Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Covid-19 discussion, bring your own statistics
Trinucleus
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by Trinucleus » Wed Jul 01, 2020 10:43 am

Herainestold wrote:
Wed Jul 01, 2020 2:15 am
shpalman wrote:
Mon Jun 29, 2020 2:11 pm
outbreaks related to choirs
Singing seems to be one of the most dangeropus practises in terms of spreading the virus.
The article says it was probably the mixing before and after that was the risk, not the singing?

Herainestold
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by Herainestold » Wed Jul 01, 2020 7:22 pm

Trinucleus wrote:
Wed Jul 01, 2020 10:43 am
Herainestold wrote:
Wed Jul 01, 2020 2:15 am
shpalman wrote:
Mon Jun 29, 2020 2:11 pm
outbreaks related to choirs
Singing seems to be one of the most dangeropus practises in terms of spreading the virus.
The article says it was probably the mixing before and after that was the risk, not the singing?
Most things are multi factoral.

I'm a little skeptical of the article.
“Air was only propelled about half a metre in front of a singer, and that is not far enough to cause the infection levels of these outbreaks.”
Many of the other studies are now telling us that loud talking expels droplets for two metres or more.

But yes, the socializing and mxing associated with the choir could account for the spread of infection.

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Bird on a Fire
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by Bird on a Fire » Tue Jul 14, 2020 9:43 pm

The spread of Covid-19 inside care homes has been fuelled by a lack of personal protection equipment (PPE) – according to new research from the University of East Anglia.

Researchers studying the spread of the virus in Norfolk care homes found that once the virus was present, its spread was most strongly linked to a lack of PPE, particularly facemasks and eye protection.

But the introduction of the virus into the homes wasn’t dependent on PPE but rather the total numbers of non-care staff working there.

Covid-19 was more likely to get into residential care homes when there were more non-care staff such as maintenance people, cooks and those in administrative roles.

The research is the first to observe how Covid-19 seems to enter and spread through care homes. Due to the rapid-response nature of this study, it has not yet been peer reviewed.
Blog post: https://www.uea.ac.uk/about/-/ppe-short ... tudy-finds

Preprint: https://www.medrxiv.org/content/10.1101 ... 20133629v1
Born at 356.32 ppm CO2

raven
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by raven » Fri Jul 24, 2020 9:47 pm

I found an interesting paper on masks made from different fabrics if anyone's interested: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7185834/

Suprisingly, 4 layers of silk did quite well. High thread count cotton looks good, and even better in combination with silk/chiffon/flannel thanks to electrostatic effects. They modelled gaps due to poor fit with some holes in the apparatus and found that reduced efficiency by 50% or more. Not sure how precisely that reflects real-world mask-wearing, but it does emphasis how important the fit is.

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Martin Y
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by Martin Y » Sat Jul 25, 2020 10:59 am

raven wrote:
Fri Jul 24, 2020 9:47 pm
I found an interesting paper on masks made from different fabrics if anyone's interested: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7185834/

Suprisingly, 4 layers of silk did quite well. High thread count cotton looks good, and even better in combination with silk/chiffon/flannel thanks to electrostatic effects. They modelled gaps due to poor fit with some holes in the apparatus and found that reduced efficiency by 50% or more. Not sure how precisely that reflects real-world mask-wearing, but it does emphasis how important the fit is.
Thanks for that. If there's one thing Covid has taught me, it's sewing terminology. Just as a previous paper introduced me to "interfacing", this one adds "batting" (which I discover is quilt wadding).

I like the idea they used to simulate leakage with drilled holes to bypass the sample, as that will become more of an issue if the mask fabric is harder to breath through; you'll just suck more air from around the sides rather than through the thick material. A slight frustration is that they don't seem to have considered humidity. If electrostatic attraction is so important to small particle filtration, the fact that you're constantly exhaling through the same mask and keeping it damp is surely worth considering.

raven
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Re: Hi guys, there is lot of empahsis on face mask during COVID19. Is it worth it?

Post by raven » Sat Jul 25, 2020 11:17 am

I like the idea they used to simulate leakage with drilled holes to bypass the sample, as that will become more of an issue if the mask fabric is harder to breath through; you'll just suck more air from around the sides rather than through the thick material.
Yes, my homemade mask is quite thick so I worried about that. But it seems to seal relatively well at least. Most of the disposable masks I've seen people wearing gape quite a lot so I don't know how effective they are.

I imagine 2 layers of cotton and batting would be quite hot, and I wondered what sort of sample they'd used for that. Quilting usually has stitching to keep the batting in place, and that might involve holes where you don't want them -- all the official advise is not to have seams over the mouth/nose area.

Yes, it would've been great if they're had a look at what humidity does too.

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