The two-meter distance rule for pandemic protection is a rather arbitrary and randomly selected number, despite some clear security measure, according to a new scientific study from the University of Cambridge in Britain, led by a Greek diaspora scientist.
The researchers, led by the professor of applied thermodynamics Epamineondas Mastorakos of the Department of Engineering (and with the contribution of another Greek researcher at the same school, the mechanical engineer Savvas Gandonas, a graduate of AUTh), who made the relevant Physics of Fluids used computer models and simulations to study how cough droplets spread.
They found that without the use of a mask, a person with Covid-19 who coughs can infect another person at least two meters or more away, even in the open. It has been found that the way of coughing differs significantly from person to person, with the result that the “safe” distance is from one to three meters, depending on how risk-tolerant a public health authority wants to be.
The findings, according to the researchers, show that physical distance alone is not an effective protection measure, so vaccinations, good indoor ventilation and mask use continue to be important, especially as winter approaches. northern hemisphere (including Greece).
Despite focusing on hand washing and cleaning surfaces during the early stages of the pandemic, it was quickly realized that the coronavirus primarily spreads airborne, not only through coughing or sneezing, but also through simple speech and even exhalation. .
Mastorakos is an expert in fluid mechanics and during the pandemic, together with his colleagues, he has developed various models for the way Covid-19 spreads. The new study confirms that there is no clear limit to the spread of potentially contaminated droplets. When one coughs and does not wear a mask, most droplets of larger size and weight quickly fall on nearby surfaces. But the smaller and lighter droplets float in the air for longer and can easily spread beyond two meters.
“Even if I drop the same number of droplets every time I cough, because the flow is disturbed, there are fluctuations. If I cough, fluctuations in speed, temperature and humidity mean that the amount one sends at a distance of two meters can it is very different every time “, said Mastorakos.
As he pointed out, although the two-measure rule is an effective and easy-to-remember message for the public, it does not signal a real security, given the large number of parameters associated with an airborne virus. That is why, he said, vaccines, aerators and masks – although not 100% effective – are vital in reducing coronavirus.
“We are all desperate to see the end of the pandemic, but we strongly recommend that people continue to wear masks indoors, such as in offices, classrooms and shops. There is no reason to expose oneself to such danger.” “While the virus is still with us,” added the Greek researcher, who is a graduate of the Department of Mechanical Engineering at Imperial College London, where he received his doctorate (1993), and has been a professor at Cambridge since 2000.
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