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Comment by swader999 | Hacker News Reader

N95 have a warning they aren't meant for asbestos which is fifty times larger than corona virus. Cloth masks? As effective as stopping flies with a chain link fence. The studies that purport masks work use mannequins with sealed surgical masks. It doesn't work irl that way unfortunately.

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The "95" in "N95" refers to their 95% efficiency at filtering particles of the size they are least efficient at (.3 microns IIRC). They are more effective at sizes larger and smaller. The smaller particles get stuck to the mask via static electricity.

Which doesn't work as soon as they become moist.

The point of the masks isn't that they're 100% effective, but that they reduce the probability of spreading a virus-laden droplet to someone else. The difference between having a pandemic and not having a pandemic is the question of whether the average infected person infects more than one other person or less than one. N95s or basic cloth masks are a relatively straightforward way to get a population on the other side of that threshold, even if some people wear them incorrectly were just unlucky.

If there are better masks than N95s for dealing with carcinogens like asbestos, you should use those for that application. Maybe they would work better for Covid too, but providing super high-quality fancy masks to hundreds of millions of people in a pandemic isn't really practical, though. You use the tools you have on hand. Even distributing N95s was challenging.

The infection is aerosol not droplet.

> N95s or basic cloth masks are a relatively straightforward way to get a population on the other side of that threshold, even if some people wear them incorrectly were just unlucky.

Controlled tests (with correct fitting) show cloth masks at around 10% efficiency and surgical masks at around 12% efficiency, vs up to 60% for correctly fitted R95/KN95 masks. The difference is huge. The measures that most people are taking with their loosely-fitting cloth masks are having negligible impact on coronavirus transmission.

[0] https://aip.scitation.org/doi/10.1063/5.0057100

The worry is much bigger exhaled droplets that carry the virus, not individual virus particles.

The droplet narrative is a year expired. Sure it happens but recent studies with infected chimps and masks shows full room dispersion after a relative short time.

"A study from the National Academy of Sciences Press establish that most of the COVID-19 particles emitted from those infected are aerosols, or consisting of 0.3 to 0.5 microns. “Droplets” consist of particles much greater in size than aerosols. The science shows however, that most COVID-19 particles are aerosols, not droplets. As such, they are less than 1 micron in size."

See Edwards 2/23/21

And this for a thorough analysis: https://thecivilrightslawyer.com/2021/04/06/masks-do-nothing...

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