In an effort to encourage evacuees to return, the Minami-Soma government dispensed 100 portable dosimeters to 25 city employees in Minami-Soma, Tajimi in Gifu Prefecture, Fukuyama in Hiroshima Prefecture and Nanto in Toyama Prefecture. The employees were asked to carry the dosimeters and measure their external dose to radiation in the environment:
Shintaro Egawa (2017, September 5). Fukushima city shows radiation level is same as in west Japan. The Asahi Shimbun, http://www.asahi.com/ajw/articles/AJ201709050042.htmlThe claim relies on dosimetric readings, which have some fundamental limitations, in particular, related to detection of tritium and "hot particles," which under normal circumstances are very difficult to detect with a dosimeter, especially if embedded in food, water, and biological bodies.
The median value of the external radiation dosage of the 25 staff of Minami-Soma was 0.80 millisieverts per annum, while the average value was 0.82 mSv per annum, according to Masaharu Tsubokura, the head of the committee and a physician at Minami-Soma general hospital. No significant difference was found in the three western cities.
Both figures were adjusted to include the natural radiation dose, and are below the 1-mSv per annum mark set by the national government as the acceptable amount of long-term additional radiation dosage, which is apart from natural radiation and medical radiation dosages.
I wonder how many hot particles, tritium and noble gasses spew into the atmosphere each day from Fukushima's ruined reactors?