain activity was measured before and after exposure using an MRI machine.

During the experiment, researches analysed changes in the brain’s default mode network (DMN) which is a set of inter-connected brain regions which support memory and internal thought. These areas had decreased functionality after being exposed to diesel fumes compared to filtered air.

“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 Dr. Jodie Gawryluk, a psychology professor at the University of Victoria.

“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.”

Dr. Carlsten suggested there are a few ways in which people can protect themselves from harmful emissions like ensuring your car’s cabin air filter is in working order, driving with your windows up in traffic, or walking/biking away from busy roads.

“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 Dr. 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.”