Tuesday Jan 31, 2023
Breathing in diesel exhaust fumes while stuck in traffic could be extremely harmful to your brain.
According to a recent scientific study of the nervous system from the University of British Columbia, after exposure to traffic pollution, brain scans reveal increased impairments in brain function. In fact, it only takes two hours for evidence of diminished brain function to become apparent.
The study, published in the journal Environmental Health, concentrated on a measure of a person's functional connectivity, assessing how well various brain regions communicate. The study's authors claim that this is the first controlled experiment to demonstrate that exposure to air pollution in humans can change brain network connectivity.
“For many decades, scientists thought the brain may be protected from the harmful effects of air pollution,” said Chris Carlsten, a professor and head of respiratory medicine and the Canada Research Chair in occupational and environmental lung disease at UBC, in a university release. “This study, which is the first of its kind in the world, provides fresh evidence supporting a connection between air pollution and cognition.”
In a lab setting, the team temporarily exposed 25 healthy persons to either filtered air or diesel exhaust. Prior to and following each session, their brain activity was measured using functional magnetic resonance imaging (fMRI). The default mode network (DMN) in the brain was one of the regions they examined for potential changes. The DMN is a network of interconnected brain areas that contribute to people's internal thoughts and memories. According to the results of the fMRI scans, those who are exposed to diesel exhaust have lower DMN activity than the air-filtered group.
“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,” explained study first author Jodie Gawryluk, a psychology professor at the University of Victoria.
There has to be more research to properly understand how these changes may affect people's capacity to operate, but it's possible that they will make it harder for people to think or function at work.
The good news is that the effects of diesel exhaust on the nervous system were only transient.
Every subject who had been exposed to air pollution experienced a restoration to regular brain function. The study's authors hypothesise that repeated exposure, such as daily sitting in standstill traffic, may result in more severe long-term harm. Dr Carlsten argues that it's preferable to avoid exposure altogether, even if it's unclear how much car exhaust could result in permanent brain damage.
“People may want to think twice the next time they’re stuck in traffic with the windows rolled down,” says Dr Carlsten. “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.”