What is smoke brain? How air pollution harms the mind

As air quality continues to fluctuate across Canada in response to ongoing wildfires, scientists warn that even brief exposure to smoke or air pollution can harm your brain function.

While it’s not known exactly how smoke particles affect the brain, experts tell the star there’s a litany of evidence about the health damage, both short-term and years down the line.

“I have no doubt that wildfire smoke affects our brains when it occurs,” Sarah Henderson, the scientific director of Environmental Health Services at British Columbia’s Center for Disease Control, told the Star.

As carbon emissions continue to rise and the climate warms, wildfires are only expected to become more frequent and last longer. Experts say now is the time to prepare.

Short-term exposure to wildfire smoke and impact on the brain

In the short term, studies have shown that exposure to smoke from wildfires generally lowers brain performance, Henderson said. While the effects may be too subtle to notice on your own, research has found that people who inhale more air pollution consistently perform worse on cognitive tests.

“We did a study using data from the brain training platform Lumosity,” said Henderson, whose article appeared last year. “What we found is that when it was smoky, people didn’t do as well (on the platform). That was especially true for younger adults… and it was true for older adults, too.

Her results are confirmed by numerous other articles, including one 2022 US longitudinal study of over 10,000 adults which found drops in test performance in regions where smoke from wildfires was present. A similar study of the 2018 California fires found brain function was still impaired even six to 12 months after the event.

In addition, a study earlier this year found that just two hours of exposure to traffic pollution can impair brain function. The lead author, Chris Carlsten, told the Star he believes his findings also apply to wildfire smoke, given the similarities in composition.

Anecdotally, Henderson has encountered “so many” people asking about their elderly parents with dementia, “who seemed more confused on smoky days.”

“For individuals who are already in cognitive decline, they may experience more confusion and more decline on those days when it’s smoky,” she continued.

Long-term effects of smoke inhalation on the mind

Although fewer studies have been done on long-term smoke exposure, Dr. Samantha Green, a physician at Unity Health in Toronto and prospective president of the Canadian Association of Physicians for the Environment, says we can extrapolate from what we already know about air pollution.

“We know that particulate matter and other components of air pollution can cause long-term neurological damage,” Green said. “For example, there is increasing evidence that long-term exposure to air pollution and an increased risk of dementia

“There is also a similar one increased risk of Parkinson’s disease from prolonged exposure to air pollution, and increased risk even for ALSGreen continued.

These diseases are often associated with seniors, but air pollution also harms young children, Green continued. “Even in prenatal and early lifeexposure is associated with an increased prevalence of ADHD, lower IQ scores, a greater need for academic support, and other neurobehavioral impairments.

Jeff Brook, an associate professor at the University of Toronto’s Dalla Lana School of Public Health and Department of Chemical Engineering and Applied Chemistry, agrees, adding that studies have also shown “strong correlations” between air quality and the development of autism.

For example, a Harvard study linked particulate matter to air pollution to a significantly increased risk of autism in children, especially with exposure during the third trimester of pregnancy or early childhood.

While we’ll probably spend less time on the smoke from wildfires than on general air pollution, Green says, during intense fire seasons, cities can be engulfed in smoke for months — “enough time to see an effect.” As climate change exacerbates fires around the world, Green expects these incidents to become more common.

How to protect yourself from air pollution

The most important thing people can do is monitor their local air quality, Green said. “Pay close attention to the air quality health index, because it can shift over hours and between municipalities and regions.”

When the air quality is seven or higher, Green advises that you “don’t go outside and exert yourself” and “keep windows closed inside.” It’s also helpful to invest in an air purifier and place it in the room where you spend the most time, such as a bedroom or office, she said.

If air purifiers are too expensive, Brook says you can always build your own, adding that one of his students did when they investigated wildfires earlier this year.

“It was $75 to order oven filters and a fan,” he said. “When she turned it on in the hotel room, it cleaned the air 90 percent very quickly.” Here’s how to create the design for yourself.

If you have to go outside, Henderson advises wearing an appropriate respirator or N95 mask: “If they fit your face properly, they can be very effective at reducing that exposure.”

Finally, if you’re more vulnerable to the effects of air pollution, Green says you should consider staying indoors, even if the air quality dips below seven.

“People who are more vulnerable with underlying chronic conditions or pregnant women, young children, the elderly should take precautions even when air quality is in the moderate range.”

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