Temporal changes of 7 Be and 210 Pb concentrations in surface air at temperate latitudes 40 degrees N.

Atmospheric concentrations of (7)Be and (210)Pb 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 (7)Be and (210)Pb were 5.02 mBqm(-3) and 664 microBqm(-3), respectively, characteristic of the latitude of 40 degrees N. Monthly atmospheric concentrations of (7)Be 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 (7)Be concentrations and a number of meteorological parameters revealed that the sunspot number and temperature are the most significant parameters affecting the concentrations of (7)Be in surface air. The observed strong positive correlation between the mean monthly concentrations of (7)Be 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 (7)Be. Highest values of the mean monthly atmospheric concentrations of (210)Pb were observed in the autumn and lowest in the spring period. The positive correlation that was observed between (210)Pb and (7)Be concentrations during the summer months suggests that these two radionuclides could be used together as tracers of environmental processes.