Radioactivity and Air Dose Rate
ＱAir dose rates at flat locations without soil disturbance have decreased faster than expected by the half-life. Where did the radioactive cesium move to?
ＡRadioactive cesium gradually moves deeper into soil over time. When cesium moves downwards, air dose rates above the ground lower due to the shielding effect of the soil.
(These figures were made by JAEA based on results obtained in work for the Nuclear Regulatory Agency in 2014.)