Atmospheric concentrations of 7Be and 210Pb in weekly aerosols at Hirosaki, a heavy snowfall area in Japan

To understand the regional properties of atmospheric 7Be and 210Pb concentrations at Hirosaki, aerosol samples were collected weekly for the investigation. Total suspended particles (TSP) concentration ranged from 0.14 to 1.19 mg m-3 with a mean value of 0.29 ± 0.08 mg m-3. The activity concentrations during the observation period have shown a similar trend between 7Be and 210Pb, comparable to reported studies. The activity concentrations of 7Be and 210Pb ranged from 0.46 to 4.94 mBq m-3 with an average of 2.22 mBq m-3 and from 0.26 to 1.29 mBq m-3 with an average of 0.64 mBq m-3, respectively. The relation between precipitation and radionuclide concentrations indicated that precipitation is an essential factor in the radionuclide removal process. The rainfall/snowfall had a significant impact on the deposition, and the process was greatly affected by the changes in the features of raindrops and snowflakes, such as intensity, shape, surface area, and falling speed.