Coronavirus droplets may travel further than personal distancing guidelines, study finds
- Research conducted before the new virus emerged suggests the two metre rule is no protection against a direct cough
- Separate US study shows droplets carry considerable distance in uncovered speech, making case for face masks
A Canadian study found an unobstructed cough could travel two metres (six feet) in less than three seconds and keep going, well beyond the internationally accepted minimum distance that people are being asked to observe during the pandemic.
The study, led by Canada’s Western University and accepted for publication by the journal Indoor Air, was conducted well before the emergence of the current health crisis – up to the 2017-18 flu season – but has clear implications for the fight against Covid-19.
“Even when you are 2.5 metres away, the airflow in the cough can still be moving at 200mm [eight inches] a second,” said Eric Savory, professor from Western University’s department of mechanical and materials engineering. “The very fine droplets are going to remain suspended for a long time, even after four seconds.”
Research published by The New England Journal of Medicine found significant differences between the number of droplets produced, and their distance of travel, when a person spoke with their mouth covered and uncovered.
