How about the N99 mask... Having trouble finding the virus size. Do you have the smallest size of particles a person coughs up?
I see the N95 mask will work on 0.4.
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I’m pretty sure that the N99 means it will work on 99% of the particles - but the particle size that it still filters is the same as the N95 mask. On mine it says it filter things greater than 0.3 microns. (Oh - so I guess that would mean 0.4! - or 0.31?)