Shinzo Kimura was a scientist with the Research Institute under the Japanese Ministry of Health and Welfare, and he did a survey on the health effects on the citizens of Narodichi, Russia after the Chernobyl accident. Right after 3-11 the Ministry pressured him not to publish any of his data and not to provide any information to the public. He quit in protest. As his wife is a medical doctor, they decided to stay in Tokyo. On March 15 he called several friends living in Tokyo with small children and told them to stay indoors to avoid radiation. Then he took air samples and sent them to Kyoto University Nuclear Researcher Hiroaki Koide for analysis. Later he left for Fukushima to do additional radiation measurements.
Here is a link to an NHK Special program in English language featuring Shinzo Kimura’s work
Koide analysed the data that he had received from Kimura but was told by Kyoto University (a Japanese national university) not to make it public, according to his testimony at the administrative committee meeting of the House of Councillors held on May 23. The data was published for the first time in this meeting which was aired on the internet, but amid information clampdown by the Government, the printed press and TV didn’t report it.
Analysis of the fallout measured during the period 11:14~12:14 in Taito-ku, Tokyo on March 15 was calculated into a 24-hour dose. See the main table above. The total becomes 2021Bg/m3 equivalent to 210uSv/day.
The analysis was presented at Koide’s university seminar class on March 18. See Page 13 of this PDF.
The Tokyo Metropolitan Government measured I131, I132 and Cs134, Cs137 in Fukazawa, Setagaya-ku, which were detected every hour on March 15. Their total readings for I131, I132, Cs134, Cs137 was 1247.8Bq/m3 equivalent to 141.9uSv/day.
Koide says that Kimura’s measurement data covers the radioactive particles collected, but gaseous nuclides could not be measured. He thinks that the total internal and external radiation exposure including gaseous nuclides was about 1mSv/day on March 15.
The following video streams show Koide’s testimony (in Japanese only – no subtitles) at the House of Councilors on May 23: