Thread by @glenpyle

With the publication of an excellent review of the benefits of masking by @trishgreenhalgh & colleagues, some are recycling misinformation about the basic physics of masks.

Let me, a biophysicist, take this opportunity to explain the physics of masks.

A 🧵

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The idea that viruses are too small for masks to filter assumes there is only one layer in a mask.

In fact, they are woven with several layers to create a mesh network with much smaller openings.

Below is an image showing the weaving of different mask types.

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Besides physically blocking viruses & particles, masks work by electrostatic interaction.

Basically, the fibres in the mask act like a magnet to attract viruses & particles.

Up to 80% of filtration is through this mechanism (Xu, J. et al. One Earth, 2020).

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The "charges" are introduced into masks by hitting them with electrons or heating the material to create a “polarized” state.

This creates an electric field that traps particles & viruses.

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But I saw a guy blowing through a mask & creating "fog" on glasses!

What you see being deposited on the glasses is water.

Water is a molecule that is about 3 angstroms in diameter. That is ~10,000X smaller than SARS-CoV2 aerosols (M Alsved et al Infect Dis, 2023).

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Ironically, people who show water molecules passing through masks are often the same ones claiming masks deprive people of oxygen or cause a build-up of carbon dioxide.

These molecules are similar in size to water, which they show passes through.🤦

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forbes.com/sites/victoria…

The bottom line is that when people claim to be scientific experts on COVID & masks, while misunderstanding basic physics, you should question what else they get wrong.

Spoiler alert: it's a lot.

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For those who are interested, here is the paper mentioned at the beginning.

Give some of the authors a follow: @trishgreenhalgh @Globalbiosec @ShovonBhattach2 @doctorahmad75 @DFisman @AmandaKvalsvig @DALupton @sameo416 @Mark_Ungrin @jvipondmd

journals.asm.org/doi/10.1128/cm…

@ForeverBored_AU @trishgreenhalgh Also, I am correcting the misinformation brigade & pointing out if they don't understand basic science, you should question what else they get wrong.

@LynnRobsHay @trishgreenhalgh I would also point out that if they want to be absolute on this, they should speak up against plastics (& petroleum products which have similar endocrine disrupting chemicals) & refuse to.use those as well. This would include a lot of medical equipment which has plastic tubing.

@LynnRobsHay @trishgreenhalgh For the record, I agree we should decrease plastic use. My lab studies the effects of chemicals found in these products & have found effects on the heart at levels we are typically exposed to. Levels that were there pre-pandemic. In other words, this is not a new problem.

@m_jade1632 @CanadianvapeT @trishgreenhalgh And before you reply with, "but it doesn't decrease infection"...

https://twitter.com/glenpyle/status/1777766135200407772?t=gYB78yAx9sKbGxkBWXXUOcIaNYNEiXUz1vlmIoGZ93I&s=19

@BiTurbo290bhp @ForeverBored_AU @trishgreenhalgh Thank you for your honesty about wearing masks: "even if they work I won't wear them" speaks volumes about how informed you are in decisions & what you think of others. 🙄