Summer hasn't officially started, but already smoke from wildfires across the Prairie provinces has descended on us, sparking states of emergency and evoking memories of the 2023 wildfire season — the smokiest on record in Edmonton and Calgary.
In the short term, that means watery eyes, scratchy throats and irritated lungs. But what about the cumulative, long-term impact of wildfire smoke on our health, when we're contending with it year after year?
Anne Hicks, a University of Alberta professor of pediatric respiratory medicine, says wildfire smoke contains fine particulate matter known as PM2.5, which can penetrate deep into the lungs. Although short-term exposure levels are often deemed acceptable, extended periods of poor air quality — such as those we've been experiencing during wildfire season — begin to count as longer-term exposures, leading to still-unknown but potentially significant health consequences.
"We're losing the gains we made"
"There's increased mortality, or death rates, across the human population with higher levels of PM2.5," says Hicks. The likelihood of severe illness from common infections, such as bronchiolitis or pneumonia, also rises, often necessitating emergency medical care or hospitalization.
Long-term exposure heightens the risk of asthma, chronic obstructive pulmonary disease, heart disease and stroke. Exposure during pregnancy or early life has been associated with an increased risk of autism or ADHD in children, and in adults it can speed up the progression of dementia and Parkinson's, says Hicks, who is also a member of the Women and Children's Health Research Institute.
She also notes that repeated exposure may be taking public health in the wrong direction, citing a large 20-year study showing that kids' lung health improved in the two decades following clean air regulations that cut pollution in the Los Angeles Basin. Children had fewer cases of bronchiolitis and less asthma. Kids' overall lung function improved — they had bigger lungs and better lung function.
With the constant pressure of wildfire smoke, "In the United States, they have noted that they are losing the gains they made by cleaning up car exhaust, and we are in the same situation," Hicks says.
Harder on the health system
Much like how researchers are still uncovering the long-term consequences of COVID-19 infection, the long-term consequences of wildfire smoke exposure remain somewhat uncharted, Hicks says.
It will be challenging to parse which negative outcomes arise from the smoke and which come from heat exposure, which is also especially dangerous for children and older adults. Other environmental factors also play an unknown role.
However, though the literature is sparse, Hicks says there are known correlations between smoke exposure and health — both physical and mental.
"At the 10-year mark following long-term exposure, there are studies that show decreased lung capacity and adverse mental health disorders — including things like anger, PTSD, depression and anxiety," she says. "By the 20-year point, we still see mental health problems, but we also see cardiovascular disease and cancer incidence increase.
"If you think about it that way, there will be an uptick in health-care utilization."
How can we protect ourselves?
There are some changes we can make to avoid health risks from wildfire smoke, Hicks says.
On smoky days, she recommends rescheduling outdoor events, moving activities indoors, limiting vigorous physical activity and using respiratory protection like masks when there is no option to avoid the smoke. The focus should be on creating clean, cool indoor spaces for activities — especially for children, to protect their developing lungs, she notes.
But one of the first changes we can make — and one of the most challenging — is a shift in our actions.
"We need to be nimble and we need to respond to good weather," she says.
"We need to say, 'Hey, nothing is burning, the sky is clear. Now is your moment. Get out; take a picnic. Go for a run.' Do whatever you can to get your outside time and get all the positive effects of that when you can, because too often we're reactive, and we need to be proactive."
