The Centers for Disease Control and Prevention is recommending that everyone wear two face coverings — after a new study found that doubling up can improve mask performance against COVID-19 by about 50 percent.
Wearing a cloth covering over a medical procedure mask or disposable mask significantly helps reduce exposure to the deadly bug, the CDC study found.
The agency said it studied two ways of improving the use of medical masks — “fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a medical procedure mask and then tucking in and flattening the extra material close to the face.”
It said that “each modification substantially improved source control and reduced wearer exposure.”
In lab tests with dummies, exposure to potentially infectious aerosols decreased by about 95 percent when they both wore tight-fitting masks, according to the study.
Other effective options to improve mask use include using a mask fitter or a nylon covering, the CDC said.
It recommends choosing a mask with a nose wire — a metal strip along the top that prevents air from leaking. The wire should be molded over the nose for a snug fit, which can be checked by cupping your hands around the outside edges of the mask.
Users should make sure no air is escaping from the area under their eyes or from the sides of the mask, the agency said.
The CDC also recommends adding layers of material, including using a cloth mask that has several layers of fabric.
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Meanwhile, the agency warns against combining two disposable masks, which are not designed to fit tightly, or combining a KN95 mask with any other covering.
“What we want to do is now help consumers make mask-wearing work better for them,” Dr. John Brooks, the CDC’s chief medical officer for COVID-19 response, who co-authored the new study, told Business Insider.
“There’ve been a number of different ways, simple ways, low-tech ways, that people can improve the performance of their mask,” he added. “More layers helps, better fit is critical.”
In the study, the researchers put masks on two dummy heads — one that coughed and breathed into the air and another head about six feet away from the first.
They measured how much of the would-be infectious particles the first dummy spewed made it over to the second head.
Both cloth and surgical masks alone did “OK” at filtering particles out of the air, Brooks said.
A surgical mask alone on the cougher blocked about 42 percent of the particles from the healthy head, while the cloth one blocked more than 44 percent, the study found.
But when they put a cloth mask over a surgical mask, they found the double masking dramatically improved the performance of both masks, blocking 92.5 percent of the cough particles.