[zzzcpan]

Masks are complicated. There is a bunch of research on practical use of protective face masks, respirators and in that effectiveness showed to be massively reduced due to leaks, improper wear, moving them or taking them off because it's hard to talk in them, hard to breathe in them and so on. Masks that claim 99% don't necessarily improve much over an 80% mask or at all. DIY masks are not much worse for the same reason.

But at the same time masks is the only significant personal protection measure against this virus when you have to be in close proximity to other people. Literally any mask would help in such case.

> They are only somewhat effective in preventing droplets being transmitted when you cough or sneeze.

They are even less effective at that, than filtering stuff coming in.