What Science Tells Us About the Dangers of Wildfire Smoke
Wildfire smoke is particularly bad for humans, and that has to do with both the size of the particles involved and what those particles are made of.
Dark orange skies caused by wildfire smoke hang over San Francisco in September 2020.
Photographer: San Francisco Chronicle/Hearst N/Hearst NewspapersAs thick layers of smoke from hundreds of Canadian wildfires descended on a large swathe of North America this week, millions of people were urged to stay indoors, run HEPA filters and venture outside only with a high-quality face mask. Wildfire smoke, a seasonal hazard in parts of the US, had virtually overnight become an everyone problem.
“It’s a risk to our health,” says Christine Wiedinmyer, the associate director for science at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. “It’s everything from respiratory impacts like asthma to cardiovascular outcomes. There’s been evidence that women who are exposed to wildfire smoke during pregnancy have statistically lower birth weights."