Posted by:
run0emma0run
(
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Date: July 10, 2020 08:00PM
One of the reasons many people on the right refuse to wear masks is because they actually believe THEY are following Science. You see, a physician posted an article saying wearing a cloth mask (anything other than an N-95 or more restrictive) is like "using a chain-link fence to keep out a mosquito."
Due to that being a physician who posted that article, many on the right take it as "gospel" and believe masks are useless against the SARS-CoV2 virus because it is so tiny - much smaller than the pores in the masks. However, the physician who posted that claim, although correct in saying the virus is many times smaller than the pore size in the mask, was unaware of the virology and engineering physics associated with viruses. That physician was not a virologist. Neither was that physician knowledgeable in the physics of how a virus moves.
Here's a quote from an article in USA Today:
The N95 filter indeed is physically around the 0.3 micron size. But that doesn’t mean it can only stop particles larger than that. The masks are actually best for particles either larger or smaller than that 0.3 micron threshold.
“N95 have the worst filtration efficiency for particles around 0.3,” Marr said. “If you’re smaller than that those are actually collected even better. It’s counterintuitive because masks do not work like sieving out larger particles. It’s not like pasta in a colander, and small ones don’t get through.”
N95 masks actually have that name because they are 95% efficient at stopping particles in their least efficient particle size range — in this case those around 0.3 microns.
Why do they work better for smaller ones? There are a number of factors at play, but here are two main ones noted by experts:
The first is something called “Brownian motion,” the name given to a physical phenomenon in which particles smaller than 0.3 microns move in an erratic, zig-zagging kind of motion. This motion greatly increases the chance they will be snared by the mask fibers.
Secondly, the N95 mask itself uses electrostatic absorption, meaning particles are drawn to the fiber and trapped, instead of just passing through.
“Although these particles are smaller than the pores, they can be pulled over by the charged fibers and get stuck,” said Professor Jiaxing Huang, a materials scientist at Northwestern University working to develop a new type of medical face mask. “When the charges are dissipated during usage or storage, the capability of stopping virus-sized particles diminishes. This is the main reason of not recommending the reuse of N95 masks.”
Also,
The COVID-19 particle is indeed around 0.1 microns in size, but it is always bonded to something larger.
“There is never a naked virus floating in the air or released by people,” said Linsey Marr, a professor of civil and environmental engineering at Virginia Tech who specializes in airborne transmission of viruses.
The virus attaches to water droplets or aerosols (i.e. really small droplets) that are generated by breathing, talking, coughing, etc. These consist of water, mucus protein and other biological material and are all larger than 1 micron.
Here's a link to the full article:
https://www.usatoday.com/story/news/factcheck/2020/06/11/fact-check-n-95-filters-not-too-large-stop-covid-19-particles/5343537002/