The science of face masks

@humy said
which part? The part about the kitchen sieve? If not, specify exactly WHAT you claim isn't true...

"Smells are generally made by particles many times smaller than airborne virus infected droplets"

What is your source of info?

@metal-brain said
"Smells are generally made by particles many times smaller than airborne virus infected droplets"

What is your source of info?

science.

https://www.nanooze.org/the-sense-of-smell/
"... Odor molecules are really small, at most a few nanometers in size. They have to be small to be smelled. .."

and compare that with;

as for typical virus-infected droplets;
https://www.pnas.org/content/115/10/E2386
"...airborne particles with diameters ≥15.3 µm, ≥7.9 µm, ≥4.7 µm, and ≥1.5 µm ..."

and

https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30323-4/fulltext
"...Current infection control policies are based on the premise that most respiratory infections are transmitted by large respiratory droplets—ie, larger than 5 μm—produced by coughing and sneezing..."

and

https://www.who.int/news-room/commentaries/detail/modes-of-transmission-of-virus-causing-covid-19-implications-for-ipc-precaution-recommendations
"...Respiratory infections can be transmitted through droplets of different sizes: when the droplet particles are >5-10 μm in diameter ..."

etc.

So, much greater size. The first (odors) is only a few nanometers across at most while the latter is generally larger, and at least ten times more.

also
https://www.dailymail.co.uk/sciencetech/article-8275855/Professor-answers-question-jeans-stop-fart-mask-prevent-coronavirus.html
"...Molecules in farts are just 0.4 nm, where viruses range from 20 up to 400 nm
The current coronavirus spreading around the world ranges from 60 to 140 nm ..."
(-I just cannot believe there is an actual link specifically about such a ridiculous subject matter! But there you have it )

Well?

@metal-brain said
That is not true. You didn't post a single article on this page.

You don't have any evidence face masks are effective. It really comes down to common sense. If you can smell a person's fart being filtered through 2 layers of clothing, including denim jeans, how safe do you feel wearing that mask?

Think about it.

Is that an analogy? It doesn't make any sense.

The evidence obviously exists, and this is extremely clear via gobs of data and studies. I am curious as to why you remain so imperceptive given all that has been shared on this thread. You've even read some of the studies. How can you still posit the lack of evidence for face mask use to prevent SARS-CoV-2 transmission rates?

@wildgrass said
Is that an analogy? It doesn't make any sense.

The evidence obviously exists, and this is extremely clear via gobs of data and studies. I am curious as to why you remain so imperceptive given all that has been shared on this thread. You've even read some of the studies. How can you still posit the lack of evidence for face mask use to prevent SARS-CoV-2 transmission rates?

Nope. We are talking about face masks. How small can a cloth face mask filter a small particle? Not smells or viruses. Both are too small. Humy is a moron.

@Metal-Brain
Masks only stop a certain percentage of virus loads and NOBODY says otherwise.
We need ANYTHING that helps stop the spread of C19.
And if such masks are only say, 50% effective, that is that much less viral load.
Right now that is the ONLY thing that helps, that and social distancing.
And even a 95% effective vaccine means one in twenty will still be able to transmit the virus but the general viral load will be a lot less and will effectively stop it being a pandemic.

@metal-brain said
How small can a cloth face mask filter a small particle? Not smells or viruses. Both are too small.

How do you know viruses are too small to be filtered by a face mask? What is your source of information? I have just shown my source of information, the links that show often they aren't too small, while you still haven't shown yours, because you have none. Typically the viruses are over 20nm wide and the particle containing them (either still-wet or dried out airborne droplets) are a lot wider. If the air gaps through a face mask are on average about 10 micrometers wide (which for typical modern face masks is approximately right) and a particle containing a virus is wider than 10 micrometers at its narrowest point, say 30 micrometers wide, explain to us how that virus laden particle can physically squeeze through a 10 micrometer gap in the face mask...

@humy said
How do you know viruses are too small to be filtered by a face mask? What is your source of information? I have just shown my source of information, the links that show often they aren't too small, while you still haven't shown yours, because you have none. Typically the viruses are over 20nm wide and the particle containing them (either still-wet or dried out airborne droplets) ...[text shortened]... how that virus laden particle can physically squeeze through a 10 micrometer gap in the face mask...

Masks were never intended to be a perfect filter for viruses.

It's true that viral particles can go through masks. Different masks made of different materials have different filtering properties. But the goal with mask use indoors isn't to completely block all viral particles (like a wall would do to wind), the goal is to block some and slow down others (like a picket fence would do to wind). The pore size is besides the point. The functional experiments to show that this works have been done and the results are unequivocal. The most convincing evidence in my view are the epidemiological studies I posted showing the dramatic reductions in transmission (~80% ) while people were doing the same group activities with masks vs. without.

