Atmospheric concentrations of 7 Be and 210 Pb were measured for 15 years (1987–2001) in ground-level air at Thessaloniki, Northern Greece (40°38′N, 22°58′E). Mean activity concentrations of 7 Be and 210 Pb were 5.02mBqm −3 and 664μBqm −3 , respectively, characteristic of the latitude of 40°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.