4 ms·

I saw a comparison yesterday that claimed with a cloth mask, being in the same room with someone for 30 minutes was enough to catch Covid. A surgical mask prov

I saw a comparison yesterday that claimed with a cloth mask, being in the same room with someone for 30 minutes was enough to catch Covid. A surgical mask provided an hour of protection. With an N95, you would need to be in the room for 25 hours. I believe that was with both people wearing a mask

larubbio 5y ago
I think that stat came from a chart in this article https://yourlocalepidemiologist.substack.com/p/a-quick-note-on-masks-and-cdc-guidance https://yourlocalepidemiologist.substack.com/p/a-quick-note-...
- paulcole 5y ago
  Also this one: https://www.axios.com/n95-mask-protection-covid-958039c9-07f1-45a1-81e7-b7436707fee5.html https://www.axios.com/n95-mask-protection-covid-958039c9-07f...
Scoundreller 5y ago
There’s a 5x5 or so graphic floating around of how many hours are safe in different masking situations. While I agree with the relative arrangement, there’s a risk of misinterpretation. Early in the pandemic some claimed their interactions are short so They can wear no/crappy masks, overlooking that it’s a police officer and their entire day is made up of short interactions…
deleted 5y ago
[deleted]
hcks 5y ago
Interesting intuitive point of view. Too bad there's no evidence for any of that
- Zoneman 5y ago
  The infographic is based on ACGIH's Pandemic Response Task Force[1]. The list of references for respirator/mask information is available on their site[2]. I can't speak to the veracity of the evidence provided, but there is evidence. [1]: https://www.acgih.org/covid19/ https://www.acgih.org/covid19/ [2]: https://www.acgih.org/covid19-references/#resp https://www.acgih.org/covid19-references/#resp
micromacrofoot 5y ago
I wish they included KN95s for comparison... I prefer them because they're easier to take on and off, and the seal seems reasonable to me (breathing in/out causes the mask to deform, so it's clearly filtering some air)
- gandalfgreybeer 5y ago
  Aren’t KN95s just N95s with the Chinese standards (vs US standards) but should technically work for the same particle sizes?
  - robjan 5y ago
    GP is probably referring to KF94, the Korean standard. Their form factor is somewhere between a surgical mask or an industrial / medical N95. They are quite popular, here in HK, with people who want to protect their makeup. Example: https://www.amazon.com/KF94-Protective-Individually-Packaged-Certified/dp/B08J95F5TR https://www.amazon.com/KF94-Protective-Individually-Packaged...
  - micromacrofoot 5y ago
    Technically yes, but US standards require a headstrap... which is generally tighter in my experience. I'm wondering if the ear loops reduce efficacy significantly (assuming fit is proper otherwise).
Symmetry 5y ago
You can't really give a time like that. People with detectable levels of covid might have anywhere between 100 and 10^14 viral copies/cc in fluid samples taken from them depending on their immune system and stage of progression. Infectiousness is probably proportional to that viral load. How much fluid escapes a person into the air also varies by a few orders of magnitude depending on whether they're sitting quietly enjoying a movie all the way to singing loudly.
- notabee 5y ago
  You can if it's an average and you're not being overly literal about it. Don't break out a stopwatch and assume you're safe if you run out of the room before the average time is up.
  - Symmetry 5y ago
    It's not a matter of differences you need a stopwatch for, it's that the times plausibly vary between a second and years.

larubbio 5y ago

I think that stat came from a chart in this article https://yourlocalepidemiologist.substack.com/p/a-quick-note-on-masks-and-cdc-guidance https://yourlocalepidemiologist.substack.com/p/a-quick-note-...

paulcole 5y ago
Also this one: https://www.axios.com/n95-mask-protection-covid-958039c9-07f1-45a1-81e7-b7436707fee5.html https://www.axios.com/n95-mask-protection-covid-958039c9-07f...

Scoundreller 5y ago

There’s a 5x5 or so graphic floating around of how many hours are safe in different masking situations. While I agree with the relative arrangement, there’s a risk of misinterpretation. Early in the pandemic some claimed their interactions are short so They can wear no/crappy masks, overlooking that it’s a police officer and their entire day is made up of short interactions…

deleted 5y ago

[deleted]

hcks 5y ago

Interesting intuitive point of view. Too bad there's no evidence for any of that

Zoneman 5y ago
The infographic is based on ACGIH's Pandemic Response Task Force[1]. The list of references for respirator/mask information is available on their site[2]. I can't speak to the veracity of the evidence provided, but there is evidence. [1]: https://www.acgih.org/covid19/ https://www.acgih.org/covid19/ [2]: https://www.acgih.org/covid19-references/#resp https://www.acgih.org/covid19-references/#resp

micromacrofoot 5y ago

I wish they included KN95s for comparison... I prefer them because they're easier to take on and off, and the seal seems reasonable to me (breathing in/out causes the mask to deform, so it's clearly filtering some air)

gandalfgreybeer 5y ago
Aren’t KN95s just N95s with the Chinese standards (vs US standards) but should technically work for the same particle sizes?
- robjan 5y ago
  GP is probably referring to KF94, the Korean standard. Their form factor is somewhere between a surgical mask or an industrial / medical N95. They are quite popular, here in HK, with people who want to protect their makeup. Example: https://www.amazon.com/KF94-Protective-Individually-Packaged-Certified/dp/B08J95F5TR https://www.amazon.com/KF94-Protective-Individually-Packaged...
- micromacrofoot 5y ago
  Technically yes, but US standards require a headstrap... which is generally tighter in my experience. I'm wondering if the ear loops reduce efficacy significantly (assuming fit is proper otherwise).

Symmetry 5y ago

You can't really give a time like that. People with detectable levels of covid might have anywhere between 100 and 10^14 viral copies/cc in fluid samples taken from them depending on their immune system and stage of progression. Infectiousness is probably proportional to that viral load. How much fluid escapes a person into the air also varies by a few orders of magnitude depending on whether they're sitting quietly enjoying a movie all the way to singing loudly.

notabee 5y ago
You can if it's an average and you're not being overly literal about it. Don't break out a stopwatch and assume you're safe if you run out of the room before the average time is up.
- Symmetry 5y ago
  It's not a matter of differences you need a stopwatch for, it's that the times plausibly vary between a second and years.