8 ms·

I would love for N95 usage to become more widespread, but that is hampered by the dogmatic clinging to the belief that cloth masks actually work, unfortunately.

I would love for N95 usage to become more widespread, but that is hampered by the dogmatic clinging to the belief that cloth masks actually work, unfortunately. Do N95s work for source control though? They certainly do work for self infection but I haven’t personally read any N95 studies on source control so am not sure.

sterlind 5y ago
the ones without exhalation valves do. the barrier is bidirectional. the ones with valves bypass this which is why those shouldn't be used for source control but are popular for wildfires etc.
- __blockcipher__ 5y ago
  Thanks. That was my thinking but glad to see it confirmed. Kind of ironic that you’re not allowed to wear an N95 with an exhale valve, but are encouraged to wear a surgical mask, bandana, cloth mask, or dirty T-shirt, none of which provide any source control. Again, the elephant in the room is respiratory viruses in general, and SARS-2 in particular, spread via aerosols. Non-N95 face coverings cannot block aerosols. Indeed mask wearing leads to deeper breaths to maintain homeostasis (this has been studied), therefore lead to a greater net volume of air, therefore lead to increased aerosol emission before even accounting for the potential to nebulize large droplets into a shower of tiny aerosol particles. But I digress.
  - loosescrews 5y ago
    A surgical mask, bandana, cloth mask, or dirty T-shirt over a particulate mask (e.g. N95) is typically allowed. There are serious benefits to the wearer to having an exhaust valve. Wearing a second, less effective face covering over the particulate mask retains the benefits of the particulate mask and exhaust valve while maintaining the same level of source control as without the particulate mask.
arrrg 5y ago
Where are you from that FFP2 usage is not common? Sure, cloth masks were widespread for about a year but by now usage of FFP2 masks is becoming extremely widespread, especially since the supply is by now overwhelming.
- __blockcipher__ 5y ago
  I live in California. I see maybe 95% cloth masks in public.
tempestn 5y ago
Cloth masks work better than no mask, so they made sense early on when surgical masks couldn't be found. There are certainly better options now though.
- __blockcipher__ 5y ago
  There is no RCT that shows cloth masks work any better than no mask. You’re relying on mechanistic studies at best (or crappy associative studies). Masks incur costs; at a minimum you must admit they alter risk appraisal if nothing else. Anyway, nobody in this thread has addressed the point that masks don’t even work in theory if aerosol transmission is the dominant transmission mode. That’s before accounting for the incredible cross contamination and misuse of masks that you see in the community.
  - claytongulick 5y ago
    In Texas, the mask mandate has been lifted for weeks. There has not been a surge of new cases. Throughout 2020, Broken Bow, OK received millions of tourists, it was the #2 short-term vacation rental destination in the country, according to VRBO. It's a small town with crowded bars. Very few locals or visitors wore masks. There was not a significant rise in severe Covid cases, and schools mostly kept masking optional.
Semaphor 5y ago
In Germany, you are required to use surgical or FFP2/(K)N95 masks (in 2 states surgical ones are not allowed) to enter any store. At least in my city, the majority of people wear FFP2 masks.
loosescrews 5y ago
If cloth masks don't work, they aren't doing much for source control either. They don't magically filter better in one direction than the other. If everyone was wearing a particulate mask (e.g. N95), source control wouldn't matter as much. Masks with an exhaust valve are significantly more comfortable and comfort is the reason the CDC is currently citing in regard to their recommendation for people not to wear particulate masks. If your protection plan relies on everyone else doing something complicated correctly, you have already lost. I think controlling the spread of a virus in the general population using source control is not something our species is capable of.
- __blockcipher__ 5y ago
  To be clear, I agree. I think the whole concept of source control is silly. Actually I’ll go one step further and say I think the whole concept of trying to artificially slow transmission of SARS-2 in the general population is a bad idea period.

sterlind 5y ago

the ones without exhalation valves do. the barrier is bidirectional. the ones with valves bypass this which is why those shouldn't be used for source control but are popular for wildfires etc.

__blockcipher__ 5y ago
Thanks. That was my thinking but glad to see it confirmed. Kind of ironic that you’re not allowed to wear an N95 with an exhale valve, but are encouraged to wear a surgical mask, bandana, cloth mask, or dirty T-shirt, none of which provide any source control. Again, the elephant in the room is respiratory viruses in general, and SARS-2 in particular, spread via aerosols. Non-N95 face coverings cannot block aerosols. Indeed mask wearing leads to deeper breaths to maintain homeostasis (this has been studied), therefore lead to a greater net volume of air, therefore lead to increased aerosol emission before even accounting for the potential to nebulize large droplets into a shower of tiny aerosol particles. But I digress.
- loosescrews 5y ago
  A surgical mask, bandana, cloth mask, or dirty T-shirt over a particulate mask (e.g. N95) is typically allowed. There are serious benefits to the wearer to having an exhaust valve. Wearing a second, less effective face covering over the particulate mask retains the benefits of the particulate mask and exhaust valve while maintaining the same level of source control as without the particulate mask.

arrrg 5y ago

Where are you from that FFP2 usage is not common? Sure, cloth masks were widespread for about a year but by now usage of FFP2 masks is becoming extremely widespread, especially since the supply is by now overwhelming.

__blockcipher__ 5y ago
I live in California. I see maybe 95% cloth masks in public.

tempestn 5y ago

Cloth masks work better than no mask, so they made sense early on when surgical masks couldn't be found. There are certainly better options now though.

__blockcipher__ 5y ago
There is no RCT that shows cloth masks work any better than no mask. You’re relying on mechanistic studies at best (or crappy associative studies). Masks incur costs; at a minimum you must admit they alter risk appraisal if nothing else. Anyway, nobody in this thread has addressed the point that masks don’t even work in theory if aerosol transmission is the dominant transmission mode. That’s before accounting for the incredible cross contamination and misuse of masks that you see in the community.
- claytongulick 5y ago
  In Texas, the mask mandate has been lifted for weeks. There has not been a surge of new cases. Throughout 2020, Broken Bow, OK received millions of tourists, it was the #2 short-term vacation rental destination in the country, according to VRBO. It's a small town with crowded bars. Very few locals or visitors wore masks. There was not a significant rise in severe Covid cases, and schools mostly kept masking optional.

Semaphor 5y ago

In Germany, you are required to use surgical or FFP2/(K)N95 masks (in 2 states surgical ones are not allowed) to enter any store. At least in my city, the majority of people wear FFP2 masks.

loosescrews 5y ago

If cloth masks don't work, they aren't doing much for source control either. They don't magically filter better in one direction than the other. If everyone was wearing a particulate mask (e.g. N95), source control wouldn't matter as much. Masks with an exhaust valve are significantly more comfortable and comfort is the reason the CDC is currently citing in regard to their recommendation for people not to wear particulate masks. If your protection plan relies on everyone else doing something complicated correctly, you have already lost. I think controlling the spread of a virus in the general population using source control is not something our species is capable of.

__blockcipher__ 5y ago
To be clear, I agree. I think the whole concept of source control is silly. Actually I’ll go one step further and say I think the whole concept of trying to artificially slow transmission of SARS-2 in the general population is a bad idea period.