- This data was created based on the "Readings of Dust Sampling by The Federation of Electric Power Companies of Japan (Member Companies)" released to the public in the Monitoring Information of Environmental Radioactivity Level portal site by the Secretariat of the Nuclear Regulation Authority.
- The sampling of dust was conducted from March 2011 to July 2011 for six points outside the 20 km Zone of TEPCO Fukushima Dai-ichi NPP.