A study carried out by researchers from the Bambino Gesù Children’s Hospital in Rome has shown with a three-dimensional video simulation how the coronavirus spreads in a hospital waiting room through salivary droplets and their movement due to ventilation systems.
The results of the study, carried out with the Ergon Research University and the Italian Society of Environmental Medicine (SIMA), were published in the scientific journal Environmental Research, and provide important information for contain the spread of the SARS-CoV2 virus in closed environments, they assure it’s a statement.
The researchers used “computational fluid dynamics” (CFD) tools to virtually recreate the waiting room of a pediatric emergency room equipped with a ventilation system, with 6 children and 6 adults without masks inside.
In this way, in this virtual waiting room the droplet and aerosol behavior in the 30 seconds after a cough in three different scenarios: with the aeration system off, at standard speed and at double speed, to assess how much polluted air each person present would breathe.
Using the series of physical parameters that regulate the aerial dispersion of biological particles (speed, acceleration, quantity, diameter of the drops, turbulence, movements generated by the air conditioning), the researchers obtained a “physically correct” 3D simulation, which reproduces exactly what would happen in a real environment.
The results of the study confirm that air conditioning systems play a decisive role in the control of the dispersion of droplets and aerosols produced by breathing in closed environments.
In fact, for the first time, it has been documented that double the air conditioning flow (calculated in cubic meters per hour) inside a closed room reduces the concentration of contaminated particles by 99.6%.
At the same time, twice the speed causes the dispersion of droplets and aerosols in the air faster and longer distances than standard air conditioning or off: with the air conditioning off, the people closest to the coughing child (1.76 meters in the simulation) breathe 11% of the polluted air while those farthest (4 meters) are not reached by the infected “cloud”.
With double speed system pollutant concentration is reduced and the closest people breathe 0.3%, but even those furthest away are quickly reached, and in this case they breathe 0.08% of contaminated aerosol, very low percentages and substantially irrelevant for contagion purposes.
“The exchange of air in the rooms also through systems of aeration, purification and mechanical ventilation Scientifically controlled is fundamental in the diffusion of the virus and its transfer, as far as possible, to the outside, that is, in the mitigation of biological pollutants present in the air in droplets, which significantly reduces the concentration of the pathogen in the air “, underlined Alessandro Miani, president of SIMA.