@desantis
Well, regarding the actual size of viruses, the fact, that the can "swim" in fluids and be airborne by aerosoles, the use of masks is only relative to masks quality and application. Masks even can disperge the viruses into aerosoles. So the situation of use makes, that it is helpful, at least a little. Most cases masks don't make much difference or are counterproductive.
All evidence so far is on drops and droplets, a risk you can manage by distance either.
Passphrases are helpful