Local Radiation Measurement Results of Public Facilities in the City

Since June 2011, the city has been conducting regular measurements of ambient radiation levels at 38 fixed points. However, due to the establishment of new facilities, the number of measurement points was changed from 38 to 40 starting in April 2015.
Considering that the results of the fixed point measurements were similar to various measurement results from the national and Tokyo metropolitan governments, we believe that these levels do not pose a health risk and do not interfere with children's activity areas or citizens' daily lives.
However, it has been reported in other cities that there are relatively high radiation areas (hotspots) as a new phenomenon. To ensure that citizens can use public facilities in the city with greater peace of mind, the city has established a policy for measuring ambient radiation levels and has been conducting radiation measurements at locations within each facility that are believed to have relatively high radiation levels in accordance with this policy.

About the Suspension of Local Measurements

Since 2012, the measurement results have been stable, remaining below the standard value set by the Ministry of the Environment (0.23 microsieverts per hour). Additionally, the values from the radiation monitoring posts in Shinjuku, which were established before the Great East Japan Earthquake, have decreased to levels seen before the disaster. For these reasons, local measurements were suspended from the fiscal year 2017. However, if any concerns arise, measurements will be resumed immediately. For more details, please see the link below.

• Change in the Measurement Frequency of Indoor Radiation Levels

Criteria for Implementing Radiation Dose Reduction Measures

As a unique standard of the city, for locations where the measurement results exceed 0.23 microsieverts per hour at a depth of 1 centimeter from the ground surface, we will implement measures to reduce radiation levels, such as cleaning.
Note: According to the Ministry of the Environment's "Decontamination Guidelines," for soil in places like schoolyards, if the radiation level at a depth of 1 meter is below 0.23 microsieverts per hour, no further decontamination will be carried out as a general rule. However, to ensure greater safety, the city has established its own standards for response.
Reference: According to the recommendations of the International Commission on Radiological Protection (ICRP), the indicator for the radiation dose received by the general public during normal times is set at below 1 millisievert per year (excluding natural radiation levels, etc.). When converting the threshold value of 0.23 microsieverts per hour to an annual basis, it amounts to 0.99864 millisieverts, which is below the annual limit of 1 millisievert.

Annual Conversion Calculation Formula

Annual equivalent value 0.99864 millisieverts = (Measured value 0.23 - Natural radiation level 0.04) × (8/24 [Time spent outdoors] + 16/24 [Time spent indoors] × 0.4 [Indoor radiation reduction rate]) × 24 hours × 365 days ÷ 1000 [Conversion to millisieverts]

• Local Measurement Results of Ambient Radiation Levels at i Plaza (Updated April 1, 2017)
• Results of Local Measurements of Ambient Radiation Levels at Municipal Elementary and Junior High Schools (Updated October 19, 2020)
• Local Measurement Results of Radiation Levels in Parks and Green Spaces (Updated October 19, 2020)
• Local Measurement Results of Ambient Radiation Levels at City Hall (Updated November 1, 2016)
• Local radiation measurement results at the fire brigade substation and community disaster prevention center (Updated March 15, 2017)
• Local Measurement Results of Ambient Radiation Levels at Inagi Fire Station (Updated January 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at the City Hospital (Updated February 15, 2017)
• Local Measurement Results of Space Radiation Levels at the School Lunch Joint Cooking Facility (Updated January 1, 2017)
• Local Measurement Results of Space Radiation Levels in Sports Facilities (Updated January 15, 2017)
• Local Measurement Results of Ambient Radiation Levels at the Cultural Center (Updated April 1, 2017)
• Local radiation measurement results for the Central Library and SHIROYAMA EXPERIENCE STUDY INSTITUE (Updated August 15, 2016)
• Local radiation measurement results of the Inagi City Education Center Central Educational Consultation Room (Updated January 1, 2017)
• Local Radiation Measurement Results for the Complex Facility Friend Hirao (Updated January 1, 2017)
• Local Radiation Measurement Results of Kamiyato Green Space Experience Learning Center (Updated February 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at the Health Center (Updated January 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at the Welfare Center (Updated August 15, 2016)
• Local Measurement Results of Ambient Radiation Levels at the Environmental Learning Center (Updated March 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at the Consumer Affairs Center (Updated January 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at Hirao Branch Office (Updated August 15, 2016)
• Local Measurement Results of Ambient Radiation Levels in Community Centers, etc. (Updated March 15, 2017)
• Local Radiation Measurement Results of the Community Promotion Plaza (Updated November 1, 2016)
• Local Measurement Results of Space Radiation Levels at the Children's Center and After-School Childcare Program (Updated February 1, 2017)
• Local Measurement Results of Space Radiation Levels in Childcare Centers for Infants and Young Children (Updated January 1, 2017)
• Local Measurement Results of Space Radiation Levels in Kindergarten (Updated January 1, 2017)
• Local Measurement Results of Ambient Radiation Levels at Inagi Fureai Forest (Updated February 1, 2017)