I fail to see how my post is implying that you should be fine with non-necessary irradiation. I'm quoting and linking the manufacturers website.
I am anticipating that someone will come forth to defend this illegal searching by claiming that the radiation dose is negligible or irrelevant. I want to counter this defense by posing the matter as philosophical rather than an empirical question of whether the irradiation is harmful or not.
EDIT: Ah, in the time that it took me to write this, I have been proven correct.
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.
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.
"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.
I refuse to be scared.
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.
"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.
Person A says 1 does of product A is Amount X.
What I'm saying is: That's not entirely relevant if we don't know how many doses people actually get.
I agree about irrational, among other things.
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.
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.
The cop took physics in high school and got a 'B'. Oh, wait, no, that wasn't physics, that was physical ed.
And, without any other information, the specific quotation being presented appears to imply you think it's no big deal (since you didn't offer any interpretation or make a statement relating to your opinion on the matter).
(though to note, I didn't downvote you, I'm just explaining how the information could be seen as "subjective" and not "objective").
As others have mentioned, there are also issues regarding whether those numbers can really be interpreted to mean that they are relatively safe. The manufacturers of backscatter tech claim that's true, but others suggest that because of the concentration in the skin, it's not a good estimate of safety. To interpret your cited numbers, the discussion also needs that side of the story, which other commenters have provided, but your original post did not.
And contributing the manufacturer's stated specifications ADDS to that conversation, which meets the criteria for 'goodness'.
Not directing this at you, as you've already acknowledged that the OP should not have been downvoted, but additive facts should, probably as a rule, never be downvoted on account of knee-jerk reactions.
My dentist had to take a course in health physics before being allowed to use an X-ray machine on humans. So did my doctor. What makes TSA agents and New York cops so special?
Because regardless of what your post's purpose was, people are obviously gonna read that extract as "hey, it's inside safety limits, so it's ok".
When we post something without further comment it's quite safe to assume that people will think we agree with it, and we're using it to pass a message (especially the most obvious reading it has). The only other interpretation that's (a little less) common, is for people to think we've quoted it sarcastically.