Trying to get a handle on what is happening with Japan's nuclear power plants has not been particularly easy.
Since the tsunami inundated and then crippled the Fukushima plants we’ve read, heard or seen stories about: radiation plumes wafting across the Pacific to California; Californians depleting stocks of potassium to prevent radiation-induced thyroid cancer; and radiation discovered in Japanese milk, water and food.
Not to take a metaphor too far, but nonexperts following the developments have, in a sense, been inundated with information rarely put into perspective.
So, how much radiation did we get exposed to in California as a result of the nuclear crisis in Japan? And how does that radiation compare with our typical daily exposure? Or yearly exposure?
Well, it may not answer all of your questions, but a very cool graph was constructed by webcomic author and webcomic xkcd host Randall Munroe that sheds some light on all of this.
Working with Ellen McManis, a nuclear operator at the Reed Research Reactor, Munroe built a chart that displays in a simple way the sources of radiation we are exposed to every day, and how much radiation those sources emit.
The graph uses the sievert as its unit of radiation measurement. A sievert is used to quantify the degree to which each type of radiation – gamma rays, beta rays, alpha particles, etc. – affect the body.
Munroe moves from small, daily exposures – such as how much radiation you get by sleeping next to someone – to the amount of radiation required to kill someone.
Depending on your outlook, the graph will either bring comfort or terror.