When picking a mask, experts say emphasis on the fabric, fit and breathability.

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By Maria Godoy/NPR

(Washington) — so you desire to stay a face mask? good call.

A growing body the evidence supports the idea that wearing challenge masks in public, also when you feeling well, can aid curb the spread out of the coronavirus — because people deserve to spread the virus also without reflecting symptoms. That’s the key reason to wear a mask: to protect other civilization from you.

Face masks can also offer the wearer some security — though just how much varies greatly, relying on the type of mask. No mask will offer full protection, and also they need to not be regarded as a replacement because that physical distancing of at least 6 feet from others, regular hand-washing and also avoiding crowds. As soon as you incorporate masks through those measures, they deserve to make a large difference.

But what type of mask is best?

When picking a mask, experts say emphasis on the fabric, fit and breathability. How well a mask protects is a duty of both what it’s do of and how fine it seals to her face. But if you can’t breath well with it, then you’re much less likely to store it on.

Here’s a watch at different kinds that masks you can consider and also how reliable they room at protecting the people around you — and also you as well.

Since the Centers for an illness Control and Prevention says civilization should wear towel face coverings in public, we’ll talk about fabric masks first. However if you’ve purchased a clinical mask or respirator, scroll down for some necessary notes — like exactly how to clues if you’ve got a fake.


Max Posner / NPR

A neck gaiter and also a towel mask

Fabric Masks

First, take into consideration the cloth itself. “The tightness the the weave is really important. That’s the first thing I would certainly ask people to look into,” says Supratik Guha, a professor of molecular engineering at the college of Chicago and co-author that an oft-cited file in ACS Nano on the filtration efficiency of usual fabrics used in fabric masks. To check your fabric, host it up to a light: If friend can conveniently see the overview of the individual fibers, it’s no going to do a great filter.

Researchers speak a special 100% noodle weave is a an excellent bet. That’s since at the microscope level, the organic fibers in cotton tend to have an ext three-dimensional framework than man-made fibers, which room smoother, says Christopher Zangmeister, a researcher in ~ the national Institute the Standards and Technology. The 3D structure have the right to create an ext roadblocks that have the right to stop an just arrived particle, he explains.

Zangmeister co-authored a new study in ACS Nano that tested how well dozens of different materials filtered. While 2 synthetics, consisting of one that’s 100% polyester, go well, many synthetics ranked close to the bottom, the says. Yet even a mask made out of fabricated fibers is much better than no mask in ~ all, he says.

Think lot of layers. Guha’s study and also other study have found that masks make of multiple layers are an ext effective in ~ blocking small particles.

A an excellent option: a mask make of 2 layers of a thick-weave cloth with a built-in pocket wherein you have the right to place a filter, says might Chu, an epidemiologist at the Colorado school of Public wellness who co-authored a paper published top top June 2 in Nano Letters on the filtration efficiency of family mask materials.

The ideal bet for the product to on slide in together a filter is polypropylene, i m sorry is derived from plastic, states Chu. “If you walk to Walmart, girlfriend look because that Oly-fun, i m sorry is the brand surname of the fabric. It’s additionally called spunbond,” states Chu, who’s a clinical adviser to the people Health Organization and helped craft its recent detailed guidance on fabric masks.

Chu states polypropylene is good as a physical filter but has another benefit: that holds an electrostatic charge. In other words, it provides the power of revolution electricity. Think of the static cling that can happen when you rub 2 pieces of cloth together, claims Chu. That’s usually what’s happening through this fabric: the “cling” effect traps just arrived — and also outgoing — droplets. “That’s what you desire — the cling is what’s important,” Chu says.

And unlike various other materials, polypropylene keeps the electrostatic charge in the humidity developed when you breathe out, says Yi Cui, a professor of materials science and engineering at Stanford college who co-authored the Nano Letters study through Chu.


The room of Justice has actually issued one alert about a map circulating digital falsely claiming the holders space legally freed from put on a mask. Public health officials overwhelmingly recommend wearing a mask when going the end in public.

Cui and Chu keep in mind that polypropylene will lose its electrostatic charge once you to wash it, but you deserve to recharge that by ironing the or through rubbing it with a plastic glove for around 20 seconds. Once you’ve acquired static cling, ka-ching — you’re ago in business. Cui claims a two-layer thick-weave noodle mask alone can filter out about 35% of little particles. But adding a filter made out of two layers of charged polypropylene could boost that filtration performance by as lot as an additional 35%, Cui says. You still desire a noodle layer closestly to your face, he says, since it’s a much more comfortable material.

If friend can’t acquire your hands on polypropylene fabric, reach for tissues: Take two sheets of face tissue, fold them over and put them inside your mask’s pocket so the you finish up through a four-layer filter that you can readjust out daily. “Surprisingly, the 4 layers of paper gives you adequate protection,” says Chu — though tissues don’t have the added power of electrostatic charge.

If no of those space options, a mask do of three or more layers of strict woven noodle will additionally do a decent job, Chu says.

Though part sites digital have suggested that coffee filters can make an excellent mask filters, Chu and Zangmeister both advise versus this. Zangmeister notes the coffee filters are hard to breath through, so you finish up breathing roughly the filter quite than with it.

“Imagine if you have actually a hose. You put your ignorance over part of it, and the water just goes approximately it. In this case, the flow will go approximately that filter,” i beg your pardon defeats the function of making use of a filter, that explains.

