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Published Mar. 22, 2022

Two years (and counting) into the COVID-19 pandemic, most of us have gotten used to wearing a face mask. Since the disease’s earliest days, cloth masks offered a convenient and stylish way to don the essential accessory, but most common textiles aren’t great at filtering out the tiniest droplets, called aerosols, that might carry the SARS-Cov-2, the virus that causes COVID-19. As the highly contagious Omicron variant dominated virus cases in the US and around the world, the CDC leaned on recommendations for switching to a high-filtration mask (also called a respirator). These masks—which bare standards like N95, KN95, and KF94—will provide you with the highest level of protection from COVID-19. In January 2022, the US government started a program giving out free N95s at pharmacies. Anyone can also supplement the freebies with readily available and relatively inexpensive options, as well. But how do you know which of these masks will provide the best protection? Here’s what you need to know to pick the right one.

How we chose the best high-filtration masks

To learn the science behind high-filtration masks, we talked to three engineers with expertise in aerosols, three doctors in areas like infectious diseases and emergency medicine, a nurse with expertise in disease prevention, and a pediatrician (for the wee faces). We also referenced the facewear-centric YouTube channel of self-styled “mask nerd” Aaron Collins—a mechanical engineer with a background in aerosols who’s been testing the masks on his and compiling the results into a publicly available spreadsheet—as well as the testing by mask company Armbrust. In addition, we consulted scientific studies about general mask use and the effectiveness of high-filtration models, though few formal studies have compared different brands.

Based on our expert source’s experiences with masks and filtration data, we selected eight adult masks and four children’s masks to try out ourselves. We also tested four ways to make a surgical mask more effective. We evaluated the options based on their fit and comfort, while also making sure the masks didn’t leave any gap that allowed exhalations to escape—and that they were easy to put on and to wear for long periods of time.   

Things to consider before buying a high-filtration mask

Filtration

N95, KN95, and KF94 masks all have high filtration efficiency, meaning the materials they are made of, which usually consist of several layers, are extremely effective at filtering out tiny particles. These materials, such as polypropylene, are usually non-woven and sometimes carry an electrostatic charge, which attracts these particles and traps them in the filter. N95 masks are approved by the United States government agency the National Institute for Occupational Safety & Health (NIOSH). NIOSH greenlights these masks’ use for people in workplaces who are exposed to any kind of hazardous small particles, from viruses to smoke to remnants from construction or industrial processes. The “95” means that the mask is designed to filter out 95 percent of particles that are 0.3 microns across. (For comparison, a single human hair is usually between 50 and 90 microns wide.) Because of the way these filters work, smaller or larger particles would be filtered out more effectively. N95 masks attach to your face using headbands, creating a tight seal.

KN95 is a similar designation for masks in terms of filtration, but these masks meet standards set by the Chinese government. It’s more common for non-healthcare workers in the US to wear these than N95s. These masks also often have ear loops, making them easier to put on and more comfortable to wear than N95s, though there are some headband-style versions. This standard has, however, proven problematic: The CDC warns that many KN95s in The States are counterfeit, so if you choose this route buying from a reputable seller is key—and we prioritized varieties that have mechanisms for verifying their authenticity. 

KF94 masks are usually made in South Korea—the “KF” stands for “Korean filter,” while the “94” denotes 94 percent filtration of the same type of tiny particle. Like KN95s, the masks are used mostly by the general public and have ear loops. Though KF94s technically filter out 1 percent less particles than KN95s, they’re “really pretty close to a KN95,” says Nina Shapiro, a pediatric ear, nose, and throat doctor at UCLA Health. A very small August 2020 study also found that KF94s and KN95s provided similar protection.

Fit

Although there are small differences between these types of masks, no product will be effective unless it fits your face. A small January 2021 study found that even slight facial differences had a significant impact on how well any mask, even a NIOSH-approved N95, fits and therefore functions effectively.

“Everyone’s faces are different,” says Thomas Russo, professor and chief of infectious disease at the Jacobs School of Medicine and Bioscience at the University of Buffalo. “And masks are designed differently as well.” From cup-shaped and “duckbill” N95s, to KN95s that fold down the middle, to the boat shape of many KF94s, there are a lot of options to fit different face shapes and sizes.

If you’re trying to figure out if your mask fits well, “the best way to do that is that is to look around the seal itself to assure there are no gaps,” says David Marcozzi, chief clinical officer at the University of Maryland Medical Center and professor of emergency medicine at the University of Maryland School of Medicine. This means the mask forms a firm seal around your nose, mouth, and chin that conforms as closely as possible to the contours of your face.

