radiation in the air

Hello, I am Japanese and living in Japan. After Fukushima nuclear plants accident, a lot of information about radioactivity are diffused.
I am going to write about such a things.
It is a strange time. Something is the first thing we human being are facing clearly. But the other would be the same old story.

First of all, as I am a timid jellyfish, I looked for a good information which made me feel secure. Yeah!  I got it. Environmental radiation levels in Tokyo is lower than some cities of China. (at 2011/03/30). Did China have nuclear plants accidents recently? Nope, maybe...

Environmental radiation levels is measured by the unit "sievert (Sv)" or "gray(Gy)". The unit gray shows the absorbed radiation(I am sorry I don't know what it mean). The unit sievert shows how much human being are affected by the many kinds of radiation in the air. Roughly speaking, 1 gray = 1 sievert.

As of 2011/03/31
Beijing 78.6 nGy/h (12:00-15:00)
深圳市 106.0 nGy/h (12:00-15:00)
Tokyo 0.103 μGy/h = 103 nGy/h (14:00-14:59)

Environmental radiation levels at Tokyo

Environmental radiation levels at many cities in China