Again, though, IN THE REAL WORLD the case for mask mandates is incredibly weak. Even a 50% reduction in droplet spray only increases exposure time from 15 to 30 minutes (most of the masks in use don't even reduce it that much), and there are only a limited number of cases for which that will reduce infections—school, where students are around each other for hours, is not one of them. (Though this doesn't affect most students, facial hair, particularly a beard, renders a mask useless.) You'd have to have an N95 mask, with something to catch and prevent any breakthrough droplets such as a face shield, and a ban on facial hair (never going to happen) to achieve meaningful drops in transmission... and even then, you look at hospitals, and they're still the leading place of infection outside the home according to multiple assessments.
