Frequently Asked Questions Q&A Collection

After the accident at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station in March 2011, approximately 4,300 facilities under the jurisdiction of the city were measured during FY2011. .
As a result, there were no regional bias or problematic values due to the radiation dose in the space where we usually live. The results of monitoring by aircraft and road running surveys conducted by the government have confirmed that the value is no problem.
In addition, schools, nursery schools, and other city-owned facilities, where radiation doses are measured very locally, such as under gutters and gutters on roads, are likely to become so-called micro spots. However, since October 2012, no high values exceeding the standard of response have been confirmed.
In addition, space radiation dose in the city announces measurement result (outside site) of monitoring post (measured every hour in 24 hours a day) which city installs at any time.

There are no national standards for the concentration of soil radioactivity, such as schoolyards, nursery schools, and parks.
According to estimates made immediately after the accident at the Atomic Energy Society of Japan, etc., the effects of internal exposure to soil ingestion of soil dust into the body are about 2 to 4% of the effects of external exposure in the area, and the effects of internal exposure from soil intake by infants are about 0.04 to 0.3% of the effects of external exposure in the area.
Based on these facts, Yokohama City measures space radiation near the ground surface, etc., mainly because it is appropriate to grasp the effects on the human body mainly by radiation from outside. .

When the Ministry of Education, Culture, Sports, Science and Technology (MEXT) stated on May 27, 2011, "Aiming to increase the additional exposure in schools to 1 millisievert per year", the additional exposure per hour was not shown. Therefore, Yokohama City decided to go to school for 210 days and spend 8 hours outdoors and 9 hours outdoors.
<Calculation method>
1 mSv / year / 210 days / 8 hours = 0.00059 mSv / hour = 0.59 microsieverts / hour

After that, the Ministry of the Environment indicated the standard of "0.23 microsieverts per hour at a height of 50 cm or 1 m above the ground", but in addition to that standard, "0.59 microsieverts per hour at a height of 1 cm above the ground" as a city We decided to measure it as a "standard" of the response.
This is because if the air dose of 1 cm above the ground is 0.59 μSv / h or more, even if it is less than 0.23 μSv / h at 50 cm above the ground, it will take measures such as removal, so it is safer than national standards. It has become.

The basis of radiation control is how to reduce the impact on humans, and this is a basic idea regardless of whether the radioactivity concentration is high or low.
For this reason, Yokohama City has taken measures such as taking distance and shielding as measures to reduce the effects of radiation, regardless of the concentration of removed soil, and the spatial radiation dose, which indicates the impact on humans, is properly managed by ensuring that it is about the same as the surrounding values.
Although the concentration of the removed soil is not measured, it is properly managed by measuring the spatial radiation dose generated from the removed soil, and the government is taking radiation measures based on the same concept.

In fiscal 2015, as in fiscal 2015, as in fiscal 2025 and fiscal 26, we will conduct efficient inspections based on the status of detection in the city and other cities that have been conducted so far, while focusing on “food and milk for baby/infant,” which has set high detection standards for marine products and children.
In addition, Yokohama City has published its test results.

• About test result of radioactive material of food that we carried out in Yokohama-shi

Please refer to the following website for radiological inspection of school lunch ingredients such as elementary school school lunch and nursery schools.

• Measurement results of radioactive materials in elementary school school lunch ingredients
• About measurement of radioactive material of school lunch ingredients in nursery schools

We do not carry out radiological inspection by bringing in from citizens.
In addition, the Ministry of Health, Labour and Welfare has posted a “Registered Inspection Organization (outside site) that can conduct inspections of radioactive substances in food” on its website.
(Please check with the inspection organization individually for inspection costs.)