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CDC Says Ebola Droplets Can Only Travel 3 Feet … But MIT Research Shows Sneezes Can Travel Up to 20 Feet

George Washington's picture




 

This week, the Centers for Disease Control (CDC) admitted that Ebola can travel through the air in aerosols, but claims that it can never go more than 3 feet.

Let's check their math ...

CDC (like the World Health Organization) admits that Ebola can be spread through sneezing or coughing.

But the CDC itself admits that flu droplets can travel 6 feet.

Mythbusters demonstrated that sneezes can nail people some 17 feet away:

But engineers at MIT show that sneezes can actually travel up to 200 times farther than previously thought ... up to 20 feet.

How?

Gas clouds:

“[The study] changes our current ideas of how far germs can spread in aerosols such as coughs or sneezes,” Mary B. Farone, Ph.D., associate professor of biology at Middle Tennessee State University, told weather.com. “We used to think if we could see the spray, that was the limit of the dissemination, but this study shows that tiny particles, such as bacteria and viruses, can be spread much further on gas clouds.”

MIT explains:

A novel study by MIT researchers shows that coughs and sneezes have associated gas clouds that keep their potentially infectious droplets aloft over much greater distances than previously realized.“When you cough or sneeze, you see the droplets, or feel them if someone sneezes on you,” says John Bush, a professor of applied mathematics at MIT, and co-author of a new paper on the subject. “But you don’t see the cloud, the invisible gas phase. The influence of this gas cloud is to extend the range of the individual droplets, particularly the small ones.”

Indeed, the study finds, the smaller droplets that emerge in a cough or sneeze may travel five to 200 times further than they would if those droplets simply moved as groups of unconnected particles — which is what previous estimates had assumed. The tendency of these droplets to stay airborne, resuspended by gas clouds, means that ventilation systems may be more prone to transmitting potentially infectious particles than had been suspected.

***

The researchers used high-speed imaging of coughs and sneezes, as well as laboratory simulations and mathematical modeling, to produce a new analysis of coughs and sneezes from a fluid-mechanics perspective. Their conclusions upend some prior thinking on the subject.

***

The study finds that droplets 100 micrometers — or millionths of a meter — in diameter travel five times farther than previously estimated, while droplets 10 micrometers in diameter travel 200 times farther. Droplets less than 50 micrometers in size can frequently remain airborne long enough to reach ceiling ventilation units.

A cough or sneeze is a “multiphase turbulent buoyant cloud,” as the researchers term it in the paper, because the cloud mixes with surrounding air before its payload of liquid droplets falls out, evaporates into solid residues, or both.

The study notes:

Our key findings are as follows. The turbulent multiphase cloud plays a critical role in extending the range of the majority of pathogen-bearing drops that accompany human coughs and sneezes. Smaller droplets (less than 50 µm diameter) can remain suspended in the cloud long enough for the cough to reach heights where ventilation systems can be contaminated (4–6 m).

6 meters equals 19.685 feet.

While Slate may have gotten the numbers wrong, they made an entertaining video about the MIT study:

 

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Tue, 10/28/2014 - 10:20 | 5385823 mastersnark
mastersnark's picture

No one's stopping you from heroing.

Dick.

Tue, 10/28/2014 - 10:19 | 5385817 DonutBoy
DonutBoy's picture

Hmmm...  Well since you are the virus - best you go kill yourself in your backyard.

Tue, 10/28/2014 - 08:28 | 5385429 Rememberweimar
Rememberweimar's picture

If Ebola survives in human feces like they say it does for (months), then the big cities across America are going to experience an epidemic. Because, thanks to the Bankers, there is currently the largest population of homeless Americans in history. There is literally shit everywhere, you can't even walk a block thru the city without getting human shit on the bottom of your shoes. Then, when you take your shoes off for a minute, you get EBOLA on your hands. And you know where it goes from there...

Tue, 10/28/2014 - 10:29 | 5385855 BigJim
BigJim's picture

I don't know about you, but when I remove my shoes I don't usually do it by grabbing the underside of the sole. I alos tend to wash my hands when I get home. But each to their own.

Tue, 10/28/2014 - 13:21 | 5386539 nukeaduke
nukeaduke's picture

We may need to think about tracking it inside, too, before we got around to taking shoes off, especially with rug rats on floors/carpets.

Might be best to just go Japanese, everybody takes outside shoes off at door and puts on house slippers.

Tue, 10/28/2014 - 12:18 | 5386311 12ToothAssassin
12ToothAssassin's picture

GW - I appreciate your angles most of the time but they have you chasing your tail on this Ebola thing. Youre being distracted. Oh well, guess it runs up the hit counter. As you were shitizen!

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