what to use as a filter in a mask
This story originally ran in February. Information technology'southward been updated throughout to reflect new developments and the latest science.
With delta surging and wellness officials urging indoor mask use in many places, you lot've likely pulled out your sometime cloth masks. But information technology may be fourth dimension for an upgrade.
"Masks still work, simply with delta, we need better-performing masks," says Linsey Marr, a researcher at Virginia Tech who studies airborne virus manual.
The delta variant transmits more than twice equally easily every bit the original strain of the coronavirus. It'southward now one of the nigh contagious respiratory viruses we know of.
And it also replicates quickly in the noses and throats of infected people, so they could be walking around with ane,000 times more virus in their torso than with the original strain. All of that means information technology'south imperative that you make sure your mask is protective, and non simply a bedazzled ornament for your face.
And so what makes a high-performing mask? Marr says a mask's filtration efficiency is a part of both what material it's fabricated of and how well it seals to your face. So whatever you exercise, make sure in that location are no gaps under cheeks or chin where the virus could sneak in.
Read on for more tips on how to seriously boost the protection your face mask offers.
1. Consider N95s and KN95s
Some public health experts accept suggested that the spread of delta calls for donning more than seriously protective masks similar the gold standard of protection, N95 respirators, which block out at least 95% of particles when worn correctly.
The skillful news is N95s are plentiful these days. Notwithstanding, they do have a downside. Considering they seal so tightly to your face (that's why they work so well), N95s aren't exactly fun to clothing, notes Dr. Ibukun Kalu, a pediatric communicable diseases physician at Knuckles Children's Hospital.
"No one wants to wear an N95 for viii hours," Kalu says. She says they're corking protection when you are in a high-adventure situation such as caring for a COVID-19 patient, "but it can be quite uncomfortable."
If you lot decide to opt for an N95 anyway, scout out for fakes. Check the CDC's site for advice on how to spot a counterfeit and a listing (last updated in June) of trusted sources for surgical N95s. You can too find more guidance on choosing a good fit among different N95 styles, and buy a NIOSH-canonical mask at companies similar Aiden and the nonprofit Project N95.
Some people have a harder time with the straps that N95s use to attach to your head. In that example, you tin can likewise consider KN95 respirators, which frequently attach with more comfortable ear loops. KN95s are regulated by the Chinese government, and, like N95s, they're supposed to filter out at least 95% of small airborne particles, although the testing standards differ in each land.
Yet, counterfeits have also been a problem with KN95s. And the FDA recently revoked the emergency use authority information technology had granted to KN95s, which immune them to be used in wellness intendance settings. Even so, you can still search the FDA'due south list of formerly approved KN95s. You may also want to bank check NIOSH's listing of foreign-fabricated respirators it tested for filtration efficiency in the past, though the bureau has now stopped doing those tests.
If you opt for one of these respirators, make certain they also fit tightly to your face. And remember, no matter what you cull, the best mask is ultimately the 1 you will wear consistently.
2. Wearable 2 masks
Layering a cloth mask on acme of a surgical mask helps reach a tighter fit while too calculation an actress layer of filtration. Double-masking like this increases protection against the coronavirus. Michele Abercrombie/NPR hide caption
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Michele Abercrombie/NPR
Layering a material mask on height of a surgical mask helps achieve a tighter fit while also adding an actress layer of filtration. Double-masking like this increases protection against the coronavirus.
Michele Abercrombie/NPR
Ane expert way to get a better mask is to double upward, says Marr. Start with a surgical mask closest to your confront, she says, and and so add a cloth ane on summit.
The downside of surgical masks is that many of them fit loosely — and a mask's ability to filter out particles depends partly on how well information technology seals to your face. Past layering a cloth mask on top, you tin can achieve a tighter fit while likewise calculation an actress layer of filtration, says Marr, who co-wrote a commentary earlier this yr recommending double-masking.
Choose a surgical mask made out of a nonwoven material called polypropylene, considering that material holds an electrostatic charge that allows it to trap particles. (Some surgical masks are made of paper.) Then add a good quality cloth mask.
Merely don't keep piling on masks, Marr warns; just one additional mask is plenty. If your masks become too hard to breathe through, air volition leak in and out through the sides instead. "And so it's like you have a hole in your mask," Marr told NPR before this year.
three. Make your mask fit tighter
Tie the ear loops close to the edges of the mask and tuck in the side pleats to minimizes gaps (left). Or utilize a hair clip to hold the ear loops tightly at the back of the head to achieve a tighter seal. Michele Abercrombie/NPR hide caption
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Michele Abercrombie/NPR
Tie the ear loops shut to the edges of the mask and tuck in the side pleats to minimizes gaps (left). Or use a hair clip to agree the ear loops tightly at the back of the head to achieve a tighter seal.