You might be able to feel on your face if air is coming out of any gaps. “When you exhale, you can feel the jets of air coming out” if the mask doesn’t fit well, says Scott Sanders, a professor of mechanical engineering at the University of Wisconsin, Madison. You can also try holding up your hands to the edges of your mask while you exhale to see if you can feel the air that way. If you wear glasses, fogging them up might be a sign you don’t have a good seal; though “mask nerd” Aaron Collins points out in a video that minor fogging isn’t necessarily an issue, since a well-fitting mask can trap the warm, humid air of your breath as you exhale, causing it to flow upward and condense on your glasses.

Healthcare workers and others using N95 masks undergo a formal fit test. This includes using a spray with a scent, like banana oil, around a person’s head, and if the person can smell the spray with the mask on, the process gets repeated with a different mask until one passes the test. Obviously, the average person won’t go through this, but Marcozzi says you can try holding a lit match or lighter about six inches from your face with the mask on and blowing on it: If the flame wavers or goes out, your mask might not be working well. You can also smell perfume with the mask on and off to see if you can tell the difference.

Comfort

“If it’s an uncomfortable mask, it doesn’t matter how good it is if you’re not going to wear it,” says Shapiro. This is especially true for children, she says, who might just take their mask off if they think it’s uncomfortable. To be functional, a mask should also be breathable, easy to put on and take off, and wearable for long periods of time. Like fit, many of these things depend on your face shape and personal preference.

“For one person, they might find the elastic strap [around the head] something that is too tight, it’s uncomfortable, they don’t like dealing with it. And another person, it makes them feel more secure,” says Russo. “There’s a certain amount of individualization here in terms of what works best for you.”

The best masks: Reviews & recommendations

Best N95 mask: 3M Aura N95 

Why it made the cut: A favorite for its comfort and adjustable fit, this mask offers one of the best seals. 

Specs: 

  • Fit: Headband 
  • Nose piece: Foam padding and wire
  • NIOSH Certification: Yes

Pros: 

  • Excellent, adjustable fit
  • Tight seal
  • Very breathable, and no fogging
  • Great for smaller faces and head sizes

Cons:

  • Fit can be too tight

3M masks in general are one of the standards for industrial and medical uses. These have foam padding around the nose, making them more comfortable as well as better-fitting than many other N95s. Sanders calls the Aura mask “pretty forgiving” as far as the fit goes. “As long as you wear it,” he said, “you get a good seal.” Like many N95s, they are on the tighter side, but I found that once I got used to it, this mask was not uncomfortable—especially if, like me, you have a relatively small head and face. The mask is also very breathable and easily passed the glasses-fogging test, due to its foam and very flexible nose wire. The tri-fold “boat” shape, more common in KF94s, means the mask conforms more closely to the face than many masks, including the Powecom KN95.

Most comfortable N95 mask: Kimberly-Clark PROFESSIONAL N95 Pouch Respirator (a.k.a., the “duckbill”)

Kimberly-Clark

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Why it made the cut: Compared to other face-squeezing N95 options, this funny-looking respirator gains great points for its comfort. 

Specs:

  • Fit: Headband
  • Nose piece: Bendable wire
  • NIOSH Certification: Yes

Pros: 

  • Extremely comfortable
  • Excellent breathability
  • Fits most adult faces

Cons: 

  • Funny looking
  • Looser seal than some other N95s

Though these masks aren’t intended for healthcare workers, they’re true N95s. Plus: you’ll probably not find an N95 as comfortable, wearable, and easy to adjust as these bill-like offerings. With headband straps made of comfortable, stretchy fabric and broad, extremely bendable nose wire, they can adjust to fit snugly over almost any face, though not quite as snugly as the Aura masks. They are also super breathable. Their main downside is that they look a bit strange, which is why you likely won’t see as many in public places. Some people might also prefer tighter N95 masks if they feel that it gives them a more secure seal. But with a NIOSH certification, these masks will still protect you extremely well. If you want great protection and don’t care what you look like, these might be perfect.

Best KN95 mask: Powecom KN95 (ear loop version)

Powecom

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Why it made the cut: In a sea of potentially counterfeit masks, this comfortable, affordable option offers a way to verify its authenticity. 

