Air dose rates and cesium-137 in urban areas; Deposition, migration, and time dependencies after nuclear power plant accidents

Yoshimura, Kazuya  

Our goal is to review and synthesize knowledge obtained after the Fukushima Dai-ichi and Chernobyl Nuclear Power Plant accidents to provide important information to better understand environmental radiation in urban areas. As was reported in Europe, the cesium-137 (Cs) inventory (Bq m) was high on soil grounds but relatively low on impermeable surfaces such as roads and roofs because of the high initial runoff and wash-off of Cs from surfaces. The air dose rate in urban areas decreased faster than that in other land uses owing to large Cs wash-off on pavements and anthropogenic effects, such as decontamination. Thus, environmental recovery in urban area was thought to be facilitated by human activities and Cs wash-off, reducing radiation risk of local residents comparing to the other land uses.