Surface air radon progeny at Sao Jose dos Campos, Brazil

Radon is a noble gas naturally occurring in the atmosphere with its progeny. Such progeny can be divided into short- and long-lived daughters. In the winter and spring of 2004 a field campaign at Sao Jose dos Campos (SJC, 23.1 degrees S, 45.5 degrees W, 600m above sea level) in Brazil was conducted to determine the outdoor concentration of the short-lived Po-218, Pb-214, and Bi-214 and the long-lived Po-210. It was adopted the methodology of measuring the integrated counts of alpha particles from atmospheric aerosols captured on a cellulose membrane filter sampled with outdoor surface air. Integrated counts for the short-lived daughters at 3 different minute-based periods of time were carried out immediately after the end of sampling and applied to a system of 3 equations, whose solution is the short-lived daughters' air concentrations. For Po-210 the air concentration was directly released from alpha counts and volume of probed air. Radionuclides' uncertainties were calculated too. Average values of volume activity (25 +/- 21) (1 standard deviation, sd), (6 +/- 4), and (4 +/- 2)Bqm(-3) for Po-218, Pb-214, and Bi-214, respectively, and (81 +/- 30)mu Bqm(-3) for Po-210 were found in the campaign. Atmospheric parameters of temperature, humidity, precipitation, pressure, and wind were taken during sampling. Correlation with temperature and humidity were obtained at 95% confidence level. (c) 2005 Elsevier Ltd. All rights reserved.