How to pick the best air purifiers in 2022, according to experts

In addition to physical distancing, wearing face masks, washing your hands and getting vaccinated, one of the Covid mitigation strategies the Centers for Disease Control and Prevention (CDC) recommends is improving ventilation indoors, and one of the ways to do so is by using an air purifier. The organization states that improving ventilation — which can also be done by opening windows and using fans — can reduce the spread of Covid and lower the risk of exposure, and it specifically recommends using portable high efficiency particulate air (HEPA) fans and filtration systems to enhance air cleaning. The CDC also states that portable air cleaners with filters less efficient than HEPA filters can contribute to cleaning the air in rooms.

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As indoor public spaces like schools, offices and restaurants open across the country, many are adding air purifiers to rooms, especially as concerns over Covid variants spark changing CDC masking guidelines and vaccination requirements. Companies like Dyson are even selling air purifier models specifically designed for businesses. And if you already experience irritation from dust or allergens or have asthma, allergies or other respiratory conditions — or live in an area with frequent wildfires — it may be smart to invest in an air purifier, said Josh Davidson, MD, an allergy and immunology specialist in California.

“We are all trying to do what we can right now. It’s one of those factors that can only help, given everything that’s happening,” he said. “Don’t run out and buy air purifiers in mass and hoard them like toilet paper, but consider it, especially if you are at higher risk.”

We consulted experts to learn more about air purifiers and how they differ from air cleaners and filters. We also dug into how air purifiers may help decrease the spread of Covid indoors. Here’s what you need to know about air purifiers and some tips for figuring out which air purifier is best for you.

Do air purifiers prevent coronavirus? No.

Air purifiers do not prevent the spread of coronavirus, but the CDC states that portable HEPA filtration units specifically “are effective at cleaning air within spaces to reduce the concentration of airborne particulates, including SARS-CoV-2 viral particles.” Formerly, the World Health Organization (WHO) and other groups were resistant to acknowledge the spread of Covid through the air. But such groups now agree that airborne transmission is one of the main ways Covid spreads, which the CDC describes as “breathing in air when close to an infected person who is exhaling small droplets and particles that contain the virus.”

Previously, Varghese explained that simply filtering airborne particles wouldn’t help stop the spread of the virus, given the small size of coronavirus particles — according to the CDC, the particle size of Covid is around 0.1 micrometers, which is less than the 0.3 micron limit for HEPA filters, Varghese added. However, the CDC notes that “the virus generally does not travel through the air by itself,” and is often trapped in larger droplets like respiratory droplets and other exhaled particles, which are less than 5 microns in size. Thus, “HEPA filters are no less than 99.97 percent efficient at capturing human-generated viral particles associated with SARS-CoV-2,” according to the CDC.

The difference between air purifiers, air cleaners and air filters

Air purifiers are often conflated with air filters, but they differ slightly, said John McKeon, MD and CEO of Allergy Standards — an organization that certifies products as “asthmas and allergy friendly,” among other things.

Air filters trap and collect dirt and debris in a filter, and are commonly found in heating and ventilation systems. They can significantly reduce the amount of pollutants, allergens and dust in your home.

Air cleaners remove more particulate from the air than the average filter, said McKeon. The device consists of a fan to draw air in and a filter to remove particulate from that air. While air cleaners often include filters, they are overall more robust in cleaning the air than air filters. Regardless, most companies will use the terms air cleaner and air purifier interchangeably.

Air purifiers use a process to “deactivate” airborne toxins like pathogens, McKeon explained. Some purifiers use ultraviolet light sterilization to kill mold and bacteria while others use an electrostatic filter to draw particles to metal plates. Most air purifiers rely on a combination to trap as many particles, gases and bacteria as possible.

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What is a HEPA filter?

You’ve likely seen this designation on air purifiers and other products before. HEPA stands for “high efficiency particulate air.” HEPA filters are physical filters designed to clear out at least 99.7 percent of particulates that are 0.3 microns or larger in size