Michele Abercrombie/NPR
Fifty-fifty at this tardily stage in the pandemic, it nevertheless bears repeating: Don't permit your nose hang over your mask – that defeats the purpose! And to get the best protection, you lot also need to make sure that your mask fits as snugly as possible over your mouth and nostrils, up to your nose span and that you don't run into any gaps.
A mask's filtration efficiency varies depending on how well it conforms to your confront, as a written report in JAMA Internal Medicine illustrates. Researchers found that the surgical masks they tested blocked out merely 38.5% of small particles on boilerplate when worn ordinarily. Merely filtration efficiency jumped when they tried various hacks to make the mask seal better.
Ane fob they tested: Necktie the ear loops into a knot as close to the edges of the mask as possible, and so tuck the side pleats in to minimize any gaps that appear along the edges, as in the left photograph, below. This boosted the surgical mask's filtration efficiency to 60%.
Another simple hack is to use a hair clip, equally in the photo in a higher place at right to hold the ear loops tightly at the dorsum of the head. That raised the mask's filtration efficiency to nearly 65%.
You could also endeavour a mask fitter or brace — an rubberband frame that fits over a mask to make it seal more tightly to the wearer'due south nose, mouth and face. One report from researchers at the University of Wisconsin-Madison plant that using a mask fitter enhanced a surgical mask's filtration efficiency from under xx% to over ninety%.
"That shows you how of import the fit is and how good a surgical mask can exist if you are able to eliminate the leaks," notes Marr.
To test if your mask fits well, try wearing it with glasses, suggests Jamie Weaver, a research chemist at the National Institute of Standards and Technology who has been studying the filtration efficiencies of mask materials. "If you start fogging upwardly your spectacles, that's a sign of a leak. I've also seen people put niggling mitt mirrors next to the edge of their masks and breathe and see if they fog upwards mirrors."
4. Add together a filter
You tin can achieve a boost in filtration efficiency by wearing a two-layer mask with a pocket for a filter. Insert a surgical mask or a carbon filter in that pocket. Michele Abercrombie/NPR hide caption
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Michele Abercrombie/NPR
You tin boost filtration efficiency by wearing a ii-layer mask with a pocket where you can insert a filter. The outer layers should exist made of a tight-weave fabric.
Marr suggests using a surgical mask in the filter pocket. (You can cut the surgical mask to fit the pocket if need be.) She says HEPA filters cut out from the filters used in portable air cleaners piece of work very well (here's her how-to video). You lot tin as well buy cloth masks with a filter layer permanently attached.
Another filter pick: a textile available at cloth stores called spunbond, too sold under the brand name Oly-Fun. It'south made out of polypropylene, so it as well uses the power of static electricity to trap particles. Adding a filter fabricated out of ii layers of polypropylene could boost a cotton wool mask's filtration efficiency by equally much equally 35%, Stanford University researcher Yi Cui told NPR concluding year.
When it comes to mask filters, "the size of the filter seems to matter," says Weaver, who co-authored a recent study on the topic in the journal ACSNano. Choose a filter that spans the material of your cloth mask, Weaver says — and make sure it'due south breathable.
5. Cull a amend cloth mask
For a textile mask, in general, you want to look for a fabric with a tight weave. Multiple studies have shown that 100% cotton is a proficient bet (call back slightly stiffer dress-shirt cotton fiber). Michele Abercrombie/NPR hide caption
toggle caption
Michele Abercrombie/NPR
For a cloth mask, in general, yous want to look for a fabric with a tight weave. Multiple studies have shown that 100% cotton is a adept bet (call back slightly stiffer dress-shirt cotton).
Michele Abercrombie/NPR
If y'all're sticking with a cloth mask, make sure the ane you vesture is as protective as it tin be. Opt for at least 2 layers in your mask — three layers are even ameliorate: Studies take shown that a iii-layer mask made from tightly woven cotton wool fabric works well.
Await for fabrics that don't let light pass through when held upwardly to a light source. (Think slightly stiffer dress-shirt cotton rather than sparse T-shirt cotton.)
One excellent pick: cotton fiber flannel, says Weaver. She and her colleagues have found that a 2-layer cotton flannel mask's filtration efficiency jumped by an boilerplate of 33% when information technology becomes humid — the kind of atmospheric condition created when you're animate into the mask.
Synthetic fibers didn't perform as well, and they saw no boost from humidity. Perhaps not surprisingly given these findings, Weaver says her become-to mask of choice is a homemade multi-layer cotton fiber flannel mask.
As Christopher Zangmeister, a researcher at NIST, explained to NPR concluding year, tightly woven natural cotton wool fibers with a raised nap, similar flannel, tend to have more three-dimensional construction than synthetic fibers. That tin create more roadblocks to cease an incoming particle. That said, filtration tests have shown that some masks made of other fabrics, similar an engineered knit, can be highly effective.
NPR's Rob Stein contributed to this written report.
Source: https://www.npr.org/sections/health-shots/2021/02/03/962197192/5-hacks-to-make-your-face-mask-more-protective
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