Stay 6 Feet Apart, We’re Told. But How Far Can Air Carry Coronavirus?

Most of the big droplets travel a mere six feet. The role of tiny aerosols is the “trillion-dollar question.”

A sign on the Coney Island boardwalk in Brooklyn advised visitors to keep a distance of at least six feet from each other, but some experts say that might not be enough.
A sign on the Coney Island boardwalk in Brooklyn advised visitors to keep a distance of at least six feet from each other, but some experts say that might not be enough.Credit…Caitlin Ochs/Reuters

By Knvul Sheikh, James Gorman and Kenneth Chang

The rule of thumb, or rather feet, has been to stand six feet apart in public. That’s supposed to be a safe distance if a person nearby is coughing or sneezing and is infected with the novel coronavirus, spreading droplets that may carry virus particles.

And scientists agree that six feet is a sensible and useful minimum distance, but, some say, farther away would be better.

Six feet has never been a magic number that guarantees complete protection. The Centers for Disease Control and Prevention, one of the organizations using that measure, bases its recommendation on the idea that most large droplets that people expel when they cough or sneeze will fall to the ground within six feet.

But some scientists, having looked at studies of air flow and being concerned about smaller particles called aerosols, suggest that people consider a number of factors, including their own vulnerability and whether they are outdoors or in an enclosed room, when deciding whether six feet is enough distance.

Sneezes, for instance, can launch droplets a lot farther than six feet according to a recent study.This 3-D Simulation Shows Why Social Distancing Is So ImportantWe visualized a cough to show how far respiratory droplets can spread. If you haven’t been keeping your distance to fight the coronavirus, this may persuade you.

No scientists are suggesting a wholesale change in behavior, or proposing that some other length for separation from another human, like seven, or nine feet, is actually the right one.

“Everything is about probability,” said Dr. Harvey Fineberg, who is the head of the Standing Committee on Emerging Infectious Diseases and 21st Century Health Threats at the National Academies of Sciences, Engineering and Medicine. “Three feet is better than nothing. Six feet is better than three feet. At that point, the larger drops have pretty much fallen down. Maybe if you’re out of spitting range, that could be even safer, but six feet is a pretty good number.”

One complicating factor is that aerosols, smaller droplets that can be emitted when people are breathing and talking, play some role in spreading the new coronavirus. Studies have shown that aerosols can be created during certain hospital or laboratory procedures like when using nebulizers to help patients inhale medication, which makes such procedures risky for doctors who do them.

If the aerosols that people exhale in other settings are significant in spreading the disease, the six-foot distance would not be completely protective because those are carried more easily by air currents.

Aerosols are generally considered to be particles under 5 microns in diameter, about the size of a red blood cell, and can be spread in the environment by talking and breathing. But some researchers argue that this is a false dichotomy. Infectious droplets can’t easily be divided into those that are big enough to fall to the ground quickly and those that stay aloft because so much depends on environmental conditions and how deeply they penetrate into the respiratory tract.Sign up to receive an email when we publish a new story about the coronavirus outbreak.

“It’s really a continuum,” said Dr. Donald Milton, who studies bioaerosols at the University of Maryland School of Public Health.

Even without the launching power of a sneeze, air currents could carry a flow of aerosol sized virus particles exhaled by an infected person 20 feet or more away.

“In any confined geometry like an office room, meeting room, department store, food store,” said Eugene Chudnovsky, a physicist at the City University of New York. In a study not yet peer reviewed, he analyzed air flow and showed how, “the vortices in the air are taking the virus to different places.”

A preliminary study at the University of Nebraska Medical Center found evidence of coronavirus genetic material on various surfaces in isolation rooms where infected patients were being treated, including on air vents more than six feet from the patients. The research, which has not yet been peer reviewed, indicates that the virus can occasionally travel long distances.

“The virus is so small, it can hitch a ride even on tiny, tiny particles,” Dr. Fineberg said. “But how important is each size and how well they can transmit disease is not fully understood.”

It is also unclear how many virus particles it takes to start an infection, how long the viral particles remain viable or if studies like the one in Nebraska simply detected the genetic calling card the virus left behind.

Spacing is an effective solution because it also reduces the number of people in a confined space. That reduces the likelihood of an infected person being in the group. And if there is one, fewer other people might be infected.

Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the six-foot distance would clearly “reduce the number of droplets you come in contact with. I have no doubt about that.”

But, he said: “The question is what does it take for you to get infected? And that I think is the trillion-dollar question we have.”

He said, “Maybe all it takes is an aerosol. You don’t need any droplets at all.” If that’s the case, he said, then someone who is at high risk would not want to be in the same room with someone who is infected or might be infected.

Current guidelines already suggest that anyone at high risk should stay home and not be out in public in the first place. And they seem to be working. Places where people reduced travel and started social distancing weeks ago, especially in California, New York and Washington, are starting to show a reduction in the number of new coronavirus cases.

