Mass Epidemic

[FoxtArt]

N95s filter 95% of particles at a 0.2 micron size. Not sure this virus size, but other Corona family are often around .1-.12 micron-ish I've heard. At any rate, viruses like this are usually spread via aerosol. Stop the water droplets (or dust) and you stop the virus. If a dry virus or two made it through it likely wouldn't have any effect - #1 they don't survive well isolated and #2) everything has a viral load. One, two, ten or a hundred won't get you sick. A thousand will. They have horrible success rates, but manufacture tens of thousands which spill out of a "finally" infected cell.

The best success is when sick people wear them... Stopping the aerosol an inch from the source makes it meaningless if any individual virus particles get through thereafter. - this is why they are especially helpful to prevent spread inside your family of things like influenza, once someone is sick.