Sources for Pu in near surface air.

This paper provides evidence that most of the Pu in the near surface air today is due to resuspension. Vertical and particle size distribution in near surface air over a period of three years were measured. The seasonal variations of Pu in air and the influence of meteorological parameters on these variations are shown. Samples were taken before the Chernobyl accident in an area where only Pu fallout from the atmospheric nuclear tests of the early sixties occurs. The comparison of the behavior of Pu with other trace elements, which were also measured, showed similar behavior of Pu and elements like Ca, Ti and Fe in near surface air. This confirms that most Pu is resuspended because the main source for these elements in air is the soil surface. Resuspension factors and resuspension rate are estimated for all measured elements. A resuspension factor of 0.8 X 10(-8) m-1 and a resuspension rate of 0.09 X 10(-9) s-1 is calculated for Pu.