Fukushima Radiation – Comparison Map

* Note: I’m pleased to announce a new animated graphic of Fukushima radiation regional effects. Click here.

New Updated map – March 30th


Original map – March 17th


Click for detailed image.

Updated Commentary (March 30th)

The new map incorporates many of the changes requests by readers, while new features include a time series visualization of regional effects, a local site map, selected news reports, and data up through March 30th. Radiation by distance has also been updated to show several trend lines at different dates.

The time series data provided by Marian Steinbech, “A Crowdsourced Japan Radiation Spreadsheet”, was visualized with custom C/OpenGL software to overlay circles on geographic maps of Japan. Recent versions of the data, going back to March 1, can be downloaded from his blog here: http://www.sendung.de/japan-radiation-open-data/.  These moments in time were selected to highlight how the radiation has effected Ibaraki prefecture and Tokyo, and demonstrate that while direct gamma radiation dissipates with the square distance law, particle-based radiation also dissipates with distance due to weather scattering. Although much attention has been placed on Tokyo, a very interesting finding was that Ibaraki prefecture, population 2.9 million, has received a radiation dose equivalent to nuclear worker levels while its distance from Fukushima, 100km, places it outside the current evacuation zone of 30km.

From March 17th to 30th, despite media reports which vary widely, indications are that radiation levels continue to decline. Of course, the reactors are still not completely stabilized, so future events are unknown. A significant problem is that huge amounts of seawater pumped in to control reactor temperatures must be discharged somewhere, thus ocean and nearby water measurements have increased significantly. This may be expected to continue so long as large amounts of seawater are pumped in to keep the reactors cool.

Overall, the most concerning factor is the difference between Western and Eastern responses. In the western media, very minute levels of radiation in Nevada and California are presented as if they are a major risk, which is clearly unfounded. Levels may be reported as “two times above normal” in a US city, but the overall background radiation of the world varies by up to 10 times! (0.5 to 5 mSv/year). Even in Tokyo, 206 km away, levels have not yet gone over the equivalent of adding a single CT Scan for the year. Yet the levels are presented as if they are an imminent threat to the west. Meanwhile, in Ibaraki prefecture (100km away), an area with over 2 million people may be exposed to levels unsafe for nuclear workers while the evacuation zone remains at 20km. The total number of people who have died from the earthquake and tsunami is now at 10,743 confirmed dead and 17,443 still missing (likely dead), which is usually reported as an after-thought in new media, while the total number dead from Fukushima nuclear radiation is still less than 100.

News reports, also plotted above, present an inconsistent view of events. Although only 12 articles are plotted in the map above, over 64 articles were reviewed for data accuracy. Some of the key findings are as follows. The most significant problem media faced appears to be how to correctly report radiation levels, which has been inconsistent both in terms of units of measurement, other levels to compare to, and background levels for reference. Friday, March 18th, “A radioactive hazard zone? Chernobly’s example” (CNN), they compare lifetime amounts of radiation in 1 km areas near Chernobyl (350 mSv) to momentary peak radiation levels at the main gate of Fukushima (400 mSv), and thus suggest that recent events are higher. The distances and time spans are not given, only the levels, thus giving an inaccurate picture of events.

On March 25th, several news agencies reported levels at 10,000,000 times above normal. The following day, a retraction was posted in an article called “Utility retests reactor water after radioactivity spikes”. In this follow up, the corrected report says levels were 100,000x above normal at Fukushima, 10,000x above normal at Reactor #3, 1850x above normal at a nearby monitoring post, and 330x above normal for the average person. What does it mean to be 100,000x above normal, and why is this number exactly one hundred thousand? Actual radiation units are never used, and in many cases the baseline upon which this multiplying factor is derived are never given. The entire concept of reporting levels “above normal” is misleading since it fails to address the fact that radiation is cummulative, and thus the duration of time that one is exposed to a given level is of key importance. In FOX News, out of several dozen articles reviewed, only a few provide actual sievert levels, while most articles indicate levels as a factor “times above normal”.

