[M T]

I think the evidence is that the dominant mode of transmission is via droplets.  While I don't think we can exclude aerosols entirely (and it has been established that in certain procedures, like intubation, aerosols are generated), it doesn't seem to be the dominant form of transmission.

If the infections were spreading by aerosols, how would the CDC distinguish that from spreading by droplets?  Since we haven't had time for formal studies, the evidence is from what we've experienced in the real world (and, in particular, China).   "Oh, you live in the same house?  You must have gotten it from droplets."   "Oh, we don't know how you got it... We'll call that community transmission, presumably from someone that got within 6' of you and coughed without you noticing."  It takes unusual circumstances to show that transmission could only have been by aerosol.

It may be that most people killed by guns are shot at directly, but I wouldn't want to be in a room where someone started firing a gun at a brick wall, especially if there were thousands of bullets.

Results show that cough-generated aerosol particles spread rapidly throughout the room, and that within 5 min, a worker anywhere in the [exam] room would be exposed to potentially hazardous aerosols.
(I will note that being exposed to potentially hazardous aerosols does not necessarily mean the worker would suffer the hazard.)

The recent measuring of air currents followed by simulation of the Wuhan restaurant described the spreading as by aerosols (but without  specifying the minimum/maximum size of the droplets/aerosols that contributed to the spread in their simulation).  It does appear they had video of the time of the spread.  There was no mention of coughing.  The measurements involved air flow consistent with breathing & speech.
The studies I quoted earlier indicated there were far more aerosol-sized droplet nuclei generated in a cough than those larger than aerosol-sized,  Of course the viral load is higher in the larger droplets/nuclei

I suppose some day there will be animal studies that figure out how many of various sized droplet nuclei are required for infection.  By then, the question may be only of historical interest.

[M T]

I think the evidence is that the dominant mode of transmission is via droplets.  While I don't think we can exclude aerosols entirely (and it has been established that in certain procedures, like intubation, aerosols are generated), it doesn't seem to be the dominant form of transmission.

If the infections were spreading by aerosols, how would the CDC distinguish that from spreading by droplets?  Since we haven't had time for formal studies, the evidence is from what we've experienced in the real world (and, in particular, China).   "Oh, you live in the same house?  You must have gotten it from droplets."   "Oh, we don't know how you got it... We'll call that community transmission, presumably from someone that got within 6' of you and coughed without you noticing."  It takes unusual circumstances to show that transmission could only have been by aerosol.

It may be that most people killed by guns are shot at directly, but I wouldn't want to be in a room where someone started firing a gun at a brick wall, especially if there were thousands of bullets.

Results show that cough-generated aerosol particles spread rapidly throughout the room, and that within 5 min, a worker anywhere in the [exam] room would be exposed to potentially hazardous aerosols.
(I will note that being exposed to potentially hazardous aerosols does not necessarily mean the worker would suffer the hazard.)

The recent measuring of air currents followed by simulation of the Wuhan restaurant described the spreading as by aerosols (but without  specifying the minimum/maximum size of the droplets/aerosols that contributed to the spread in their simulation).  It does appear they had video of the time of the spread.  There was no mention of coughing.  The measurements involved air flow consistent with breathing & speech.
The studies I quoted earlier indicated there were far more aerosol-sized droplet nuclei generated in a cough than those larger than aerosol-sized,  Of course the viral load is higher in the larger droplets/nuclei

I suppose some day there will be animal studies that figure out how many of various sized droplet nuclei are required for infection.  By then, the question may be only of historical interest.