Even a weak wind makes social distance useless – it carries droplets of saliva when sneezing and coughing at a much greater distance than two meters. This conclusion was made by scientists from the University of Nicosia, whose work was published in the journal Physics of Fluids.
A new type of coronavirus is transmitted by airborne droplets – that is, by sneezing and coughing (in this case, droplets of liquid with the virus fly up to a distance of 8 m), talking, and also when the virus is transferred from hand to face from infected surfaces.
According to the recommendation of the World Health Organization (WHO), adopted by most countries of the world, during the epidemic of a new type of coronavirus in crowded places, it is necessary to maintain a social distance of 1.5-2 meters. This, according to experts, should reduce the risk of infection in the event of a meeting between a healthy and a sick person.
In a new study, scientists decided to check how social distance is effective if there is a slight breeze in the street. To do this, they built a computer model of the distribution of droplets of saliva in the air after a person sneezed or coughed.
Modeling showed that a relatively weak wind at a speed of 4 km / h in 5 seconds spreads a cloud of saliva particles by six meters. Such a cloud gradually settles – therefore, for children and people of short stature, the probability of getting into it will become higher.
With a stronger wind, saliva particles move faster and cover a distance of six meters in 1.5 seconds, the authors of the study note.
“A cloud of particles of saliva can affect both adults and children of different sizes. At the same time, for lower adults and children, the risk is higher, since they are in the way of settling of these particles”.
Dimitris Drikakis, lead author of the research