COVID-19: the two meters distance could be insufficient if there is wind

Current physical distance measures, which require a two-meter distance between people to prevent the spread of the coronavirus, may be insufficient in certain environmental conditions such as wind speed, which can spread saliva droplets from coughing. more than 5 meters away.

This is noted by a study published in the scientific journal "Physics of Fluids" and led by researchers Talib Dbouk and Dimitris Drikakis, from the American Institute of Physics. The research, which aims to deepen the understanding of how the particles of the virus that causes COVID-19 travel and are transmitted through the air when people cough, finds that with a light breeze of 4 km / h, saliva travels almost 5 , 5 meters in 5 seconds and that the droplets expelled in a sneeze can infect adults and children.

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"The droplet cloud will affect both adults and children, regardless of their height. In fact, adults and smaller children may be at greater risk if they are within the path of the traveling saliva droplets." Drikakis assures. Saliva is a complex fluid that travels suspended in a large amount of surrounding air released by cough.

There are many factors that affect the way saliva droplets travel, from size or quantity to how they interact with each other and with the surrounding air as they disperse and evaporate, or what humidity and the air temperature at that time.

To study how saliva moves through the air, Dbouk and Drikakis created a computational simulation of fluid dynamics that analyzes the state of each drop of saliva since a person coughs and expels it.

The simulation, which took into account aspects such as humidity, dispersion force, interactions of saliva and air molecules, and how these droplets evaporate, forced to solve 3.7 million equations to simulate the propagation of a thousand droplets of saliva.

Each operation collected data on "variables such as pressure, fluid velocity, temperature, droplet mass, droplet position, etc.," Dbouk details.

However, further studies will be needed to determine the effect of soil surface temperature on the behavior of saliva in the air and on indoor environments, where air conditioning significantly affects the movement of particles through the air, the authors warn.

Still, "this work is vital because it concerns remote health and safety guidelines, advances the understanding of the spread and transmission of airborne diseases, and helps form precautionary measures based on scientific results." Drikakis concludes.

Source: EFE ecg / icn