Saliva droplets can travel large distances, depending on environmental conditions such as wind speed, temperature, pressure and humidity. Wind shown blowing left to right at speeds of 4 kph (top) and 15 kph (bottom) can transport saliva droplets up to 6 meters (18 feet). CREDIT: Image courtesy of the authors
Airborne transmission of viruses, like the virus causing COVID-19, is not well understood, but a good baseline for study is a deeper understanding of how particles travel through the air when people cough.
In a paper published in Physics of Fluids, from AIP Publishing, Talib Dbouk and Dimitris Drikakis of University of Nicosia discovered that with even a slight breeze of 4 kph, saliva travels 18 feet in 5 seconds.
“The droplet cloud will affect both adults and children of different heights,” Drikakis said. “Shorter adults and children could be at higher risk if they are located within the trajectory of the traveling saliva droplets.”
Saliva is a complex fluid, and it travels suspended in a bulk of surrounding air released by a cough. Many factors affect how saliva droplets travel, including 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.
To study how saliva moves through air, Dbouk and Drikakis created a computational fluid dynamics simulation that examines the state of every saliva droplet moving through the air in front of a coughing person. Their simulation considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapor and evaporate.
The computational domain in the simulation is a grid representing the space in front of a coughing person. The analysis involved running partial differential equations on 1,008 saliva droplets and solving approximately 3.7 million equations in total.
“Each cell holds information about variables like pressure, fluid velocity, temperature, droplet mass, droplet position, etc.,” Dbouk said. “The purpose of the mathematical modeling 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.”
Further studies are needed to determine the effect of ground surface temperature on the behavior of saliva in air and to examine indoor environments, where air conditioning significantly affects the particle movement through air.
“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,” said Drikakis.
The Latest Updates from Bing News & Google News
Go deeper with Bing News on:
Covid-19 transmission
- Covid-19 Pandemic Led To Growing Acceptance Of Doctors Withholding Treatment
According to a new study there is a steadily growing acceptance of the view that it could be ethically acceptable for doctors to refuse care.
- Scientists discover higher levels of CO₂ increase survival of viruses in the air and transmission risk
A new study has revealed for the first time the vital role carbon dioxide (CO2) plays in determining the lifespan of airborne viruses—namely SARS-CoV-2, the virus that causes COVID-19. It clearly ...
- Did California's pediatric COVID-19 vaccination program reduce reported cases and hospitalizations?
Changes in the incidence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related hospitalizations.
- COVID-19 pandemic alters view that doctors are obligated to provide care: Study
The unique circumstances arising from the COVID-19 pandemic altered a long-held convention that doctors provide care regardless of personal risk.
- WHO redefines airborne transmission: what does that mean for future pandemics?
The World Health Organization was criticised for being too slow to classify COVID-19 as airborne. Will the new terminology help next time?
Go deeper with Google Headlines on:
Covid-19 transmission
[google_news title=”” keyword=”Covid-19 transmission” num_posts=”5″ blurb_length=”0″ show_thumb=”left”]
Go deeper with Bing News on:
Covid-19
- ‘Last Week Tonight’ Turns 10: See the 10 Most-Viewed Clips from the Series (VIDEO)
John Oliver’s show has been satirizing politicians, corporations, and other news programs for a decade now, and these rants are some of his greatest hits.
- Guilty Pleas in Major COVID-19 Aid Fraud Case in Lancaster County
Two principal culprits embroiled in a substantial fraud case related to the COVID-19 pandemic have admitted guilt in Lancaster County Court. The case, brought by the Lancaster ...
- Covid-19 Pandemic Led To Growing Acceptance Of Doctors Withholding Treatment
According to a new study there is a steadily growing acceptance of the view that it could be ethically acceptable for doctors to refuse care.
- Wooster native struggling with possible after-effects of COVID-19 vaccine
She was diagnosed with POTS − Postural Orthostatic Tachycardia Syndrome, a disorder in which the autonomic nervous system doesn't function normally.
- Class of 2024 reflects on college years marked by COVID-19, protests and life’s lost milestones
The unrest at campuses over the Israel-Hamas war has marked an emotional end to the college experiences of those graduating in 2024 that started amid a pandemic.
Go deeper with Google Headlines on:
Covid-19
[google_news title=”” keyword=”Covid-19″ num_posts=”5″ blurb_length=”0″ show_thumb=”left”]