Dangers of breathing wildfire smoke 

Rice Ridge fire in Montana, 2017

Scientists know an awful lot about the dangers of smoking tobacco. However, they know surprisingly little about the long-term effects of exposure to wildfire smoke. 

The need for that information has become brutally apparent since the huge Rice Ridge fire pumped an enormous amount of smoke into Seeley Lake, Montana last summer. Some 160,187 acres were consumed between the fire’s discovery in July, 2017 and its full containment the following October. 

Seeley Lake is a small town in Missoula County that sits in a valley between two mountain peaks—the perfect place for wildfire smoke to settle in and transform the air into dangerous smog. The fire created a temperature inversion which held the smoke down on the ground, preventing it from being fully dissipated by sunlight.  

Temperature inversions are fairly common in areas with complex topography, e.g. small valleys enclosed by high mountains; think Telluride. Normally, air temperature decreases as altitude increases, but mountain wildfires can reverse that, trapping smoke below a thin layer of colder air. 

Young lungs are especially vulnerable to smog, which made the town’s high school unsafe to use; a nearby dude ranch at a higher elevation donated its buildings so that the kids could safely continue their education.  

Senior citizens, pregnant women, and people with chronic health issues were also endangered by the smog. That totaled 30 percent of Seeley Lake’s population, according to Missoula County air quality specialist Sara Coefield, who was responsible for keeping residents informed. So just how bad was it? “Seeley Lake was the worst smoke event we have ever seen, and I think possibly has been seen, at least in the United States and Canada,” Coefield reported to Sophie Yeo, of “Every single day, the smoke is hazardous. I’d wake up every hour at night, and check the smoke, and then fret about Seeley Lake. What do I say in the morning? ‘It’s terrible. Again.'” 

Now, we know what the short-term effects of prolonged exposure to wildfire smoke are likely to be, i.e. asthma attacks, upper respiratory inflammation, cardiovascular problems, and neurological difficulties. Seeley Lake was a perfect example: emergency room visits for respiratory illness by residents in 2017 doubled over 2016 levels; most of them happened after the smoke had hung around for a month. 

However, the medical community knows very little about long-term repeated exposure to wildfire smoke. This is a concern, because climate change and the misguided historical policy of total suppression have led to wildfires that are bigger, longer-lasting, and more frequent, especially in the West. 

For Seeley Lake Elementary School principal Chris Stout, the concern is quite personal. “My own kids have spent their entire life here, and we’ve had at least four major forest fire events, and that’s not including the smoke we get from other places. When you start to think about that, for four or five summers out of 12, they’ve spent two months breathing unhealthy levels of smoke. I do worry,” he admitted to Yeo. 

Fortunately, there is growing interest amongst scientists in studying the long-term effects. Unfortunately, they haven’t yet invented an effective way of doing it. There are a number of obstacles. It’s hard to track the long-term health of an entire community and its individuals. Also, there isn’t much data available to begin with. Then, of course, you need to get financing, which is challenging. 

Wildland firefighters are exposed to intense wildfire smoke on a regular basis and suffer the most serious effects. But, even doing research on these heroes can be difficult, according to John Balmes, professor of Environmental Health Sciences at the Berkeley School of Public Health. “Occupational studies of wildland firefighters are a problem because it’s a workforce that tends to turn over a lot.” He did do one study in which he kept track of a group of firefighters over a fire season to monitor their smoke exposure. But he was unable to get the funding needed to follow up on their health the next year. Sadly, an important opportunity to learn was lost.  



About the author

Dave Segal

Dave Segal

Dave Segal, a Detroit native, has been a journalist since 1977. He has worked as a reporter, commentator, and news director at radio stations in Detroit, Denver, and Montrose.

Dave has been writing and editing for the Monitor since its first print issue in 2003. He is editor and senior writer for the digital magazine. On the side, Dave has also done freelance writing, media relations, and a variety of volunteer work.