Covid-19, how and how much of the virus transmits with and without a mask
19.01.2022
The study entitled, Modelling the direct virus exposure risk associated with respiratory events, conducted by an international research team, includes those from the Universities of Padua, Udine, Vienna, and Chalmers, demonstrate that it is possible to quantify the risk of infection from Covid-19 as a function of interpersonal distance, temperature, humidity levels, and type of respiratory event. A person speaking without a mask on, can emit infected droplets over a distance of one meter, up to 3 meters when coughing, and 7 meters when sneezing. Those wearing a surgical mask or an FFP2 mask reduce the risk of contagion to the point that whether you talk, cough or sneeze the risk becomes practically negligible.
Viruses, such as SARS-COV-2, spread from an infected individual to other susceptible individuals through virus-laden droplets emitted while speaking, coughing or sneezing.
Emitted from the salivary glands, droplets spray when pushed through the expulsion of air where they evaporate, settle or remain suspended. Droplet transmission is associated with larger and heavier droplets falling in a ballistic motion before evaporating, while smaller droplets behave as aerosols that spray and remain airborne before falling.
Led by Francesco Picano of the Department of Industrial Engineering of the University of Padua, the study used an effective model for assessing the direct contagion risk considering the non-existence of a universal safety distance, rather the risk depends on ambient conditions, viral load measurements, and the type of respiratory event.
Published in the "Journal of the Royal Society Interface", researchers used the most recent experimental data available on the reduction of droplet emission by masks by testing the model to quantify how personal protective equipment reduces the risk of contagion. Findings prove that the use of a mask, surgical and even more so FFP2 are an excellent protection tool that reduces the risk of infection. Stating that when worn properly, the risk while wearing a mask becomes negligible even at short distances (about 1m), regardless of the environmental conditions or the respiratory event.
