With a new study published in the journal Environmental Health on Monday, scientists in Canada have taken the first step to understanding how pollution affects the brain.
The findings suggest that participants exposed to diesel exhaust for a brief time experienced decreased functioning in areas of the brain that are connected with internal thought and memory, called the “default mode network,” as reported by Science Daily.
“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 Jodie Gawryluk, a psychology professor at the University of Victoria and the study’s first author, told Science Daily.
In the past, studies have focused more on how pollution affects the lungs, per the American Psychological Association. But in the last decade, the question of how pollutants affect the brain has been a topic of mounting concern among scientists.
Previous studies — like the one conducted by Jennifer Weuve of Rush Medical Center — have used previous addresses of study participants and potential pollutants in those places to find a correlation between living in places with high pollutants and the cognitive decline of older participants.
“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,” Dr. Chris Carlsten — head of respiratory medicine and the Canada Research Chair in occupational and environmental lung disease at the University of British Columbia — told Science Daily.
This study is unique from past studies like Weuve’s because it was conducted in a controlled setting, rather than using already collected data. Diesel exhaust or filtered air was administered to randomly-selected participants from the group of 100, per the study.
Carlsten called the study “the first of its kind in the world,” per Science Daily.
But the method does bring up a concern for the safety of the participants.
To test how the brain reacts to pollution safely, the study used a diluted and aged diesel exhaust — simulating real-world exhaust levels.
Since the study only focused on brief exposure to diesel pollution, more research would be necessary to understand more about the long-term effects of prolonged exposure.