Science: Masks and Aerosols
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2020-07-04 14:10 by Karl Denninger
in Covid-19 , 2412 references Ignore this thread
Science: Masks and Aerosols*
[Comments enabled]

Let's look at physics and mathematics folks.

We'll start with a single cough or sneeze.

Everyone "knows" that if you cover a cough or sneeze, and you should do it into your sleeve instead of your hand, this will reduce the risk of someone else getting a virus you may have, right?


It doesn't.  So says the science!  This is a myth, just like it is a myth that you can wear a mask and reduce transmission.

Wait -- you say!  YUCK; that's obvious that it helps.

Well, no.

Here's why.

You sneeze and a huge loogie comes out your nose.  Yuck!  Nasty!  Mucus, full of germs.

It goes, if uncovered...... downward, on the floor.

And harms nobody.

It's disgusting, but that's it.  You should still do it anyway because it's disgusting not to, but you won't stop a virus by doing so.

What?  If I stop the loogie then how come that doesn't do anything?

Because in addition to the loogie out come a bunch of large drops, each also laden with virus.  Maybe a few hundred drops.  Yuck!  Thus covering or physically blocking those will reduce transmission to other people, right?

Wrong again, statistically speaking.


Because in that same forceful exhale are an enormous number of sub-micron water droplets that are formed as the saturated vapor in your lungs (100% RH in expired air) cools slightly as it travels up from the lungs to the trachea and out the mouth or nose and comes into contact with the ambient air (well, unless it's over 98.6F in the air where you are anyway!)

Remember your basic physics:  As any saturated vapor cools it condenses.  Any saturated vapor that cools by even a tiny amount will condense -- that is, coalesce the individual vapor molecules into larger aggregates.

Ordinary "tidal volume" (that is, the amount of air you move in a resting condition with each inhalation) is about 500ml.  For a cough or sneeze it is much larger; the maximum volume of air that can be inspired in adult human lungs typically is in the range of 4-6L, or eight to 12 times the "at rest" breathing amount.

When we breathe normally we produce very few or no large droplets.  When we sing, play a wind instrument, yell, scream, cough or sneeze we produce a fairly large number of them.

But none of this matters at all, statistically, because with each breath we produce millions of small condensate drops, and all of them which do not aggregate beyond the pore size of the medium in a mask will go right through said mask in either direction, most of those condensed molecules are produced between the lungs and either before or just after exit from the body due to condensation of the 100% RH water vapor and each of them individually, if you are infected with a virus, can carry enough virons to infect another person.

We've all "seen our breath" outside when it's cold.

That's aggregation and condensation to a great enough degree that the aggregates are visible; there are thousands to millions more said aggregates that are too small to see and when it's not cold outside none of them aggregate and condense sufficiently to be visible but they are all still there.

Note that during ordinary breathing the mean particle size is sub-micron.  Statistically none of these are filtered in either direction by anything less than an N95.

This is why physics says that masks don't work against viruses and exactly zero RCTs show that they do.

Never mind the repeated attempts to mandate masks in 1918 which did nothing to prevent the spread.  Of course the revisionism of today says "well it's because people didn't adhere to it."  Sure, there were people who put up the middle finger; after all, they threw people in jail for refusing -- but the facts are that nearly everyone complied.

Every single person that has ever "seen their breath" in the winter months knows, if they think about it for 30 seconds, why masks can't work and don't.

They can't work because blocking 1,000 pretty-large droplets sounds like it's great except hundreds of thousands or even millions of condensed water vapor molecule clusters were also expelled, they have enough virons on them to infect another person and very nearly zero of those are caught by the mask in either direction.  The ones you see when you breathe out in the winter are >50um in size (the limit of visibility to the unaided eye); more than 50 times the size of the mean particle you actually exhale.  Worse, every one of those tiny particles, unless condensed out or breathed in by someone else can remain in the air for hours since they are small enough to remain within the purview of brownian motion of air molecules; that is, they "float" so to speak because the energy of said molecular vibration and ordinary air currents, even indoors, is large compared to the pull of gravity toward the ground and thus they remain suspended in the air.

The reason we have a flu season, as I've noted, is that the higher the absolute humidity, which tracks with temperature, the greater the odds that further agglomeration of these clusters of molecules will occur and once they get large enough gravity takes over as they are too heavy and they fall to the ground harmlessly.

So your mask stopped the nasty-looking and smelling loogie which can infect exactly one person, unless you wipe it around on people, and 1,000 of the 5,000 modest-size droplets you expelled. This is why the mask gets nasty all over the inside (which, by the way, if left on for any length of time or reused will breed bacteria on the inside surface which you can inhale, and it will be very bad for you if you do so.)

But it's worthless in terms of protecting anyone else because at the same time you expelled the 5,001 droplets and stopped 1,001, which sounds like a decent hazard reduction, you also expelled anywhere from thousands to several million micrometer-size drops, an effective none of which were stopped, all of which are infectious, and thus you actually caught materially less than 1% of the potential infections that can screw someone else!

1% is not statistically significant.  Filtering out 0.1-1% of the infectious events out at the source DOES NOTHING.

The reason workers in a virus lab wear moon suits, go through multiple e sets of sealed doors with decontamination procedures before that suit is removed and breathe pressurized outside air while inside the lab is that these are facts and said virus -- any virus -- will go right through any "mask."

