Wind can blow thin infectious droplets up to 5 meters

May 21, 2020
Walking

ONE of the safety protocols currently being enforced by the Inter-Agency Task Force on Emerging Infectious Diseases (IATF) is social distancing of up to two meters in all public places.

This would ensure everyone, aside from wearing facemask or face covering, from catching the deadly virus now that lockdowns had been eased in many areas and people are back to work.

However, a new study found that this “short” distance might not be safe to prevent virus transmission.

Researchers found that even in light winds -- the speed needed for smoke to drift through the air -- saliva can travel 18 feet in just five seconds.

Researchers examined how saliva travels through the air in a simulated computer simulation that looks at how every saliva droplet, large and small, moves through the air after a person coughs.

They found that about 3,000 droplets are expelled from single cough, with many of them dispersing in different directions. From a sneeze, as many as 40,000 droplets might be expelled.

Researchers said many factors can affect how droplets travel through the air including the size and number of droplets, humidity and how droplets evaporate. These were all considered in the study.

The model used by a team from the University of Nicosia in Cyprus, ran different equations regarding how far, and how quickly, 1,008 saliva droplets can travel.

Results showed that even in the slightest breeze of 4kph, saliva can travel 18 feet - the length of three refrigerators laying down side by side - in five seconds. 

Dr. Dimitris Draikakis, professor in the Medical School and the School of Sciences and Engineering at the University of Nicosia, said the droplet cloud will affect both adults and children of different heights especially if they are located within the trajectory of the traveling saliva droplets.

“This work is vital, because it concerns health and safety distance guidelines, advances the understanding of spreading and transmission of airborne diseases, and helps form precautionary measures based on scientific results,” Dr. Draikakis said.