So far, through the entire crisis at the nuclear power plant in Fukushima, radiation levels in Tokyo have not come close to dangerous levels to human health. They would have had to increase more than a thousand-fold to have done so so far. Once again, the radiation levels at Tsukuba dropped yesterday. The levels are well within range of pre-quake levels. (For a comparison of current radiation levels and pre-quake levels in Shinjuku, see here: http://modernmarketingjapan.blogspot.com/2011/03/radiation-levels-in-shinjuku-tokyo-from.html)
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This chart is updated daily and hourly from the Advanced Industrial Science and Technology Unit in Tsukuba (Tsukuba is between Tokyo and the accident site at Fukushima. It is about 75 kilometers north of Tokyo, and 150 kilometers south of Fukushima). It is an updated hourly summary of radiation measured in
Here is an chart from the National Institute of Advanced Industrial Science and Technology's National Metrology Institute of Japan webpage. It shows what typical radiation levels (measured in are in our daily lives:
At the bottom left, you see the mark of 190. That's the amount of radiation you get on a one-way flight from Tokyo to New York. Above that, you see the number 2400. That is the amount of radiation that a person gets annually from nature. At the top left is the number 10000. That is annual radiation amount a person who lives in Karapari City in Brazil gets. At the top right, you see 6900, that's the amount of radiation you get from a CT scan. Bottom right? That's 50, the amount a person receives from one X-ray.
As you can see, there is absolutely no radiation risk in Tsukuba and Tsukuba is much closer to the accident site than is Tokyo. One gets a much bigger dose of radiation flying from Narita to New York. In fact, at 0.05 microSv per hour, you would have to be standing outside in the elements everyday for nearly 158 days straight to equal the amount of radiation you'd receive on just that single one-way flight from Tokyo to New York.
If you are interested in the radiation rate currently in Shinjuku in downtown Tokyo, see here:
今日の東京 新宿区人形町での放射線測定記録 (