In American West's Fire Ecology, The Biggest Overall Risk May Be Smoke - And Little Can Be Done
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Scientists have been warning for decades that the West is due for purging wildfires. Now that the blazes are here, we’re beginning to grapple with a harsh reality. If you live in the West, you’ve heard plenty about the need for communities to adopt fire-resistant building codes, bury power lines, establish evacuation routes, and remove fuel through routine clearing and prescribed burns. Meanwhile, policymakers—though not politicians—are coming around to the idea that we should stop spending our national treasure and risking the lives of firefighters to battle remote blazes, even if a handful of homes are at stake. The age of wildland fire suppression has to end.
Over a period of decades, controlled burning and fire-wise construction should dramatically reduce the impact of blazes on settlements across the West. But those measures, along with natural changes like the conversion of some forests to grasslands, won’t do a damn thing to protect us in the near term from what may be the greatest hazard to human health in our new climate: smoke.
Wildfire smoke has been a natural part of life on earth for at least 400 million years. In North America, Native people lived with the air pollution from lightning-sparked wildfires as well as the burns they lit on purpose. But in general, those regular smaller fires were far less intense than the infernos we’re experiencing now. In the West today, wildfires aren’t just burning grasses on the floor of a ponderosa pine forest or wiping out high-elevation stands of lodgepole every 100 to 250 years—they’re burning forests from weeds to canopy and covering vast acreages. They’re also burning longer, persisting for as much as seven months of the year in most of the West (compared with the four-to-five-month fire season that was typical 50 years ago), and producing more smoke.
In addition to hazardous chemicals that are released when structures ignite, wildfire smoke commonly contains toxic ingredients. The chief threat, however, is prolonged exposure to the fine particulate matter suspended in smoke. When inhaled, these particles, which are as small as 2.5 micrometers in diameter (a grain of table salt is 100 micrometers), can have serious health effects. Research has shown that wildfire particulate is associated with increased risk of respiratory infection and death. One study estimated that some 1,700 fatalities per year in the U.S. are linked to particulate from wildfires, and that number could double by the end of the century. “The smoke we’re experiencing now is causing us to reevaluate how we live our lives,” says Tony Ward, chair of the School of Public and Community Health Sciences at the University of Montana. Unfortunately, he adds, there’s been little funding for studies that focus on the issue. “Very large populations are being exposed. We need to devote more resources to protecting the public.”
Last fall, during the deadly Camp Fire near Paradise, California, San Francisco was in the national news when it was estimated that wildfire smoke made breathing the city’s air for a single day equivalent to smoking ten cigarettes. As bad as that was, a more revealing case study is Seeley Lake, Montana. In the summer of 2017, several nearby fires caused smoke levels to reach hazardous levels on 36 out of 50 days. How nasty was the air? By the EPA’s standards, things start to get unhealthy when the pollution-borne particulate levels reach 35 micrograms per cubic liter of air. In Seeley Lake, the particulate levels were routinely in excess of 300 micrograms per cubic liter. Twenty times that summer, the hourly levels measured 1,000 micrograms or higher, effectively maxing out the devices that measure particulates.
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https://www.outsideonline.com/2397137/wildfire-smoke-health-risks
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