Q: How does wildfire smoke affect lung cancer risk? And how does this compare to things like passive smoking?
In the summer of 2020, as wildfire smoke turned the skies of the San Francisco Bay Area red, Stanford University physician and scientist Dr. Kalinado thought about the most vulnerable. She worried about the local winery workers competing to protect the harvest. Children who lived near the refinery and inhaled the pollutants every day.
During that August, September, and October, she saw air quality reach unhealthy levels for those not wearing masks on a daily basis. said in a public panel Being outside and breathing that air was like smoking seven cigarettes a day.
But now, she thinks the health effects of inhaling the ferocious smoke of wildfires are probably worse. said Dr. Nadeau, Director of the Research Center.
Tobacco smoke, even passive smoking, Proven to cause lung cancer, no wildfire smoke.Some recent limited studies published in the last few years have found correlations between people exposed to wildfire smoke and lung cancerHowever, none of the scientists who conducted these studies have proven a causal relationship, and more research is needed.
“We don’t know much about the long-term health effects of wildfires,” said Scott Weichenthal, assistant professor in the Department of Epidemiology, Biostatistics and Occupational Health at McGill University in Montreal. has been studied as a one-off hazard, but it is not known what effects short-term exposure to smoke can have, whether it is serious or long-term, on people’s health.
Experts say that even in the short term, particulate pollution from wildfires (such as tiny amounts of ash, dust and soot) can exacerbate heart problems, reduce lung function and exacerbate asthma. I know that As such, wildfire smoke can have the same health effects as diesel exhaust and cigarette smoke.
Wildfire smoke can also contain heavy metals such as lead and arsenic, and toxic chemicals such as benzene and formaldehyde gases, all of which are found in cigarette smoke and can cause cancer. There is a possibility
“There is enough evidence to suggest that we shouldn’t look the other way,” Dr. Nadeau said.
To understand how the air we breathe affects the risk of lung cancer, we need to know what toxic substances are present in the air, how much they are present, and how long we are exposed to the air. Scientists say understanding is essential.
According to the Centers for Disease Control and Prevention, exposure to secondhand smoke at work or at home, for example, May increase the risk of lung cancer in nonsmokers 20 to 30 percent.
However, calculating health risks from wildfires is much more difficult. What the smoke contains, and the potential health risks it can pose, depends in part on what the fire consumed. , electronic equipment, or tool sheds pose a different hazard.
Wildfire smoke is also capricious. It literally blows away with the wind. The toxic substances carried by fire are temporary and can be difficult to characterize, Dr. Weihenthal says. Also, measuring how much people are exposed can be difficult.
But as climate change causes wildfires to intensify, grow in size, and accelerate their spread, researchers have recently begun to look at people exposed to smoke and fire for extended periods of time. Experts at the University of California, Davis, are tracking survivors of a 2018 camp fire in Butte County, California. Also at McGill University, Dr. Weichenthal was part of a team that analyzed almost 20 years of Canadian public health. A record to better understand the health impacts of wildfires. This was partly motivated by years of record wildfires in Ontario and British Columbia.
“It’s not shocking to us that we’re seeing some sort of elevated cancer risk in these places,” he said. “We know the chemicals being released are carcinogenic.” increase.”
Dr. Weihenthal’s research Published in The Lancet in Maythat people who lived within about 30 miles of a wildfire in the past decade were about 5% more likely to develop lung cancer and 10% more likely to develop a brain tumor than those who lived farther away. I understand.
Although the study had some limitations, Dr. Weichenthhal said these findings were “important because so many people could be exposed.”
So far, the best evidence linking lung cancer to wildfire smoke comes from studies of firefighters. During peak fire season, tens of thousands of workers work long hours every day without masks.
of Studies published in 2019Kathleen Navarro, who studies environmental workplace safety issues for firefighters at the National Institute for Occupational Safety and Health, along with her colleagues, spent five to 25 years working on the front lines for at least seven weeks each year for short periods of time. Firefighters have an 8-26% increased risk of dying from lung cancer as a result of smoke exposure. They calculated that a firefighter who worked twice as many hours each year had a 13-43% increased risk of dying from lung cancer during the same period.
Dr. Navarro, who worked as a Hotshot firefighter in Oregon in 2019, said, “But there’s still a lot of uncertainty about what happens cumulatively each season. He said he is working to track and analyze trends and risk factors more closely among U.S. firefighters. national registry It will open this fall for firefighter health.
But even without evidence that wildfires cause lung cancer in the general population, Dr. Nadeau said there was plenty of evidence to call for more protective measures and take safety measures.
“We need to use this as an opportunity to be more prepared to adapt to wildfires and climate change,” she said. And when the smoke becomes conspicuous, it says, “Evacuate.
Molly Peterson is a Los Angeles-based investigative journalist focusing on the intersection of climate, catastrophe and public health.