Specs:

  • Fit: Ear loops
  • Nose piece: Adjustable wire
  • NIOSH Certification: No

Pros: 

  • Anti-counterfeit QR code
  • Fits well on small faces
  • Very breathable and no fog on glasses

Cons: 

  • Prone to copycats
  • Not US certified

Though these were my go-to mask before researching this guide, several sources also recommended these Chinese-made KN95 masks. They have a common bi-fold style and ear loops (though they’re also available with headbands), with a wire across the top to create a better seal around the nose. The masks are comfortable to wear even for long periods of time, take almost no time to put on, and fit even smaller faces like mine snugly and securely. 

They are also extremely breathable; I found mine to be far more breathable than a cloth mask. The nose wire also bends well to fit the shape of the nose with minimal adjustment, and did not fog up my glasses after I molded it in place. (Note: I do not typically wear glasses and tested each mask using clear blue light glasses and sunglasses.)

Powecom masks also come with an anti-counterfeit code that you can enter on their website to make sure the product isn’t a knock-off. The numbers are at the bottom of a small QR code on the bottom of the packaging, and you scratch off a protective coating in order to reveal them.

Best KF94 mask: Bluna Facefit KF94

Why it made the cut: Adjustable straps make this South Korean mask variety ideal for finding a fit that’s both comfy and snug. 

Specs:

  • Fit: Ear loops
  • Nose piece: Adjustable wire
  • NIOSH Certification: No

Pros: 

  • Adjustable ear loops
  • No glasses fogging
  • Somewhat stylish
  • Good for larger faces

Cons:

  • Can dig into noses
  • Not a great fit on smaller faces

This mask is unobtrusive, stylish, and conforms to the profile of the face without sticking out. The straps are adjustable, and I got the mask to conform well enough to my nose and cheeks to not fog up my glasses by substantially pinching the nose wire and pulling it away from my face. The mask forms a secure seal that, as the name suggests, fit my face, extending from the bridge of the nose to the very bottom of the chin (another KF94 mask I tested, the BOTN mask, only covered a portion of my jaw and chin, which felt far less secure).

While this mask is effective and convenient, it dug into the bridge of my nose, making it increasingly uncomfortable to wear over time. Because the mask was very large on me without adjusting the straps, I had to tweak them significantly to get a good seal around my chin—all of which possibly contributed to the mask’s tightness on the upper half of my face. This mask might work well for you if you have a wide chin and jaw, and a broad, less prominent nose.

Best mask to make a statement: MaskLab KF-style

Masklab

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Why it made the cut: Held to the same standard as other high-filtration offerings, this facewear offers a variety of colors and patterns that add a little extra flair. 

Specs:

  • Fit: Ear loops
  • Nose piece: Adjustable wire
  • NIOSH Certification: No

Pros: 

  • Available in a variety of colors
  • TIght seal
  • Good for larger faces

Cons:

  • Some glasses fogging
  • Not ideal for smaller faces
  • Nose wire doesn’t always hold its shape

Because these masks are made in Hong Kong, they are technically not true KF94s, but still conform to rigorous safety standards for high-filtration masks. This mask did not have adjustable ear loops, though it is easy to knot and/or twist the straps to adjust the mask (you can even make a slip knot for easier adjustability). The design of KF94s means this will not create any gaps or otherwise negatively impact the fit.

Besides the non-adjustable ear loops, this mask felt very similar to other KN94s. It formed a secure seal that went all the way down to cover my chin, but also dug into the bridge of my nose. The nose wire did not conform to my shape quite as easily as the one on the Bluna mask. Though I managed to bend it enough to avoid fogging up my glasses all but very slightly, the nose wire did not hold its shape as well as the one on the other mask. This mask might work well for you if you have a generally larger face and head, as well as the broad chin and less prominent nose described above.

Best mask for kids: BOTN Child Fit KF94

Why it made the cut: Of the four masks we tried, our pint-sized tester’s parents preferred this one due to its comfort and adjustability. 

Specs: 

  • FIt: Ear loops
  • Nose piece: Adjustable wire
  • NIOSH Certification: No

Pros: 

  • Adjustable ear loops
  • Tight seal
  • Comfortable

Cons: 

  • Flat black color may not entice kiddos 

This mask fit our tester, age 5, the best and most securely out of the four tried—largely because of the adjustable ear loops. As with adults, a high-quality mask is only as good as its fit, and because children have such variable face sizes, an adjustable mask like this one may be especially helpful. Our tester also preferred earloop masks over headband-style ones because they were easy to put on and didn’t mess up her hair.  

