Philosophically, the government should not be irradiating people without their consent under any circumstance. Empirically, there is no* health risk from doing so with these vans.
* By any reasonable measure of increased incidence of cancer from small doses of radiation.
Except there's nothing to support the latter statements. The statement made by the manufacturer 1) could be totally false, 2) refers to a specific single-use of the technology.
They're claiming a specific output per-scan. What if the police are using this van with 10-second scan intervals, pointed at the same building, with people inside, for several hours? That's a fairly plausible scenario which could result in several ORDERS OF MAGNITUDE more irradiation.
> That's a fairly plausible scenario which could result in several ORDERS OF MAGNITUDE more irradiation.
"Orders of magnitude" is not a magic phrase you get to throw around to scare people.
Assuming 10 seconds intervals and instantaneous scans going on for 8-12 hours you've gone up just about 3 orders of magnitude. That is, from banana-equivalent dose to about the background radiation dose, per this handy radiation reference[0]. In other words, people in that building receive twice the amount of radiation that they would naturally do.
That is assuming a hell and a lot of scans while also ignoring the protection offered by distance and the building itself.
It wasn't thrown around to scare people, it was used because it's accurate. I fail to see how my statement is inaccurate considering by your own admission there are indeed several (3) orders of magnitude difference.
The point I was trying to make was saying that it's some negligible number is wrong. By your own handy reference, it's the equivalent of 2 Dentist x-rays.
The dentist at least has the decency to put a lead bib over you.
> I fail to see how my statement is inaccurate considering by your own admission there are indeed several (3) orders of magnitude difference.
"Three orders of magnitude" is a meaningless thing without context, and I just pointed out that in this context it still doesn't change the conclusion that the exposure is neglible and not worth considering.
> The dentist at least has the decency to put a lead bib over you.
That's because people are irrational and you need to dance around them for their own sake.
> What I'm saying is: That's not entirely relevant if we don't know how many doses people actually get.
True. But then if we count up the reasonable upper bound of possible doses you could get, like "several thousands times a day times amount X", and it still adds up to "not harmful", should we keep being distressed about it?
Assuming 100nSv per scan (first comment in this post). 10s per scan. ~4000 scans in 12h.
-> 400uSv = 0.4mSv.
Background where I live: 2mSv per year. So this is a fifth of the yearly background dose at my place. But in a single day.
For example, scan the entrance/exit of a parking garage (such as one under supervision) regularly, and you have a realistic chance of severely harming the guy at the ticket booth.
I skipped an order of magnitude here. Your calculation seems correct, so we're up to about a mamogram / day (still ignoring the distance and shielding effects of the building, but we're computing the reasonable upper bound on exposure).
Over the year this 0.4 mSv adds up to about 146 mSv. Per the Handy Chart, it's between EPA dose limits for emergency workers protecting valuable property and for those in lifesaving operations. It's about 1.5 times the "lowest dose clearly linked to increased cancer risk".
So in the worst reasonable case, this seems to be indeed causing an unnecessary increase of cancer risk. Personally I think the conditions for that upper bound are very extreme so the real dose in actual use would not be nowhere near the amount calculated above, but at this point I have to agree there's a reason to be concerned and demand more information about the deployment and capabilities (especially radiation output in failure modes) of those machines.
In short: most likely still not in any way dangerous, but the revised margins are much slimmer, therefore there is a reason for concern.
I apologize for misleading anyone by accidentally skipping a zero.
> Philosophically, the government should not be irradiating people without their consent under any circumstance.
So you are against public broadcasting systems? You also don't think that a government should have a moral duty to operate an emergency broadcast system for helping people deal with natural disasters? X-rays and radio waves are both EM radiation.
To be even more pedantic, this stance also means that a government building would not be able to have any lights or heaters (amongst other things). Or a cop searching for a suspect at night wouldn't be able to use a torch.
I think it's a bad, absolutist philosophical point to make.
I think the poster was referring only to ionizing radiation (the kind proven to increase cancer risk). Light fixtures and heaters (infrared) don't fall into that category.
You are correct - I was mostly speaking for effect. But the absolutism is still a problem. For example, if you get into a car accident and are taken to an emergency department in a state where your life is in jeopardy but you are unable to provide consent - should the medical staff have the moral right to do x-rays, which greatly aid their diagnoses?
Also, the medical staff are irradiating you for the direct purpose of aiding you specifically. The police are irradiating you because they've decided you are by default a suspect worthy of search simply by virtue of passing by - the benefit you receive in return for any health risk is debatable at best.
Philosophically, the government should not be irradiating people without their consent under any circumstance. Empirically, there is no* health risk from doing so with these vans.
* By any reasonable measure of increased incidence of cancer from small doses of radiation.