People still need to shop and take care of necessities, Dr. Osterholm said, but reducing the risk of exposure to all possible modes of transmission — infected surfaces, droplets and smaller aerosols — is important.

“Your job is to limit it as much as you can.”

Share this article

174 thoughts on “Stay 6 Feet Apart, We’re Told. But How Far Can Air Carry Coronavirus?”

  1. Hi my family member! I wish to say that this post is awesome, great written and come with
    approximately all significant infos. I would like to peer more
    posts like this .

    Here is my web site Ann

  2. Woah! I’m really loving the template/theme of this site.
    It’s simple, yet effective. A lot of times it’s difficult to get that
    “perfect balance” between usability and appearance. I must say you’ve done a
    superb job with this. In addition, the blog loads super fast for me on Chrome.

    Excellent Blog!

    Review my web page – Glenda

  3. whoah this blog is magnificent i love studying your posts.
    Stay up the good work! You understand, lots of people are hunting around for this info, you could help them greatly.

    My website – Arlie

  4. This is very interesting, You’re a very skilled blogger.
    I have joined your rss feed and look forward to seeking more of your wonderful
    post. Also, I’ve shared your web site in my social networks!

    My homepage: Mikayla

  5. Howdy just wanted to give you a quick heads up and
    let you know a few of the images aren’t loading properly.
    I’m not sure why but I think its a linking issue.
    I’ve tried it in two different internet browsers and both show the same results.

    Here is my web blog: Isabella

  6. Wow! Finally I got a website from where I know how to truly get helpful facts concerning my study and knowledge.

    Check out my homepage Wilhemina

  7. Very soon this web site will be famous among all blogging and site-building viewers, due to it’s
    fastidious content

    Feel free to surf to my web-site: Kristofer

  8. You’ve made some good points there. I looked on the internet
    to learn more about the issue and found most individuals will go along
    with your views on this web site.

    Also visit my blog – Harlan

  9. My brother recommended I may like this blog. He was once entirely right.
    This submit actually made my day. You cann’t believe simply how so much time I had spent
    for this info! Thank you!

    Also visit my webpage Leonida

  10. I’m not that much of a internet reader to be honest but your
    sites really nice, keep it up! I’ll go ahead and bookmark your site to come back down the road.
    Many thanks

    Feel free to surf to my website – Carole

  11. I know this website presents quality based articles and other information, is there any other
    web site which offers these stuff in quality?

    My page – Cara Daftar Judi Online – https://tracka.com.au/,

  12. I am sure this paragraph has touched all the internet visitors, its really really fastidious article on building up
    new website.

    Feel free to surf to my web-site 10timing.com

  13. Wonderful site you have here but I was curious about if you
    knew of any user discussion forums that cover the same topics discussed here?

    I’d really love to be a part of community where I can get comments from other knowledgeable individuals that share the
    same interest. If you have any suggestions, please let me know.
    Appreciate it!

    Here is my site – Judi Online

  14. Nice post. I learn something totally new and challenging on blogs I stumbleupon on a daily basis.
    It will always be useful to read articles from other writers and
    use something from their web sites.

    Have a look at my web site: Situs Judi Online Terbaik

  15. Hi, I think your website might be having browser compatibility issues.
    When I look at your blog in Chrome, it looks fine but when opening
    in Internet Explorer, it has some overlapping.
    I just wanted to give you a quick heads up! Other then that, very
    good blog!

    my homepage … Cara mudah daftar situs judi online (Emory)

  16. You’re so interesting! I don’t believe I have read through anything
    like that before. So wonderful to find somebody with genuine thoughts on this issue.
    Really.. many thanks for starting this up. This website is one thing that is needed on the web,
    someone with a bit of originality!

    Also visit my blog: Cara mudah daftar situs judi online (Freddie)

  17. you’re really a just right webmaster. The site loading speed is incredible.
    It kind of feels that you’re doing any distinctive trick.

    Also, The contents are masterpiece. you have performed a wonderful activity in this subject!

    my web site; Cara Daftar Situs judi online (forums.ggcorp.ninja)

  18. Right here is the right web site for anyone who hopes
    to find out about this topic. You know a whole lot its almost hard to argue
    with you (not that I actually would want to…HaHa). You definitely put a new spin on a topic that has been discussed for years.
    Excellent stuff, just wonderful!

    my web page :: Langkah Daftar Situs Judi Online; dunkindont.us,

  19. Write more, thats all I have to say. Literally, it seems as though you relied
    on the video to make your point. You obviously know what
    youre talking about, why throw away your intelligence on just
    posting videos to your site when you could be giving us something enlightening to
    read?

    My website … inmadica.com

Comments are closed.