What are the health impacts of forest fires?
British Columbia suffered through its worst fire season in at least six decades this year, with more than 11,500 square kilometres of land burning and hundreds of homes and other buildings destroyed. The fires are expected to continue into the fall.
They forced more than 45,000 British Columbians to leave their homes, and 12,000 people still remain on evacuation alerts even in September. Smoke from the fires also blanketed the surrounding areas, resulting in air quality warnings even provinces away.
Experts worry that fires like this are becoming the new normal, and that rates will continue to rise in B.C. and Alberta, as well as the U.S. – much of the west coast of the States is also currently burning. And it’s not just North America: Australia has had serious fires this year as well.
At the same time, Canadian researchers are looking into the health effects of forest fires, spurred in part by the wildfire in Fort McMurray last year, which sparked the evacuation of the entire town.
Those health impacts of forest fires are wide ranging, from people having post-traumatic stress disorder (PTSD) after evacuations, to problems controlling asthma and chronic obstructive pulmonary disease-like symptoms from the smoke. Here’s what we know:
Where there’s smoke, there’s pulmonary issues
When it comes to the health impacts from forest fires, firefighters are much more affected than the general population. Nicola Cherry, an epidemiologist at the University of Alberta, is studying the health of firefighters after the Fort McMurray fire. In her preliminary research, she found that “a significant number of them – even those without existing conditions – had respiratory problems like wheezing and breathlessness” four months after the fire. (They’re still researching longer-term effects). Those who were from the local area, who fought the wildfires for longer, were most at risk.
For the general population, the impact from the fires is similar to what you’d see from air pollution from other sources, such as heavy traffic. That’s because forest fire smoke and urban pollution share a key ingredient: fine particulate matter. These tiny particles get deep into the lungs, causing irritation and inflammation that can affect all parts of the body. But because the smoke is so much worse than it is on a bad traffic day in Toronto, those effects are magnified.
The number one impact of forest fire smoke is on breathing problems, especially among the 12 percent of Canadians who have asthma or chronic obstructive pulmonary disease (COPD). Exposure to smoke results in increased visits to doctors and the emergency department for breathing problems, and increased hospitalization as well. “When there’s a really high air pollution event, the people who are affected might have trouble controlling their respiratory illness,” says Colleen Reid, an assistant professor at the University of Colorado Boulder and the author of a review of the health effects of exposure to wildfire smoke. There’s also some evidence that smoke is linked to heart attacks, and to slightly lower birth weights when pregnant women are exposed to it.
Overall, there’s a small increase in the number of deaths during very smoky days, mostly from people with pre-existing health issues. “Anybody with pre-existing disease within the population is going to be at higher risk, but we don’t expect new incidence of disease because of these smoke episodes,” explains Sarah Henderson, a senior scientist of Environmental Health Services for the B.C. Centre for Disease Control.
Evacuation to avoid smoke inhalation isn’t necessarily the answer. Evacuating people “is incredibly expensive and stressful, and its effectiveness is questionable,” says Henderson. “We’ve found that by the time people were evacuated, the smoke was clearing in half of the cases. That’s a lot of expense and stress without a lot of public health benefit.”
Instead, the recommendation is generally to “shelter in place.” That’s means that on smoky days, people should limit their time outdoors, not exercise outside, and turn on their air conditioning or use a portable air cleaner. (Masks that have an N-95 rating also work, but they must be fitted properly and can make breathing more difficult, so they’re only recommended for people who work outside.)
Over time, researchers expect we’ll likely see cumulative health effects as well. “The more smoky summers we have, the more it will change the lifetime exposure profile of Canadians, and that puts us at higher risk of developing chronic diseases such as asthma, heart disease and cancer,” says Henderson. But we’re lucky that across Canada in general, there is good baseline air quality. That means forest fires aren’t going to affect health as much as, say, smoking cigarettes; it’s likely more in line with the amount of air pollution you’d be exposed to from living in a big city.
Mental health issues & evacuations
Firefighters don’t just have physical effects; they’re also at a high risk of PTSD. Cherry explains that in Fort McMurray, “people who were from the original area, who were fighting fires in their own backyard, were very much more susceptible [to mental health issues] than people who flew in.”
The general population was also seriously affected. Unpublished research suggests nearly 13 percent of the population of Fort McMurray suffered from PTSD six months after the fires. “It’s well known that when individuals experience life threatening trauma, many will develop anxiety disorders, and some will develop PTSD. Clearly large forest fires that put people at risk can trigger this,” says Peter Silverstone, a psychiatrist who is researching the effects of the Fort McMurray fires on children. “There’s also a sense of loss: losing your home, job, or possessions can have major psychological impacts.”
In Fort McMurray, much of the area affected included Indigenous communities, says Stephanie Montesanti, a health services and policy researcher at the University of Alberta who is beginning research focused on the impacts of the fires on First Nations communities this fall. Around Fort McMurray, there were three communities that were devastated by the fires, and in those, 70 percent of the residents were First Nations or Metis.
In B.C., many Indigenous communities were evacuated because of a risk of fire and, less often, because of smoke as well, says Evan Adams, MD and chief medical officer for the First Nations Health Authority in B.C. He says that since the fires, they’ve seen both the innate strength of their communities and the need for more mental health and spiritual support.
One issue over the summer was that there wasn’t enough communication with leaders around evacuating, making communities feel like they had lost control of the ability to decide whether to stay or go. “One of the chiefs was profoundly angry, and said, Why do you have the ability to declare an evacuation? And one of them actually actively defied an evacuation order, and he kept whoever wanted to stay in the community with him,” says Adams.
Another issue is the enduring impact of past trauma, such as that from residential schools. “The Indigenous population have been through trauma before, so when they experience trauma again, through a wildfire, it can be very triggering,” Adams explains. “[After this summer], people have been saying to us, we didn’t get burned alive, but boy, our mental health suffered. It hurt us profoundly.”