Since New York is on the far end of receiving the radioactive cloud in the US, most likely pretty much all of the US is receiving sprinklings of Iodine-131 and Cesium-137 similar or higher. A couple days ago up to “0.1 picocuries” of Cs137 were detected “in one cubic meter” of New York air. Source: Kyodo: http://english.kyodonews.jp/news/2011/03/82133.html
I’m gonna run with this data and “translate it into floating lanterns”:
To get this visual, I decided to calculate the number of Cs137-ATOMS this actually meant. If I could imagine these radioactive atoms as beautiful floating Japanese lanterns, and get an idea of how many surrounded me on my way from work to home, perhaps this nuclear nightmare wouldn’t seem as bad as I think it is. (Today on April 2nd, I still think it is a Level 7 on the INES scale, on par with Chernobyl and that it still has the potential to become much worse). So how many lanterns are shining upon me?
0.1 picocuries (one-trillionth of a curie) per cubic meter in air Conversion: http://www.unitconversion.org/radiation-activity/picocuries-to-becquerels-conversion.html 0.1 pCi =0.0037 Becquerel.
0.0037 Becquerel per cubic meter of air.
– One gram of Cs-137 has an activity of 3.215 terabecquerel (TBq)
– Cs137 atomic mass: 136.907089473 u
– 1 u = 1.660 538 782 × 10−27 kilogram
– 136.907089473 u = 2.273395×10^-25 kilograms
so, the number of Cs-137 atom in 1 gram of Cs-137can be found by dividing the gram by the weight of 1 atom. That gives: 602,409,638,554,216,867,469,879,518 Cs-137 atoms per gram. And thus I can get the radioactivity in Bq for 1 atom, by dividing the radioactivity of 1 gram by the number of atoms in that one gram:
3,215,000,000,000 divided by 602,409,638,554,216,867,469,879,518 which is:
5.3369 E-15 Bq per atom of Cs137
0.0037 Becquerel in a cubic meter of New York air means how many atoms? o.oo37 Bq/m2 divided by 5.3369 E-15 Bq/atom gives the number of atoms in the kind of fallout air we’ve all been breathing in the USA this week:
693,286,364,700 atoms per cubic meter of air Or, to round it off downward: a half trillion radioactive atoms floating right around us. Forget about the lanterns… There’s not enough room for that to be a pretty picture. The number still seems “too many”, in my opinion, but given Cs-137 half-life time of about 30 years, perhaps it emits beta radiation at such a slow pace (and then Ba-137 that emits gamma radiation from there) that it takes A LOT of it to make a serious dent in the background radiation levels (which have barely changed in the US in the period March 11 – April 2). It is what it is…
As the fallout continues to come down (in extremely low doses compared to natural background radiation), the particle accumulations show up in rainwater first, in plants and dairy next. The EPA and a couple universities are taking samples in so few locations and so sporadically, that most of the effects on US crops remain de facto unmonitored.