Shape additionally matters: A mask’s ability to filter out particles counts on not just what it’s made the end of but how fine it seals to her face. When it come to towel masks, those the cup tightly to your confront are best, Cui says. Masks v pleats or wrinkle are likewise a an excellent choice: The folds expand so that you have an ext air flowing v the fabric itself instead of leaking out through gaps in ~ the sides of the mask. Masks v a flat front design are less effective, he says.

Another trick to boost the seal of your mask: Add a class of pantyhose. Reduced a size of hose about 8 to 10 inches long, from top to bottom, native one leg on a pair the hose, and also pull the on optimal of her mask. This pressures particles that could have otherwise gone approximately the loose edges the the mask and also been inhaled to rather go with the mask, which have the right to filter them out, says Loretta Fernandez, a researcher in ~ Northeastern University.

What about neck-gaiter masks (also well-known as buffs)? frequently made of man-made fabric, they room designed come cover your face, nose and also mouth and wrap around you. “There would certainly theoretically be much less chance for the air come escape laterally the end of the sides choose it would from a mask that’s open up on the side,” states Dr. Abraar Karan, a doctor at Harvard clinical School who’s functioning on Massachusetts’ COVID-19 solution team.

Avoid masks through exhalation valves. Some cloth and disposable masks come with an exhalation valve at the front. The valve provides it easier to breath out, but it additionally releases unfiltered air, so it doesn’t defend others if you’re contagious. And protecting rather is the primary reason come wear a mask.

Keep the clean. Experts say cloth masks should be washed daily with soap or detergent and also hot water. Make sure the mask is completely dry before you reuse it, together a wet mask can make that harder to breathe and also can promote the expansion of microorganisms.


Max Posner / NPR

A KN95 mask and also a surgical mask.

Medical Masks

N95 respirators: N95 respirators are designed to produce a chop seal around the nose and also mouth. Once worn correctly, they deserve to block at the very least 95% of small airborne particles. This respirators are good at protecting both the wearer and the people around the wearer. One reason they’re for this reason effective: N95s room made out of countless layers of fine polypropylene fibers, which, as we’ve discussed, use the power of static electricity to trap incoming and also outgoing particles and droplets.

But experts say N95s remain in short supply and have to still be reserved for health care workers and first responders. If girlfriend do acquire your hands on one N95, girlfriend should know that several of these respirators out there are fakes. The Centers for condition Control and Prevention has some advice on how come spot a counterfeit respirator.

KN95 respirators: A KN95 respirator is regulation by the Chinese government; choose an N95, it’s supposed to filter out at least 95% of little airborne particles. However, testing has actually revealed that the actual power of countless of the KN95s for sale in the U.S. “is almost everywhere the place,” and many space counterfeit, says Avilash Cramer, a doctoral candidate in ~ the Harvard-MIT health Sciences and technology program and also a volunteer with PanFab, an initiative to attend to shortages of medical devices and personal protective tools amid the pandemic.

While some counterfeits may certainly filter the end at least 95% that particles, “some room catastrophically bad. Some room falling personal in our hands,” says Cramer, who recent occupational with PanFab has focused on spotting and testing fake respirators. Do the efforts to identify if a KN95 is counterfeit deserve to be hard, the says, however here’s one telltale sign: If the packaging claims it’s NIOSH approved, don’t to trust it — due to the fact that a U.S. Government firm like NIOSH (the nationwide Institute for work-related Safety and also Health) would not grant a mask made to one more country’s standard. If you’ve acquired a KN95, Cramer states to check Appendix A of the Food and Drug Administration’s emergency usage authorization to view if the model you have actually is authorized.

DAVID MAIALETTI / Philadelphia Inquirer

Carly Heller, an ICU nurse at Einstein, at right, holds up a sign with her coworkers outside Einstein Medical facility in Philadelphia, PA ~ above April 15, 2020. Nurses and healthcare professionals gathered outside area hospitals ~ above Wednesday to need PPE and safe patient treatment standards together they fight the coronavirus. Heller said they need to wear the exact same mask for 20 shifts before they are given a new one.

Bottom line: If you have a KN95, simply know it’s possible you could not be getting virtually as much protection together you think. So be certain to store up v those other habits to help keep girlfriend safe, consisting of physical distancing. “Wearing also a genuine respirator doesn’t make you invincible, for this reason those habits are good no issue what,” Cramer says.

Surgical masks: Surgical masks room disposable coverings worn loosely around the face. In quick supply in ~ the begin of the pandemic, they’re becoming an ext widely available. They’re generally designed to safeguard other human being from the wearer and to block huge particle droplets or splashes in the air, although not very tiny particles. Plenty of surgical masks room made of paper, though some room made through polypropylene, says Lisa Brosseau, a study consultant v the university of Minnesota’s facility for Infectious disease Research and Policy. Research study has uncovered that operation masks deserve to block the vast majority of respiratory tract droplets emitted by an infected person. But how fine a surgical mask protects you, the wearer, from smaller sized particles can vary widely when tested v the same techniques used to check N95 respirators. Because that example, one surgical mask the Cui tested blocked about 30% of little particles, while others filtered out approximately 80%.

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Brosseau says she’s checked out some surgical masks that have actually been clearing for clinical use by the FDA and have better filtration efficiencies, but most masks offered in the U.S. Haven’t gone v the FDA approval process.

Regardless of whether you choose a fabric or surgical mask, she says, be conscious that this doesn’t mean you can suddenly it is in in an extensive close contact with others. These masks can buy friend a few extra minute of protection, she says, yet “not hours. Not prolonged periods of time.”