The American flights back the folks transporting them were wearing level 4 biohazard with rebreathers. An N95 mask won’t do a damned thing. I’ve heard this is 0.02 microns in size.
The N95 was shown in a recent study to decrease flu transmission by 80 % when exposed to an infected person in an enclosed area. It is probably due to preventing larger particles which are known to have higher densities of bacteria. And probably have higher viral densities. Especially if it is a human cell under viral control lol. But N95 should only be used by people long term if they just want to postpone getting the disease. N95 is useful to minimize minor exposure or ambient exposure. Not for prolonged long term exposure. IE If someone coughs, sneezes or is identified as sick, leave the room asap even with a N95.