First-Of-Its-Kind Study Shows How Traffic Pollution Impairs Brain Function

Researchers in Canada have, for the first time ever, demonstrated how acute exposure to traffic pollution can immediately impair human brain function, offering unique evidence of the connection between air quality and cognition.

Healthy adults were exposed to diesel fumes before having their brain activity imaged in a fMRI machine.

Air pollution in urban environments has long been associated with poor cardiovascular, respiratory and brain health.

It’s difficult to accurately quantify a person’s exposure to air pollution beyond associating rates of certain diseases in geographical areas of high pollution.

Plenty of cell and animal studies can demonstrate how air pollution affects organisms.

In a lab setting, 25 healthy adults were exposed to either diesel exhaust, or filtered air for two hours and had their brain activity measured using fMRI before and after each exposure.

The main focus of the study was on the impact of this kind of traffic-associated air pollution on what is known as the default mode network.

The findings revealed brief exposure to diesel exhaust caused a decrease in DMN activity, essentially yielding a drop in functional connectivity between different brain regions, compared to what was seen when subjects were exposed 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 Gawryluk.

Alongside a growing body of epidemiological and preclinical studies linking air pollution with a number of neurodegenerative diseases, these findings may be much more significant.

They effectively demonstrate the acute effects of air pollution on the human brain in a way never before shown.

According to senior author on the study Chris Carlsten, it is unclear what long-term effects this kind of pollution exposure will have on a human brain.

On the positive side of things the researchers did seen DMN brain activity return to normal relatively soon after the diesel fume exposure.