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The key to a good mask: fit and filtration

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What makes a good mask? Virginia Tech’s nationally-recognized expert in the airborne transmission of viruses, Charles P. Lunsford Professor Linsey Marr explains why it comes down to fit and filtration.

The keys for good masks are good fit and good filtration. So when we talk about fit, we're talking about not having leaks around, especially around the cheeks and around the nose or the chin. And then with filtration, now we're thinking about upgrading from just your regular old kind of cloth material to something that has a filter in there. Something, a type of material that's designed to filter out small particles. There's, of course there's N95s which are used in healthcare and those are available now. The fit is still really important on those. There's also some alternatives from China and Korea called KN95s or KF94s. That's what I usually wear just because it fits me well. Yeah. You want to find something that fits and that's going to have very good filtration capability. So that's going to reduce the, you know, if you happen to be infected, without symptoms, that will greatly reduce the amount of virus you're spreading into the air around you. And it will protect you also. And then another type of mask is the, well I mentioned the cloth mask with a filter built-in. Those are the main ones. The other thing you can do is we talked about double masking several months ago, and that achieves good fit and filtration using two different masks. You get the good filtration from a surgical mask, medical type of mask, because that material, melt blown non-woven polypropylene is designed to filter out particles really well, better than 95%. And then, but those really leak, you're trying to stick a rectangle to your face. Nobody space is shaped like a rectangle. And so the cloth tight cloth mask over that helps improve the fit, reduce leaks, and so then you get good filtration and good fit from that combination.