The same article then also goes on to reason why this doesn't seem to be the dominant way of transmission outside special circumstances (like ventilation).
I don't have a background in this topic at all, but apparently actual airborne viruses are really small: Measles is about 200 nm and Influenza about 100 nm in diameter, while Sars-Cov-2 is about 1000 nm, so 5 to 10 times the diameter and thus 100 to 1000 times the mass.
But as far as we know, the bare virus does not travel through the air, it only travels in droplets. Although there is some disagreement on how large those droplets are.
There are two types of viruses: airborne and not airborne. Airborne can survive for some time outside bodily fluids.
Aerosol == bodily fluid that is still liquid. It is just in the form of very small droplets that are now drying out. Depending on conditions this lasts very shortly. It spreads the virus, of course, but aerosol dries out quickly and viruses that are not airborne die (well.. viruses do not live in the usual sense, basically their proteins get damaged).
Of course if somebody coughs in your direction some of the aerosol can be inhaled or reach your retina or get on your hands and you can get infected.
No, I am not suggesting droplets cannot spread the disease, the opposite is true. Droplets are much better transmitter of disease if they can reach the target.
No, the WHO was right, and still is, epidemiologically speaking. The problem is that there is a difference in meaning between "this virus is airborne" and "this virus can spread through the air via aerosols".
The former means that the virus itself can survive being exposed to the air, which means it can float for hours and spread easily over large distances.
The latter means that the virus can only survive in the air when encapsulated in a liquid, which means it can not hover in the air for long (due to the weight of the droplet) and thus not spead over large distances.
That agrees that the virus is mostly transmitted via droplets rather aerosolized virus particles. A bare virus can float in the air for quite a while but all the evidence we have, especially stuff like form that site, seems to show that that isn't a route by which people are being infected. Instead its being transmitted over shorter distances, generally around 6 feet but longer if someone is shouting, singing, coughing without covering, or just directly downwind.
The virus isn't truly airborne. The respiratory droplets can be carried in the air short distances, but direct infection from that is extremely unlikely outside of someone literally sneezing in your face.
This is in contrast to diseases like anthrax, where particles can be carried on air currents basically indefinitely and direct infection from the airborne disease is likely.
The virus isn't going to be airborne naked as an individual thing in the free air - it's going to be in droplets of stuff (from sneezing, coughing, etc).
Even droplet based spread (which is not airborne) can transfer over distances on to surfaces. This is why there is advisory for a 6+ ft physical distance.
That does not mean it is an airborne disease, as it seems the virus needs to survive in droplets.
It is no surprise to me that a choir singing could easily spread droplets on to surfaces and inadvertently touch their faces during that time.
Even a heavy breath that expels air and droplets from the lung can cause spread. That doesn't mean its airborne.
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