LogFAQs > #961811997

jramirez23 posted...

I dont understand why anybody says that face masks dont work given that its a respiratory virus we are talking about.

Mostly, the rationale there is that the masks aren't fine enough to filter out viral particles and/or don't provide an airtight seal. There's some merit to that (greater protection can indeed be had by using a fit tested N95 mask instead of a standard cloth one), but the fact that the virus is droplet-borne (droplets being a few orders of magnitude larger than viral particles and therefore much easier for coarser filters to catch) and that any covering reduces air speed (and therefore dispersal radius) mean masks do provide a considerable amount of protection.

My personal favourite demonstration of this is Bill Nye's: Try blowing out a candle with a mask on. It's pretty much impossible, which means the air leaving your mouth is being slowed down dramatically by the mask. Even if we assume nothing is actually being filtered out from your breath, the mask means the air simply isn't moving quickly enough to carry it past the mask, which prevents it from spreading.