Counting radiation

I love Top Gear, always have, and I always will love the episodes with Jeremy, Richard and James. I even love this clip because it helps showcase exactly how easy it is to scare people about radiation without any lies, but merely by selectively choosing the information to give.

How many people do you think watched this episode and immediately wondered how the BBC could have possibly allowed these men into this area, let alone make jokes about the challenge that landed them there? You can feel the tension in the music and that clicking hum of the Geiger counter in the background.

The problem is that it’s disingenuous. Those swings up of the needle are barely anything for the simple reason that 200 counts per second is not that much more than what you get by pressing your face to your new granite counter tops in your newly remodeled kitchen.

Yes, you are in fact irradiating your bell peppers, basil and avocados. How much should you care? Less than about how much those damned avocados cost.

But what are those ticks that are being counted? 200 of what per second? Luckily this has a simple answer, but unfortunately it opens the door to more questions. What the Geiger counter counts is the number of decay event emissions that reach the detector. So every time an atom decays via any possible decay path and emits a radiation particle there is a chance for a Geiger counter to detect it. If you have a reading of one decay per second, that’s called a Becquerel. It’s the modern unit for describing how radioactive an object or area is, and is the way that is used to determine relative amounts of radioactivity.

Now, even though the Becquerel is the best way to let people know how much radiation is in an area, it doesn’t really inform anyone as to how dangerous an area is. All it tells is how many counts of any type of radioactive decay are happening in any second. Health effects are defined in units of Sieverts. If you ever see a warning about receiving a dosage at the level of Sieverts per hour or even day, step back quickly and go far, far away. But since you will probably never stand directly in the beam of a particle accelerator, or anywhere near a nuclear explosion you’re probably safe from that huge of a dose. Now I want you to imagine standing in one of the most radioactive places in modern popular understanding, Fukushima prefecture in Japan.

What do you think the dosage you would receive there is if you stood there for an hour? A tenth of a Sievert? A hundredth? Or maybe lets assume that they are doing an amazing job at cleaning up and maybe you’ll only receive a thousandth of a sievert ( AKA a millisievert for our non-metric friends south of the border) of radiation dose standing in the middle of Fukushima city….

If those numbers sound reasonable to you, then boy do I ever have a surprise for you. the current average dose rate in Fukushima city is 0.15 microsieverts per hour. That is 0.00015 millisieverts. Don’t believe me? Here are two real time monitoring aggregate sites that maintain a 24 hour watch over the ambient radiation in the area thanks to the operation of thousands of monitoring stations and real time dosimeters that have been set up around the prefecture.

Current radiation doses are about 1/4 what you get from visiting Grand Central Station in New York City

So seeing those numbers, and the first link even offers some handy comparisons to other cities average radiation levels around the world, do you think that Fukushima prefecture is really “dangerous” as so many anti-nuclear people would want you to believe? I get that it might feel a bit uncomfortable to think about living that close to a site of a nuclear accident, but at this point it’s basically no different from living next to a set of train tracks that had a chemical spill 8 years ago. The work continues and the important part is to know that life can return to normal. The biggest hurdle to regular life returning to Fukushima is the fact that too many people simply don’t know enough about radiation, and that some people for whatever reason are trying to take advantage of that to spread fear.

Yes radiation can be dangerous. Yes a radioactive release is something that should be taken care of immediately, just like every other dangerous goods spill. But people should not be so ignorant of what the actual danger of a radiation is.Because nuclear power is not only here to stay, hopefully it will be becoming more and more common as we fight to protect our homes and our livelihoods against the excesses of our current fossil-fuel based civilization.

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