Yes, it is gross but necessary. Sorry in advance.
The question of social distance is back on the table, at least according to the UK’s Daily Mail (reporting today on Dr Fauci’s nuanced answer to a question . . . and no, this isn’t Babylon Bee spoofing on April Fool’s Day):
Illustrating, i/l/o a 2014 study — early progress of a super-sneeze or cough:
Notice, the drifting cloud?
Here’s MIT, in 2014:
The next time you feel a sneeze coming on, raise your elbow to cover up that multiphase turbulent buoyant cloud you’re about to expel.
That’s right: 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.
With this in mind, architects and engineers may want to re-examine the design of workplaces and hospitals, or air circulation on airplanes, to reduce the chances of airborne pathogens being transmitted among people.
“You can have ventilation contamination in a much more direct way than we would have expected originally,” says Lydia Bourouiba, an assistant professor in MIT’s Department of Civil and Environmental Engineering, and another co-author of the study.
As DM mentions, this can go up to 27 feet — the whole nine yards.
For Antigua and Montserrat, MIT’s remarks about air circulation on airplanes hits close to home. For, on Tue March 10, BA 2157 from London was later shown to have carried not one but two patient zeros. One, for each territory. contamination of the air and/or of the ventilation system now seems to be an even more relevant issue.
So, should we be setting a 30 foot safety zone and refuse to enter an air conditioned building?
Perhaps, not; it is an odds game and we are reducing odds of infection by multiple preventative actions. 6 ft is said to be quite good enough to allow particles from more ordinary breathing etc to precipitate. Sneeze into the crook of the elbow (in an emergency!) looks likely to block formation of a moving mini cloud. Using a filtered face mask looks likely to help to block droplets moving in or out. Goggles help too — a simple solution here is swimming goggles. Hand and face washing and/or sanitiser help also. And more.
Layered defence in depth.
Thing is, it looks like we are going to have to go through two or more full isolation cycles, a month or more, given what has been noted.
Then, there’s that story about research on bats in labs near enough to the notorious wet market.
Then, there’s the other story that there may be, not two or three but up to 49 strains of this virus already.
Okay, enough of the daily two-minute fright.
Chloroquine looks likely to hold up as a treatment and several dozen others are in train. We may at last be getting somewhere on broad spectrum antivirals.
Ventilators are coming by the tens of thousands.
Testing is down to five minutes.
Vaccines will be coming, too. END