Every time I talk to family/friends/read news article about Fukushima/Chernobyl/Nuclear Energy I run into a lot of ignorance about what radiation actually means. What surprised me when I did some research on the topic a few years back is how you don’t need a lot of sophisticated mathematics to be able to understand the risks. You need at most elementary level mathematics and some basic facts.
Two questions to ask about any radiation news story:
What type of radiation is it? (alpha,beta,gamma)
Alpha is only deadly if ingested or inhaled. Beta doesn’t travel far and won’t penetrate thick clothing. Gamma will penetrate in the deep tissue and cause cancer.
How much radiation? (rems,sieverts or grays).
Death from cancer in population is 20% before any radiation exposure listed bellow. That means 1 out of 5 people in the world will die from cancer. Usually cancer happens later in life.
LINEAR HYPOTHESIS: model used in radiation protection to quantify radiation exposition and set regulatory limits. It assumes that the long term, biological damage caused by ionizing radiation (essentially the cancer risk) is directly proportional to the dose.
Linear Hypothesis appears to be biased with a pessimistic outlook on effects of low radiation exposure for humans.
Measuring Radiation: milliSievert
0.1 uSv = Eating a banana
7 uSv = Dental X-Ray
3.1 mSv/year = US from all sources including medical
Fukushima 1.42uSv/hr for 2 weeks = Additional 0.16 mSv
Exposure: 2.0 Sieverts = 10% chance increase of cancer
1.0 Sieverts = 5% chance of increase of cancer
0.2 Sieverts = 1% chance increase of cancer
All in addition to the 20% chance of getting cancer we all have.
Additional risk of exposure after two weeks at Fukushima? 0.008% increase of cancer for a grand total of 20.008%.