I'm curious how much the type of mask matters. I have two kinds of masks for construction projects:

(1) the simple paper ones, and

(2) a fancier one with good rubber gaskets for my face, and replaceable filters.

Although the fancier mask (2) is more reliable for intake filtration, I suspect it's less useful for exhaust filtration, e.g. from coughs and sneezes. Because (2) uses a flapper valve to release exhaust, whereas the filtration in (1) is somewhat bidirectional.