ABSTRACT

Atmospheric bulk deposition and aerosol samples were collected simultaneously in the surface air over the west coast of Japan (38°46'N, 139°44'E), and analyzed for ²¹⁰Pb. By coupling data with those previously reported for ²¹⁰Po (Suzuki, 1994), the following results have been obtained. (1) The ²¹⁰Po/²¹⁰Pb activity ratios in aerosols were consistently larger than those in atmospheric depositions, and (2) the activity ratios in April were larger than those in July and October in both aerosol and deposition samples. The results can be variously attributed to the difference of residence time between atmospheric suspending and settling particles, and the difference of contribution from various sources in which ²¹⁰Pb and ²¹⁰Po are in over-, under- or secular-equilibrium.