Local radiation measurement results for public facilities in the city

Since June 2011, the city has been regularly measuring air radiation doses at 38 fixed points, but due to the construction of new facilities, the number of measurement points has increased from 38 to 40 since April 2015. changed in place.
Based on the fact that the fixed-point measurement results were similar to the various measurement results of the national government and the Tokyo metropolitan government, it is believed that the values ​​do not affect the health of children and that they do not interfere with the range of activities of children and the lives of citizens. I'm here.
However, as a new phenomenon, the existence of places (hot spots) where the radiation dose is relatively high locally has been reported in other cities. A radiation dose measurement response policy was established, and according to this response policy, radiation dose measurements were carried out in areas where radiation doses were thought to be relatively high in each facility.

Regarding the measurement results from 2012 to the present, the numerical value is stable and is below the standard value (0.23 microsieverts per hour) indicated by the Ministry of the Environment. Local measurements have been suspended since 2017 due to reasons such as the radiation monitoring post figures in the ward dropping to pre-earthquake figures. However, if any uneasiness arises, we will resume immediately. For more information, please visit the link below.

Criteria for implementing radiation dose reduction measures

According to the city's own standards, in areas where the measurement result is 0.23 microsievert per hour or more per centimeter of the ground surface, cleaning will be carried out as a measure to reduce the radiation dose.
Note: According to the Ministry of the Environment's "Decontamination-related Guidelines," as a general rule, no further decontamination of soil in schoolyards, etc. should be carried out if the radiation dose at 1 meter of the ground surface is less than 0.23 microsieverts per hour. Masu. However, the city has established its own standards to ensure greater safety.
Reference: According to the recommendations of the International Commission on Radiological Protection (ICRP), the indicator of the radiation dose received by the general public during normal times is less than 1 millisievert per year (excluding natural radiation dose, etc.). The standard value of 0.23 microsieverts per hour is converted into an annual value of 0.99864 millisieverts, which is less than 1 millisievert per year.
　
[Annual conversion formula]
Annualized value 0.99864 millisievert = (measured value 0.23 - natural radiation dose 0.04) x (8/24 [time outdoors] + 16/24 [time indoors] x 0.4 [indoor radiation reduction rate] ) x 24 hours x 365 days ÷ 1000 [millimeter conversion]