Air Dose Rate Measurements in the Distribution Survey of Radioactive Substances
FY 2011 - FY 2016   The Ministry of Education, Culture, Sports, Science and Technology, and the Secretariat of the Nuclear Regulation Authority

This series of data was created based on results of the air dose rates measured using NaI(Tl) scintillation survey meters and ionization chamber type survey meters from FY 2011 to FY 2016 in the Di...
This series of data was created based on results of the air dose rates measured using NaI(Tl) scintillation survey meters and ionization chamber type survey meters from FY 2011 to FY 2016 in the Distribution Survey of Radioactive Substances by the Ministry of Education, Culture, Sports, Science and Technology, and the Secretariat of the Nuclear Regulation Authority.

Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From August 2016 to October 2016 )
  1. This data was created based on results of air dose rates measured from August 22 2016 to October 4, 2016 in the FY2016 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6577 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From August 2015 to September 2015 )
  1. This data was created based on results of air dose rates measured from August 3 2015 to September 8, 2015 in the FY2015 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6577 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From November 2014 to December 2014 )
  1. This data was created based on results of air dose rates measured from November 4 2014 to December 5, 2014 in the FY2014 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6565 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From July 2014 to September 2014 )
  1. This data was created based on results of air dose rates measured from July 15 2014 to September 5, 2014 in the FY2014 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6572 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From October 2013 to December 2013 )
  1. This data was created based on results of air dose rates measured from October 28, 2013 to December 2, 2013 in the FY2013 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6554 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From June 2013 to July 2013 )
  1. This data was created based on results of air dose rates measured from June 3, 2013 to July 4, 2013 in the FY2013 Distribution Survey by NRA.
  2. The measurements to obtain this data were conducted to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6562 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI (Tl) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From November 2012 to December 2012 )
  1. This data was created based on results of air dose rates measured from November 5, 2012 to December 7, 2012 in the Third Distribution Survey by MEXT.
  2. The measurements to obtain this data were conducted to ascertain the influence of typhoon to the change of air dose rate and also to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6549 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Measurement of Air Dose Rates within the 80 km Radius from Fukushima Dai-ichi NPP. ( From August 2012 to September 2012 )
  1. This data was created based on results of air dose rates measured from August 14, 2012 to September 7, 2012 in the Third Distribution Survey by MEXT.
  2. The measurements to obtain this data were conducted to ascertain the influence of typhoon to the change of air dose rate and also to ascertain the changing trend of air dose rate from the past measured results taken within the 80 km radius from the Fukushima Dai-ichi NPP.
  3. The area within an 80 km radius from the Fukushima Dai-ichi NPP was divided into 1 km × 1 km grids. Excluding the non-habitable areas and the areas that were inaccessible due to blocked roads, one measurement point in each grid was selected (total 6551 measurement points).
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at a height of 1 m above the ground.
  5. The data include air dose rates by natural radionuclides.
Results of Air Dose Rates in Eastern Japan ( From December 2011 to May 2012 )
  1. This data was created based on results of air dose rates measured from December 5, 2011 to May 29, 2012 in the Second Distribution Survey by MEXT.
  2. The measurements to obtain this data were conducted to acsertain the perspective of the accident and to confirm the changing trend of air dose rates.
  3. The measurements were conducted in the area where the air dose rate was 0.2 µSv/h and above including neigbhoring area of Fukushima prefecture based on previously conducted air dose rate / deposition denities measurements and air-borne monitoring.
  4. Air dose rates at the height of 1 m from the ground were measured using NaI(Tl) scintillation survey meters.
  5. The data include the air dose rates due to natural radionuclides.
Air Dose Rate Readings at 2,200 Locations in Fukushima Prefecture and Neighboring Prefectures ( From June 2011 to July 2011 )
  1. This data was created based on results of air dose rates measured from June 6, 2011 to June 14, 2011 (Period I) and from June 27, 2011 to July 8, 2011 (Period II) in the Investigation of Distribution Map of Radiation Doses, etc. by MEXT.
  2. The measurements to obtain this data were conducted to continueously ascertain the influence to people's health and environment. The measurements had taken place before rainy season that affected soil condition.
  3. The distribution of the measurement points is one point per every 2 km x 2 km grid in habitable area within 80 km radius from the Fukushima Dai-ichi NPP while one point per every 10 km x 10 km grid in the area between radius 80 and 100 km as well as the area west of Fukushima prefecture.
  4. At points where air dose rates did not exceed 30 µSv per hour, NaI(TI) scintillation survey meters were used, and at points where air dose rates exceeded 30 µSv per hour, ionization chamber type survey meters were used to measure air dose rates at the height of 1m from the ground.
  5. The data include the air dose rates due to natural radionuclides.
Time Series Analysis ( 2011 - 2016 )
  1. This data was created based on results of air dose rates from the Distribution survey conducted from 2011 to 2016 (10 times) by MEXT and NRA, using NaI scintillation and ionization chamber type survey meters.
  2. Time series data were created based on the third area partitions (100 m x 100 m grid). For the grids that had five or more than five data points, regression models were estimated using the least-squares method and attenuation rates were derived.
  3. The original data contain instrument errors due to measuring instruments and positioning errors (about 20 m) by GPS.
  4. The analysis range was set to an 80 km radius from the TEPCO Fukushima Dai-ichi NPP, where many points of high accumulation of radioactive substances were confirmed.
Publicly available data collected from the website of the relevant organizations and converted into CSV, XML, and KML formats that were easy to use.

Results of Air Dose Rates in Eastern Japan ( From December 2011 to May 2012 )
There is no content for 'Download File'
CSV files that have common item names over different survey projects for comparison analyses.