Coronavirus researchers warn 2-metre distance rule may not be far enough
- A light wind can carry an infected cough three times further in just five seconds, study finds
- More research needed into effects of temperature and humidity
Public health officials in many countries may need to reconsider their safety guidelines – which usually consist of social distancing and wearing a mask – after the publication on Tuesday of the research paper in the journal Physics of Fluids.
Authors Talib Dbouk and Dimitris Drikakis, from the University of Nicosia in Cyprus, found two metres was a safe approximate distance in still conditions, with droplets taking about 15 seconds to fall below human waist level.
However, they found that “when a person coughs, the wind speed in an open space environment significantly influences the distance that airborne disease-carrier droplets travel”.
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Using a computational fluid dynamics model to compare the distance travelled by human saliva droplets in different wind conditions, the researchers found droplets could reach as far away as six metres (18 feet) in five seconds at a wind speed of just 4km/h (2.5mph). At 15km/h (9.3mph), the wind can carry droplets the same distance in just 1.6 seconds.