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Originally Posted by JayTeeMe
https://www.theatlantic.com/health/a...-masks/609235/
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A few studies suggest that homemade cloth masks are less effective than proper medical ones, but are still better than nothing. In one experiment, a surgical mask filtered 89 percent of viral particles from the air, a tea towel blocked 72 percent, and a cotton T-shirt blocked 50 percent.* In general, thicker materials are better than thinner ones, Marr said, and a tight fit across the face is important.
This seems to say something different.
Here's the study they link:
https://pubmed.ncbi.nlm.nih.gov/18612429/
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Principal findings: All types of masks reduced aerosol exposure, relatively stable over time, unaffected by duration of wear or type of activity, but with a high degree of individual variation. Personal respirators were more efficient than surgical masks, which were more efficient than home-made masks. Regardless of mask type, children were less well protected. Outward protection (mask wearing by a mechanical head) was less effective than inward protection (mask wearing by healthy volunteers).
Conclusions/significance: Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission.
I just don't understand how droplets large enough to fall to the ground fairly quickly (forget the 3 hour thing - that was an experiment with a nebulizer basically) wouldn't be affected at all by a think amount of cloth in to baffle the air coming out. The idea that a surgical mask doesn't even slow it down seems crazy.
Your article, which is prefaced with "COMMENTARY:" seems to have an axe to grind and sure loves the CDC:
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Ways to best protect health workers
We recommend that healthcare organizations follow US Centers for Disease Control and Prevention (CDC) guidance by moving first through conventional, then contingency, and finally crisis scenarios to optimize the supply of respirators. We recommend using the CDC's burn rate calculator to help identify areas to reduce N95 consumption and working down the CDC checklist for a strategic approach to extend N95 supply.
For readers who are disappointed in our recommendations to stop making cloth masks for themselves or healthcare workers, we recommend instead pitching in to locate N95 FFRs and other types of respirators for healthcare organizations. Encourage your local or state government to organize and reach out to industries to locate respirators not currently being used in the non-healthcare sector and coordinate donation efforts to frontline health workers.
Also from your article:
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In sum, wearing surgical masks in households appears to have very little impact on transmission of respiratory disease. One possible reason may be that masks are not likely worn continuously in households. These data suggest that surgical masks worn by the public will have no or very low impact on disease transmission during a pandemic.
No one is suggesting a surgical mask is going to prevent you from giving it to someone you live with. The suggestion is to wear them in public. If we can knock down 90%, or even 50% of the viral load being spewed into the public environment - that's a big win - even if it's not enough to prevent someone from giving it to a household member.
Last edited by suzzer99; 04-02-2020 at 11:23 PM.