In an article on Wed, March 23rd, FOX news reports “Japan Commission Estimates Elevated Radiation Outside 30-Km Radius”, where they state that:

“In some parts of cities and towns more than 30 kilometers northwest and south of Tokyo Electric Power Co.’s (9501.TO) Fukushima Daiichi nuclear power station, people may have been exposed to a total of more than 100,000 microsieverts of radioactive iodine since the beginning of the nuclear disaster following the March 11 earthquake and tsunami in Japan, the estimate showed.”

This suggests that people outside the 30km zone have been exposed to 1000 mSv/hr (milli-sieverts/hour). Looking at the map above, this is clearly impossible, as this is the highest level reported directly near the core. If this amount of radiation were found in the surrounding areas, severe radiation sickness would already have been recorded.

Another reporting phenomenon is the unintentional amplification of disaster. On March 22nd, NHK world (a Japanese news source), reports that soil levels 25 miles away are 430x above normal soil levels. They also state clearly that the average exposure to a human being is likely to be only 4 times above normal. In a follow up report by CNN, on the same day, and apparently in the interest of providing a brief summary, this later clarification is omitted. The report states only that soil levels are 430x above normal, which presents an alarming figure. This article is then picked up by smaller networks and outlets, such as Village Voice, that reports a news snippet which states “Japan records soil levels 430x above normal 25 miles away”. The ultimate effect is that western readers receive a greatly amplified report of the disaster.

On March 23rd, based on analysis, Bernie Rano reports in a live interview that “There will be no big impact at all in the United States. This is not damaging radiation in the US.” The Daily Show with Jon Stewart, on March 23rd, catches Nancy Grace (CNN reporter) declaring his entire scientifically-based report as “magic”, when his actual words are “this is science, it is not magic”. How have we arrived at a point where news reporting celebrities with no real knowledge have the right to openly defy independent experts? When experts, defined here simply as those who have actually studied the problem, cannot speak above the background noise of news commentary there is little hope for a coherent picture of reality. Feel free to view the full episode here: http://www.thedailyshow.com/full-episodes/wed-march-23-2011-richard-lewis

Despite current media fluctuations, one can have hope in the future that clear thinking, taken at the proper pace (and perhaps combined with data visualization), can provide the context that allows us to distinguish reality from fiction and to eventually determine the proper perspective on current events.



Radiation Comparison  (March 17th, original post)

This map was created to provide a visual way to communicate risks associated with radiation dosage.

All units are converted to mSv/h. Typically, background radiation, chest CT scans, and food levels are given in mSv/year (milli-sieverts per year). More extreme amounts of radiation, such as those found in nuclear disasters like Chernobyl are given in Sv/h (sieverts). To provide a basis for reasonable communication and comparison all units were converted in mSv/h on a logarithmic plot.

Nuclear Incident Levels are shown from 0 to 7, but keep in mind that specific events trigger an incident level rather than radiation dosage. Only at levels 1,2 and 3 are specific dosage limits set. An incident level of 5 was recently set for Fukushima based on melting of exposed nuclear rods.

At 1 mSv/h, cancer risk from radiation is 1 in 20,000 which is still well below the normal cancer risk associated with  other causes, 1:25. The onset of radiation poisoning starts at 100 mSv/h. Low level symptoms include itching and nausea, while high level symptoms include dimentia, hemmoraging and death within one day.

Comparison to Atomic Bombs

So far, these levels have only been reached at Fukushima within 100 meters of the unit cores. Distance falloff with radiation is shown in comparison to Chernobyl. Note that there are many other factors, such as prevailing winds, containment of the  core, and release of radiation by gas or dust, which will affect the distance profile of radiation exposure. In the case of atomic bombs, such as those released at Hiroshima and Nagasaki, the radiation is 30,000 mSv/h within the crater zone (<1 km). Atomic bombs produce an intense burst of radiation in less than one second, but this radiation is sufficient to cause death in a few days. Other effects, such as vaporization, intense heat and fire, and concussion, are greater causes of death within the immediate area of an atomic blast. Outside this area, the effects of fallout are much more significant as radiactivity is no longer isolated to a specific location, but carried in particles suspended in the air. Thus nuclear explosions, unlike the events of Fukushima or Chernobyl, carry much greater risk since sources of radiation is no longer localized.

