It is said that silence is golden. It may even be platinum in these times of the Covid-19 pandemic. A study, published Wednesday May 13 in the American journal PNAS (Proceedings of the National Academy of Sciences), indeed reveals that speech, as well as coughing and sneezing, is a probable vector of transmission of the virus, via the microdroplets of saliva which it generates, and which can remain suspended in the air of a closed space for more than ten minutes.
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Concretely, the study shows that, when we speak, we project, via these microdroplets, invisible but potentially viral particles. And the smaller they are, the longer they stay suspended in the air, while the heavier ones, by the effect of gravity, will, on the contrary, fall back more quickly to the ground. In the experiment in question, the person repeated, with a loud voice, “Stay healthy” for 25 seconds, sending droplets that remained in the air for an average of twelve minutes.
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By taking into account the known concentration of coronavirus in saliva, scientists estimate that a strong word can generate the equivalent per minute of more than 1,000 contaminated droplets that can remain suspended in the air for eight minutes, at the very least , in a closed space. A discovery echoing the work published in April in the journal NEJM, where the same team had observed that speaking less loudly produced relatively fewer droplets.
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