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東京在住のインド人の友人が調べたところ、「東京の放射線量は現在でも米国の半分以下」ということです。以下、了解を取って転記。

The media is all in a frenzy about radiation in Tokyo (currently averaging around 0.10 to 0.15 microsievert/hr)( http://ftp.jaist.ac.jp/pub/emergency/monitoring.tokyo-eiken.go.jp/report/report_table.do.html, I micro gray = I micro sievert). However I could not find any “benchmark” to figure out what this means (other than some data about how much one gets from a long distance flight or an X-ray scan – but then one is not flying or getting X-rayed all the time…)

So I decided to do some research on my own. Here is a report from USNRC (US Nuclear Regulatory Commission) – they should know what they are talking about.
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html
According to this, the average US radiation dose is 620mrem per year, or 6.2 millisievert (mSv) which is 6200 micro sievert. Of this half is due to manmade sources – so let us say this is 3100 micro sievert per year.

That would imply that the radiation level in Tokyo is actually LOWER than what the average US citizen is getting (0.15x24x365 = 1314 micro sievert/year).
 
And by the way, those of you who are planning to buy skiing cottages around Denver – you may be interested to know that due to a combination of high altitude and Uranium in the ground, the radiation levels there are 10,000 micro sievert / year (or 8x of current Tokyo level). And those of you who are flying out to avoid radiation, please keep in mind that aircraft flights deliver 6 micro sievert / hour of radiation – So the “break even” for a trip to New York (11hr flight from Tokyo) would be 37 days (i.e. you need to stay in NY for 37 days before you can justify the incremental radiation resulting from the flight). And this is of course assuming that NY natural radiation is zero, if – as per the NRC statistics above – it is already comparable to Tokyo – then there is no break even….

どこかに答えを求めるのではなく、こうやって自分で分析するのが｢インド式教育」ということなんでしょうね。