Homepage for Radiation Monitoring in Hokkaido

Survey Methods at Each Survey Site

*Radiation measurement methods and sites have changed as of April 1, 2012.

• Measurements are taken continually using the monitoring post of the Hokkaido Institute of Public Health building, at the request of the Ministry of Education, Culture, Sports, Science and Technology.
  You can see real-time monitoring results for sites throughout Japan, including Hokkaido, on the Ministry of Education, Culture, Sports, Science and Technology website (real-time radiation measurement system).
• The monitoring post for Sapporo measurements is on the roof (16m high) of the Hokkaido Institute of Public Health building (Kita 19-jo Nishi 12-chome, Kita-ku, Sapporo). Measurements for other regions of Hokkaido are taken around 1m above the ground at sites in each subprefecture.
• Measurements are taken over a period of ten minutes – for example, the 9:00 data is measured from 8:50-9:00.
  For details, see Monitoring Data from the Hokkaido Institute of Public Health.

• Air radiation levels are regularly measured at 22 sites around the Hokkaido Electric Power Co., Inc. Tomari Nuclear Power Station, in order to monitor environmental radiation in those areas. Click site names to view detailed results (links to the Hokkaido Nuclear Energy Environmental Research Center website.)

Units

• Measurements for the monitoring post are made in units of 1μGy/h (microgray per hour). However, measurements are converted using the formula 1μGy/h (microgray per hour) = 1μSv/h (micro Sievert per hour) and displayed in micro Sievert per hour on this website.
• m (milli) = 1/1,000; μ (micro) = 1/1,000,000; n (nano) = 1/1,000,000,000.

Other

• Radiation levels may temporarily increase on rainy days, because rain contains a small amount of natural radioactive substances.

Monitoring data at other sites

• *Environmental radioactivity level by prefecture, reported by the Ministry of Education, Culture, Sports, Science and Technology [English, Korean and Chinese are available: Please click ‘English’ and find the pages from UPDATES.]
• Monitoring Data from Hokkaido Institute of Public Health
  • In Hokkaido, the level of air radiation is monitored continually, and the gamma radiation level of tap water and fallen matter is measured with a germanium semiconductor, at the request of the Ministry of Education, Culture, Sports, Science and Technology.
• *Environmental radiation monitoring data, reported by the Ministry of the Environment (Hokkaido data is collected in Rishiri Town) [Japanese only]
• The Sapporo government’s response to the Tohoku disasters [Sapporo government page]
• Click here for information on radiation levels in Singapore (Singapore National Environment Agency page)
  Click here for information on radiation levels in Australia (Australian Nuclear Science and Technology Organisation)

*Information on environmental radiation monitoring data, reported by Hokkaido Nuclear Energy Environmental Research Center

• See the "Topics" column on this page.

Information on radiation exposure, provided by the National Institute of Radiological Sciences [English is available: Please click ‘English’.]

• Measurements are conducted in January, April, July and October (as of August 2012.)
  *Measurements are not taken at Cape Erimo during the winter due to prohibitive road conditions.
• Radiation levels are measured at one meter above the ground.
• Measurements for the monitoring post are made in units of 1μGy/h (microgray per hour). However, measurements are converted using the formula 1μGy/h (microgray per hour) = 1μSv/h (micro Sievert per hour) and displayed in micro Sievert per hour on this website.
• Radiation levels may temporarily increase on rainy days, because rain contains a small amount of natural radioactive substances.

• In Hokkaido, radionuclide analysis (measurement of radioactive substances) is performed on tap water samples in Sapporo at the request of the Ministry of Education, Culture, Sports, Science and Technology.
  Measurements were taken every day from March 18 to December 27, 2011, with "Not detectable" indicating a level of less than 0.2Bq/kg. This has been reduced to once every three months as of January 2012.
  Due to continuous “Not detectable” results under the old system, precision has been improved for subsequent analyses (the lowest detectable amount in previous analyses was 1mBq/kg; precision is now around 100 times greater.)
  For more details, see the Hokkaido Institute of Public Health web page (Measurements of Radiation in Water (Tap Water)).[Japanese text only]
  See the Ministry of Education, Culture, Sports, Science and Technology Nuclear Disaster Response and Support Office web page for measurements of radiation in tap water in the 47 prefectures of Japan.
• The Hokkaido government is also sampling and surveying tap water at four locations in Hokkaido, but no radioactive substances have been detected.
  Measurements are due to be taken once a month at these four locations for some time to come.("Not detectable" indicates a level of less than 0.2-0.5 Bq (Becquerel)/kg.)
• Radiation levels are also being measured in tap water supplied by water authorities (communities) around Hokkaido.
  Please refer to the websites of the respective water authorities for the results of the measurements.
  • Sapporo City website
  • Kushiro City website (Japanese only)
  • Chitose Municipal Homepage
  • Shinhidaka municipal government homepage [PDF]