Thorium, uranium and plutonium in surface air at Vardö

Aerosol samples collected in 1989 and 1990 at Vardö (north Norway) were analysed for thorium, uranium and plutonium. The mean activity concentrations found for 232Th, 238U, 239,240Pu and 238Pu were 65, 68, 0.68 and 0.077 nBq m−3, respectively. The results are compared with the relevant data from north Germany. The 232Th and 238U activity concentrations are less, by one order of magnitude, than activity concentrations in north Germany—not only due to the lower dust content but also to the lower specific activity of the inorganic aerosol components. The 238Pu/239,240Pu and 239,240Pu/137Cs activity ratios are comparable with those found in aerosols from north Germany. There are no indications of regional sources of plutonium aerosols.