For those wondering, the units on the dosimeter might be milliroentgen/h. One of the replies mentions that it's a RKS 20.03 "Pripyat" dosimeter.
11.37 mR/h? Not great, not terrible.
11.37 mR/h? Not great, not terrible.
Or, alternatively, the average yearly background radiation of about 2 milisievert takes about 18 hours of being glued to those tiles.
I'm actually astounded this is allowed to be there in a public place, because at home you can reasonably expect protect against someone shattering a tile, but in public? One drunk guy is all you need.
Then again there are well practiced methods for removing sources of similarly hazardous air-bourn particulates such as asbestos, i'm not sure how much difference there is between the two beyond the low risk of pure exposure (inhalation being the serious risk here).
There's also the difference that this is a U-Bahn station in use, in the rough middle of a line. Closing it down for a prolonged period of time, and fully sealing it from the rest of the line to avoid the spread of dust through the metro tunnels would be a significant and disruptive undertaking.
And keep in mind that this is a subway station, places where the pm2.5 levels are routinely extremely high because of the dust released by train breaks, so a microscopic amount of uranium dust is really negligible in such an environment.
I saw 11.37 on the display, wouldn't that be 0.01137 ?
Roentgen (R) used by the instrument only measures exposure, but this is not the same as absorption which depends on the type of radiation, the type of biological tissue exposed, the duration of exposure etc. The parent is using Sv which measures absorption for the purpose of more usefully assessing biological risk. I'm not sure how the parent is converting them, there are probably some good rules of thumb.
At the other end of the scale the minimum annual dose with a clear link to increased risk of cancer is supposedly 100 mSv [1]. But the risk is different depending on the distribution over time, so if we make it hourly for comparison that is 0.0114 mSv/h making this reading about 1000 times higher than that risk threshold (but the risk is over a year is effectively assuming continuous exposure).
Seconds or minutes isn't going to be terrible, but in only 9 hours leaning against it you would get a years worth of high risk cancer dose!... I'd stay away from the wall. happy to be corrected, this stuff is hard to interpret if you are not an expert. The falloff is really fast though, so it's basically harmless if you are just walking through... maybe the original intent was to stop people touching the walls :D like an electric fence without the need for power.
[0] https://en.wikipedia.org/wiki/Background_radiation
[1] https://upload.wikimedia.org/wikipedia/commons/9/9f/Exposure...
[edit]
Fixed various calculations.
Speaking of which, radon gas is the main way in which uranium affects the health of people. Depending where you live and the construction methods, it may be worth getting your basement checked, and ventilated properly if necessary.
Even the extreme scenario there is still far short of causing acute radiation sickness. People who live in such regions are sometimes exposed to such levels their whole lives, which can still be long and healthy. But not quite as long and healthy as those without such exposure, on average.
- You work about 2k hours per year in the orange office
- That would then be about 200 mSv per year
- "Exposure to 100 mSv a year is the lowest level at which any increase in cancer risk is clearly evident" (https://www.reuters.com/article/us-japan-quake-radiation-idU...)
I guess then that maybe we could (barely) observe a higher incidence of cancer for those who spend a lot of time next to the walls?
Besides, Uranium radiation is mostly absorbed by the skin, and your skill will be replaced many times on that timeframe.
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EDIT 2: Looking more closely it appears that the dosimeter in the video is switched to µSv/h, so it's reading 0.1 mSv/h anyway and the whole discussion below can be skipped if you're not interested in the difference between Gy and Sv.
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If I remember my lectures correctly (Wikipedia did help me here), the conversion is 1 Roentgen ~ 00.1 Gray (Gy), which is a slightly different unit from Sievert (Sv).
1 Gy is 1 J/kg of absorbed energy, however the biological effects change depending on the type of radiation. Sv is Gy adjusted by a weighing factor. It's 1 for gamma rays, where 1 Gy = 1 Sv, but for alpha particles it's 20 [0].
Uranium-238 emits alpha particles, which get stopped by a few cm of air or even dead skin. So the effective dose you are receiving from the decay of U-238 is probably closer to 0 mSv/h.
Or, if you eat it and it's inside you, 2 mSv/h, at which point you should probably be quite worried.
The decay products of U-238 however are beta emitters, which changes the calculation again. The beta particles can penetrate the skin, but the weighing factor for beta radiation is 1, so it can reach you but is also less dangerous. So what's the actual final value? I honestly don't know, radiation can be complicated, and I just wanted to share the difference between Gy and Sv!
[0]: https://en.wikipedia.org/wiki/Sievert [1]: https://en.wikipedia.org/wiki/Uranium_tile