Comparison to Chernobyl

In Chernobyl  the core itself exploded, releasing large chunks of the reactor core outside the containment vessel.  Radiation levels of 10,000 mSv/h were recorded outside the building, where workers used shovels to remove pieces of the radioactive reactor core without knowledge of the material. Since the core itself exploded, radiation produced fallout and suspended radioactive particles similar to a nuclear explosion (but less severe). This had the effect of spreading radioactive material away from the accident center. At Fukushima, the largest peak observed as of March 16th was 1000 mSv/h near the core. While fuel rods have been exposed to air, the release of suspended radioactive particles is much less than at Chernobyl.

Thus far, as of March 16th,  the maximum radiation dose at the Fukushima main gate is 11 mSv/h, which presents a cancer risk but is below the onset of acute radiation poisoning. Twenty kilometers away (20km), at the edge of the evacuation zone a level of 0.3 mSv/h was recorded. This is just above the  International Limit for Nuclear workers for a full year (100 mSv/year = 0.01 mSv/h. These levels would be severe if they were sustained, but the values recorded represent peak measurements over the past few days. Continuous exposure within the area of 20 km may cause health problems in the future, but is unlikely to cause radiation sickness based on the current status of the accident.

In areas as far away as Tokyo, 206 km,  residents and workers from other countries have been evacuating. Recently, countries including USA, France, Britain and Australia were instructing people to leave Tokyo ( http://news.xinhuanet.com/english2010/world/2011-03/17/c_13783578.htm). Is this need to evacuate Tokyo based on radiation from Fukushima warranted? Radiation falls off with the square of distance, so the amount of radiation in Tokyo will be an order of magnitude less than the 20 km evacuation zone. Recent news articles have indicated that radiation in Tokyo is twice the normal background radiation for the city. At first, this may seem significant. Normal background radiation levels in Tokyo were 0.00004 mSv/h. As of March 18th, radiation levels due to Fukushima have been recorded  as high as 0.00012 mSv/h, three times background.

However, background radiation in certain cities in Iran, India, China and Brazil are recorded at 0.006 mSv/h, which is fifty times higher than the radiation recorded in Tokyo due to Fukushima. Thus, if one is evacuating from Tokyo to any of these places, exposure will increase because of where one is evacuating to.  Considered another way, smoking cigarettes produces greater radiation exposure than that produced by the effects of Fukushima in Tokyo. Of greater concern is the possibility of individual radioactive particles themselves being relocated to Tokyo by importing them in clothing or hair from people inside the Fukushima evacuation zone. Hopefully, measures are being taken to screen residents coming from areas closer to the nuclear plant.

Comparison to Three Mile Island

A recent news article in CNN declared “Fukushima on par with Three Mile Island”, with the implicit subtext that Three Mile Island was the worst disaster in US history, so therefore Fukushima must be very serious. What this fails to address is that Fukushima is significantly worse in many ways. They are similar in that loss of coolant and backup cooling has led to increasing decay heat in a nuclear reaction which has automatically shutdown, but in many other respects they are very different. First, only one reactor at Three Mile Island experienced a partial melting of the fuel rods, while all four out of six independent reactors at Fukushima are undergoing partial fuel melting. Second, the events at Three Mile Island were entirely contained within the reactor vessel, while in Unit 4 at Fukushima a fire was reported in a spent fuel pool outside the primary reactor container. Third, at Three Mile Island, the build up of pressure resulting for lack of coolant led to a moderate internal explosion inside the building, while at Fukushima in Units 1 and 3 the hydrogen explosion was powerful enough to blow the concrete top off the buildings. Fourth, in both accidents it was necessary to release the vessel pressure by venting to the outside air – this is the most significant factor contributing to public exposure to radiation. At Three Mile Island, a single core was vented once (as far as my sources say), which resulted in a voluntary evaluation of the surrounding area. At Fukushima, several cores have been vented multiple times thus far, and a mandatory evacuation has been called for up to 20 km. Ultimately, at Three Mile Island, it was learned much later that 50% of the rods have melted, while at Fukushima it has already been reported that 70% has melted in reactor Unit 1 and 30% in reactor Unit 2.

