A cough droplet can travel more than 6 meters under windy conditions

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Man coughing in public (Image: Pexels.com)
Man coughing in public (Image: Pexels.com)

New Delhi : With coronavirus hampering the world, there have been many types of research on how long a cough droplet can travel? In one of the recent studies, it has been found that a single cough droplet can easily cover a distance of around 6.6 meters under a wind speed condition of 2 meters per second.

The researchers in Singapore did the study to analyze the transmission rate of viral infections, including COVID-19.

In a paper published in the journal ‘Physics of Fluids’, researchers from the Institute of High-Performance Computing in Singapore conducted a numerical study on droplet dispersion using high fidelity airflow simulation.

"In addition to wearing a mask, we found social distancing to be generally effective, as droplet deposition is shown to be reduced on a person who is at least one meter from the cough," said study author Fong Yew Leong. 

In a normal cough, thousands of droplets of different sizes come out from the mouth. Due to gravity, many of them settle to the ground at short distance but smaller ones can easily travel up to 1 meter under no wind condition.

Medium-sized droplets could evaporate into smaller droplets, which are lighter and more easily borne by the wind, and these travelled further.

"An evaporating droplet retains the non-volatile viral content, so the viral loading is effectively increased," said author Hongying Li. 

"This means that evaporated droplets that become aerosols are more susceptible to be inhaled deep into the lungs, which causes infection lower down the respiratory tract, than larger unevaporated droplets."

Meanwhile, the researchers have claimed that the travel distance highly depends on the environmental conditions like wind speed, humidity, air temperature and more.

"While this research focused on outdoor airborne transmission in a tropical context, the scientists plan to apply their findings to assess risk in indoor and outdoor settings where crowds gather, such as conference halls or amphitheatres," the study said.