Sept. 14, 2022

A hack to stop hacking from smoky skies? Look no further than your N-95 mask

UCalgary air quality expert says N-95 masks are good defence against wildfire pollutants
students wearing masks sitting on a bench
UCalgary students wear masks on campus. N-95 respirators are effective against wildfire pollutants. Michael Platt, University of Calgary

There’s not much that’s convenient about a sky full of wildfire smoke — but the timing of this year’s blast of burning British Columbia means protection is probably close at hand.

That’s according to a UCalgary expert in air pollution, who says the same N-95 masks we’ve been using to avoid COVID-19 are also a useful defence against the particulates that lead to sore throats and stuffy noses.

“The short-term exposure to high PM2.5 concentration can cause sensitive people irritation in their respiratory system, and the N-95 mask is designed to remove 95 per cent of particles smaller than 0.3 microns,” explains Dr. Ke Du, PhD, an assistant professor at the Schulich School of Engineering.

“The removal efficiency will be higher for particles greater than 0.3 microns. So, this mask is effective to reduce PM2.5 exposure for people working outdoors.”

Soot, metals and soil

Basically, the filter in the recommended COVID mask blocks most microscopic pollutants that are carried in wildfire smoke, which can include “ acids, inorganic compounds, organic chemicals, soot, metals, soil or dust particles, and biological materials,” according to the U.S. Environmental Protection Agency.

Du, whose research includes air pollutants in urban areas, says ideally people caught in a high PM2.5 environment (PM2.5 is hazardous fine particulate matter two-and-one-half microns or less in width) should stay indoors, especially in spaces with modern HVAC systems.

“During high PM2.5 events, it is recommended to stay indoors as HAVC systems often have HEPA filters to remove particles entering the building from outside,” he explains.

Smoke across the West

Smoke from wildfires in British Columbia, as well as Washington and Idaho, has prompted air quality advisories across B.C. and Alberta.

Environment Canada has extended air quality statements across southern Alberta, with similar conditions expected for the next few days.

  • Masks are no longer required on UCalgary campuses, but are still required in some settings. Learn more