[Svartalfiar]

IMO the effectiveness numbers in this piece are too optimistic.

Those numbers might be decently accurate, in a controlled lab environment where 100% of the testing air is channeled through the fabric. For example, the blue/white surgical masks are #2 with ~90% efficiency, yet that doesn't include the fact that they aren't sealed, so about 70% of your breath is going around the mask, not filtered through it.

[Yardstick]

Seems like I’ve read that surgical masks are only about 40% efficient at stopping aerosols even in ideal conditions (no leaks). I will say that I think most masks probably do a decent job of stopping larger droplets from traveling as far. As such I’m open to the idea that they’re better than nothing. Definitely don’t think they’re the game changer that some make them out to be though.