Adding a nylon stocking layer....

[kadee79]

During World War II, nylon stockings disappeared from store shelves as the valuable synthetic material was diverted to make critical wartime supplies such as parachutes, flak jackets and aircraft fuel tanks. Now, new research suggests that nylon stockings could once again play a critical role in a national battle — this time by making homemade cloth masks significantly more protective.

Researchers at Northeastern University have found that adding an outer layer made from nylon stockings to a homemade face covering can boost its ability to filter out small particles in the air by creating a tighter seal between the mask and the wearer's face. In some cases, that extra nylon layer helped homemade cloth masks match or exceed the filtering capability of medical-grade surgical masks. 

"It really improved the performance of all of the masks, and it brought several of them up and over the baseline mask we were using, which was a 3M surgical-type mask," says Loretta Fernandez, an assistant professor of civil and environmental engineering at Northeastern University and one of the scientists who conducted the research.

Even the surgical mask performed better with stockings in their study: Testing showed that it went from blocking out 75% of small particles to 90% with the addition of a pantyhose overlayer. An N95 respirator, by comparison, is designed to block out at least 95% of small particles when worn properly.

"Adding a layer that keeps the mask tight to the face is going to improve the function of any of these masks," Fernandez explains, "because how well they protect us is not only a matter of what material we're using to do the filtering but also how well [the mask] seals to the face, so that we're trying to avoid air making it around the mask into our breathing zone." The pantyhose layer, she says, helps creates a tighter seal around the face to reduce how much air leaks around loose edges — similar to the seal on an N95 respirator.

www.npr.org/sections/goatsandsoda/2020/04/22/840146830/adding-a-nylon-stocking-layer-could-boost-protection-from-cloth-masks-study-find

[Gardening Grandma]

I saw that earlier. I’m thinking of trying it.