A person standing two metres from a person coughing without a mask will be exposed to over 10,000 times more respiratory droplets than they will be from someone standing just half a metre away wearing a basic mask.
The finding, outlined in a new research paper from University of Edinburgh academics, suggests that face coverings can substantially reduce the probability of a person infected with COVID-19 transmitting the virus.
Large respiratory droplets are probably the main driver of COVID-19 transmission, the researchers say.
Even a single-layer cotton mask is enough to reduce the exhalation of droplets by 99.9 per cent.
The researchers used a manikin to simulate the trajectory of droplets from coughing and talking, then backed up their findings using real humans.
The academics say their research suggests that physical distancing can be reduced if people are wearing masks.
However, the research did not measure the impact of masks on the trajectory of smaller aerosol droplets. If aerosol transmission is later found to be a significant driver of infection, then the findings could overestimate the effectiveness of face coverings.
The research is published in the peer-reviewed Royal Society Open Science journal on Wednesday.
Australian Associated Press