“Mask hacks” and alternatives

If you have a bunch of surgical masks and really don’t want to or can’t afford to invest in these high-filtration masks, there are a few ways that you can try to make your surgical mask more effective. Most surgical options are made of high-filtration material but do not conform well to the face. To give yourself a better seal, you can double-mask. One study published in American Journal of Infection Control found that wearing a cloth mask over a surgical one made protection about 85-91 percent effective at filtering out aerosols. You can also try this mask-knotting trick to make your face covering tighter-fitting.

Another option is using a mask brace, which gives you a tight seal by holding a surgical mask closely against the face. The same study found that an elastic mask brace can make your surgical mask up to 95-99 percent effective, similar to an N95. I tried three mask braces: the University of Wisconsin, Madison’s Badger Seal, Fix the Mask’s Essential Mask Brace, and a brace made from a Fix the Mask template that you can make yourself. 

At around 8 dollars for a pre-made brace, the Badger Seal was the most affordable as well as the easiest to put on. This brace isn’t made of purely elastic materials, but Aaron Collins found that it performed basically the same as Fix the Mask’s brace; when worn over a surgical mask, both made it so that the mask filtered out about 97 percent of the particles in his test. But here’s the bad news: I found these braces to be uncomfortable. They press down very firmly on the face, particularly the bridge of the nose. In fact, they are as tight as many N95s, but are harder to put on. Most people would prefer a KN95 or KF94 mask for comfort and convenience.  

FAQs

Where can I get N95 and similar masks?

The best way to get many of these masks is to order them online, though some pharmacies also carry them. Some N95 masks, like the 3M Aura ones, are also available at hardware stores that sell protective equipment for building and construction projects, such as Home Depot. If you do buy online, be sure to go directly to the manufacturer’s page—either their own or their dedicated page on Amazon.

When should I wear these masks?

You should consider wearing a high-filtration mask when you are in a crowded public, indoor space and cannot easily keep social distance from other people, especially if there isn’t good ventilation or air circulation. On February 25, 2022, the Centers for Disease Control and Prevention revised guidance on masking, recommending that people in high-risk areas wear masks indoors, while people in medium-risk areas should consider wearing a mask if they are immunocompromised or at risk of severe illness, or if they live with or interact with these people. The CDC also said that people in low-risk areas may still wear a mask based on personal preference. In situations where you might wear a mask, a high-filtration mask provides the best protection for you and others against the highly contagious Omicron variant.

How many times can I reuse these masks?

Though these masks were originally designed to be disposable after a single use, they can be reused. The CDC recommends that you should reuse an N95 or similar mask no more than five times, though it could be more depending on how long you’ve worn the mask during a given day and under what circumstances. 

Russo (and other experts PopSci has consulted) recommends that people rotate their masks out. One way to do this is to wear a new mask each day of the week. After a week, any viruses and bacteria on your mask will be dead, so it’s safe to wear these same masks on the same days of the next week. One way to do this is to keep used masks in separate, numbered paper bags when you are not wearing them. You can even number the masks themselves or mark them for each day of the week. 

That said, Marcozzi says that within reason, you can keep reusing masks for “multiple days” beyond the five times the CDC recommends as long as they look clean and undamaged on the inside and are not noticeably wet. If you’ve worn a mask long enough to stretch the ear loops out, he says, you need to replace it to get a good fit. You should never wash these masks; it will destroy them.

I’ve heard that some masks are counterfeit. How do I avoid buying fakes?

You can buy the masks above using any of our links, and suitable N95 masks that you buy from a hardware store are also safe. You should make sure, though, you are buying the kind without valves: Those won’t protect others as well if you have COVID-19, according to the CDC. You can also buy masks from the Project N95 website, which are vetted by healthcare professionals. If you are buying from Amazon, it’s better to make sure that the seller is the company that makes the mask, not a third party, and you can also check the reviews to see if anyone thinks the product is counterfeit. For KF94 masks, websites that sell Korean health and beauty products are usually good sources. You can also look up the company that makes the mask online and see if you can order it directly from them.

The final word on high-filtration masks

High-filtration masks like N95s, KN95s, and KF94s provide the best protection against COVID-19. For the best possible filtration, wear a mask that is a good fit for your individual face shape. These masks can be comfortable, breathable, and affordable, and in some cases, may be available for free. No matter how prevalent the virus is in your area, these masks can help protect you, your community, and the people you love from COVID-19.

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