About microspots

Yokohama City has been measuring the spatial radiation dose of about 4,300 facilities, such as nursery schools and elementary and junior high schools, but there is no problematic value due to the radiation dose in the space where we usually live (0.01 μSv / h) ~ Maximum 0.21 μSv / h).
The current air dose in Yokohama City is a value that allows you to live a normal life with peace of mind.
However, the existence is known throughout the country, and there are several places in the city that show locally high spatial radiation doses that are expressed as so-called micro spots.

• September 21, 2011 "About measurement result of radiation dose in municipal nursery school and municipal school in Kohoku Ward" (PDF: 159KB)
• September 17, 2011 "Confirmation of places where radiation doses higher than the surrounding area were measured and future countermeasures" (PDF: 303KB)

• Measurement results of municipal nursery school (Kohoku Ward)

In the so-called microspots, radioactive materials released by the hydrogen explosion that occurred in mid-March fell with rain and immersed in earth and sand, repeated drying and deposition, resulting in a relatively high radioactivity concentration.
Generally, it is said that under gutters and road gutters are likely to become microspots.
The radiation dose in the micro spot is related to the distance, and the air dose will be lower if it is a little far away, such as 50 cm or 1 m. In addition, frequent cleaning is effective for places such as the following micro spots that are likely to become micro spots.
If you are worried about daily cleaning of your home, please refer to the following website.

In Yokohama City, we measure sequentially about places that are likely to become microspots, mainly at elementary and junior high schools and parks where children gather.

• Dust pool
• Near rain gutters and their drains, around drains and manholes, dry traces of puddles, etc.

• Hot spot discovery / decontamination manual (outside site) for private homes(Japan Society for Radiation Safety Management)
• Guidelines for dealing with local contaminated areas caused by radioactive materials (external site)(Ministry of the Environment)