Temporal changes of 7Be and 210Pb concentrations in surface air at temperate latitudes (40°N)

Atmospheric concentrations of Be-7 and Pb-210 were measured for 15 years (1987-2001) in ground-level air at Thessaloniki, Northern Greece (40 degrees 38'N, 22 degrees 58'E). Mean activity concentrations of Be-7 and Pb-210 were 5.02 mBq m(-3) and 664 mu Bq m(-3), respectively, characteristic of the latitude of 40 N. Monthly atmospheric concentrations of Be-7 showed a strong seasonal trend with the highest values being observed in the summer and the lowest in the winter period. Multiple regression analysis of the data of Be-7 concentrations and a number of meteorological parameters revealed that the sunspot number and temperature are the most significant parameters affecting the concentrations of Be-7 in surface air. The observed strong positive correlation between the mean monthly concentrations of Be-7 and the temperature confirms that the increased rate of vertical transport within the troposphere, especially during the warm months, has as a result to carry down to the surface layer air masses enriched in Be-7. Highest values of the mean monthly atmospheric concentrations of Pb-210 were observed in the autumn and lowest in the spring period. The positive correlation that was observed between Pb-210 and Be-7 concentrations during the summer months suggests that these two radionuclides could be used together as tracers of environmental processes. (c) 2005 Elsevier Ltd. All rights reserved.