A few weeks ago, I woke up with a sore throat, which I attributed to the dry mountain air here in Montana. When I set out on a jog soon after, I found myself breathing hard within minutes—obviously due to the stupid steep hill my running buddy selected for that day’s route, right? To top it off, my allergies were acting up: My eyes were itching like crazy. When we finally reached the summit of what felt like Mt. Everest (Note: Said “mountain” might have only been 300 feet high), I realized I’d been in a haze all morning. A real haze: Smoke cloaked the nearby foothills, and the mountains in the distance were completely obscured by the wall of gray.
I suddenly saw my symptoms in a new light, and I felt silly for not putting the smoke-caused irritations together sooner. I grew up in Montana, after all, and wildfires are a hallmark of summer. When I got home, I checked the fire maps from the National Oceanic Atmospheric Administration (whose white masses representing smoke are drawn in by hand every day) to see which nearby forest was going up in flames. Turns out, the blazes polluting my view and irritating my body weren’t close by—they were in Alaska and Canada. “Daaang,” I thought. “That stuff can travel.”
Then I talked to Christine Wiedinmyer, a chemical engineer with the National Center for Atmospheric Research in Boulder, Colorado—and a little obsessive when it comes to wildfires, specifically the smoke plumes the blazes produce. “I try to record when there are hazy days where I live, and I’m always surprised at how many there are,” says Wiedinmyer. Around the time of my grumpy run, however, even she was “blown away” to wake up to hazy skies. That’s because she was in Atlanta—and the smoke she saw had blown all the way down to the Gulf of Mexico from those wildfires in Alaska and Canada. “We’re talking thousands of miles,” says Wiedinmyer, who was impressed with local weathercasters who accurately attributed the pollution to fires and warned locals of the poor air quality.
Ask most folks, and they’ll probably say the only people at risk from wildfire are firefighters and those living in conflagration hot spots—like California, where the out-of-control Rocky Fire north of San Francisco is busy consuming 43 homes, 70,000 acres and counting. But as we’re seeing this summer, that’s not the case. Smoke plumes can carry dangerous gases and toxins hundreds or thousands of miles, exposing hundreds of millions of Americans each fire season to harmful particulates. Even as the United States continues to make strides to reduce air pollution—here’s looking at you, Clean Air Act and Clean Power Plan—the risks from smoke plumes are only likely to worsen as climate change continues to spur bigger, badder fires.
Wildfire seasons are nearly 20 percent longer today on average than they were 35 years ago, found a recent Nature Communications study. These long-winded burns are connected to changes in vapor pressure and the timing of snowmelt and spring rains—all of which have been linked to climate change. “Conditions across the U.S. are becoming more conducive to fires,” Matt Jolly, lead author of the study and a U.S. Forest Service scientist, told Climate Wire. “We may be moving into a new normal. If these trends persist, we are on track to see more fire activity and more burned area.”
That uptick will spread more nasty wildfire byproducts into the air and around the country. The smoke can pour high into the atmosphere, where it can get pushed by the jet stream heading east. A 2013 NRDC report found that about two-thirds of people in the United States—nearly 212 million folks—lived in counties affected by smoke conditions in 2011.
“Wildfire smoke is a brew of bad stuff blowing downwind,” says Kim Knowlton, NRDC Science Center Deputy Director and an assistant clinical professor of environmental health sciences at Columbia University’s Mailman School of Public Health (disclosure). That includes harmful gases like NOx and ozone, as well as heavy metals, PAHs, and other fine particles. Short-term exposure to plumes has been linked to everything from asthma attacks to stroke to anxiety. People with preexisting respiratory and cardiovascular problems are particularly vulnerable, as are the elderly and the very young. One study found that babies whose moms had been exposed to wildfire smoke during pregnancy had lower birth weights. And even perfectly healthy folks (joggers, like yours truly) may suffer sore throats or itchy eyes when a haze descends.
Air-quality alerts are essential for warning people of the dangers that might be blowing through their area (like the ones I’d have seen if I’d turned on the news or opened the paper before I set out on my run), but when it comes to tools measuring fire pollutants, there is unquestionably room for improvement. We need a mix of real-time air-pollutant monitors, laboratory experiments, and satellites. It’s not simple to gauge what proportion of haze in a given area stems from a wildfire, much less what’s making up that smoke. The calculation involves understanding a bunch of small-scale processes, including emissions, transportation, and the changing chemical makeup of plumes. “Fires are just chaotic and challenging,” says Wiedinmyer. “Every fire is different.”
Wiedinmyer has developed a model, Fire INventory from NCAR, or FINN, that uses satellite observations of active fires to estimate daily emissions. Combined with chemical transport models, they can help quantify the impact fire emissions have on air quality. One of FINN’s limitations, says Wiedinmyer, is that it, like any model that relies on satellites, undercounts wildfires. “If a fire is too small or there’s a gap in the area it covers, you miss it.”
Wiedinmyer notes that FINN is “just one piece of the puzzle, one of many different efforts out there to understand how much fires contribute to air pollution.” Such research is about to get a big boost, through FIREX, or Fire Influence on Regional and Global Environments Experiment, NOAA’s five-year interdisciplinary effort to study how wildfires affect climate and air quality.)
In the meantime, anyone looking to breathe a little easier during wildfire season can take precautions. The CDC offers some excellent tips, including:
- Check air quality reports.
- Consult local visibility reports.
- Keep indoor air as clean as possible.
- Don’t be a dolt and go out for a run when a thick plume of wildfire smoke descends on your backyard.
Er, that last note might not be a CDC-approved message but rather one I wrote to myself.
onEarth provides reporting and analysis about environmental science, policy, and culture. All opinions expressed are those of the authors and do not necessarily reflect the policies or positions of NRDC. Learn more or follow us on Facebook and Twitter.