Coronavirus FAQ: Is It A Good Idea To Buy An Air Filter For My Home?

Do you remember how hard it was to buy Lysol hand sanitizer and wipes in March? (Not to mention yeast!) Back then, not many people had portable air washers or air purifiers. However, engineers and doctors say these devices could play an important role in protecting your family from COVID-19, especially if people spend more time indoors when the temperature inside the house starts to rise. . The outside air in the northern hemisphere is decreasing.

"It's a relatively easy way to get clean air in a place where people are in close contact," says Joseph Gardner Allen , associate professor of exposure assessment science who leads the Buildings program. healthy at Harvard TH Chan School of Public Health. "It's a simple plug-and-play solution in this area." (Bought in March).

If you given the new awareness of the role that aerosol microdroplets could play in disseminating COVID-19, quickly buy a portable air cleaner for home use?

The short and frustrating answer is, "It depends."

It is believed that the coronavirus can be transmitted in a number of ways, although less is known how each contributes to the transmission of the disease. These possible transmission methods include particles in the air from short distances, ballistic droplets from coughing or sneezing, particles in the air from long distances, and contaminated surfaces.

Portable air purifiers can limit the spread of the virus through long-range airborne particles by trapping most of those particles in a HEPA filter and cleaning the air at up to six times the speed. per hour. In a typical house without an air filter, the air is completely changed every two hours by an air leak, often using mechanical ventilation systems in newer homes.

Therefore, portable air purifiers provide an extra layer of protection under the right circumstances.

If you live alone and have no guests, you won't be adding any protection (against COVID-19 anyway ... you might want one to fight cat dander or devastating smoke).

However, if you're hosting the occasional family member who works on the frontline, planning a learning module for kids, or your student comes home from an on-campus exhibition, the benefits are likely worth it. costs. What if someone in your household gets COVID-19? The investment is definitely worth it.

The exact meaning of air purifiers is a bit open, but Richard Corsi , Dean of the College of Engineering and Computer Science at Portland State University, used models and tested air purifiers. Portable air with obvious benefits that greatly reduces particulate levels. a great bedroom in your home.

Why do some doctors wonder if portable air purifiers can get rid of the virus?

You are just wrong, say Corsi and Allen. In fact, they are wrong in two ways, says Allen. HEPA filters remove at least 99.97% of the particles in the air that are 0.3 microns in size, and even more particles of other sizes, smaller or larger.

"And the virus is never naked in the air," he says.

While the virus is about 0.1 micrometers in size, or one-thousandth of the cross-section of a human hair, it is released into the air, embedded in a particle of mucus and saliva, Corsi says. "It cannot survive outside of this particle," he says. "And these particles can be easily removed with HEPA filters."

Of course, portable air purifiers are not a quick fix. They provide an extra layer of protection, "not a substitute for anything else. And that wouldn't change how well I do all other things," says Abraar Karan , a doctor at Harvard Medical School. "We know masks and distance are important, but when aerosols spread them, staying two meters from people may not be enough."

To put it numerically, masks offer a risk reduction of at least 50%, says Corsi. A personal air filter could reduce this 50% more, which equates to an overall risk reduction of 75%. The increase in ventilation could be reduced to 85% or 90%. However, if you remove the mask, that percentage drops.

How to Buy a Portable Air Filter

Look for a unit with a HEPA filter and a clean air flow (CADR) of 300 cubic feet per minute (not per hour) or better and not much more, says Corsi. "You don't need any other device," he says. In fact, sometimes more bells and whistles can produce ozone, so it's best to keep it simple. Use this tool, which Allen helped design for classrooms, to work out the size you need for your space. it works for the home too, he says. Prices are on the order of $ 250.

How to use

This in turn depends on your individual situation. In general, place the air purifier near the person whose germs you want to avoid (e.g. in the room of a person suffering from COVID-19). When Corsi greeted a father who works in nursing homes, he and his wife installed a portable air purifier in their guest room and downstairs, as well as masks and opening windows. They added a fan in their guest room that blew air.

Conclusion

The only downside to a personal air purifier is the cost (in addition to the initial cost, you need to factor in the cost of replacement filters and energy). When thinking about buying, think about a healthcare tool, Allen suggests. And don't forget that personal air purifiers also remove chemicals, allergens, and dust.

For Karan, even without randomized controlled trials showing portable air purifiers prevent COVID-19, this is a simple calculation for most people who are not fully isolated.

"At this point, the potential benefits outweigh the costs," he says. "If more studies show that air purifiers could work and have an impact, you don't want to think, 'I could have.' ""

Sheila Mulrooney Eldred is a freelance health reporter based in Minneapolis. He has written about COVID-19 for Medscape , Mpls St. Paul Magazine , Science News for Students, and The Washington Post . Learn more at sheilaeldred.pressfolios.com . On Twitter: @milepostmedia

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