- This data was created based on the "Results of Measurement of Air Dose Rates at Fixed Observation Points using a Monitoring Car" released to the public in the Monitoring Information of Environmental Radioactivity Level portal site by the Secretariat of the Nuclear Regulation Authority.
- The survey was conducted every day from March 2011to March 2016 at the fixed observation points outside the 20 km zone of Fukushima Dai-ichi NPP. From April 2016, the survey was conducted from September to October every year.