Best NIOSH

As people become increasingly concerned about the "tripledemic" — the simultaneous circulation of Covid-19, the flu and respiratory syncytial virus (RSV) — many are opting to wear face masks in public spaces or restock their supply at home. We’ve previously highlighted disposable and cloth masks in our guides, but if you’re looking for the best protection, the Centers for Disease Control and Prevention say you should look for respirators like N95s. President Joe Biden even announced an initiative to get free N95s into Americans’ hands earlier this year, which has now rolled out across the country.

SKIP AHEAD Where to get free N95 masks | Can you reuse N95 masks? | Should kids wear N95s?

According to the CDC, when worn consistently, well-fitting respirators approved by the National Institute for Occupational Safety and Health — including N95s — "provide the highest level of protection from particles, including the virus that causes COVID-19." The CDC further sorted everything by efficacy, prioritizing respirators above masks and emphasizing the importance of a proper fit:

The CDC stopped short of directly recommending one mask over another, saying Americans should "wear the most protective mask you can that fits well and that you will wear consistently." But medical experts have been encouraging the public to make respirators their first choice for face coverings at this point in the pandemic, as they told us in our guide to KN95 masks. (Most people use "mask" and "respirator" interchangeably, but when the CDC and medical professionals say "respirator," they specifically mean fitted face coverings with certified filtration, like N95s, KN95s and KF94s).

To learn more about N95s, we consulted medical experts about who should use them, when to wear them and how to source and shop for them. We also compiled highly rated N95s that are approved for use by NIOSH and available online.

Experts told us you should only purchase N95s listed on NIOSH's list of approved models — they’ve undergone specific testing to meet NIOSH's performance and quality requirements, among those a check on ensuring they filter out at least 95 percent of very small particles (0.3 microns in size). There are also some specific features to look for in an N95 including:

There are dozens of N95s featured on NIOSH's list of approved models but some of them are surgical N95s, which the CDC said should be reserved for medical workers. After filtering those out, we chose the models below, each meeting NIOSH requirements and expert-recommended criteria — they’re also all available online and have earned high average ratings from users. Some N95s come packaged together, while others are individually wrapped, which we indicated below.

DemeTECH's N95 has a foldable design, meaning it folds flat when it's not in use. The respirators are available in a pack of 20. They’re designed with five layers of material, an adjustable nose bridge and two head straps.

3M's Aura N95 Respirator is available in a pack of three, 10 or 20. It comprises a three-panel design and is foldable. The face covering is made to be low profile around the nose and eye area to accommodate glasses, and it has two head straps as well as an adjustable nose bridge. The respirators come individually packaged.

BYD's blue foldable N95s are designed with three layers of material and come individually wrapped in a pack of 20. The respirators have two head straps and an adjustable nose bridge.

Harley's N95s are built with two latex-free head straps and an adjustable nose piece that has a piece of padded foam underneath for added cushioning. The respirators are foldable and come in a pack of 20.

Aegle's N95 respirators are foldable, have two head straps and an adjustable nose bridge. They come in a pack of 50. The brand offers anti-counterfeit verification through programmed near-field communication tags — the brand says that by using an NFC-enabled device like some Android and Apple products, you can learn more about the product, including details about its testing and manufacturing.

Protective Health Gear's N95 respirators are foldable and come with elastic head straps as well as an adjustable nose bridge. They feature four layers of material and are available in a pack of 20 or 50. The respirators come individually wrapped.

The pouch design of Kimberly-Clark Kimtech N95s creates a large breathing chamber, making it easier to talk while wearing the respirators, the brand says. They’re built with two head straps and an adjustable nose bridge. The N95s come in a pack of 50.

Makrite's N95 respirators have two head straps and an adjustable nose bridge. They’re foldable and come in a pack of 40.

WellBefore's N95 respirator offers four layers of protection and is available in a flat-fold design. It comes in white or black and is built with adjustable head straps and an adjustable nose piece. The N95s are individually wrapped and come in a 10-pack.

Honeywell's N95s fold flat when they’re not in use. They have head straps and an adjustable nose clip with a foam cushion that the brand says helps create a tight seal against the face. Masks come in multipacks ranging from five to 50 per box.

Aidway's N95 mask offers five layers of protection and has a flat-fold design. It's built with two elastic head straps as well as an adjustable nose piece. You purchase the masks in packs of 10, 20, 50, 100, 500 or 1,000.

Breath Healthy's flat-fold N95 mask comes with two wide elastic head straps and an adjustable nose piece. They come in a pack of 20 and are available in black and white.

BNX N95 masks fold flat when they’re not in use and have two latex-free head straps. They come with an adjustable metal nose bridge and are available in a pack of 10.

You can purchase Shawmut N95 respirators in a case of 10, 20, 40 and 240. The masks are built with a piece of foam that lines the inside of the adjustable nose piece, which the brand says helps reduce eyeglass fogging. The N95 respirators have two elastic head straps and come in small and medium/large sizes.

