AILSA CHANG, HOST:
New, more contagious variants of the coronavirus are spreading across the U.S., which has many people wondering if there's more that they can do to protect themselves and help stop that spread. One thing some public health experts suggest - double masks. For more on that, we're joined now by NPR health correspondent Maria Godoy.
MARIA GODOY, BYLINE: Hi.
CHANG: All right. So really, I have to layer two masks on my face now?
GODOY: Yeah, that's the idea.
CHANG: (Laughter) Aw.
GODOY: These new variants are more transmissible, and that means we need to improve our level of precautions. And one of the easiest ways to do that is to improve our mask by doubling up. That's according to Linsey Marr. She's a researcher at Virginia Tech who studies how viruses transmit in the air.
LINSEY MARR: A cloth mask might be 50% effective at blocking viruses and aerosols. We're at the point now, though, with so many people who are infected and these more easily transmissible variants that we need better than 50%.
GODOY: By double-masking, Marr says, you can end up with something that's 75% effective or more.
CHANG: OK, well, I'm thinking about my parents right now who like to go hardcore on this kind of advice. If two masks are better than one, I could see them trying to wear, like, three masks at once now. Is that a good idea?
GODOY: No, because adding layers will improve filtration but only up to a point. If your masks make it too hard to breathe, then air is going to start flowing through the gaps on the sides.
CHANG: Got it. All right. So what type of masks are best - like, two cloth masks, a cloth and surgical mask? Should we, like, double up on N95s? What do you think?
GODOY: (Laughter) In an ideal world, we'd all be wearing N95s, but they are still in short supply and still need to be reserved for health care workers.
GODOY: You can buy a mask called the KN95, which is a mask that meets a Chinese standard for particle removal, but there are a lot of fake KN95s out there. So if you're going to buy one, you should check the CDC website to see which brands are authorized. And as for cloth versus surgical mask, you should be wearing both. Marr says you should wear the surgical mask closest to your face because they're made out of non-woven material that's very effective at filtering particles. The downside is a lot of these masks fit loosely, so wear a cloth mask on top of it to get a tighter fit and to add an extra layer of filtration.
CHANG: Right. Fit is really important. You don't want your mask slipping.
GODOY: No, absolutely not. People, please don't let your nose hang over your mask because that...
CHANG: Oh, I hate that.
GODOY: ...Defeats the purpose.
GODOY: Me, too. A mask works best if it seals tightly to your face, and that is true regardless of what it's made of. You want to create a tight seal so that air isn't escaping out of the sides, and double-masking can help with that. So can making sure your mask fits properly.
CHANG: OK. So bottom line, should we be double-masking all of the time right now?
GODOY: If you're just going out to walk the dog, you're fine with a single mask. But if you're heading to the grocery store, it's time to double-mask. And don't forget, you still need to physical distance, wash your hands, avoid crowds and poorly ventilated spaces. It all adds up.
CHANG: That is NPR's Maria Godoy.
Thank you, Maria.
GODOY: Thanks so much.
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