HQ Team
February 15, 2023: Exposure to typical levels of traffic-related air pollution can diminish brain function within hours, according to researchers at the University of British Columbia.
A controlled human exposure study, the first such, using magnetic resonance imaging with an order-randomized double-blind crossover study of diesel exhaust and filtered air, was conducted by the scientists.
Most of the randomized controlled trials are blinded studies, meaning one won’t know which treatments they are receiving. Some tests are run as crossover studies, where you may have the chance to swap to another cure after a time.
The Columbia study was done on 25 adults, 11 females and 14 males, between 19-49 years. All adults went through the exposures, and functional MRI imaging was collected.
Filtered or diesel exhaust exposure occurred for 120 minutes. During orientation, participants cycled on a stationary bicycle at light effort for 15 minutes during the first quarter of each hour to maintain a representative activity level.
Brain regions
The scientists focused on generally considered effects of traffic-related air pollution (TRAP) on the default mode network (DMN), a set of inter-connected cortical brain regions in which activity is maximal at rest or during internal thought engagement.
“We focused on the DMN, given the preferential vulnerability of this network to ageing, toxicity, and disease states…exposure to diesel exhaust yielded a decrease in functional connectivity compared to exposure to filtered.”
“We observed short-term pollution-attributable decrements in default mode network functional connectivity.”
“Decrements in brain connectivity cause many detrimental effects to the human body, so this finding should guide policy change in air pollution exposure regulation,” the study noted.
Adverse health effects
Exposure to traffic-related air pollution has been associated with various adverse health effects, primarily cardiovascular and respiratory.
The pollution posed an enormous global burden in terms of morbidity and lost productivity, as well as deaths estimated at approximately five million yearly.
According to the study, the data deepens the evidence base for direct evidence of neurocognitive effects due to acute exposure to TRAP.
“As the changes in cognition, we have demonstrated may put individuals at risk for impaired vocational performance, this is an important consideration for public health.”
Changes in brain connectivity have been associated with decreased working memory and behavioral performance and deterioration in productivity at work.
The researchers said that a combination of observational and experimental evidence has long driven change in policy surrounding air pollution exposure.
The combination “is most compelling, especially in the face of interests aggressively opposed to regulation that foster improved air quality.”
