A study has found that moderate levels of traffic pollution have the potential to damage human brain function in a matter of hours. The study found that exposure to diesel exhaust for just two hours reduced functional connectivity in the brain.
Researchers from the University of British Columbia and the University of Victoria in Canada used functional magnetic resonance imaging (fMRI) to measure how brain activity changed before and after exposure to diesel exhaust and filtered air in 25 healthy adults.
What the researchers looked at is the change in the brain’s default mode network (DMN). The DMN is an area of the brain that becomes active when you are sleepy or dreaming. It is a network of neurons that spreads over the medial prefrontal cortex, posterior cingulate cortex, and parietal cortex, and plays an important role in memory and insight by connecting all areas together.
In this study, functional connectivity was reduced in a large area of the DMN after exposure to diesel exhaust compared to filtered air.
“Since changes in functional connectivity in the DMN are known to be associated with cognitive decline and depressive symptoms, it is concerning that these same networks are disrupted by traffic pollution,” the researchers said. A lot of research is needed, but it has the potential to damage people’s thinking and ability to work.”
The changes to the brain were temporary and brain connections returned to normal after exposure, the researchers speculated, and that these effects could be long-lasting where exposure continues.
Although the study only looked at the cognitive effects of traffic, the researchers said other products of combustion could also be a problem.
“Air pollution is now recognized as the greatest environmental threat to human health, and we are seeing increasing effects on all major organ systems,” the researchers said. A similar effect is expected,” he added.
The results of this study were published in the journal ‘Environmental Health’ under the title ‘Comprehensive diesel exhaust exposure severely impairs functional brain connectivity in humans: a randomized controlled crossover study’.