On the positive side, in all four reactors the radioactive fuel rods are still contained within their primary vessels – which was not the case at Chernobyl. Based on news reports, I am strongly tempted to say that the media is attracted to equivalent comparisons with Three Mile Island because it likes to focus on the sufferings of westerns more than those around the world, or the history of Three Mile Island – or perhaps there is still a significant amount of pressure to downplay the seriousness of the events at Fukushima. At present, however, I would agree with the International Nuclear Event scale rating Fukushima at Level 5, “accident with wider consequences”, which resides above Level 4 at Three Mile Island,  ”accident with local consequences”, but still well below Level 7 at Chernobyl which was a “major accident”.

Another positive aspect is that the response at Fukushima is probably much more adequate than either Three Mile Island or Chernobyl. Nuclear standards and procedures are much more detailed now than before. Instrument panels are better designed now, which was one of the primary factors contributing to the Three Mile Island incident. The danger of radioactive materials is known, so that rescue workers and fire teams know what they are dealing with; problems that were not addressed well at Chernobyl. The fact that three reactors have partially melted with loss of cooling to all of them, yet there has not been any containment breach yet, is practically a marvel of management of limited human and material resources. Of course, it would have been nice if the reactors could be designed to be automatically cooled in the event of a power loss, but I’m no nuclear engineer. These are the dangers of fission-based nuclear power. Personally, I’m looking forward to fusion, which is an inherently stable power souce (See: http://en.wikipedia.org/wiki/National_Ignition_Facility and http://en.wikipedia.org/wiki/ITER)

The Fukushima incident is clearly a cause for concern. As the events unfold, the question is whether the peak radiation levels will go much higher than the 8000 mSv/h currently reported near the core. This level already represents a significant radiation incident, which places Fukushima along side other major nuclear accidents. To achieve the same status as Chernobyl, however, levels would have to be at least ten times higher than the current peak, which is unlikely to happen unless there is a core meltdown or explosion as there was at Chernobyl. At present, fuel rods are still contained within the core. For the sake of those in Japan, and the immediate area, we can hope the radiation levels will not go any higher.

Fukushima Accident Events

The map above also shows specific events that took place after the start of the crisis. Data for on-site measurements of radiation levels were taken from TEPCO Press Releases, March 17th (http://www.tepco.co.jp/cc/press/betu11_j/images/110317e.pdf). The timing of events are from several sources listed on the Wikipedia page for Fukushima I Nuclear Accident.

Interestingly, the times of particular events such as hydrogen explosions, pressure increases, fires, and cooling failures do not coincide with any of the peaks in the radiation levels. In fact, none of the events corresponds with a peak. There could be several causes for this. First, the times of events may be reported incorrectly. While the time of the hydrogen explosions is likely to be exact, since these are such noticeable events, times reported for cooling failures and fires may be inexact due to the nature of these events. Often, in the wikipedia article reporting these events, as single source is used as the only citation for a particular event in several locations in the article. Thus, one may suspect that times reported by the news agencies themselves are possibly inaccurate. Only after a thorough analysis could we be sure that the news is presenting correct data based on its own sources.

The main cause  for a lack of coincidence between events and radiation peaks is likely to be the underlying physics at the site. A cooling failure is unlikely to be a peak, since it represents the start of the problem. A hydrogen explosion may also not be a radiation peak, since it does not directly release radiation. A fire, such as the one that occurred in the fuel pool in Unit 4,  is a more likely source of a direct radiation, but this is difficult to correlate due to the nature of fires. The only event in the graph that does correlate with radiation release is the intentional release of pressure, which is necessary to keep the core from exploding.

