Throughout May, more than 140 wildfires have burned across Alberta and British Columbia. On Sunday, the thick, ashy haze billowing from these infernos drifted across the U.S. border, casting a blanket of smoke over Minnesota and Wisconsin, which eventually made its way to Iowa and other parts of the Midwest earlier Tuesday morning.
Counties throughout these Midwestern states have issued air quality alerts and warned residents to stay indoors until the smoke subsides. The problem? In many cases, wildfire smoke follows you inside, seeping through the cracks and crevices of a house or building.
As warmer temperatures and drier conditions fuel more frequent and severe wildfires, an emerging field of research is uncovering the pernicious threat of poor indoor air quality from wildfire smoke. For today’s newsletter, I am parsing this veil of smoke to investigate the ways poor indoor air quality could affect individuals—and how experts are trying to keep indoor air clean.
Polluting From the Outside In: The “dirty secret” of outdoor air pollution is that you are breathing most of it when you’re inside, according to Joseph Allen, the director of Harvard University’s Healthy Buildings Program, where he studies indoor air quality.
“That sounds wild and maybe even incorrect but it’s right,” Allen told me. He broke down the numbers for me to explain how that works: While a typical older home in the U.S. has about a 50 percent infiltration rate of outdoor pollution air seeping in, the catch is that Americans spend around 90 percent of their time indoors. So even though there are less pollutants inside, people can still be exposed to harmful levels of smoke during a wildfire event, which has been associated with a slew of health risks, from cardiovascular issues to asthma flare-ups.
