Radon progeny concentration is measured with a total alpha counting system in 185 dwellings in the town of Thessaloniki. The Equilibrium Equivalent radon Concentration (EEC Rn) follows a lognormal distribution with an arithmetic and geometric mean value of 28 Bq/m and 16 Bq/m respectively. Simultaneous in situ alpha and gamma spectroscopy measurements were performed in 60 schools of Thessalonik...