1. Department of Physics, Division of Atmospheric Sciences; University of Helsinki; Helsinki Finland
2. Institute of Nuclear and Radiological Sciences and Technology; Energy and Safety - Environmental Radioactivity Laboratory, N.C.S.R. “Demokritos”; Athens Greece
3. Department of Environment; University of the Aegean; Mytilene Greece
4. Finnish Institute of Occupational Health; Helsinki Finland
5. Department of Mechanical Engineering; Aalto University; Espoo Finland