Comment by superkuh on Contra Dance Mask Policy · 2022-05-07T16:43:52.848Z · LW · GW

P100 are nice, but it's very hard to find a disposable P100 that actually seals to the face properly like disposable N95/ffp2 do. Since sars-cov-2 is primarily spread via aerosols the most important thing is not the absolute filtration effectiveness of your mask but instead to completely seal it. An N95 sealed with medical tape to the face will far outperform an P100 that has a couple mm^2 gap along edges and nose.

Full P100 respirators made of rubber and plastic do seal well, but yeah, they almost always have an exhaust valve with a small aperture. This makes these impossible to filter manually because the pressure drop is too high.

The best option in most situations is an N95/ffp2 that is sealed to the face. Masks that don't fit or seal properly are more of a fashion statement. Anything that requires masking for sars-cov-2 reasons should require fitted masks that seal.