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Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
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5 Jan, 61 tweets, 15 min read
I got a few questions on that thread about particles floating. Here's a quick explainer although of course there are plenty of air experts on here as well, so I will try to do a with a lot of pictures to be different.
Historically, humanity has had two major theories of disease spread: miasma (arises in swamps and floats in air) and contagionism (disease spread by contact between people).
In the 1800s we learned about germs, and that they live in us, and that we spread them.
In 1912 a guy named Chapin wrote a book that examined spread of disease. He thought it was spread by droplets.
He thought so because 1. most spread was at close distance 2. he thought things stuck to water and don’t get thrown off it, 3. they could not culture bacteria well at the time and 4. he thought that if you told people disease was in the air they would act like dirty animals.
But to him, remember, droplets meant “not airborne” and “airborne” meant floated over great distances.

Even though we knew smallpox was somewhat airborne at the time.

Even though he had earlier in 1887 noted scarlet fever sometimes struck over longer ranges

In 1917 he wrote a summary and presented at Harvard. It was all about droplet.

And droplet became the predominant theory.
Even though later scientists like Wells and Wells wrote articles debunking this such as this one in 1936 explaining why everything floated in small particles in the air, the more prominent scientists believed Chapin and continued to push his work.

Even though articles were written in the 30s (and on) about infection in hospitals and air

Even though by 1941 it was proven you could infect ferrets around a corner, which is impossible for droplets

Even though by 1948 it was shown bacteria floated in air 15 minutes

Wells, and later scientists like Riley (who worked under Wells and proved TB was airborne in the 60s) were not listened to.

Even though measles was once a droplet disease but was later accepted as airborne

Even though TB was once a droplet disease but was later accepted as airborne

Even though chickenpox was once a droplet disease but was later accepted as airborne

Even though we knew cold coronavirus was in the air

Even though a CDC book listed all kinds of things as “airborne”

Even though rhinovirus in air

Even though hoof and mouth in the air

... more hoof and mouth in air...

In fact, here’s a list of things that might be in air...

... and it's been a long time we had discussed things in air (summary thread):

And even though we found spread on planes

And even though TB and SARS spread on planes looked the same

And found MERS coronavirus in the air in a hospital

Part of the problem was “airborne” didn’t have a great definition. it just meant “we saw it transmit more than 1 or 2m or so”
And part of the problem became we then connected “airborne” to providing workers N95s, because if virus spread via droplets that fall to ground, a surgical mask is good enough
No. They all transmit via floating aerosols. Some just more infectious so we see spread at longer range
So, as we entered this pandemic, the predominant thinking was disease is spread by larger droplets that fall to the ground in 1m, 1.5m, or 2m. They either land in our eyes (etc) or on a surface and we touch it.
Even though this theory is full of holes, even per the @WHO’s writings.

And even though their writings accidentally prove airborne.

And even though evidence of fomites is poor

But droplet kept being cited with nobody checking the work.

This is not how respiratory disease spreads.
Disease spreads in the small particles in the air, called aerosols. An “aerosol” is technically a suspension of fine particles in air (or another gas) of any size.
Because of droplet theory, we’ve come to believe virus is transmitted in droplets that fall to the ground relatively quickly (few seconds).
In fact, they float for hours.
Older ref says:
A 0.1um particle floats practically forever. It settles at a rate of .007 feet per minute.
A 10um particle settles at .59 feet per minute.

Here is a picture of how far they travel in a light breeze (not stiff, I mis-spoke there)

Newer ref says the same of course, because this is physics:

We cough these particles out in various sizes, but many are in the smaller sizes
(This is an older ref)

Sizes cont’d

And another study, again showing small sizes ejected

These small particles float for hours and hours.
They are cleared out faster when you have good ventilation.

This is why we say be careful entering a space where people are, OR HAVE BEEN. Their breath is still floating there.

And we need the WHO to change to acknowledge this because their guidance trickles down to national groups, and means healthcare are not getting N95s to protect against these smaller particles

Le fin.
Summary 1

Summary 2

Here is my list of air experts, who know far more about this stuff than I do.

I highly recommend many of @jljcolorado 's and will add them to this thread. I just had bookmarks to my own threads handy.

twitter.com/i/lists/128046…
@jljcolorado A more fulsome history is in our preprint here, with a collection of people who have been yelling this stuff for ages, most of them air experts in that list of experts.

papers.ssrn.com/sol3/papers.cf…
@jljcolorado A chart of all the experiments for various viruses, and how many have proven "airborne" is here, as well as short thread on that.

.@jeremychrysler also dove into the history of droplet/airborne, which you can read here:

And of course this thread (whipped up quickly) is in no way complete.
I left out tons of references, such as this one about knowledge from the 1700s about ventilation slashing transmission rates.
Miasma was wrong, but its cures were in part right
Direct link to the chart showing various respiratory viruses airborne:

Other fields were spot on for years, but not unfortunately the field of infectious disease as a whole (although some in the field were)

Here are engineers getting it right in 2011:
Here is a list of review articles talking about airborne. They're overview articles.

Some are from decades ago.

And here is the ramifications of "droplet" which is 6 feet and 15 minutes were always made up nonsense. Sure you can use them as cutoffs for contact tracing, but they're meaningless

And @kprather88 saying, yet again, that aerosols float

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More from @jmcrookston

Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
4 Jan
Particle settling in turbulent air
Ha, well named: Aerosol 101

cdc.gov/niosh/topics/a…
Ooh
Read 12 tweets
Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
4 Jan
Unable to imagine a return to distance learning?

We've peaked as a species my friends.
I should again clarify as I have in the past that I have great sympathy for those who have real child care needs or issues caused by these changes.

However these dramatic statements of hardship always in my timeline seem to come from a certain demographic ...
I have nothing more to say other than a reminder minorities poor and disabled are dying at multiples the rate of middle and upper class whites.
Read 4 tweets
Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
3 Jan
Lot of mutation space between delta and omicron ... Don't assume it can't get worse ...
Delta: fit
Omicron: fit

So you're telling me all of the differences between the two make O worse? I'd bet against actually.

I should have posted this a long time ago really. Sorry for brevity
Yeah figured. It's two types rattling around now.

Read 4 tweets
Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
3 Jan
If we're doing "infect everyone", where's my serology surveillance to know where we're at? And analysis? Humm?

Oh everybody's at the cottage maybe when they get back then?
I'm sure this was in the plan.
Uh Image
Read 4 tweets
Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
2 Jan
Thread for me. Please do not look at it. Your co-operation is much appreciated, thank you.
I saw that like. Stop looking. This is private.
Read 11 tweets
Jonathan Mesiano-Crookston /Denial Is Bad Strategy Profile picture
2 Jan
Maybe medical officers of health (MOHs) need to be reminded of what the Ontario Medical Association thinks their role is:

"Guarding the Health of Citizens".

Hmm.

And all I'm doing is clearing out old PDFs. Imagine I started making a case for their abdication of their duty?
It's almost comical
This report is entertaining to me because it's the OMA lobbying for more jobs. They encouraged the maintenance of all the local community boards and that there needed to be an MOH (who are very well paid) in each one. The opposite of what SARS Commission said was needed.
Read 4 tweets

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