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Comment by wlesieutre | Hacker News Reader

Things I Won't Work With: Thioacetone

https://www.science.org/content/blog-post/things-i-won-t-wor...

> To convince them otherwise, they were dispersed with other observers around the laboratory, at distances up to a quarter of a mile, and one drop of either acetone gem-dithiol or the mother liquors from crude trithioacetone crystallisations were placed on a watch glass in a fume cupboard. The odour was detected downwind in seconds.

How is the smell able to travel so quickly? And through walls no less?

Nigel of the NileRed youtube channel has just the other day disputed this claim. Diffusion isn't very fast and the wind would have to have been going 15mph or more. He says he wants to create this compound and test it, as he has done with a few other "horrific smell" compounds.

However, there's a running theory that he has kinda burnt out his nose working with certain compounds, as he seems mostly unphased by smelly chemicals that other people very much struggle working with.

> the wind would have to have been going 15mph or more

15 mph really isn't much for wind, though? In fact that's about how much wind there is where I am right now, so that doesn't strike me as an unreasonable condition.

The specific claim he disputed was "smelled one mile away almost instantly" which would be a much bigger claim.

In the thioacetone TIWWW, Lowe says that "the workers in the laboratory did not find the odours intolerable". It sounds like in higher concentrations it just overwhelms and numbs a strong reaction people have at even extremely low concentrations.

A fume cupboard has an exhaust fan. Think of it like an enclosure with a built-in fume hood.

Individual molecules of air travel at speeds in the hundreds of meters per second (https://pages.mtu.edu/~suits/SpeedofSound.html). So it seems quite possible that individual molecules may be found quite far away from their origin quite quickly, even if the bulk is much slower in mixing (I'm not an expert here and would love to hear more if someone knows more about this).

It sounds like this substance is bad enough that a couple of molecules per Litre would make the air smell awful, which together with the previous point may explain how the bad smell could be detected at such a distance so quickly.

This is it, and holy hell it's worse than I remembered.

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