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An N95 is the opposite. It only filters on the way in. Which is the direction we should be going, anyway. High risk people who cannot get vaccinated should w

An N95 is the opposite. It only filters on the way in. Which is the direction we should be going, anyway. High risk people who cannot get vaccinated should wear an N95. Edit: As numerous people have pointed out, this is wrong. All the N95 masks I’ve seen had a valve, but apparently this is uncommon. TIL.

pdabbadabba 5y ago
I'd actually like to see the data on the degree to which N95 masks also reduce the number of virus particles expelled. I'd be pretty surprised if an (unvented) N95 really did little to block virus particles from being expelled, even though that's certainly not what they are designed to do. But, in any case, its consistent with my point that, supposedly, there are benefits to cloth masks, even if they don't fit tightly around the face. That's not to say it wouldn't be better if everyone wore an N95/KN95/etc.--especially people who are at high risk.
- nostrebored 5y ago
  It's going to come down to the ventilation of the space you're in regardless. We're back to square zero: improperly ventilated indoor spaces are a huge public health concern, even beyond covid.
  - pdabbadabba 5y ago
    Ventilation is certainly important and I'd like to see much greater focus on this. But, to state the obvious, we're not going to improve the ventilation of existing spaces overnight, unfortunately, so we also need to figure out how to mitigate risk in the meantime.
fuzzy2 5y ago
> It only filters on the way in. Absolutely not? How would that even work. A well-fitting half-face mask has virtually no leakage when breathing in or out.
- parkingrift 5y ago
  Yes, thank you. I had incorrect information and edited my post.
stephen_g 5y ago
That’s only for the versions that have an exhalation valve, which people shouldn’t be using for COVID.
GuB-42 5y ago
> An N95 is the opposite. It only filters on the way in. Only if they have a valve. Masks with valves are usually considered inappropriate for covid. All valveless masks, including N95, surgical and cloth masks protect both ways, there is no difference between the front and the back of the filtering material. Some masks are better than others, but none are one-way unless there is a one-way valve. That's also a reason why they recommend N95 and not N99. Most N99 masks have valves (can be uncomfortable without them) and are therefore inappropriate. These are mostly to protect construction workers from harmful dust.
ashtonkem 5y ago
The valve masks are designed for industrial use, like sanding or spray painting. Until 2020 those were the ones you’d see the most, since they’ve been readily available in home improvement stores for obvious reasons.

pdabbadabba 5y ago

I'd actually like to see the data on the degree to which N95 masks also reduce the number of virus particles expelled. I'd be pretty surprised if an (unvented) N95 really did little to block virus particles from being expelled, even though that's certainly not what they are designed to do. But, in any case, its consistent with my point that, supposedly, there are benefits to cloth masks, even if they don't fit tightly around the face. That's not to say it wouldn't be better if everyone wore an N95/KN95/etc.--especially people who are at high risk.

nostrebored 5y ago
It's going to come down to the ventilation of the space you're in regardless. We're back to square zero: improperly ventilated indoor spaces are a huge public health concern, even beyond covid.
- pdabbadabba 5y ago
  Ventilation is certainly important and I'd like to see much greater focus on this. But, to state the obvious, we're not going to improve the ventilation of existing spaces overnight, unfortunately, so we also need to figure out how to mitigate risk in the meantime.

fuzzy2 5y ago

> It only filters on the way in. Absolutely not? How would that even work. A well-fitting half-face mask has virtually no leakage when breathing in or out.

parkingrift 5y ago
Yes, thank you. I had incorrect information and edited my post.

stephen_g 5y ago

That’s only for the versions that have an exhalation valve, which people shouldn’t be using for COVID.

GuB-42 5y ago

> An N95 is the opposite. It only filters on the way in. Only if they have a valve. Masks with valves are usually considered inappropriate for covid. All valveless masks, including N95, surgical and cloth masks protect both ways, there is no difference between the front and the back of the filtering material. Some masks are better than others, but none are one-way unless there is a one-way valve. That's also a reason why they recommend N95 and not N99. Most N99 masks have valves (can be uncomfortable without them) and are therefore inappropriate. These are mostly to protect construction workers from harmful dust.

ashtonkem 5y ago

The valve masks are designed for industrial use, like sanding or spray painting. Until 2020 those were the ones you’d see the most, since they’ve been readily available in home improvement stores for obvious reasons.