Information on this is readily available and extremely easy to find. Anyone claiming they can't find it is not looking. It is even clearly laid out and explained on the FDA website that was referenced here. If people would bother to read more than the title they may understand there is nuance to the topic and any questions they had were very clearly answered. https://www.fda.gov/medical-devices...n95-respirators-surgical-masks-and-face-masks Many viruses need a medium to hitch a ride. Stop the water droplets and you stop the virus. This is why surgical masks work even though a virus is small enough to slip through the gaps in the cloth. Surgical masks are mainly too protect others from contracting something YOU have, not to protect you from getting something from someone else. N95, the US standard (or KN95, the chinese standard) without vents protect you from contracting and spreading the virus. If the mask has vents it only protects you from contracting a virus, not from you spreading anything.