Radioactivity monitoring in ground level air in Belgrade urban area

Concentrations of beryllium-7 (7Be), lead-210 (210Pb) and caesium-137 (137Cs) 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 Inst. 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 7Be and 210Pb exhibit a similar seasonal pattern. The mean monthly concentrations of 7Be 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 210Pb 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 137Cs were mainly below the limit of detection. (authors)