Social distancing is a much better method for reducing transmission. But we still need to work and interact with each other. Since shutdowns are impractical, masks are an effective next best thing.

@wildgrass said
Masks were never intended to be a perfect filter for viruses.

For now that's true but that might one day change with an invention of a more suitable material for masks with an air pore size always less than 20nm wide but which, despite that, still allows the passage of air without too much air friction, and that's part of the tricky part; making a material that has both of those properties but which, in addition, is still cost effective.
Unfortunately I don't remember were or when or much of the details or context but I think I once a very long time ago heard of such a material made in the lab except it's very costly, something like ~£10000 per gram, thus currently not cost effective and currently no good for wide spread use. It wasn't proposed for face masks but for something else; don't remember what though.

But if we do find such a suitable material with an air pore size always less than 20nm wide that still allows the passage of air without too much air friction and doesn't cost much, that would be a great bases of a new type of face mask that blocks 100% of viruses.

@wildgrass said
Masks were never intended to be a perfect filter for viruses.

It's true that viral particles can go through masks. Different masks made of different materials have different filtering properties. But the goal with mask use indoors isn't to completely block all viral particles (like a wall would do to wind), the goal is to block some and slow down others (like a picket fe ...[text shortened]... d interact with each other. Since shutdowns are impractical, masks are an effective next best thing.

"The most convincing evidence in my view are the epidemiological studies I posted showing the dramatic reductions in transmission (~80% ) while people were doing the same group activities with masks vs. without."

What kind of masks? Surgical masks? Home made cloth masks? Not all masks are equal. Some studies are done with wet washcloths for some stupid reason. Nobody wears wet washcloths on their faces, but some idiot did a study with them anyway.

How was the study done? Were actual people wearing these masks or were they fitted on a machine to test filtration?

https://www.wired.com/story/the-face-mask-debate-reveals-a-scientific-double-standard/

Coen Berends, a spokesperson for the National Institute for Public Health and the Environment, said:

“Face masks in public places are not necessary, based on all the current evidence. There is no benefit and there may even be negative impact.”

That negative impact is the false sense of security masks brings, leading people to let down their guard and forsake the more important effort of social distancing

https://liveandletsfly.com/dutch-face-masks/

@humy said
For now that's true but that might one day change with an invention of a more suitable material for masks with an air pore size always less than 20nm wide but which, despite that, still allows the passage of air without too much air friction, and that's part of the tricky part; making a material that has both of those properties but which, in addition, is still cost effective.
...[text shortened]... esn't cost much, that would be a great bases of a new type of face mask that blocks 100% of viruses.

Among the extremely effective masks out there, polarity, not pore size, is more important for filtering viruses. These are expensive and unnecessary for everyday use.

@metal-brain said
"The most convincing evidence in my view are the epidemiological studies I posted showing the dramatic reductions in transmission (~80% ) while people were doing the same group activities with masks vs. without."

What kind of masks?

Whichever kinds of masks that were worn by the majority of people that wear masks. Research shows (links already shown in past posts) most kinds of masks used these days block a significant proportion if not most of the virus-laden airborne particles; and that's all they need to do to significantly slow the spread. So your question is irrelevant and you make no point.
We have shown you the links with the evidence. You have nothing to complain about and no counterargument. I advise you to for once in your life accept the truth.

@wildgrass said
Among the extremely effective masks out there, polarity, not pore size, is more important for filtering viruses.

I don't understand the intended meaning of your above assertion. "polarity"? Is that a misedit/misspelling? What do you mean?

@humy said
Whichever kinds of masks that were worn by the majority of people that wear masks. Research shows (links already shown in past posts) most kinds of masks used these days block a significant proportion if not most of the virus-laden airborne particles; and that's all they need to do to significantly slow the spread. So your question is irrelevant and you make no point.
We have ...[text shortened]... ng to complain about and no counterargument. I advise you to for once in your life accept the truth.

You are lying again. You have no such proof. It does not exist.

@humy said
I don't understand the intended meaning of your above assertion. "polarity"? Is that a misedit/misspelling? What do you mean?

By polarity I was referring to the use of polarized materials to create a local electrostatic charge in the mask. N95 respirators employ an electrostatic mechanism to attract and intercept foreign particles (charged or uncharged). These electrostatic interactions are essential to raise the filtration of N95 masks to the 95% level.