This is a linkpost for https://slatestarcodex.com/2020/03/23/face-masks-much-more-than-you-wanted-to-know/
This post seems to be a bit confused
Respirators are tight pieces of fabric that form a seal around your mouth and nose. They have various “ratings”; N95 is the most common, and I’ll be using “N95 respirator” and “respirator” interchangably through most of this post even though that’s not quite correct. When used correctly, they theoretically offer complete protection against incoming and outgoing droplet and airborne diseases; since aerosol diseases are a combination of these, they offer complete protection against those too.
Filtering out 95% of viruses doesn't give you complete protection. It gives you 95% protection.
Sorry, by "complete" I meant "against both types of transmission". I agree it was confusing/wrong as written, so I edited it to say "generalized".
Face Masks: Much More Than You Wanted To Know