Radiation Chart

There’s a lot of discussion of radiation from the Fukushima plants, along with comparisons to Three Mile Island and Chernobyl. Radiation levels are often described as “<X> times the normal level” or “<Y>% over the legal limit,” which can be pretty confusing.

Ellen, a friend of mine who’s a student at Reed and Senior Reactor Operator at the Reed Research Reactor, has been spending the last few days answering questions about radiation dosage virtually nonstop (I’ve actually seen her interrupt them with “brb, reactor”). She suggested a chart might help put different amounts of radiation into perspective, and so with her help, I put one together. She also made one of her own; it has fewer colors, but contains more information about what radiation exposure consists of and how it affects the body.

I’m not an expert in radiation and I’m sure I’ve got a lot of mistakes in here, but there’s so much wild misinformation out there that I figured a broad comparison of different types of dosages might be good anyway. I don’t include too much about the Fukushima reactor because the situation seems to be changing by the hour, but I hope the chart provides some helpful context.

(Click to view full)

Note that there are different types of ionizing radiation; the “sievert” unit quantifies the degree to which each type (gamma rays, alpha particles, etc) affects the body. You can learn more from my sources list. If you’re looking for expert updates on the nuclear situation, try the MIT NSE Hub. Ellen’s page on radiation is here.

Lastly, remember that while there’s a lot of focus on possible worst-case scenarios involving the nuclear plants, the tsunami was an actual disaster that’s already killed thousands. Hundreds of thousands more, including my best friend from college, are in shelters with limited access to basic supplies and almost no ability to contact the outside world. If you’re not sure how to help, Google’s Japan Crisis Resource page is a good place to start.

Edit: For people who asked about Japanese translations or other types of reprinting: you may republish this image anywhere without any sort of restriction; I place it in the public domain. I just suggest that you make sure to include a clear translation of the disclaimer that the author is not an expert, and that anyone potentially affected by Fukushima should always defer to the directives of regional health authorities.

809 replies on “Radiation Chart”

  1. Note that there are different types of ionizing radiation; the “sievert” unit quantifies the degree to which each type (gamma rays, alpha particles, etc) affects the bodygodd


  2. Regarding cell phone radiation, I am both a grateful cancer survivor of 35 years, and a 2 time “stent heart attack” survivor.

    So, I have Cell Phone Shield Tabz on my cell phone, on my computer screen and on my tv to minimize the radiation for cheap insurance, as cancer has many sources including radiation.

    Now work I to educate you the public, on the “rest of the story and alternatives” for cancer and heart attacks that I have learned the hard way over the last 35 years.

    If cancer or heart attacks has affected you or yours and you want to know how to prevent it or minimize it, see www. CellPhoneShield.Me and www. StopStentHeartAttacks.Info
    or email me for more information > Lance@myqci.com

    Lance in Colorado


  3. Good overall, but did you remember to mention radioactive *daughter products*? Think, when many nuclei decay, they don’t turn into a stable isotope, but into another radioactive one. What if the DP has a half-life of a year? So say, after 80 days most of an original isotope of half-life 8 days has decayed, but leaving plenty of highly radioactive stuff with HL of one year! etc. I don’t know the case for e.g. Iodine (and REM also could be mix of isotopes), just making general point.

    So many well-meaning people forget, so many ill-meaning people use to deceive.

    “Fine minds make find distinctions.”


  4. its so hard to say on the cell phone theory… i think there are worse, more powerful things out there that we use/cross on a daily basis and discount


  5. At 5:58 on November 1, 2011, Shenzhou VIII spacecraft will be at the Jiuquan Satellite Launch Center. Is expected to rendezvous and docking time is 2 to 3 am Monday night, when the spacecraft and the Temple I was flying in China, Gansu, Shaanxi over.


  6. Is it just me or should the 40 mSV next to the “Extra dose to Tokyo in weeks following Fukushima accident” be 40 μSV, or is it just scaled wrong?


