Scientists at Duke University have tested 14 different types of masks along with other commonly used facial coverings for their protective efficacy against the novel coronavirus. People emit droplets while sneezing, coughing, shouting and even talking, which serve as a mode for transmitting the virus from one person to another. Since almost 40% of the infected people are asymptomatic and hence unaware of their condition, they can unwittingly pass on the virus to healthy people. Masks then have become an essential preventive measure for all, and an investigation of their success becomes important.
“If everyone wore a mask, we could stop up to 99% of these droplets before they reach someone else. In the absence of a vaccine or antiviral medicine, it’s the one proven way to protect others as well as yourself.”Dr. Eric Westman, Co-Author of the Study
According to a New York Daily News report, the researchers used a cellphone-laser system to shine light on to the droplets expelled by a person wearing various kinds of masks and covers, including no mask at all, to study the efficacy of each.
What They Found
In a surprising discovery, it was proven that covering your face with a fleece wrapping is less fruitful than having no mask on at all. “We were extremely surprised to find that the number of particles measured with the fleece actually exceeded the number of particles measured without wearing any mask,” study co-author Martin Fischer, a chemist and physicist at Duke, told CNN. Knitted masks and folded bandanas weren’t very effective either.
The most effective mask, as expected, turned out to be the N-95 without the valve, which is used by healthcare workers and others on the frontline. Next in line were the three-layered surgical masks and then the cotton masks people have been making on their own.
Home-made cotton masks “provided good coverage, eliminating a substantial amount of the spray from normal speech,” the researchers said.
What the Researchers Say
“We want to emphasize that we really encourage people to wear masks, but we want them to wear masks that actually work,” said Fischer.
The scientists have also published the proof-of-concept study in the journal Science Advances. They suggest that community groups, museums and other companies can use the publication to test the success of various masks for themselves. “This is a very powerful visual tool to raise awareness that a very simple mask, like these homemade cotton masks, do really well to stop the majority of these respiratory droplets,” Fischer told CNN. “Companies and manufacturers can set this up and test their mask designs before producing them, which would also be very useful.”
(With inputs from New York Daily News and CNN)
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