It’s not that masks don’t do anything to stop a submicron virus, it’s that they can’t.
Jan 2, 2022 • 22 tweets • 10 min read
🧵 on N95s:
A few reasons (many more exist) on why they don’t work and they can’t work:
1. There is no seal.
In our macroscopic world, that means “water tight”. If there is a millimeter-sized gap— it’s useless.
Even if fitted, once you talk or move your jaw—it’s compromised.
2. A 95% efficient mask at 0.3 micron is still not good enough to “stop” an aerosolized virus.
The N95 rating is nominal— not absolute, so it may be rated to stop some 0.3 micron particulates for a few moments, but that’s about it.
Nov 16, 2021 • 7 tweets • 3 min read
A breakdown of the @CDC Director’s Twitter video comment that:
“masks reduce the chance of infection by more than 80%.”
Her source is a sentence here from the CDC’s cloth mask study👇
There are 8 “small-number references” pertaining to this sentence which “prove the case”
Small-letter 5: masks stops droplets, not so good on aerosols:
Remember when you were a kid, you would look out the window on those lazy days and see dust particles floating between you and the sunlight?
Our human vision is limited to around 40 microns, or the width of a human hair, so those dust particles were around that size and bigger.
The dust floated because air currents (flow) provided buoyancy/drag versus gravity trying to pull the dust down to the ground.
Small-letter 5: masks stops droplets, not so good on aerosols: 
