If I remember correctly, the Rona virus attaches to aerosol particles emitted during a cough/sneeze. Those particles are large enough to get filtered by the masks.
I think typical masking is pure stupidity, completely disproven by results - ie public masking obviously is doing hardly anything or likely nothing at all to curb transmission, it might even be making it worse..
But a key thing is no matter what the filter might potentially accomplish, most masks don't seal to your face, so the filter type is almost impertinent. Sure they block stuff how a face shield would, but filtering isn't really going on unless you have a firm attachment system and a gasket of some sort.
I work around a lot of nasty stuff at times, dust and chemicals, and even for dust that you can basically see clear as day, I know for a fact an N95, any of those light duty styles, just aren't reliable. Of course a surgical mask does nothing.. The n95 filters can stop the dust just fine but the typical elastic and gasket system isn't very reliable.