Surface air radon progeny at São José dos Campos, Brazil: Fid-Bau Portal

Surface air radon progeny at São José dos Campos, Brazil

Silva, A.A. / Claro, L.H.

AbstractRadon 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 São José dos Campos (SJC, 23.1° S, 45.5° W, 600m above sea level) in Brazil was conducted to determine the outdoor concentration of the short-lived ²¹⁸Po, ²¹⁴Pb, and ²¹⁴Bi and the long-lived ²¹⁰Po. 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 ²¹⁰Po 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 ²¹⁸Po, ²¹⁴Pb, and ²¹⁴Bi, respectively, and (81±30) $μ$ Bqm⁻³ for ²¹⁰Po 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.