Safe Social Distancing Alert: Long Streams of Virus-Laden Droplets Can Trail Behind Infected Individuals

Cough Generated Droplets Narrow Corridor

The cough-generated droplets from a walking individual disperse differently in a narrow corridor and an open space. In narrow corridors, the droplets are concentrated in a small bubble and are left further behind. Credit: Xiaolei Yang

Fast walking in narrow corridors can increase COVID-19 transmission risk.

Long streams of virus-laden droplets can trail behind infected individuals walking through a narrow corridor, impacting safe social distancing guidelines.

Computational simulations have been used to accurately predict airflow and droplet dispersal patterns in situations where COVID-19 might be spread. In the journal Physics of Fluids, by AIP Publishing, results show the importance of the shape of the space in modeling how virus-laden droplets move through the air.

The simulations are used to determine flow patterns behind a walking individual in spaces of different shape. The results reveal a higher transmission risk for children in some instances, such as behind quickly moving people in a long narrow hallway.

Previous investigations using this simulation technique have helped scientists understand the influence of objects, like glass barriers, windows, air conditioners, and toilets, on airflow patterns and virus spread. The previous simulations have usually assumed a large, open indoor space but have not considered the effect of nearby walls, like those that might exist in a narrow corridor.

Cough Generated Droplets Open Space

The cough-generated droplets from a walking individual disperse differently in a narrow corridor and an open space. In an open space, the droplets are dispersed in a large range attached to the person. Credit: Xiaolei Yang

If a person walking in a corridor coughs, their breath expels droplets that travel around and behind their body, forming a wake in the way a boat forms a wake in water as it travels. The investigation revealed the existence of a “re-circulation bubble” directly behind the person’s torso and a long wake streaming out behind them at approximately waist height.

“The flow patterns we found are strongly related to the shape of the human body,” said author Xiaolei Yang. “At 2 meters downstream, the wake is almost negligible at mouth height and leg height but is still visible at waist height.”

Once the airflow patterns were determined, the investigation modeled the dispersal of a cloud of droplets expelled from the simulated person’s mouth. The shape of the space surrounding the moving person is particularly critical for this part of the calculation.

Two types of dispersal modes were found. In one mode, the cloud of droplets detaches from the moving person and floats far behind that individual, creating a floating bubble of virus-laden droplets. In the other mode, the cloud is attached to the person’s back, trailing behind them like a tail as they move through the space.

Cloud of Droplets

In both modes, the cloud of droplets hovers at about half-height of the infected person before reaching the ground, indicating higher risk for children to inhale the droplets. Credit: Xiaolei Yang

“For the detached mode, the droplet concentration is much higher than for the attached mode, five seconds after a cough,” said Yang. “This poses a great challenge in determining a safe social distance in places like a very narrow corridor, where a person may inhale viral droplets even if the patient is far in front of him or her.”

The danger is particularly great for children, since in both modes, the cloud of droplets hovers at a distance above the ground that is about half the height of the infected person — in other words, at mouth level for children.

Reference: “Effects of space sizes on the dispersion of cough-generated droplets from a walking person” by Zhaobin Li, Hongping Wang, Xinlei Zhang, Ting Wu and Xiaolei Yang, 15 December 2020, Physics of Fluids.
DOI: 10.1063/5.0034874

67 Comments on "Safe Social Distancing Alert: Long Streams of Virus-Laden Droplets Can Trail Behind Infected Individuals"

  1. Too bad we cannot walk around in an astronaut’s suit, where I imagine ALL infectious droplets will be contained!!! Crazy thought, we can live normally and take a leap of faith.

  2. Science works and faith works too!

  3. What a load of crap! The virus scam gets crazier every day. And the 🐑🐑🐑🐑🐑 keep buying it. New World Order Madness!

  4. My take on this is that you should avoid being indoors with people who are not in your household unless they have had a negative Covid-19 test or have been in isolation for 10 days. Also infected people cough out aerosols which are smaller particles than droplets.Aerosols can travel like smoke or clouds for long distances and for longer time than droplets.

    • 🤦
      God you people are so stupid!
      You are brainwashed beyond redemption!

      • Lerxst Dirk Pratt | December 16, 2020 at 7:19 am | Reply

        Next time you or a family member needs surgery, demand your doctor and nurses to not wear a mask during the surgical procedure. I dare you.

      • Then the devil taketh him up into the holy city, and setteth him on a pinnacle of the temple,

        6 And saith unto him, If thou be the Son of God, cast thyself down: for it is written, He shall give his angels charge concerning thee: and in their hands they shall bear thee up, lest at any time thou dash thy foot against a stone.

        7 Jesus said unto him, It is written again, Thou shalt not tempt the Lord thy God.

  5. “Long Streams of Virus-Laden Droplets Can Trail Behind Infected Individuals”

    Just like farts

  6. I’ve always thought 75% of people in this country are imbeciles. Faith does not prevent the virus spread.

  7. Would you believe smoking is allowed in casinos in Nevada with all the covid cases here. The governor does not do anything about it.

  8. Ok it is a virus.. just like the cold and the flu…therefore all the droplets fall the same…the difference is this could kill you so can alot of other things also.. science can save you but we all know when it’s your time it’s your time…maybe if you work just as hard in finding treatments as you do in putting fear in people over a virus that the MAJORITY who gets infected recover maybe we can get past this and move on with our lives….