Then there is an often-cited NIH review that claims that masks "might" work.  Well, that depends on the mask.  If you read the actual study you'll find that there is a RCT (again, the gold standard for medical science) that found that cloth masks increased transmission -- in other words, they were worse than the control group that was wearing nothing!  That study found N95s to be effective (no surprise) and that surgical masks might be, but non-medical masks aren't part of the debate -- and yet that, and cloth, are what we're talking about here in the general public.  That same review also noted that coronaviruses appear to be preferentially emitted in aerosols as opposed to droplets, which instantly destroys the argument for source control since anything that does not have a high quality seal and fit will pass nearly all of your aerosol (as opposed to larger droplets) right out into the space around you.

Oh, and don't run any bull**** about "oh it's only so-called droplets" nonsense in terms of being specific to Covid19 either.  That's another common claim but there's zero scientific evidence for that.  I'm not the only one who's noticed this -- there's a group of 239 scientists who signed a letter to the WHO.  Not that they should have needed to; unless you're a mouth-breathing idiot the early outbreak in an apartment building at Wuhan and another in Hong Kong where there were no plumbing traps and thus gas (aerosol) from people's scat was getting into other people's apartments and the outbreak occurred across floors in units where the individuals had no reasonable possibility of personal or droplet contact along with the choir group that took all manner of reasonable precaution yet got infected anyway all make clear that in fact the so-called "large drop only" theory is nonsense.  It not only has no basis given the spread we have observed it has no basis in physics either.

Never mind what appears to be one very-well researched and run down super-spread event in Germany -- in a meat-packing plant after compulsory mask-wearing was put into place for employees.  The masks were worthless; a huge number of people were infected and they were able to trace the index case too because of a fortuitous mutation that allowed them to sequence the RNA and prove it.  That put the final nail in the coffin of those who claimed this is not an "aerosol" (whether originating from feces or out your respiratory tract) disease.

Further, as I've repeatedly noted, that Covid-19 isn't following the laws of physics on the agglomeration that occurs with absolute humidity is very strong evidence (but not proof), again on the science, that it is in large part not being transmitted through the air but rather by contact with contaminated surfaces and since we know intact virus is found in feces fecal contamination is very likely involved (exactly as it is with polio, which also didn't follow the laws of physics on aerosol or droplet transmission because it wasn't, in the main, transmitted that way.)  A mask does nothing to prevent "fomite" (item-based) transmission whatsoever nor does it work as source control for feces, obviously.  In fact wearing a mask may make transmission materially more-likely if the mask is not taken from a clean, sterile container only after you have washed your hands, is then put on, and once removed you immediately wash your hands and do not re-use the mask until and unless it has been sterilized.  This, of course, is impossible if you are out in the public and desire to eat or drink something.  As soon as you do contamination of yourself and others, if there is contamination on your mask, is assured.  In short a mask is a filter and thus concentrates whatever is in the environment on its two surfaces; on the interior from what you exhale and on the exterior from the environment around you.  Once a mask is worn, even for a few minutes, it is biologically dangerous both to you and others and becomes more dangerous the longer you have it on.  Without proper protocol you are more likely to infect yourself or others if pathogens are present than protect anyone at all and that protocol is utterly impossible to follow in general public life.

This has been noted in the literature; this article is often cited as "supporting" community mask mandates.  If you actually read it it does no such thing because of exactly what I've noted above:

Taking a mask off is a high-risk process (34) because pathogens may be present on the outer surface of the mask and may result in self-contamination during removal (31).

If your position on "masks" is really one that includes closing all places where food and/or beverages of any sort are consumed on-premise, along with the banning of consumption of food or beverages in public where by definition you will not be able to follow good protocol with a mask to limit cross-contamination of others and self-infection then just say so and be done with it.  Those arguing for mask orders in the public in fact are arguing for a complete and permanent lockdown except to go get groceries or take a trip to the hospital; they must be forced to come clean as to their actual intent.  So long as any firm can remain in operation that permits or serves food or beverages of any sort for on-premise consumption masks are likely to increase infection rates because from an epidemiological point of view once used they are exactly identical to used toilet paper in terms of infection risk and if you put a used one on a table or bar you just contaminated that surface.  Once you put a used one back on your face without first sterilizing it you have just contaminated yourself.

We have known all of this since February, as I have documented.

Physics is not a list of suggestions folks.

It is a list of natural laws that nobody can violate.

Masks are worthless when it comes to viral transmission by aerosol and in addition they are obviously also worthless against transmission that occurs due to contact with contaminated surfaces or objects.  That's the physics of it and nobody has ever demonstrated an ability to modify the laws of physics.  Only an N95 (or better) can attenuate to any meaningful degree viruses in exhaled or inhaled breath simply because virus particles and the water vapor particles that carry them are small enough to pass right through anything less.  It is like trying to stop mosquitoes with a chain-link fence.  I'm sure you get a few, but not enough to matter.

Grow up, deal with the fact that masks are worthless, learn to live with the fact that this virus will not be responsive to voodoo or magical incantations by governors, mayors or anyone else.  Manual removal of potential contamination from your hands by washing with soap and water will help, but there is no guarantee because as we know this virus can spread through multiple vectors.  The sooner those who are not significantly harmed by this virus get it and thus inhibit transmission the sooner it will be equivalent in its impact to seasonal flu or less.

There is no other reality folks, and for reasons I've explained before a vaccine is unlikely to work either.  Don't get your hopes up for that as you are very likely to be disappointed.

If this nation cannot face the realities of physics then we are back to the persecution of Galileo and the burning of "witches" at Salem.  There is utterly no point in my, or any other thinking person's continued engagement on any matter of economics, politics, public health or other policy if that is to be the regression of intelligence and logic among the people of this nation as what was America is doomed to collapse back into the Dark Ages.

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