In early 2022, the Biden administration rolled out a program to provide free N95 masks to Americans. The respirators are available at pharmacies, supermarket pharmacy chains and community health centers nationwide. If you’re looking to find free N95s near you, the CDC offers an online locator tool — you can plug in your zip code and search for free N95s in your area. The CDC's website also lists the N95 models being given out with details about their NIOSH approval and instructions on how to wear them properly.

Buying N95s is simpler than buying international respirators like KN95s or KF94s because they're regulated in the U.S. by NIOSH, according to Dr. David Rempel, a professor in the Department of Medicine at the University of California, San Francisco.

When NIOSH gives an N95 its stamp of approval, it means "the respirator has met very specific requirements for testing. It is a quality assurance indicator that the respirator will perform as expected," explained Dr. Stella Hines, an associate professor in the Division of Pulmonary and Critical Care Medicine at the University of Maryland School of Medicine.

Medical experts told us all N95s — whether they come in cup, flat fold or duckbill shapes — should at least have the following features:

Rempel said you should not buy N95s that feature exhaust ports, which holds true for all face masks. The CDC also states that "special N95 respirators labeled as ‘surgical’ or ‘medical’ should be prioritized for healthcare workers."

Regardless of the type of mask you wear, it won't protect you or the people around you unless you wear it correctly. The CDC recommends making sure your mask completely covers your mouth and nose and fits tightly against your face to prevent gaps around the sides of the mask, nose and chin.

Hines said in settings where workers are required to wear an N95, like some construction zones and healthcare settings, they must complete an official fit test. The public, however, does not need to do a formal fit test before buying and wearing an N95. Regardless, Hines emphasized that you should still check to see if your respirator fits properly before wearing it in public.

"N95 respirators will provide the regulated, expected level of protection to the wearer only if there is a good seal to the face," she said. "You want a good seal so that all of the air that is breathed in is pulled in through the mask body. That is where all the filtration of particles and microbial contaminants occurs."

Rempel said you can do an at-home leak test with an N95 by putting it on and breathing out. If you can feel the air under your chin or around your eyes, it's not tight enough. And Hines added that if your glasses are fogging up while wearing an N95, there's leakage and it's not tight enough.

All masks— and models — fit differently, and features like adjustable ear loops and an adjustable nose bridge help you improve the fit of your mask, as do mask fitters or braces, according to the CDC. Using a fitter or brace is especially a good idea for people with facial hair, which can make it difficult to achieve a tight fit.

The CDC has said you should not double-mask while wearing an N95 or KN95 mask. You should not wear respirators with exhalation valves or vents, either, according to the CDC — this guidance applies to all masks.

Technically, N95s are disposable, single-use face coverings. But if you remove and store an N95 properly, you can reuse it multiple times — simply put, that entails taking the mask off by its head straps and then storing it in a paper or mesh fabric bag between uses, the CDC says.

Hines said N95 manufacturers often provide instructions for the suggested length of use on the box or online. But in general, you should throw out your N95 if it gets damaged — if it gets crumpled up in your bag, for example — or if you can no longer achieve a tight seal to the face. You should also replace your N95 if it gets wet, dirty or contaminated.

N95 respirators are not intended for use by children and have not been broadly tested on them, according to the CDC. However, some brands offer N95s in small and large sizes, and smaller N95s may fit some children's faces. Select brands make kids KN95s, too. When it comes to kids’ face coverings, the CDC said it's most important to choose a well-fitting and comfortable option to reduce the chance of children removing it often or wearing it incorrectly.

To recommend when Americans should wear face masks, the CDC determines an area's Covid-19 Community Level risk on a scale of low, medium or high. To do so, it analyzes how many Covid-related hospital beds are in use, hospital admissions and the total number of new Covid cases in that area. Each Covid-19 Community Level corresponds to a masking recommendation — suggested precautions increase alongside the level. To determine your area's Covid-19 Community Level, use the CDC's Covid-19 county check.

The CDC's order requiring masks on public transportation and at transportation hubs is no longer in effect, and many airlines also ended their mask mandates this spring. However, CDC said it "continues to recommend that people wear masks in indoor public transportation settings," despite being unable to enforce any rules. Before you use a specific public transportation system in your area, be sure to double check its mask requirements as they can change at any time.

Experts have repeatedly stressed that masks help reduce the risk of viral transmission. One 2021 CDC study found that, between two properly masked or double-masked people, the risk of one giving the other a virus was cut by over 95 percent. Masking up also protects other people, as demonstrated in numerous studies like these gathered by the CDC.

At Select, we work with experts who have specialized knowledge and authority based on relevant training and/or experience. We also take steps to ensure that all expert advice and recommendations are made independently and with no undisclosed financial conflicts of interest.

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Zoe Malin is an associate updates editor for Select on NBC News.