> I was under the impression that masks don't protect you that much, they protect other people from you?
That claim has been made but is questionable. The masks were designed to reduce exposure to the wearer, not so much from the wearer.
It's a matter of physics: When you inhale the suction generated automatically pulls the mask tighter on your face such that the air you breathe in essentially all has to pass through the mask but when you exhale, not so much.
In designing a mask there is a choice between a finer mesh or a looser one. If you pick a very loose mesh - say, cotton gauze - then air is easy to push through when you exhale but so are virus particles. On the other hand if you pick a very tight mesh - say, N95 or better - then air is much harder to push through but exhaling forces the mask slightly away from the face such that moist potentially virus-laden breath puffs out the sides and top. This is why your glasses fog up when wearing an N95 - moist air is escaping out the top of the mask completely unfiltered. (You can find youtube videos demonstrating this process with cigarette smoke). Double- or triple-masking doesn't help either - that makes it even harder for air to pass directly through the masks so even more air pushes out the side and top instead.
If your N95 is VERY well fitted and the strap VERY tight - tight enough to make your ears hurt - you'll get less escape, but wearing a mask that way is sufficiently uncomfortable that almost nobody does it.
In short, an N95 does plausibly filter nearly all the air you breathe IN, but if you want to filter the air you're breathing OUT, you really should be wearing a cleanroom suit.
Agreed, but I’ve taken several flights during covid all over the world and I see 1 n95 every 50 people at most. And it’s very likely that the person wearing it does not have covid anyway. The one that probably had covid is that guy with his nose out and the one snacking a little bit the whole flight to not have to wear it.
That claim has been made but is questionable. The masks were designed to reduce exposure to the wearer, not so much from the wearer.
It's a matter of physics: When you inhale the suction generated automatically pulls the mask tighter on your face such that the air you breathe in essentially all has to pass through the mask but when you exhale, not so much.
In designing a mask there is a choice between a finer mesh or a looser one. If you pick a very loose mesh - say, cotton gauze - then air is easy to push through when you exhale but so are virus particles. On the other hand if you pick a very tight mesh - say, N95 or better - then air is much harder to push through but exhaling forces the mask slightly away from the face such that moist potentially virus-laden breath puffs out the sides and top. This is why your glasses fog up when wearing an N95 - moist air is escaping out the top of the mask completely unfiltered. (You can find youtube videos demonstrating this process with cigarette smoke). Double- or triple-masking doesn't help either - that makes it even harder for air to pass directly through the masks so even more air pushes out the side and top instead.
If your N95 is VERY well fitted and the strap VERY tight - tight enough to make your ears hurt - you'll get less escape, but wearing a mask that way is sufficiently uncomfortable that almost nobody does it.
In short, an N95 does plausibly filter nearly all the air you breathe IN, but if you want to filter the air you're breathing OUT, you really should be wearing a cleanroom suit.