  7. How specific is your information on the amount of radiation in sieverts produced by mobile phones, i really need to know the amount of sieverts produced by mobiles and i dont mind how many decimal places its just i have a table and need to add mobiles to it:)


  8. How is this a useful or even accurate chart of anything?

    Firstly, I hope you’re aware there are different types of radiation. Some can give you a healthy tan or heat your dinner, another kind will turn you into the Hulk.

    But mainly, the chart makes a terrible mistake of scale. Putting a block showing a 1-week dose beside a slightly larger block showing a 1-year dose? How is that scale?

    For example, how are we supposed to compare “eating one banana” to “using a CRT for a year” compared to “one day in Colorado”? And we’re supposed to “add all these up” to make yet another little block in another chart?

    I’m sorry, but it’s a complete conceptual mess and utterly useless to form any coherent picture of anything unless you do the math to actually work out how many blocks you, as an individual, might add up to over the year. It’s great for that, but you’re trying to compare visual sizes between things that cannot be visually compared like that.

    Providing a simple chart of activities with a) #rads and b) type of radiation (x, gamma, etc) would be far more educational for people. This, as it stands, is very deceptive and give an entirely incorrect picture of things.


  9. Sorry to post again – but the other reason these figures / comparisons aren’t helpful, is that “death by rays” is not what people are worried about. Radiation “sickness”, per se, is not their concern.

    Most people are worried about cancer. Getting cancer is a matter of *likelihood*, of numbers and statistics. You’re more likely to get cancer if you do certain things – that’s on the news every day. Don’t eat too much of this, don’t spend too long in the sun, etc.

    So what people are afraid of, and perhaps justifiably, is – after spending several years living in a building made of higher-than-normal radioactive concrete – whether their chance of getting cancer later in life is significantly higher.

    That’s what they want to know. They don’t want to know what is equivalent to eating 5 years of bananas plus every other activity concerning types of radiation and exposure or ingestion which are not shown to be relevant or comparable to living long term around this specific type of nuclear isotope radiation, and if it increases their chance of getting cancer later in life.

    It’s really quite simple. Far simpler than your colourful chart indicates.


  10. Alistair, regarding the issue of scale, I completely disagree. A sentence such as “Eating one banana gives you a higher dose of radiation than you would receive over the course of a full year living within 50 miles of a nuclear power plant,” is extremely meaningful and extremely interesting. Even more meaningful and interesting: “A dental x-ray only gives half the dose of radiation an average person receives over an average day, whereas an arm x-ray is about one fifth of a dental x-ray, and a chest x-ray is about four dental x-rays, or an extra two days of background radiation…which is nothing to worry about if you only get x-rays occasionally; contrariwise, a CT scan to the head provides half the average YEARLY background dose of radiation, and a chest CT gives almost double the yearly dose, therefore CT scans should be approached much more cautiously than x-rays.” On the other hand, it’s much faster and easier to take in such information when it’s presented visually.

    As for the distinction between types of radiation, try this excerpt from http://people.reed.edu/~emcmanis/radiation.html :

    “To understand sieverts, you should first understand grays (US equivalent: rad). 1 gray is equal to 1 Joule of energy per kilogram of matter. Energy/matter provides an idea of how much effect the radiation has, scaled for the size of whatever it’s hitting. Sieverts include a quality factor in order to take into account the biological effect of the radiation (1 Sv = 1 Gy*quality factor). Alpha particles have a quality factor of 20, because they deposit all their energy in a small area. Gamma rays and beta particles have a quality factor of 1, because their energy is more spread out, meaning the tissues struck by gamma rays are more likely to recover. So, while different types of radiation have different effects, 1 Sv of alphas is equivalent to 1 Sv of gammas.”


  11. Alistair: “Firstly, I hope you’re aware there are different types of radiation. Some can give you a healthy tan or heat your dinner, another kind will turn you into the Hulk.”

    Cite your sources, Alistair. I want to read this paper documenting formation of the Hulk from radiation. I know this might ruin your weekend, but I have to break it to you: the tooth fairy and Easter bunny aren’t real either. I know, the differences between fact and fiction must be difficult for you to understand, but they’re important differences nonetheless.


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