Needless to say, an uncooled, partly controlled nuclear reaction is a complex phenomena. The data presented in the map above is all the more complex because it represents the activities at four nuclear unit simultaneously, each at different distances from the recorded data location (main gate). There are likely main different phenomena taking place within these cores which could not be fully understood without computer simulation. The many other peaks in the graph have no correlation to reported events thus far. I find it interesting that several curves show a particular profile, with a sharp peak followed by a gradual falloff of a specific shape. A question for a physicist would be, how do you explain the profile curve of these events, and would it be possible to simulate or even predict the overall data curve based on the events that took place? If so, this would be a useful tool for estimating the effects of other incidents similar to Fukushima.

45 Responses to “Fukushima Radiation – Comparison Map”

  1. David Winsemius says:

    You may want to update with material from http://www.tepco.co.jp/nu/monitoring/index-j.html

  2. Xerxes314 says:

    Hi, RC. I like your graph. I made the previous version that yours replaced; I can send you the data for later times if you’re interested. However, I think there’s a mistake in your calculation of radiation at high altitude. My impression is that the radiation in a jet is about 20x background. Even astronauts in the ISS only take about 100x background. Perhaps you’ve substituted a milli where you meant micro? You can respond on my Wikipedia talk page if you like (the e-mail is rarely checked).

  3. admin says:

    Yep, you’re right. Thanks for the observation. I found a chart of altitude that indicated micro-sieverts, not milli-sieverts. I’ll change the numbers asap. I’m interested in the data you speak of. Will contact you over on wikipedia.

  4. Martin Gotthard says:

    Very impressive. I hope you manage to get the data for later dates into this graph to show the progression of the emergency situation. I’ve been on Wikipedia and various news sites daily since this started, and as a scientist the dearth of hard information has been really frustrating.

  5. Equityval says:

    This chart is fantastic. I hope you have time to update it. Putting it all into a meaningful perspective is important and almost impossible given how the press glosses over the details.

  6. admin says:

    Thanks. I just did another one here on Tokyo low level radiation, data up to March 21st:

  7. Rena says:

    I ran across this link and am wondering if these measurements are incorrect?
    For example, 715.4 nSv/h at 22.03.2011 9:27 pm Momiyama Hokota City, Prefecture of Ibaraki


    The link appears to be coming from the RSOE Emergency and Disaster Information Service
    website in Budaphest, Hungary:

  8. andrew says:

    awesome figure, really makes you want to see those line plots going down again.

  9. admin says:

    Check the units on the Hokota city map. If those are nano-sieverts/hour, then its probably correct. It may also be correct with micro-sieverts/hour. It is definitely not milli-sieverts/hour, which is shown in the graph above.

  10. Robert Macrae says:

    My compliments on a highly informative chart.

  11. John says:

    A really great and informative chart! Thank you.

    I have a little finding on the “by distance”-graph. The data points are not placed correctly on the x-axis, see “20km Fukushma zone” being on the left side of the “10 km” mark, rather than a little to the right.

    Also the sheet has been updated on 17th the last time. this is now a whole week ago. Could you pleeeease update it again to reflect the lastest (manipulated official) readings? Thanks!

  12. admin says:

    Thanks to everyone for the comments. I have been teaching classes this past week, so I apologize for not having updated the data yet.

    If anyone has links to the recent data, up through the present date, please send me a link and I will incorporate new data asap.

    Thanks -Rama

  13. Fabrice says:

    Hi Rama,

    Enjoyed the reading. There is data available from this website:
    http://park18.wakwak.com/~weather/geiger_archives.html. the FAQ is in english. I have been monitoring the data on a daily basis from Tokyo. Based on Mr Ishikawa information, we stand roughly at 1.6mSv/year over the past week.

  14. John says:

    Perhaps here? Also has a nice overview of sensor-placement:

    How to send you data sources without using this comments area?

