Be-7 to Pb-210 concentration ratio in ground level air in Belgrade area

Be-7 to Pb-210 concentration ratios in ground level air on two monitoring stations (MS1 and MS2) in Belgrade area were determined from 1996 to 2001. The average monthly concentrations of Be-7 in ground level air were in the range of 0.6-18.3 mBq/m(3) and exhibited one or two summer/early fall maxims and one minimum in winter. The maximum concentrations for Pb-210 were generally observed in the fall, with the average concentrations in the range of 1.09 x 10(-4) to 30.9 X 10(-4) Bq/m(3). The Be-7/Pb-210 ratios were in the range of 1.7-12.7 (MS1) and 1.8-11.3 (MS2), with summer maxims and late fall/winter minimums. The mean Radionuclides Loading Indices values approach zero except for 1996/1997 (MS1) and 2001 (MS2) due to higher concentrations of Be-7 and Pb-210. The mean monthly concentrations of both radionuclides exhibited lognormal distributions. There is significant correlation between the Be-7/Pb-210 activities ratio and the air stability classes A+B+C for both monitoring stations (correlation coefficients 0.61-0.65), and no correlation with D class and E+F classes. Correlation was found between the activity of Be-7 and air stability classes A+B+C (0.46-0.68), and E+F (0.38 for MS1), while for Pb-210, a moderate correlation (0.38-0.40) was found with the E+F air stability classes. (C) 2004 Published by Elsevier Ltd