COVID-19 is in the air — literally. Research has shown that the coronavirus can be transmitted via tiny fluid particles in the air (known as aerosols), and so many of us are thinking a lot about the cleanliness of the air we breathe. One of the ways that people are seeking to protect themselves is by using air filters or air purifiers to remove harmful particulates from the air, but do air purifiers really work to kill the virus? And when there’s not a pandemic, do air purifiers work to protect your health in other ways? Read on to learn the answers to these questions, plus our recommendations for the best air filters and more.
What’s the Difference Between Air Filters and Air Purifiers?
The first thing to get straight is the difference between an air filter and an air purifier. While the terms are often used interchangeably, there is indeed a difference. Still, there’s a lot of overlap between the two products, and both have the same end goal: to make the air in your home cleaner (which is important, because indoor air pollution is a major issue). Where they differ is in how they clean the air.
Air filters do just what the name implies: they filter the air. Air passes through the filter, which then physically traps particles like dust, pet dander, pollen, mold, and other particles in the air.
Air purifiers don’t filter out particulate matter, but instead actually sanitize the air around them. The way an air purifier sanitizes the air depends on the brand you buy, but some methods include negative ions, ozone, heat, or UV lamps. Many air purifiers actually have air filters inside them, providing a one-two punch of filtration and sanitization. Which types of particles are sanitized or trapped again depends on the brand of air purifier you get, but the aim of all air purifiers is to kill airborne pathogens that cause allergies and sickness.
While air filters work for an entire home via a whole house fan, air purifiers are generally only effective for the air in the room they’re in, not an entire house or apartment. If your apartment is small and air circulation is good, an air purifier might be enough, but larger homes or those without good air circulation would either need multiple air purifiers or a whole-house air filter in addition to the purifier.
Do Air Purifiers Really Work? What About Air Filters?
The claim of air purifiers is very attractive, but is it true? Do air purifiers really work? The research so far suggests that the answer to this question is yes. While it’s important to note that this research is still fairly limited, as air purifiers are a relatively new product, what’s been found so far sends a hopeful signal.
For instance, one study found that air purifiers were effective at reducing particles associated with allergic rhinitis (aka allergic responses like sneezing, watery eyes, scratchy throat, and congestion), while another found that running an air purifier inside the home helped remove particulate matter and improve allergy symptoms of the children who lived there. A third study, which looked specifically at air purifiers that work by emitting ions, found that the purifiers decreased particular matter and black carbon and improved lung strength in children in Beijing.
The natural follow up to the question “Do air purifiers work?” is “What about air filters?” The answer here is definitively yes, with research showing that air filters do a great job of reducing particulates and improving respiratory health. The most effective type of filter is a HEPA filter, which stands for “high-efficiency particulate air” and is most effective at trapping allergens, mold, and other irritants.
Conveniently, each air filter is tagged with a number that indicates just how effective it is: the Minimum Efficiency Reporting Value, or MERV. MERV ratings range from 1 to 20, with a higher number meaning the filter is more efficient at removing small particles. What humans need to watch out for are particles smaller than 10 microns, which can pass into our lungs. Even scarier are the particles 2.5 microns or smaller, which can penetrate deep into your lungs and cause more serious damage. Thankfully, HEPA filters with a MERV rating of 17 or more can protect against all of these particles. While it’s widely reported that HEPA filters can only capture particles 0.3 microns or larger, according to NASA, HEPA filters are actually most effective at trapping super tiny particles, operating at almost 100% efficiency at 0.01 micron.
While air filters can’t protect against everything and air purifiers are still relatively new, the research and the experts say that they’re both a good bet for protecting yourself against indoor air pollution. So do air purifiers really work? We think our friends at EWG said it best:
Though no air filter alone will fully clean the air, you can improve the quality of the air in your home with filters installed in your central heating and cooling system, or with a portable air purifier.
What Are Air Filter and Air Purifier Benefits?
So it seems like air filters and air purifiers do a good job of removing or neutralizing air pollutants. But why does this matter for your health? What are the actual benefits?
Well first, it’s important to understand the risks of indoor air pollution. According to the EWG, exposure to pollutants in the home has been linked to serious health issues, including asthma, respiratory irritation, and even cancer. These conditions are serious at all times, but given that COVID-19 is a virus of the respiratory tract, they’re even more concerning today.
The good news is that, since air purifiers and air filters clean the air we breathe, most of their benefits have to do with the respiratory tract. Air purifiers can help alleviate symptoms from allergies, asthma, and COPD. Meanwhile, air filters can reduce symptoms from the same conditions, with studies showing they can reduce and prevent respiratory issues.
In order to get these benefits, it’s important to use air filters and air purifiers correctly. For an air filter, that means only choosing the best air filters, which means a HEPA filter with a MERV rating of 11 or higher, as recommended by the American Lung Association. It also means installing the filter correctly, cleaning up dust buildup, and replacing the filter regularly.
For an air purifier, it’s equally important to change the filter regularly (if the purifier has one). You should also make sure to follow the manufacturer guidelines to a tee, and leave the air purifier on at all times to maximize effectiveness.
