Gross beta activities and Beryllium-7 concentrations in surface air

were made each week during year 2002 from samples of atmospheric aerosols filtered from theair at Tehran Nuclear Research CenterMeasurement of gross beta activities and cosmogenic Beryllium-7 concentrationsMaterials and Methodssampler at the Nuclear Research Center meteorological station in Tehran (40contents of samples were determined with semiconductor gamma spectrometry. The long-livedbeta activity, i.e. total beta activity measured four days after the end of sampling (after decay of: The aerosol samples were collected weekly with high-volume airo 35. N). The 7Be220The long-lived beta activity consists mainly of amount of artificial radionuclides in the air is negligible.Rn progeny and short-lived 220Rn progeny), was assessed with an automatic beta analyzer.210Bi, the daughter nuclide of 210Pb, as the lognormal distribution during the study period 2002. The arithmetic mean of annual concentrationsof The air concentrations of both the 7Be and the long-lived beta activity displayed a7Be and 210 Pb was 6.30 and 0.50 mBqm-3, respectively. beta activities are partially correlated. Both have maximum concentrations during warmmid-year months. Despite the different origins, the concentrations of both the 7Be and the long.livedIran.