  9. Science says look both ways before crossing the street… for good reason.

  10. Crap scam fraud and more of the same. Keep up spreading your hypno psycho terror. Enjoy your creations. Everything comes back to you.

  11. More garbage to feed the sherp5

  12. Yeah well in Austria a Coke Cola tested positive for COVID-19. Numbers are inflated but we now have no one dying from Influenza or any actual respiratory issues.

  13. Wow. 1 year in and this is just discovered? A virus is light as dust and just like dust, it is carried quite a distance.

  14. The mind serves you as it creates whatever reality one wants. Every fart; sneeze; sweat; tiredness; high temp; anything, are now symptoms of covid. Don’t live anymore. Be a prisoner in your weak vessel or house.

  15. So, if you are walking along and there is someone behind you just fart when you cough and the stink will make them veer away.

  16. Stop lying you fu##ing a##holes! You and your FEAR PORN ARE OVER!

  17. @Laura V Merodio
    You are LYING!!!

  18. Welcome to 2020!! Where girls don’t know they’re girls, boys aren’t sure if they’re boys and covid vapor trails dominate news stories. I’m embarrassed for our so called news media outlets.

  19. I’ve had it with the superstitious science scare story articles. Cough into your sleeve like you were supposed to have been taught decades ago.

  20. “So, if you are walking along and there is someone behind you just fart when you cough and the stink will make them veer away.”

    Great minds think alike!

  21. Cough generated droplets. I have always held the belief that you should stay as far as possible from someone who is coughing, no big news. Since there are a lot of folks who are a-symptomatic, and do not cough, why is this research not aimed at how much virus is spread / lingers in normal breathing?

    • Lerxst Dirk Pratt | December 16, 2020 at 7:24 am | Reply

      There’s several studies. One of the best video demonstrations is on YouTube. Search the following… Slow Motion Sneeze in 4K – The Slow Mo Guys with Dr Anthony Fauci

  22. Hard to actually
    Believe, even just here, how much trash trails Trump’s clones!

  23. So if you are in a corridor, and if the person in front of you has covid, and if the person coughs, and if you are crawling on the floor behind them…there is a very negligible chance you could be infected.

  24. Faith doesn’t work? Check out ascended beings like Neem Karoli Baba

  25. Citizens are the ONLY “persons” subject to the jurisdiction of the United States.Simple solution: Don’t be a citizen. Being a U.S. citizen and WANTING to be subject to someone restricting everything they do is bloody insane. How can people be so stupid? Well that’s a long story, the fact is everyone has a choice of self-determination of legal status and the legal name I use has a status of Non-Citizen United States National. Get smart….google “8 FAM 505.2 ENDORSEMENTS” and read. Endorsements number 8 and 9. Figure it out or GO HOME.

  26. Why don’t they just start shooting everyone not following their ridiculous logic and rules?

  27. How is this ‘science’ funded? Did the scientists involved work to justify a desired outcome or work unimpeded? Was the science ‘bought’?

  28. Whenenoughenough | December 17, 2020 at 6:42 am | Reply

    Can covid-19 journalism get as anymore hysterical? Please god let there be a limit to this idiocy.

  29. 300,000 people are already dead from covid in the US. The prevention recommendations such as masks, distancing etc are brought to us by infectious disease specialists, engineers and other people educated and experienced in such matters. The folks ridiculing these recommendations don’t have an inkling of understanding, and are falling for the conspiracy theories put out by Trump and his cult of followers

  30. Covid my arse! Nothing more than a respiratory flu strain. What’s really going on mates?

    1) Destroy economy.
    2) Control the people.
    3) Use fake science with agenda.
    4) Bring fear to the masses.
    5) Fill bodies with foreign material.
    6) Bring world into One World Government.
    7) Destroy small businesses and transfer wealth to the rich while poor get poorer.
    8) Track movements of ALL peoples.
    9) Indoctrinate ALL children into Sheeple. Government good. Nationalist bad.
    10) Destroy churches and all hate within them.
    11) Enact Agenda 21.
    12) Prepare peoples for Project Blue Beam.
    13) Enact Georgia Guidestones
    14) Remove Borders
    15) Separate ALL peoples. Either Certifiable Human (Agrees to BioChip to conduct business of buying or selling) or not (cannot participate in society as a whole).
    16) Individualism will be abolished.
    17) Tyrannical local governments will be installed with the UN powers dictating all world affairs.
    18) All “Firearms” removed
    19) Fema Camps installed and filled with non compliant Sentient Beings.

  31. Nick Girdwood said:- “Faith is a tool of morons. It does not work for anything”.

    Nick. At least do some research before you make such wide-sweeping and false claims:-

    ‘Religion, Spirituality, and Health: The Research and Clinical Implications’
    NCBi paper


    “…A large volume of research shows that people who are more Religious/spiritual have better mental health and adapt more quickly to health problems compared to those who are less R/S. These possible benefits to mental health and well-being have physiological consequences that impact physical health, affect the risk of disease, and influence response to treatment….”

Leave a comment

Email address is optional. If provided, your email will not be published or shared.