Installation for determining the direction, velocity and time of passage of an aerosol cloud formed during coughing and sneezing: work results (as part of the covid-19 program)

Abstract

It is recognized that Covid-19 is mainly transmitted by airborne droplets. It is especially dangerous to sneeze and cough the patient, when together with a jet of air, moving at a high speed (when sneezing up to 150 km/h), droplets of liquid containing viruses fly out. It is known that even with a loud conversation the patient can release up to 1000 drops in the air with particles of a new type of coronavirus, especially coughing and sneezing carrier of the virus. There is a lack of experimental data to create physical and numerical models describing these processes and calculate the concentration of aerosol particles. The paper proposes an installation to determine the distribution of velocities and deformations in the time of the aerosol cloud that occurs when coughing and sneezing, as well as preliminary results of the first cycle of experiments at this installation. Based on the results, recommendations are made to counter the spread of infection. The purpose of these studies is to determine the direction and speed of the cloud carrying the droplets with the virus, as well as the time of its passage past potential recipients. Based on these data, it will be possible to estimate the received dose of infection and the dependence of this dose on the distance between the source and the potential victim. The study does not claim to be complete, which can be achieved by studying large groups of subjects, but after its completion it can serve as a source material for close to reality digital models of infection transmission. The work also contains preliminary results of the first cycle of experiments at this facility. On the basis of the results obtained, practical recommendations are given to counteract the spread of infection.