In a new study from the Chalmers University of Technology, researchers have developed a new theoretical model to better assess the risks of spreading viruses such as COVID-19—with and without a face mask.
The results showed how the standard ‘safe’ distance of two meters does not always apply but varies greatly depending on a range of environmental factors, and that face masks can indeed play a crucial role.
The current recommendations and understanding around the transmission of respiratory infectious diseases are often based on a diagram developed by the American scientist William Firth Wells in 1934.
But this model is very simplified and does not account for the true complexity of transmission.
In the study, the researchers developed a more advanced model to show that it is possible to more efficiently calculate the direct risk of spreading COVID infection by including a number of factors, such as interpersonal distance, temperature, humidity levels, viral load, and type of exhalation.
They then tested the new model using data from recent numerical experiments on droplet emissions. This allowed them to take several factors into account and quantify the risk of infection, with and without a face mask.
The team found that a person talking without a face mask can spread infected droplets one meter away.
Should the same person cough, the drops can be spread up to three meters and if the person sneezes, the spread distance can be up to seven meters. But using a face mask, the risk of spreading the infection decreases significantly.
The team found that a surgical face mask and, to an even greater extent, an FFP2 mask provide excellent protection that significantly reduces the risk of infection.
Provided that the face mask is worn correctly, the risk of infection is negligible even at distances as short as one meter, regardless of environmental conditions and if the person is talking, coughing or sneezing.
With this study complete, the research team is now already working on a new study aiming to explore the airborne spread of the disease.
If you care about COVID, please read studies that scientists find the maximum risks of COVID infection with and without masks, and what is the best mask for COVID-19.
For more information about COVID, please see recent studies that common drugs for heart disease, high cholesterol may treat COVID-19, and results showing that COVID booster shot can cut your death risk by 90%.
The study is published in the Journal of the Royal Society Interface and was conducted by Gaetano Sardina et al.
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