08-12-2020, 05:36 AM
Be aware that the study was viewing the droplets from the speech of the mask wearer. The mask wasn't being protective of the speaker. I didn't think much of the study overall, but it does point out some of the issues with consumer/home-made masks.
Regarding big or small droplets, I think it is clear that small droplets are more likely to be aerosolized (actually anything expelled under 100 microns is likely to stay afloat for many minutes to days as it will evaporate to a small nuclei before it can fall to the ground; a 50 micron droplet will travel upward in the thermal plume of a person's body heat). The smaller it is, the further it can go into your airways. (See my notes on the recent UCSF grand rounds. for this, and for how far the droplets can travel in a real environment rather than a dead-air environment.)
My opinion is that there is plenty of evidence that spread happens much further than the 6' that everyone has been warned about. Since we seemingly have no way of knowing just when someone gets infected and from whom they were infected, I don't understand why the early guidance is so doggedly clung to.
More than that, I think the body of evidence is that the effects that are most devastating to individuals most often includes infections in the lower airways, and less often infections in the upper airways (or in the eyes). I would think that suggests it is smaller particles getting into those lower respiratory areas that is causing the devastation. (The UCSF grand rounds referenced how TB seems to require smaller particles so it got into the lungs to do its worst damage.)
Hmmm.... I wonder if any one has yet done similar animal studies on the size of particles containing SARS-COV-2 and the infection course.
Regarding big or small droplets, I think it is clear that small droplets are more likely to be aerosolized (actually anything expelled under 100 microns is likely to stay afloat for many minutes to days as it will evaporate to a small nuclei before it can fall to the ground; a 50 micron droplet will travel upward in the thermal plume of a person's body heat). The smaller it is, the further it can go into your airways. (See my notes on the recent UCSF grand rounds. for this, and for how far the droplets can travel in a real environment rather than a dead-air environment.)
My opinion is that there is plenty of evidence that spread happens much further than the 6' that everyone has been warned about. Since we seemingly have no way of knowing just when someone gets infected and from whom they were infected, I don't understand why the early guidance is so doggedly clung to.
More than that, I think the body of evidence is that the effects that are most devastating to individuals most often includes infections in the lower airways, and less often infections in the upper airways (or in the eyes). I would think that suggests it is smaller particles getting into those lower respiratory areas that is causing the devastation. (The UCSF grand rounds referenced how TB seems to require smaller particles so it got into the lungs to do its worst damage.)
Hmmm.... I wonder if any one has yet done similar animal studies on the size of particles containing SARS-COV-2 and the infection course.