Excessive Radiation Exposure to Tokyo Population on March 15

Kyoto University Nuclear Researcher Hiroaki Koide's Radiation Data for Tokyo Population on March 15
Kyoto University Radiation Researcher Hiroaki Koide's table of radiation exposure in Tokyo on March 15

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 

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.

Monitoring post in Setagaya, Tokyo [pdf]

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 

The following video streams show Koide’s testimony (in Japanese only – no subtitles) at the House of Councilors on May 23:
• http://www.ustream.tv/recorded/14906087
• http://www.ustream.tv/recorded/14907869

About the Author


Permanent foreign resident of Japan for over 30 years who is praying for a better future for this country which is also MY home.