Radioactivity monitoring in ground level air in Belgrade urban area.

Concentrations of beryllium-7 ((7)Be), lead-210 ((210)Pb) and caesium-137 ((137)Cs) were measured at two sites in the city of Belgrade (Serbia). One monitoring site was located in the central city area with heavy traffic and the other within the Institute of Nuclear Sciences Vinca, in the suburbs. Presented data cover the period 2004-9. Activity of the radionuclides was determined on an HPGe detector (Canberra, relative efficiency 23 %) by standard gamma spectrometry. Activities of (7)Be and (210)Pb exhibit a similar seasonal pattern. The mean monthly concentrations of (7)Be did not exceed 7 mBq m(-3). The maxima are correlated with the seasonal increase in temperature, whereas the minima are linearly correlated with the amount of precipitation. The activity of (210)Pb was below 0.9 mBq m(-3). The activities of both radionuclides were very low in winters and were largely affected by precipitation and snow coverage. Concentrations of (137)Cs were mainly below the limit of detection.