A new study published shows that the droplets produced by speech can be suspended in the air of a closed space for more than ten minutes, which highlights the “important role” of voice transmission in the transmission of new coronaviruses.
According to Agence France-Presse, a team of researchers from the National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) asked the people under test to repeat the phrase “keep healthy” in a closed box for 25 seconds. The laser light projected into the box illuminates the droplets, allowing them to be seen and counted.
The research was published in the latest issue of the Proceedings of the National Academy of Sciences (PNAS). Studies have shown that droplets of saliva produced by speech stay in the air for an average of 12 minutes.
Taking into account the known concentration of new coronavirus in saliva, scientists estimate that speaking loudly every minute can produce more than 1,000 droplets containing the virus, able to stay in an enclosed space for 8 minutes or more.
The researchers concluded: “This direct visualization shows how normal speech produces droplets in the air, which can float for a few minutes or more and are very capable of spreading viruses in a limited space.”
The research team published another study in the New England Journal of Medicine in April that showed that the lower the voice, the fewer droplets produced.
If the infectious level of the new coronavirus can be confirmed by voice, it can scientifically encourage many countries to recommend that people wear masks and help explain the rapid spread of the virus.
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