Researchers have found that particles carrying the virus can remain in the air for several minutes after a COVID-19 sufferer coughs.
Scientists in Finland have released a 3D model showing how coronavirus is transported through extremely small airborne aerosol particles when a person coughs, sneezes or talks.
They said their findings “emphasize the importance of avoiding busy indoor spaces” during the COVID-19 pandemic.
The researchers have modeled a scenario where a person coughs in an aisle between shelves, like those found in supermarkets.
They found the aerosol-cloud spreads outside the immediate vicinity of the coughing person and dilutes – but this can take up to several minutes.
“Someone infected by the coronavirus can cough and walk away but then leave behind extremely small aerosol particles carrying the coronavirus,” said Ville Vuorinen, assistant professor at Aalto University in Finland.
“These particles could then end up in the respiratory tract of others in the vicinity.”
For their study, researchers modeled the airborne movement of aerosol particles smaller than 20 micrometers.
For a dry cough, which is a typical symptom of COVID-19, the particle size is typically less than 15 micrometers.
“Extremely small particles of this size do not sink on the floor, but instead, move along in the air currents or remain floating in the same place,” the researchers said.
The Finnish scientists said the spread of a virus may slow down or even be suppressed altogether as mobility decreases at “nodal points” – places where lots of people gather, such as shops, restaurants and public transport.
They added that avoiding busy indoor areas reduces the risk of droplet infection while in close proximity to others, which is the main cause of coronavirus infection.
Jussi Sane, the chief specialist at the Finnish Institute for Health and Welfare, said the results of the study highlight the importance of people staying at home if they feel unwell and maintaining “physical distance with everyone”.
The study was carried out by Aalto University, the Finnish Meteorological Institute, VTT Technical Research Centre of Finland and the University of Helsinki.
We are at a crucial moment in preventing further transmission of coronavirus, and so we must continue following the government’s guidance