Analysis of gross alpha, gross beta activities and beryllium-7 concentrations in surface air: their variations and statistical prediction model.

Measurement of gross alpha, gross beta activities and cosmogenic beryllium-7 (7Be) concentrations were made both daily and weekly during the years 2001--2004 from samples of atmospheric aerosols filtered from the air at Tehran Nuclear Research Center (35 41' N) and Zahedan (28 29' N). Weekly aerosol samples collected with the high-volume air samplers on cellulose filters were used to determine the 7Be contents of samples, using a semiconductor gamma spectrometer. Airborne dust samples were collected daily on fiber glass filters and used to determine the gross beta and gross alpha activities with automatic beta analyzer and a ZnS(Ag) counter, respectively. In this work, the concentration and meteorological data were used to determine models for gross alpha, gross beta and 7Be. The air concentrations of gross beta and gross alpha activities and 7Be concentrations displayed lognormal distributions during the study period. Both beta and 7Be have maximum activity concentrations during warm mid-year months.