2014 Volume 65 Issue 11-12 Pages 145-155
In order to obtain the geochemical knowledge of material cycle as a tracer and to contribute the concern of inhabitant about safety after the accident of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), the aerosol observation at the Geological Survey of Japan, AIST (GSJ) was continued and the new data in 2013 are reported in this paper. The Cs radioisotopes in aerosols increased a little in March 2013, then decreased from April. Those in 2012 also decreased in April, when the southerly wind often blew instead of northerly wind and rainy day increased. These facts suggest the change of weather conditions is one of controlling factors. The re-suspension of deposited particles by strong wind was thought to be more important mechanism after 2012 than the transport from the FDNPP. The Cs-137 concentration and Cs-137/Pb-210 ratio were thought to be useful parameters suggesting the re-suspension.