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Watch this: Double threat/single solution: Air filters fight both smoke and virus

Watch this: Double threat/single solution: Air filters fight both smoke and virus


The COVID-19 pandemic has driven Americans to seek sanity and social distance in the outdoors fresh air. But in Montana, that outside air may soon carry a more routine health hazard — wildfire smoke. And as temperatures rise, so do the odds of forest fire ignition, just as Montana’s virus case count has swung upward.

Fortunately, the folks who’ve spent years working on ways to avoid breathing tiny toxic particles of smoke have worked up some advice for avoiding coronavirus at the same time. It turns out a properly set up portable air cleaner can trap lots of airborne hazards, both chemical and biological.

“For less than $40, you can have clean indoor air,” said Amy Cilimburg of Climate Smart Missoula. “This is something individuals can do for themselves, their neighbors, and their families. We know 30% of our population is more vulnerable to wildfire smoke, because of demographic or pre-existing conditions like age and respiratory disease. In Missoula, that’s more than 30,000 people. And when you think about COVID-19, if you start looking at who’s susceptible, it’s the same older folks with preexisting conditions.”

Extensive research has found that extremely fine airborne particles 2.5 microns or smaller pose serious health risks when inhaled. Both industrial pollution and wildfire smoke come loaded with such PM2.5 matter. According to a recent study by researchers at Harvard University’s T.H Chan School of Public Health, coronavirus appears particularly deadly in places with lots of fine particulate air pollution. That includes urban threats such as automobile exhaust, oil refineries and power plants.

A separate study led by University of Montana researcher Erin Landguth looked at the delayed impact that breathing wildfire smoke in summer has on influenza season the following winter. It found flu cases increased by 16% to 22% in Montana counties that were hit by heavy smoke from wildfires.

“I haven’t seen a case study with COVID and wildfire smoke, so the link is theoretical at this point,” said Missoula County Air Quality Specialist Sarah Coefield. “But we know even if you don’t have COVID, wildfire smoke is bad for you. This just kicks it up a notch in importance and urgency.”

To make matters worse, one of the best practices to stay healthy in the pandemic (letting lots of outside air into your home) is the exact opposite of the rule for protection from wildfire smoke (blocking outside air from getting indoors). And the previous advice to seek out public air conditioning in movie theaters, shopping malls and libraries has gone inoperative because pandemic protocols have closed most of those spaces.

Here’s where the solutions come in. It turns out a piece of filter material attached to a simple box fan (both available at hardware stores) can clean both smoke and virus particles out of indoor room air. Cilimburg said local mechanical engineer Tom Javins ran extensive tests on the designs to see if they can operate safely without burning up the fan motor. The result is a series of videos giving step-by-step instructions on building in-home air cleaners on the cheap. People can also sign up for a regular advice blog by Coefield providing more links to professional research and household responses to air pollution hazards.

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