Variations of 210Pb concentrations in surface air at Thessaloniki, Greece (40°N) A. Ioannidou, E. Kotsopoulou, A. Karanatsiou and C. Papastefanou EPJ Web of Conferences, 24 (2012) 05003 Published online: 04 April 2012 DOI: 10.1051/epjconf/20122405003