Measurement results of radiation and radioactivity levels in Tokyo

The Tokyo Metropolitan Institute of Public Health monitors environmental radiation doses throughout the year.

In response to the accident at TEPCO's Fukushima Daiichi Nuclear Power Plant in March 2011, we have posted the latest measurement results of radiation doses in the air and radioactive material levels in tap water and fallout (dust and rain) on this website, in order to relieve health concerns among Tokyo residents.

Radiation doses in the air (latest)

Measurement at monitoring posts

21:01-22:00 Wed., 24 Apr (average value)

Shinjuku 0.0439
Koto 0.0367
Ota 0.0398
Adachi 0.0390
Edogawa 0.0511
Hachioji 0.0352
Chofu 0.0368
Kodaira 0.0347

Radiation dose per hour (microgray=µGy)

* 1 gray (Gy) of radiation dose in the air can be converted to 1 sievert (Sv).
* Three significant digits are indicated.
Dose of Radiation in the World

The dose of radiation in Tokyo is comparable with that in major cities in the world.

Radiological Monitoring data in the Major Cities

City Dose of Radiation
(uSv/h)
Date of measurement
New York 0.046 23 Jan.,2018
Paris 0.043 15 Oct.,2017
London 0.108 24 Jan.,2018
Beijing 0.070 25 Jan.,2018
Latest Radiological Monitoring data in the Major Cities (Japan National Tourism Organization)
Monitoring sites
Shinjuku Hyakunincho, Shinjuku-ku (Tokyo Metropolitan Institute of Public Health)
Koto Aomi, Koto-ku (Tokyo Metropolitan Industrial Technology Research Institute)
Ota Haneda Airport,Ota-ku
Adachi Toneri Park, Adachi-ku (Metropolitan Toneri Park)
Edogawa Kami-shinozaki, Edogawa-ku (Metropolitan Kami-shinozaki Park)
Hachioji Minami Osawa, Hachioji-shi (Tokyo Metropolitan University)
Chofu Nishi-machi, Chofu-shi (Chofu Airdrome)
Kodaira Nakajima-machi, Kodaira-shi (Tokyo Metropolitan Medical Plant Garden)

Monitoring posts in Shinjuku, Ota, Adachi, Hachioji and Chofu have been established at the request of the Ministry of Education, Culture, Sports, Science and Technology.

Monitoring posts in Edogawa and Kodaira have been established by the Tokyo Metropolitan Government’s Bureau of Social Welfare and Public Health, and the one in Koto by the Industrial Technology Research Institute.

Only the monitoring post in Shinjuku has been collecting data since before the Great East Japan Earthquake.

Examination results of radioactive materials in tap water (latest)

Unit: Bq/kg

Sampling date/time lodine Radioactive cesium
131 134 137
24 Apr.,2019 ND(not detectable) ND(not detectable) ND(not detectable)
23 Apr.,2019 ND(not detectable) ND(not detectable) ND(not detectable)
22 Apr.,2019 ND(not detectable) ND(not detectable) ND(not detectable)

Examination results of radioactive materials in fallout (latest)

Unit: Bq/kg

Sampling date lodine Radioactive cesium
131 134 137
15:00, Mon., 22 Apr. - 15:00 the following day ND(not detectable) ND(not detectable) ND(not detectable)
15:00, Sun., 21 Apr. - 15:00 the following day ND(not detectable) ND(not detectable) ND(not detectable)
15:00, Sat., 20 Apr. - 15:00 the following day ND(not detectable) ND(not detectable) ND(not detectable)

Measurement at 1 meter above the ground (latest)

Measurement results of radiation doses in the air at 100 locations in Tokyo (Jun. 2011)

June 24, 2011
We zoned the entire Tokyo area and in principle measured radiation doses in the air at one location in each zone.

Examination results of radioactive materials in soil

Measurement results of radiation doses in the air in the mountains in Tokyo (Oct. 2011)

Examination results of radioactive materials in foodstuffs and beef distributed in Tokyo

Examination results of radioactive materials in agricultural and livestock products/fishery products, etc.

Radioactive Material Examination Results for Ocean Swimming Areas

Examination results of radioactive materials in raw tap water, Etc.

Links to pages showing radiation measurement results

Links to related information

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