> t's not their little trivial masks that have been protecting them from a daily bombardment of SARS2.
Are you sure?
What if the reduction of viral load, such as social distancing or masks, is what's causing them to have COVID19 resistance?
A cotton mask has 60% filtration. An N95 mask has 95% filtration. If you "breath" in 1000 virus particles, someone with a cotton mask would only breath in 400 of them, while the one with N95 would breath in 50 virus particles.
I have to imagine that viral load would cause some kind of change.
Maybe there is a big difference between breathing in 1000-particles vs breathing in 400-particles. There seems to be no controversy that N95 works (aka: the reduction from 1000 particles down to 50-particles). But cotton masks are still an order-of-magnitude drop (at least, a binary-magnitude).
>A cotton mask has 60% filtration. An N95 mask has 95% filtration. If you "breath" in 1000 virus particles, someone with a cotton mask would only breath in 400 of them, while the one with N95 would breath in 50 virus particles
Do you have a source for this? Because from what little I've been able to find, filtration efficiency for particulate in the aerosolized size range are practically negligible with cotton masks and even surgical masks. Which makes sense considering that aerosolized particles are around 2-3 orders of magnitude smaller than pore sizes in cotton and surgical masks, putting such masks in the realm of security theatre.
I suspect studies which show cotton masks having an effect on transmission (in contrast to studies near the start of the pandemic which showed no effect) are failing to consider secondary effects of masking on behavior, namely that masks indirectly remind people of the pandemic and influence their social distancing behavior
> Do you have a source for this? Because from what little I've been able to find, filtration efficiency for particulate in the aerosolized size range are practically negligible with cotton masks and even surgical masks. Which makes sense considering that aerosolized particles are around 2-3 orders of magnitude smaller than pore sizes in cotton and surgical masks, putting such masks in the realm of security theatre.
Pretend that you're blowing out a candle: make a small "stream" with your lips and blow as far as you can. When I do so, my stream can go at least as far out as my arm, which I think is ~1.5 feet or ~2feet or something (longer than that, because my breath is still "strong" at the full length of my arm in front of me).
Now put a cotton mask on and do the same thing. How far does the stream go? Inches, at best.
Note: oxygen, nitrogen, and CO2 are all much much smaller than mask fibers. But you'll find that these things behave as a __fluid__, and thus we have a fluid-dynamics question rather than one of physical objects hitting a screen door model.
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The distance your breath goes when talking is much reduced. Similarly, the "stream" where you draw in more air is also reduced to a smaller distance when you're masked up.
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Or heck, _do_ blow out a candle. This experiment is like, $2. One dollar for a mask, and a second dollar for a birthday candle. Just measure it yourself: the mask grossly affects the distance that oxygen / CO2 / Nitrogen leaves the body.
>Now put a cotton mask on and do the same thing. How far does the stream go? Inches, at best.
>The distance your breath goes when talking is much reduced. Similarly, the "stream" where you draw in more air is also reduced to a smaller distance when you're masked up.
So instead of breath being directed downward from the nose, the aerosolized particles are redirected upward, where they linger for longer? Moreover, the difference in velocity between speech and "blowing out a candle" makes this a bit of a contrived argument. The key here is that these aerosolized particles have very long settling times - so if they are not being filtered by mask media and instead being blown higher upwards with a mask as opposed to without, then as best masks are useless, at worst they are actually counterproductive.
Your argument is that virus particles are too small for a mask to catch them.
My counterargument: Nitrogen + Oxygen is even smaller than a virus particle, and the mask seems to redirect N2 + O2 just fine. As such, your mental understanding of how streams flow around people who breath is faulty.
This physics question you're posing is one of fluid dynamics, not one of "bigger" vs "smaller" filters. This simple experiment I show proves that incredibly tiny particles (N2 / O2) behave differently than your mental model suggests.
> Which makes sense considering that aerosolized particles are around 2-3 orders of magnitude smaller than pore sizes in cotton and surgical masks
This statement you posted, this right here is wrong. Size has nothing to do with anything when we drop down to sub-microns.
No, you're completely missing my point. The fact that the particles act like fluids makes masks counterproductive.
Because exhaling into a mask redirects the fluidlike stream upwards where it lingers for longer. Breathing unmasked directs the stream straight ahead/down.
Here's an example of what I'm describing[0]. Yes, it may be helpful for talking, but otherwise you are potentially increasing the dispersal of particulate when wearing a mask and breathing normally. In this case I am agreeing that filtration is irrelevant.
The fact that you've changed your point is not lost on me. My discussion point was originally levied against your original paragraph:
> Which makes sense considering that aerosolized particles are around 2-3 orders of magnitude smaller than pore sizes in cotton and surgical masks, putting such masks in the realm of security theatre.
But sure. I'll play along and pretend that your new "particles act like fluids" statement is what you were saying all along.
> Because exhaling into a mask redirects the fluidlike stream upwards where it lingers for longer. Breathing unmasked directs the stream straight ahead/down.
Then this should be easily demonstrated with a study that shows that masking increases the COVID19 infection rate. Do you have such a study available? (And if you know anything about the mask debate over the past two years, I'm sure you know where I'm going with this)
At a minimum, I've already forced you to admit that cloth masks redirect the flows of COVID19, when originally you claimed that the particles were too small to be effectively filtered.
>At a minimum, I've already forced you to admit that cloth masks redirect the flows of COVID19, when originally you claimed that the particles were too small to be effectively filtered.
Ok hold on, I'm not playing bad faith games here. My original claim was that the masks did not filter viral particles. You responded with the birthday candle example, in effect claiming that it didn't matter whether they filtered them, because instead they redirected exhaled air from other people's faces. I then replied to effectively say that this is at best not effective, at worst counterproductive.
I don't believe that in this political climate one would be able to publish a study against the efficacy of masks. I have two studies from the start of the pandemic which showed negligible (≈1-2%) or no benefit to surgical mask wearing, and the fact that even among medical workers there has historically been some degree of dissent as to whether they are indeed effective outside of maybe open surgery.
There's plenty of mask studies. The fact that you don't know about them, despite the 1.5 years of mask discussion, is because of your bubble. Not mine.
I've generally seen 60% efficacy from 2-ply cotton designs. The textile study from acs further broke that down into different cottons: tight 600 tpi cotton was more effective than 80tpi loose cotton.
> In comparison, the 100% cotton t-shirt had a 69% mean filtration efficiency for the 1 μm particles and 51% for the 23 nm particles.
And the big one is the NIH study, conducted relatively early when the mask debate was raging. By May 2020, they already finished their study.
T-Shirt cotton was over 60% effective.
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Look, its very difficult for me to believe you're arguing in good faith. We're well over a year into this pandemic and you're bringing up talking points I haven't heard in over a year. Your talking points have been completely disproven a year ago.
It's been a theory of mine that people wearing better masks ARE getting minuscule amounts of the virus and it preps their body differently than people that get it dumped on them.
Are you sure?
What if the reduction of viral load, such as social distancing or masks, is what's causing them to have COVID19 resistance?
A cotton mask has 60% filtration. An N95 mask has 95% filtration. If you "breath" in 1000 virus particles, someone with a cotton mask would only breath in 400 of them, while the one with N95 would breath in 50 virus particles.
I have to imagine that viral load would cause some kind of change.
Maybe there is a big difference between breathing in 1000-particles vs breathing in 400-particles. There seems to be no controversy that N95 works (aka: the reduction from 1000 particles down to 50-particles). But cotton masks are still an order-of-magnitude drop (at least, a binary-magnitude).