I saw one thing that even tshirt material reduces the viral load you expel if you are contagious. Which makes sense, the virus is not truly airborne but instead travels on water droplets you expel and any fabric would catch some of them.
Right now my spouse and I are using things like scarves and headbands. We ordered 2 masks designed for bicycling that are certainly not medical grade (they do not list viruses in what they stop for example) but more to keep bicyclists from breathing in exhaust.
I think masks are great. I want to quibble with the phrase "truly airborne" and then shut up about it.
Being airborne depends on the concept of an aerosol.
Wikipedia:
"The liquid or solid particles [of an aerosol] have diameters typically less than 1 μm; larger particles with a significant settling speed make the mixture a suspension ..."
Since there is a continuum of sizes, there must be a continuum between suspensions and aerosols. Also, what is a significant settling speed?
Whether a given particle size can make a virus spread in an airborne manner may depend on the situation. If a particle only has to travel across a room, it could be airborne with a greater settling speed than what an airborne disease would otherwise require.
Dr. Kim Joo-Yoo of South Korea was of the opinion that SARS-COV-2 was for practical purposes aerosolized by the singing of a few members of the religious sect in South Korea where there was unusually rapid spread. A similar concern was raised with the choir in Washington state. In these cases, it does not seem realistic that one or two people ran around hugging tens of people or that there was some chain of physical contact with each person rubbing virus onto the next. Further, it was not spread through contagion since not enough time passed for people to become contagious. By process of elimination, suspicion falls on airborne spread within a room by someone singing and for practical purposes aerosolizing the virus.
I imagine that the vibrations from vigorous singing could break a larger droplet into smaller droplets making the droplets closer to being true aerosols.
This bothers me with sporting events. If people sing and chant loudly, the R-nought might go up dramatically. Just waiting for it to happen with The Reopening.