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
if you think muslim killed million, then forget about you,....even you grand grand father never breath in this world. muslim are generous but if you provoke they will hit with full power even if he was alone, not like you people coward you attack in number like dogs
hope the US nukes muslim lands. Islam is responsible for killing millions
we never find Iran by supporting palestinians in their difficult times , only instigate groups like Hamas to keep entire area boil ,
watch situation sunni muslims in Iraq, syria , yeman... do US or Isreil responsible ? even US interfered , who is the benefeciary...
In Yeman entire sea route is controled by US navy , even then weapons are supplied to houthis.... who is supplying weapons weather US or Iran by the help of US navy.... !
Warriors of Muslim? Nonsense. they are killing so many muslims in Yemen, they are the one who started to fight the sunnis and killing them, they have killed many in Algeria, Lebonan using thei terrorism.
Read history of the their trait before blindly trusting. their statement now is just a political gimmic. if they are so worried about muslims and so powerful and talking about defending Saudi why did they defend palastine why dint they fight israel? why they just watching so many diying muslims children an women and men in palastine where is their power. what we hear nothing bnut lies from them. they will not do anything their aim is to conqer power. Rafida or Rawafid is their name!
Warriors of Muslim? Nonsense. they are killing so many muslims in Yemen, they are the one who started to fight the sunnis and killing them, they have killed many in Algeria, Lebonan using thei terrorism.
Read history of the their trait before blindly trusting. their statement now is just a political gimmic. if they are so worried about muslims and so powerful and talking about defending Saudi why did they defend palastine why dint they fight israel? why they just watching so many diying muslims children an women and men in palastine where is their power. what we hear nothing bnut lies from them. they will not do anything their aim is to conqer power. Rafida or Rawafid is their name!
salute fo the true worrier of muslim, IRAN
you are asking help with american slaves, sorry they are loyal dogs die for them not for muslim brothers.
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