Gunning Fog Index = 11.17

Today we explore the EPA's radiation monitoring database, not because I caught someone wrong on the internet but because I had insomnia last night and occupied myself by playing with data until I could sleep. So here's a plot of beta decays vs. time before, during and after the Chernobyl disaster. Beta decays are a decent proxy for the non-actinide fission products created in a Uranium-fueled reactor. I only plotted two detector locations because they both had fairly robust and continuous datasets for both before and after the reactor failure and they show what I wanted to see, i.e. the evidence of trans-Atlantic fallout in the eastern half of the US.

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How bad is the contamination on this plot? Actually it's way less than it looks. The EPA considers less than 4 pCi/liter very low risk which requires no intervention or action (based on radon; ref: http://www.epa.gov/radiation/docs/402-k-10-008.pdf). The highest value in the data I used was 1.06 pCi/m^3. To convert to pCi/liters, divide by 1000 to get 0.000106 pCi/liter. Ignoring the fact that radioactivity and dose are apples and watermelons, a quick back-of-the-envelope calc reveals that we're talking micro rems here in terms of equivalent dose. You get exposed to around a thousand times more than that from just watching TV. (Yes, yes, yes, this is really pushing it in terms of evaluating dose but rigorous dose calcs are such a pain in the butt when all I wanted was a good qualitative arm wave. I won't stop anyone who wants to bust my chops over this from doing their own calcs and posting those as a comment...)

The beta decay measurements in this plot are for particulate matter trapped in air samplers. It would not be unsound to postulate that some of that particulate matter was true honest-to-pete fallout because the Soviets did not built a robust reactor containment around the reactor vessel - so when the reactor went critical during the accident, the explosion vented to the atmosphere. FYI - most of the rest of world builds robust reactor containments, which is why Fukushima isn't anywhere near as bad in terms of airborne contamination despite its more complex nature and the presence of multiple meltdown bodies.

I'd love to get some real beta decay data like this for Fukushima but due to Tea Party/Republican attacks on EPA funding, the radiation monitoring program was gutted starting in federal fiscal year 2010 through to mid-fiscal year 2012 (the federal fiscal year starts in October) and then again during the Sequester. We lack a lot of meaningful data for the crucial before-and-after periods of the Fukushima disaster. Mind you, that's just a personal opinion so YMMV!