  15. admin says:

    Thanks.. A link is easiest. I will take a look at these when I have a chance. If its not too much (<5 MB) you can send by e-mail also: [email protected]


  16. hank says:

    NIce, updated data from Fukushima are available at the German GRS (a German Association for Nuclear Safety)
    there is a nice plot
    and various updated stuff (but only in German) http://www.grs.de/informationen-zur-lage-den-japanischen-kernkraftwerken-fukushima-onagawa-und-tokai

  17. James Pritchard says:

    This is one of the best, most informative graphics I’ve seen. Very comprehensive!
    Thanks for creating and sharing this chrat.
    Best wishes.
    Jim Pritchard (Engineer)
    Chapman, Maine.

  18. anonymous says:

    in the radiation effects section i think you meant to write “dementia”

    its a fantastic graph btw, though I guess I prefer pictures of a hand-drawn mercury redstone rocket

  19. John B. says:

    Thank you for your work and communication.

    Where you wrote “resulted in a voluntary evaluation of the surrounding area”, should that be “voluntary evacuation”?

  20. Brian O says:

    Please update with an extended timeline! Thank you for your efforts to communicate the risks in a way understandable to the general populace. I hope you might also indicate other incidents with human impacts familiar to a general audience such as the radiation exposure for the unfortunate Tokaimura workers and lighter exposures, such as those US army personel present at Trinity and other pacific or other A-bomb tests — in these cases with the ratio of increased cancer risk, if statistically known.

  21. admin says:

    Thanks for all the feedback!
    Due to all the responses I’ve gotten, I’ve decided to work on an updated map. Hope to have something in a few days. I will post it here and on wikipedia when finished.

  22. KitemanSA says:

    Could you add something about 3MileIsland in your chart? I think it would be great in the dose vs distance segment.

  23. admin says:

    I’d like to include distances levels for Three Mile Island, but the only value I was able to find is 1 mSv/year as the maximum dose. If you know of any reliable sources of data for Three Mile Island radiation at several different distances, I’d be happy to include it (at least 3 for a distance line). I think such data may be hard to come by because the levels are so low.

  24. Eugenio says:

    Great job. An excellent example of data visualization.

    A question: what do you mean with \"normal cancer risk from other sources\", and why it is higher?

    And: what tools did you use?

  25. admin says:

    I found a source that said the average lifetime cancer risk is 1:25. I can’t seem to locate the source now, but I’m going to take this out in the next version anyway, as cancer risk is so variable.

    The visual design tools were Photoshop and Adobe Illustrator, with most of the graphic design taking place in the latter. A Perl script was used to parse the data, and MS Excel for the plot.

    I look forward to having an updated map by next week.

  26. Tom H says:

    Brilliant & Creative!!
    I have seldom seen data presented in such a clear and succinct manner!
    PLEASE create an update to include later dates, especially now since it appears one of the containment vessels may have been breached.

  27. John says:

    Aaah, great! How about an SVG-version? Smaller file size and as a vector file format the image would be scaleable while retaining perfect antialiasing

  28. admin says:

    I am pleased to announce that a new, updated map and commentary are provided above!
    Please see the updated text above for a more detailed look at what the new map shows.

    Thanks to the support of readers for providing suggestions and links to data.

    (High resolution versions can be provide, if desired, as the zoomed jpg map above was posted through WordPress which only allows uploads <2 MB.)

  29. Craig K says:

    Your new chart is very informative. Many thanks!
    And I especially agree with a comment you wrote in your blog: “How have we arrived at a point where news reporting celebrities with no real knowledge have the right to openly defy independent experts?”
    I have completely given up on mainstream news sources except as a source of humor or irony :(

  30. John says:

    Wow, that chart is amazing!
    It is also becoming very colorful and I sometimes have to pay attention not to get lost between the different associations of e.g. blue.

    How do size and color of the circles correlate? Are these two dimensions (size, color) for one value (Sv) ?

    What do me the maps on top tell?

    Again, this is a great work and a fabulous data visualization example.

  31. admin says:

    Thanks. The size and color of circles both represent mSv/hour, and correspond with the values on the large vertical bar to the left. The whole map is based on this unit of measure for radiation.

    The geographic maps tell how radiation has changed at different locations across Japan over time. I am hoping to make a video, since there is a lot more data than you’re seeing here. But these maps do show how the radiation is carried in the air over time to nearby towns and cities.

