Should you double-up your masks? One expert says it's not a good idea and explains why

SAN FRANCISCO (KGO) -- Jeremy Howard knows a thing or two about masks. He joined us often in the early days of the pandemic and did everything from tutorials on how to make your own mask to explaining in visual detail why they're so important.

He's a research scientist at USF and founded Masks4All trying to spread awareness about the effectiveness of masks.

OK, now that we've established he knows his face coverings, we have a whole new slate of questions to pepper him with:

Are cloth masks still effective?

It depends. Cloth masks can be much more effective if you're able to add a filter to the inner layer of the mask. Howard says filter material is pretty readily available online these days and it has similar qualities to N95 masks. Also, cloth masks with nose wires can help close the gap around your nose. "Without those two things, a cloth mask doesn't do a hell of a lot to protect the wearer, although it does still protect other people from you," Howard said.

How do new COVID-19 variants impact masks?

"We don't know anything about the new variants other than that they are dramatically more transmissible," Howard said. He expressed concern about how easy it can be transmitted and that we just don't know yet. He says personally he's now wearing N95 masks in public.

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What's the difference between N95 and KN95?

In theory, there's not a huge difference, according to Howard. Basically the only difference is KN95 is a Chinese certification, N95 is a U.S. certification. Also, KN95 masks have ear straps instead of all the way around the head. He says the straps that go around the head do provide a better fit. Howard also warns there is a lot of fraudulent versions of KN95 masks that can be as little as 1% effective.

Can you reuse N95 and KN935 masks?

The concern is that part of the filtration comes from the electrostatic charge that gets supplied to them which disappears if it gets moist, Howard said. However, a recent study shows that if the charge disappears they still work really well. He suggests having three masks and use them in rotation without cleaning them - that is enough time for viruses to die out.

If you're outside in public what should you wear?

Howard says N95 masks are the way to go. They've ramped up production and the frontline workers are not facing shortages. Regardless, with the new variant, it's safer to wear a higher-quality mask.

MORE: What does COVID-19 do to your body and why does it spread so easily?

If you're indoors what should you wear?

Howard suggests stepping up your protection with P100 masks. He says they look a little odd, almost like a gas mask, but they aren't used in medical facilities so there aren't issues with taking them away from healthcare workers. They are also reusable. He suggests removing the valve so it filters the air coming out as well as coming in.

Should you wear two masks instead of one in riskier situations?

"I would be very careful about that, it's not very well studied," Howard said. "Two layers of masking is less breathable and that means when you breathe out or breathe in, rather than the air coming through the mask and getting filtered, it's more likely to come around the edges." He stresses just to be cautious as we just don't know enough about two masks.

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