Facebook’s “fact check” claims that the virus particles don’t come through the mask because they’re always spread through respiratory droplets? No doubt, anything going around the mask gets out as if there were no mask, and if droplets do encounter the mask, trying to get through, if they didn’t evaporate and get through the mask, all masks would be soaking wet, dripping on the person from the massive amounts of water vapor people exhale.
Water vapors do go through the mask, just not in large, individual droplets, which cannot travel six feet anyway, when someone accidentally spits while talking, for example.
A doctor friend online who posted this video says “some of the Covid particles are not on droplets, but are free floating,” so are independent of droplets, and are tiny enough to go through the much larger fabric pores.
And regarding the particles that are on droplets, they can move through the mask material and be pushed out the other side with future exhalations that send water vapor away from the mask.