- This data was created based on the "Reading of Environmental Radioactivity Level Measured by Fukushima Prefecture (Fallout)" released to the public in the Monitoring Information of Environmental Radioactivity Level portal site by the Secretariat of the Nuclear Regulation Authority.
- The survey has been conducted since December 2011 at the Environmental Radioactivity Monitoring Center of Fukushima Fukushima Branch.
- The accumulated daily fallout substance was measured every day using a germanium semiconductor detector.