4 ms·

“if even in controlled studies N95 masks block ’57 to 90 of particles’” source? what kind of fake news is this??? they are called N95 for a reason. They filte

“if even in controlled studies N95 masks block ’57 to 90 of particles’” source? what kind of fake news is this??? they are called N95 for a reason. They filter AT LEAST 95% of the particles above a certain size. You can argue that many people wear them wrong which reduces their effectiveness…that i agree with.

fsckboy 4y ago
I'm no expert, don't know the details on masks or particles or coronaviruses or covid-19, but you did add an "above a certain size" qualifier, which hypothetically leaves room for both statements, yours and the previous, to be true. and, to that point, the previous comment included an assertion, not in exactly so many words, that suggests that the N100 - N95 = N5% of particles could be plenty to readily transmit the infection and, for an N95 mask to operate at N95 it needs to be carefully "fitted" to the face, perhaps meaning that the practical effectiveness among the general public might be below 95% and we are in a discussion here of a published paper that says "masks didn't do anything" so shooting down what the GP comment said isn't really a priority. Although what the GP comment said about masks being a psychological placebo seems to be a pure fantasy given that the comment is made in the context of talking about how much divisiveness the masks provoked (though whether they did or not isn't necessarily important, whether they work or not is.)
- detaro 4y ago
  > and we are in a discussion here of a published paper that says "masks didn't do anything" After reading Cochrane's own list of caveats about their study that feels like overstating it. Also for your specific phrasing, "masks didn't do anything", what part of the studies they looked at do you think looked at COVID mask guidance? Only a tiny part of the studies they looked at were even in the context of COVID: Two out of 78. Funnily enough, these two papers claim that masks were effective. (Why only include two COVID-times studies in this update, out of the dozens that have been published?)
  - fsckboy 4y ago
    I said a lot more interesting things than the wording of one phrase you are picking on. I read your take as "eager to defend the mainstream squarequote-science" on this topic. we know they lied about what they knew about the origins of covid-19 and gain of function research, the very same people were in charge of mitigating/vaccinating/curing covid, we know they had conflicts of interest, we know they suppressed open airing of dissent, so I don't trust what the experts are writing down at all, and I don't waste a lot of time reading about the subject. My comment you replied to I think stands as a reasonable explanation of what I was responding to, but really must be read in the context of that comment (like quote him then quote me) and not standing alone.
rossdavidh 4y ago
That's a direct quote from the article we're talking about here? It has a link.
gdavisson 4y ago
"They filter AT LEAST 95% of the particles above a certain size." That's a common misunderstanding; they filter at least 95% of particles of all sizes. It's actually intermediate-sized particles (around 0.1 - 1 micron) that're hardest to capture. Smaller particles are more subject to Brownian motion, which makes them jiggle around more, and hence makes them more likely to bump into one of the respirator's strands... where they'll stick, thanks to Van der Waals forces. N95 masks (if properly fitted) block at least 95% of particles in that 0.1 - 1 micron range (they're tested with particles around 0.3 microns), and even higher percentages of particles that're either larger or smaller than that. Reference: https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ (especially figure 2)

fsckboy 4y ago

I'm no expert, don't know the details on masks or particles or coronaviruses or covid-19, but you did add an "above a certain size" qualifier, which hypothetically leaves room for both statements, yours and the previous, to be true. and, to that point, the previous comment included an assertion, not in exactly so many words, that suggests that the N100 - N95 = N5% of particles could be plenty to readily transmit the infection and, for an N95 mask to operate at N95 it needs to be carefully "fitted" to the face, perhaps meaning that the practical effectiveness among the general public might be below 95% and we are in a discussion here of a published paper that says "masks didn't do anything" so shooting down what the GP comment said isn't really a priority. Although what the GP comment said about masks being a psychological placebo seems to be a pure fantasy given that the comment is made in the context of talking about how much divisiveness the masks provoked (though whether they did or not isn't necessarily important, whether they work or not is.)

detaro 4y ago
> and we are in a discussion here of a published paper that says "masks didn't do anything" After reading Cochrane's own list of caveats about their study that feels like overstating it. Also for your specific phrasing, "masks didn't do anything", what part of the studies they looked at do you think looked at COVID mask guidance? Only a tiny part of the studies they looked at were even in the context of COVID: Two out of 78. Funnily enough, these two papers claim that masks were effective. (Why only include two COVID-times studies in this update, out of the dozens that have been published?)
- fsckboy 4y ago
  I said a lot more interesting things than the wording of one phrase you are picking on. I read your take as "eager to defend the mainstream squarequote-science" on this topic. we know they lied about what they knew about the origins of covid-19 and gain of function research, the very same people were in charge of mitigating/vaccinating/curing covid, we know they had conflicts of interest, we know they suppressed open airing of dissent, so I don't trust what the experts are writing down at all, and I don't waste a lot of time reading about the subject. My comment you replied to I think stands as a reasonable explanation of what I was responding to, but really must be read in the context of that comment (like quote him then quote me) and not standing alone.

rossdavidh 4y ago

That's a direct quote from the article we're talking about here? It has a link.

gdavisson 4y ago

"They filter AT LEAST 95% of the particles above a certain size." That's a common misunderstanding; they filter at least 95% of particles of all sizes. It's actually intermediate-sized particles (around 0.1 - 1 micron) that're hardest to capture. Smaller particles are more subject to Brownian motion, which makes them jiggle around more, and hence makes them more likely to bump into one of the respirator's strands... where they'll stick, thanks to Van der Waals forces. N95 masks (if properly fitted) block at least 95% of particles in that 0.1 - 1 micron range (they're tested with particles around 0.3 microns), and even higher percentages of particles that're either larger or smaller than that. Reference: https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ https://blogs.cdc.gov/niosh-science-blog/2009/10/14/n95/ (especially figure 2)