  32. submandave says:

    Well done. As a former nuke worker I appreciate your efforts to accurately present a bad situation with proper perspective and scale. I, too, got sick and tire of all the “1000X normal” reports with noone either saying what “normal” was or comparing the levels in terms the public would understand.

    WRT your vertical axis, it seems you sometimes conflate dose rate with dose. For example, while the LD50/30 dose of ~ 4Sv must be received acutely to have this effect, it may be received over a period longer or shorter than an hour, depending upon the local dose rate. People should understand that old mantra of “time-distance-shielding” and how total dose depends not only upon rate but stay-time.

  33. admin says:

    Thanks, submandave. Although I’m no expert, I did what I could to convey differences between time and distance. Showing the difference between dose rate and dose was more difficult. I tried some plots with dose rate on x-axis, and dose on y-axis, but those seemed less clear. In the end, while some media reports mixed them all up, I decided to standardize all rates to mSv/hour even though a high, short dose is still different from a low, long one. I did my best with this map, while the concepts of time-distance-shielding are not easily conveyed. I’ve learned more about radiation myself this past three weeks than ever I thought possible. As with anything, experience is the best way to get to know something.

    (Note to readers: The US EPA defines safety guidelines for nuclear workers based on time-distance-shielding, which can be found here, http://www.epa.gov/rpdweb00/understand/protection_basics.html)

  34. Howard Dickson says:

    I would like your permission to post the March 30 Radiation Comparison graphic on the Health Physics Society website (www.hps.org). The Health Physic Society is an organization of radiation safety professionals and our website attempts to bring pertinent radiation safety information of this sort to the attention of our members and the public.

    Thanks for your prompt consideration of this request.

    Howard Dickson
    Web Operations Editor-in-Chief

  35. admin says:

    Permission granted. Actually, you don’t need my permission as this is in the public domain, but thanks for asking. Please feel free to use in whatever way you like. I’m glad that it will be used by the Health Physics Society.

    Rama Hoetzlein

  36. Matthew says:

    Wow. Just shows what can be accomplished with a combination of an accomplished graphic artist who also has an obvious sideline in science.

    Almost too much information; like that mapper who detailed Napolian’s retreat from Moskow.

  37. tom says:

    Be nice if you could fix the error concerning radiation exposure. The chart confuses the rate of exposure versus total exposure. Apart from acute effects (massive cell death), only the latter matters long term (eg for cancer, genetic damage). If I were exposed to 1000 millisieverts/hour for a nano-hour, little harm would come to me — a millionth of a millisievert (gamma ray equivalent of adsorbed ionizing radiation) — which adds little to my annual background adsorption of 3 millisieverts per year. The total exposure limit for Fukushima workers was reset without any basis by Tepco from the international standard of 100 to 250 millisieverts in a year. One way of fixing this is to have a second column showing the number of hours at a given millisievert level that would suffice on an annual basis to reach 100 millisieverts. Thus 100 mSv on the existing column would line up with 1 hour on the yearly doseage allowance.

  38. admin says:

    I tried a map in which I did that. But the correlations don’t appear very clearly because of the extreme timescales involved, i.e. nano-sec, hour, year. There are no intermediate measures for say 1 mSv/8 months, so the data just falls into three dense columns which is hard to see.

    Regarding the 1000 mSv/h for a nano-hour you mention, this is resolved in the map as follows. What you’re really saying is 1000 mSv per nanohour. This is not equal to 1000 mSv/h, but must be converted to mSv/h to be correct.. So, it would correctly appear in the map as: 0.000001 mSv (10^3 mSv/nanohour * 10^-9 nanohour/hour). This kind of conversion was done for all values in the graph. So although dose rate is not shown, it does correctly report different dose-level-durations. ** UPDATE: See new comments below.

  39. Jay says:

    Let’s not forget that the effects of radiation are in fact cumulative both in the atmosphere and in the human body. Most of us are sitting on the edge of radiation poisoning, even without Fukushima as evidenced by overbooked oncology clinics filled with those who are not long for this world and cancer statistics through the roof. Fukushima will not be recovered or diminished in effect before it has so poisoned the Northern Hemisphere that it becomes unlivable. Even tiny doses of radiation from a nuclear reactor are extremely dangerous. But North America is getting far more than just a tiny dose and we are being lied to even about that.

