N95 masks, you see, have but one purpose: To prevent the wearer from infecting others. To use blunt medical terminology, they work by preventing snot, spit or other virus-carrying particles from becoming airborne. Thus, if the wearer sneezes, coughs, drools, spits or talks excitedly, his or her infected fluids will be trapped in the mask and will not infect others.
N95 masks have virtually no ability to protect the wearer from other people's airborne germs.
This is only partially true. The N-95 masks we use in the hospital are designed to fit tightly around the mouth and nose. If fitted properly there is no air leakage around the mask during inspiration, all of the air inhaled passes through the mask. During exhalation the mask can be blown out from the skin but this doesn’t matter because the positive pressure keeps germs out during this time anyway. When we were trained to use them there was a testing hood we wore to determine whether we were using the correct size and were wearing it properly- if we could smell the odor in the hood there was air leakage. Used in this way they do protect from airborne pathogens carried in dust and aerosol particles. If the mask does not fit properly it is no more effective than regular surgical mask which were designed to protect the surgical field from contamination- in other words to prevent the wearer from “spraying”. The person who is sick is as well served by using a regular mask, the healthy person in the area is who needs the N-95, and it needs to be the proper size and properly fitted.
Grateful that for most of us this is “know” and not “need to know”
