COVID-19 mask efficiency: Most mask materials retain the droplets ejected when you sneeze or cough. However, at a distance of less than 1.8 meters, small amounts of fluids with viruses can reach the other person.
Just wearing masks may not be enough to protect against COVID-19, researchers at New Mexico State University said.
“The mask certainly helps, but if people are very close together, there is still a chance of transmitting or catching the virus. Not only masks help. You also need social distance, ”says prof. Krishna Kota, one of the authors of the publication that appeared in the journal Physics of Fluids.
Researchers have built a device that mimics human sneezing and coughing. A system of lasers and cameras coupled to it allows to observe the droplets ejected by the machine.
How is the COVID-19 mask efficiency identified?
With the help of the invention, scientists conducted an experiment in which they tested the effectiveness of various types of masks – plain cloth, same but double material, double plain and wet cloth, surgical mask and medical-grade N-95 mask.
Each mask retained most of the drops. The weakest, of ordinary fabric, it let through only 3.6 percent. drops, and N-95 is practically zero.
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The test did not take into account leaks resulting e.g. from improper application of the mask.
However, researchers say, at a distance of less than 1.8 meters, even when wearing a mask, small amounts of liquid with viruses can reach another person if someone sneezes repeatedly.
A single sneeze could mean ejecting 200 million virus particles, the researchers said, depending on how sick someone is.
“Wearing masks will provide significant, but not complete protection by reducing the number of droplets thrown when you sneeze or cough that would otherwise end up in a person without the mask. However, you have to be careful to avoid close face-to-face contact whenever possible “- emphasizes the researcher. (PAP)
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