tag:blogger.com,1999:blog-5056599210263969567.post3686355787341489443..comments2024-01-23T03:52:54.149+09:00Comments on Anne Kaneko's Fukushima Blog: Airborne Radiation 1Anne Kanekohttp://www.blogger.com/profile/09520490908508371344noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-5056599210263969567.post-24067421036287717102013-08-23T17:56:15.218+09:002013-08-23T17:56:15.218+09:00Thank you so much for your comments. It's real...Thank you so much for your comments. It's really good to hear from someone who knows their subject. I thought the '100 mSv' causes cancer' was one of the few generally agreed facts so it's interesting to hear of new research which proves otherwise. I like your final comment!<br />If you don't mind, I'll draw people's attention to your comment in my next post (23 August)<br />Thanks for your support.<br />AnneAnne Kanekohttps://www.blogger.com/profile/09520490908508371344noreply@blogger.comtag:blogger.com,1999:blog-5056599210263969567.post-28096038219787251102013-08-19T05:08:26.694+09:002013-08-19T05:08:26.694+09:00Hi, Anne -- Sorry, I haven't had time to visit...Hi, Anne -- Sorry, I haven't had time to visit your blog in quite a while. I continue to be amazed at the amount of work you're putting in to keep this up, and the quality of the writing and photos. Well done.<br /><br />One issue, though. At the beginning, you say "100 millisieverts (...) [can?] cause cancer." Actually, we don't know that. The RERF says that the "association remains unclear" between dose and cancer risk below "around 100 to 200 mSv":<br /><br /> http://www.rerf.or.jp/rerfrad_e.pdf<br /><br />If (and that's a big "if") the linear no-threshold hypothesis is correct, 100 mSv all at once increases your cancer risk by 1% in absolute terms, which is 5% relative because the background risk is about 20%. But the risk from 100 mSv over a period of many years is "speculated by scientists to be smaller".<br /><br />That is no longer speculation. It has been shown, by direct observation of the cellular repair processes induced by radiation damage in living cells, that those processes work better at low-rate doses but can be overwhelmed by high doses,<br />so the response is clearly not linear:<br /><br /> http://newscenter.lbl.gov/news-releases/2011/12/20/low-dose-radiation/<br /><br />I would also like to give some details of how the monitors you're using work and what their limitations are.<br /><br />The Horiba PA-1000 is a scintillation counter, meaning it contains a material that emits light when struck by radiation. Electronics then counts the flashes of light.<br />It records a running average of the rate of flashes over a minute, so it is a short-term reading.<br /><br />By contrast, the "glass badge" is a long-term average. It works by clever addition of impurites (silver) to the glass, which works in a way somewhat analogous to photographic film. Radiation causes stable "trapping sites" to occur in the glass. Later exposure to ultraviolet light causes fluorescence which can be measured to determine the overall total radiation exposure. Unlike film, the glass badge can be reset and reused by heating to 400 degrees C.<br /> <br /> http://www.intechopen.com/download/pdf/22740<br /><br />But rather than talking about the differences between small numbers, maybe it would be more useful to try to keep the whole thing in perspective. I like this site, because about 60% of the way through, it compares radation risks to other common activities. Unfortunately, they use the older mR (milliRem) unit. To conver milliRem to microSieverts, multiply by 10. So 10 mR = 100 uSv.<br /><br /> http://www.umich.edu/~radinfo/introduction/risk.htm<br /><br />So roughly 1/4 uSv/hr means 400 hours (16 days) to reach 100 uSv, which under LNT is a one-in-a-million chance of dying of cancer. But living in NYC for 2 days is also a one-in-a-million risk, due to air quality. So you're eight times safer where you are, post-accident, than being in NY. :)<br /><br />Assuming Tokyo and NY aren't so much different, say within a factor of two on air pollution, this also suggests that the people of Tokyo would be safer moving to Koriyama and soaking up 1/4 uSv/hr rather than staying where they are and breathing Tokyo air. Of course, if they all did that, Koriyama wouldn't have such nice air anymore... :)<br />DiogenesNJhttp://nuclearenvironmentalist.wordpress.comnoreply@blogger.comtag:blogger.com,1999:blog-5056599210263969567.post-46805575449291064142013-07-30T07:48:31.294+09:002013-07-30T07:48:31.294+09:00Thank you for the up date on radiation levels, but...Thank you for the up date on radiation levels, but I must say I lost my £5 bet at the local bookies, I just cant understand why "tahj" was not given to the new baby.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-5056599210263969567.post-12853333791139640132013-07-24T16:44:46.704+09:002013-07-24T16:44:46.704+09:00The calculations used here in Japan after the acci...The calculations used here in Japan after the accident are based on being 8 hours outside and 16 hours in a wood construction house. That's how you get 0.23. As I've said in an earlier post that's completely unrealistic - people have different lifestyles, on different days - so a better method is to have everyone wear a dosimeter and work out which people are at risk. Focusing on people rather than places. As you know, I'm convinced there is no risk in Koriyama. But it's still stressful.<br />Thanks for your interest. AnneAnne Kanekohttps://www.blogger.com/profile/09520490908508371344noreply@blogger.comtag:blogger.com,1999:blog-5056599210263969567.post-48993504905058633842013-07-24T10:31:59.246+09:002013-07-24T10:31:59.246+09:00Interesting post, thanks.
You said that 0.23 mic...Interesting post, thanks. <br /><br />You said that 0.23 microsieverts/hour equates to 1 millisievert/year but I don't think that's right. According to my calculations, 0.23 uSv/hr x 24 x 7 x 52 is about 2 millisieverts/year.<br /><br />I know that some of the readings might have been concerning when compared to places like London, for example, but compared to Cornwall, which has an average annual dose of 7.8 mSv/year (or 0.89 uSv/hr), even the highest readings you had are much lower than that.<br /><br />http://www.hpa.org.uk/Topics/Radiation/UnderstandingRadiation/UnderstandingRadiationTopics/DoseComparisonsForIonisingRadiation/<br /><br />I'm sure you're well aware of this anyway and it doesn't stop it from being stressful. Thanks for your posts, I always read with interest.wrightakhttps://www.blogger.com/profile/04845581219533119941noreply@blogger.com