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Study Finds Not All Face Coverings Offer The Same Level Of Protection Against Spreading Coronavirus

DURHAM, N.C. (CBS LOCAL) - Duke University researchers wanted to test how easily germs can spread even during normal conversations. They used a box, laser, lens, and cell phone camera to visualize droplets and filmed people speaking into the box.

Martin Fischer, Ph.D., is with the Departments of Chemistry and Physics at Duke University. He says, "It's astounding how much stuff comes out of you when you just speak, you didn't even have to sneeze or cough. It's the speaking itself that already generates lots of droplets."

According to Dr. Eric Westman in the Department of Medicine at Duke University, "You may not know that you're spreading the disease, you won't see it."

Dr. Fischer and Dr. Westman's team tested several types of face coverings. They found that N95s without valves were the best protection, and surgical masks were also adequate. Popular double-layer cotton masks provided good coverage as well.

But coverings like bandannas and neck fleeces did not block droplets much and may actually spread them more. "You have this mesh in front of you, these big droplets that you emit, actually get broken down by this type of fabric into a bunch of little droplets," Dr. Fischer says.

The findings drive home how critical masks are, especially since the coronavirus can spread when someone doesn't have symptoms. "If you want to reduce your risk and other people's risks of a transmissible disease, the science is clear that you should wear a mask or wear a face cover," Dr. Eric Westman says.

Researchers say a wearing mask is one step we can all take to help end this pandemic. They also emphasize that the protection healthcare workers needs such as N-95 masks are not necessary for everyday life.

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