https://www.hindawi.com/journals/av/2014/859090/
Above is a link to a paper on transmission of a flu virus. They use the term um (well , the u is the micro symbol) - so it is in micro-meters, or microns.
I was trying to find out how much of what is inhaled is a virus attached to a dust particle. I skimmed the paper but didn’t see that.
It does say though that a flu virus will have all sorts of different sizes (so maybe it is attached to dust?). Or perhaps droplets, vapor, etc. Anyway, they did experiments of the various sizes, and most of it was on the larger size. With a smaller percentage being the smaller ones that can get sucked deep into the lungs.
I think that was the paper that also talks about how you need a flu virus to reach a certain number of viruses in the air to be considered a large risk.
So bottom line as far as I can tell, anything you can do to limit exposure is helpful.
Seems very logical. You and Steve are right on.
Thanks for the paper.
I believe it was anthrax that needed just a very small number -- i.e. a handful -- of spores to create the momentum for a meaningful infection in an organism. Other pathogens, like flu viruses and coronavirus, need a lot more of whatever the unit is (virion).
It stands to reason that someone like a clinician, who is going to be inches away from an active case, needs a "more perfect" protection than a person who might just pass an infected individual now and then on the street. Avoid closed areas, though.