Pb-210 in ground-level air in Belgrade city area

Concentrations of Pb-210 in ground level air in the city area (Belgrade, Ce ntral Serbia) were measured in the period from 1985 to 1996. The activity o f Pb-210 in air filters was determined on a HPGe detector by standard gamma spectrometry. Total standard error of the method was estimated to be below 25%. The average monthly concentrations of Pb-210 in the ground level air in the period from 1985 to 1996 were in the range of 0.30-3.17 mBq m(-3) with the maxima in fall-winter periods and minimums in springs and early summers. T he seasonal indices were 1.12-1.59 for fall-winter and 0.77-0.92 for spring -summer periods. The ratios of maximum-to-minimum concentrations in each ye ar were relatively stable over the period, with slight increase in 1985, 19 89 and 1995. The investigations are part of the long-term measurements of n atural and man-made radionuclides in the ground-level air in the region. (C ) 2000 Elsevier Science Ltd. All rights reserved.