Can Air Purifiers or Air Filters Protect You From Coronavirus?
So given all of the above, how do air filters and air purifiers relate to the current coronavirus pandemic? Can they help protect you and your loved ones from COVID-19? The answer to that question largely depends on how the coronavirus is transmitted: if the virus is transmitted through the air, air filters can help. Otherwise, not so much. The way COVID-19 passes from person to person is still uncertain, but given what we know, it seems that while air filters and air purifiers are definitely not a primary line of defense against the virus, they can offer some degree of protection.
According to the CDC, the main way the virus is transmitted is through person-to-person contact and by contact with droplets from coughs or sneezes that contain the virus. Droplets from coughs or sneezes are definitely airborne, suggesting airborne transmission happens, until you consider the fact that these droplets are only airborne momentarily before settling onto surfaces within a 6-foot radius.
However, there is ongoing research suggesting that COVID-19 can be transmitted through aerosolized particles — in other words, that it can float and travel around in the air while remaining infectious. No conclusion has yet been drawn, with various experts taking different stances, but a committee from the National Academy of Sciences told the White House that it believes the virus is transmitted via the air.
If you can, indeed, contract the virus from the air you breathe, then air filters can help protect you. With a diameter of 0.125 micron, the virus that causes COVID-19 is very small — but not so small that an air filter can’t catch it. Remember, HEPA filters are extraordinarily efficient at capturing any particle 0.01 micron and above.
Another way that air purifiers can help protect you is if you are quarantining with a healthcare worker or someone who has possibly contracted COVID-19. By running the air purifier in the room of the person who has or may have been exposed to the virus, you sanitize that air and thus protect the other people in the home from exposure.
The Best Air Filters and Air Purifiers to Buy for Your Home
Regardless of whether they can protect you from coronavirus, it’s clear that air purifier and air filter benefits are real — but choosing which one to put in your home can still be challenging. To help you out, we did some in-depth vetting and found the best air filters and air purifiers for you.
Before we get to the brands, let’s establish the criteria for selecting the best air filters: First, and foremost, you want to make sure you’re getting a true HEPA filter (not “HEPA-like” or “HEPA-type,” which are terms sometimes used in marketing. Then, look for that MERV rating, ideally of 17 or higher, but definitely over 11. You’ll also want to look for a second rating, the CADR (clean-air delivery rate), which measures the cleaning speed of a filter. For a CADR, you want a rating of at least 300, ideally over 350. Lastly, look for the AHAM (Association of Home Appliance Manufacturers) seal, which indicates that the air filter or purifier meets certain standards related to safety, efficiency, and performance.
So without further ado, here are a few of the best air filters and air purifiers for your home, vetted by us:
FilterBuy air filters: These are great choices for whole-house air filters for your home. Make sure to choose one with a MERV rating of 11 or above!
Fellowes AeraMax Baby: Specifically made for a baby’s room, this ultra-quiet air purifier has dimmed lights for nighttime and a true HEPA filter plus antimicrobial treatment.
Molekule: Molekule makes various air purifiers of different sizes, and they use a proprietary technology called PECO instead of HEPA. PECO, which is short for photoelectrochemical oxidation, is a chemical process that removes not only airborne particles (which is what a HEPA filter does), but also gases.
Awair: This isn’t an air filter or air purifier, but it does provide a simple and satisfying way to answer, once and for all, the question, “do air purifiers really work?” Awair makes several different air quality monitors that allow you to measure and track the air quality in your home over time. It’s a great choice thing to have if you buy an air purifier and want to see quantifiable improvements.
(BTW — if you want recommendations for other health-boosting items to have in your home, check out the WellBe Non-Toxic Product Lists, where you’ll find 1,200+ vetted and researched non-toxic products, from food to sleep to beauty to home and more.)
Takeaway: So, Do Air Purifiers Really Work?
Based on the existing research, we feel confident saying that an air filter or air purifier will help you improve the air quality in your home, and thus your overall health. Just remember these key facts when it comes to devices to clean your air:
Air filters trap particulate matter in a filter, and operate through a forced-air system that filters air for an entire home. Air purifiers, however, use various modes of technology (sometimes including a filter) to actually neutralize and sanitize the air immediately surrounding them (generally only one room).
Much research has confirmed that air filters do a great job of filtering out air pollutants like allergens, pet dander, mold, and other harmful particles. Less research has been done on air purifiers, but signs indicate that they are also effective at removing particles from the air.
Benefits of air filters and air purifiers include reduced symptoms of respiratory issues, including allergies, asthma, and COPD.
While it’s still uncertain whether airborne transmission is a factor in the spread of COVID-19, signs point to yes. And if this is the case, then HEPA air filters will do a good job of trapping particulate matter that contains the virus.
When choosing an air filter or air purifier, make sure you look for a MERV rating above 11, and always choose a true HEPA filter (unless you’re going with a Molekule, which has its own proprietary technology, called PECO).
To ensure you end up with the best air filter or air purifier for you, refer to the list above, which includes brands that have been fully vetted by third-party experts.