London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.
Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.
In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.
"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.
According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.
They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.
These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.
In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.
The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.
Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.
The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.
"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.
However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.
They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.
This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.
Comments
Sngha parivar sarkar and Corporate pulled India 10 years back and Looting India by increasing price for oil, gas and other products, neglecting farmers, unorganised sectors, drop in GDP, high cost living, middle class people dropped thier status to poor category, no planning comision, no pancha warshika yogana.....
for common people India became hell and totally frustrated. Rulers are wwasting time to divide india in the name of religion instead of working on developments. Uneducated and stupid personality like him ruling India including burocrates. qualification is not a eligibility to rule in India. Only hate mongers are selected for all the positions. We cannot blame them as the great fools are Peoples of India repeatedly electing hate mongers. will dream "acche din ayega" jai hind
Who he is "BASTURD" chopping finger; if it is against "Stupid modi"
Cheddi sandesh spotted..!
Well said mr. Nityanand Rai. Unculture Indian people dont know how to respect our hon. PM
I am rising my middle finger against Modi. Fool. Chop my finger
If you talk againts INDIAN constituiton ready to face the worst or public may drag you from the position.
Modi is the PM elected represnetative not a God. World has seen several dictators and thier worst end.
So suggest not to jump.
All the comments all we hear is the man agenda and advise from Nagpur else who will talk such anti INDIA slogans.
The more U bring people to do EVIL , the more, RSS will reward the bow bow leaders. and a fact done with the devils to destroy the young hindu generation to do evil in the society.
Add new comment