  40. Joe says:

    Jay, while some of what you say is true (radiation is at least somewhat cumulative, etc.), you are also making mountains out of mole hills with your massive amount of paranoia about Fukushima.

    1) Chernobyl released WAY WAY WAY more radiation (see graphs) and GREATLY affected large populated areas of the USSR (Russia/Ukraine).
    2) Compared to the ridiculous number of atmospheric tests of nuclear weapons in the 40s, 50s, and 60s (and the two bombings of Hiroshima and Nagasaki), Fukushima is again quite tiny.

    It’s not to say that Fukushima isn’t serious, because it is very serious, it’s just not the end of the world.

    Also, if you look at the charts that the author so kindly put together at the top of the page, you will notice that most people recieve < 1/100,000 of the amount that they would need to get cancer from radiation. You are MUCH more likely to get cancer from bad genes (ex. BRCA1, BRCA2), exposure to chemicals (ex. benzene, smoking), birth defects, and viral attack (ex. HPV). Unless you lived near Chernobyl, Nagasaki, Hiroshima, Goiânia, or near some other nuclear blast or worked in a nuclear cleared facility or have been treated with nuclear medicine, you are VERY unlikely to suffer from radiation poisoning before you die from something else (like heart disease or nonradiation induced cancer).

  41. Brian says:

    Congratulations – that is just about the most information-dense yet readable presentation of complex information I’ve seen in a long time. If only the newspapers were capable of treating us to such informative works of art, rather than just pretty graphics, we would all be better informed. I’ve been looking at it for over 10 minutes and am still getting new information from it. Superb!

  42. Myzak says:

    I am writing to ask for your permission to use the March 30 Radiation Comparison graphic for my thesis. I’m a radiologist and writing a thesis of Fukushima nuclear accident. I’ll post the thesis on The 70th annual meeting of Japan Radiological Society website.( http://www.secretariat.ne.jp/jrs70/)
    The Japan Radiological Society is an organization of radiological professionals and this website makes pertinent information sharing for our members.

  43. admin says:

    Yes, you are welcome to use the graphic for any use.

    To provide a caption or citation, here is the preferred way:

    Hoetzlein, R. Fukushima Radiation – Comparison Map. Created by R.Hoetzlein, March 2011. Image is in the Public Domain. Retrieved from: https://rchoetzlein.com/theory

  44. Jon says:

    RC Your explanation of your values on 9 April is in error. That’s like saying if you went 60 miles/hr for 1 minute you are really going 60 miles/minute and then your conversion multiplies instead of dividing which in this case would be like saying 60 miles/minute * 1/60 hr/minute = 1 mile/hr. i.e. this some how says 60 miles/hr for 1 minute is really 1 mile/hr.

  45. admin says:

    There was a minor calculation error which was fixed above (0.000001 mSv had too many zeros). It is now correct above. The overall argument is still valid.
    Here’s why:

    When someone says “1000 mSv/hr for 1 nanohour”, or alternatively “60 miles/hr for 1 minute”, what they mean is a rate during a duration of time. We can use the D = ST formula (distance-speed-time) as follows:
    distance = speed * time (or..)
    dose = dose rate * time

    This gives us:
    60 miles/hour * 1 minute = 1 mile
    1000 mSv/hour * 1 nanohour = 0.000001 mSv

    In both cases, the time units must be properly converted to allow for the multiplication.

    However, your comment helps me to understand that what the chart shows — what was calculated — is effective dose, or mSv, and not dose rate (mSv/hour). Although the chart says mSv/hour, what this means is, take some dose rate (background, CT scan, brief spike), assume you receive it over 1 hour of time, what is the effective dose. I’ll fix the unit description in the map ASAP.
    The calculation from 1000 mSv/hour over 1 nanohour into 0.000001 mSv is still correct.

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