title: Diurnal and seasonal variation of the equilibrium state between short-lived radon decay products and radon gas in ground-level air.
abstract: To study seasonal and diurnal variations and the effect of meteorological parameters, the equilibrium factor F (i.e. the ratio of equilibrium equivalent radon daughter concentration and radon gas concentration) was determined as a result of measurements on a test field at Munich-Neuherberg, Germany, continuously from October 1995 through March 1997. On average, F was found to be 0.62+/-0.09 (95% confidence level). The time series of F showed no distinct seasonal variations. Nevertheless, typical diurnal variations as well as seasonal variations of the diurnal behaviour were observed. Generally, F was found to be increased in the early afternoon, i.e. under conditions of enhanced vertical mixing in the atmosphere. The daily differences between high and low values of F depended on the season. On average, low F values were characteristic for days with precipitation and high wind speed, i.e. under turbulent atmospheric conditions. Therefore, taking daily mean values into account, F was found to be positively correlated with the aerosol concentration, although a relationship between the diurnal behaviour of the aerosol concentration and that of F was not detectable.
authors.affiliation: GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Neuherberg, Germany. rwinkler@gsf.de
authors.forename: R
authors.initials: R
authors.lastname: Winkler
authors.forename: F
authors.initials: F
authors.lastname: Ruckerbauer
authors.forename: M
authors.initials: M
authors.lastname: Trautmannsheimer
authors.forename: J
authors.initials: J
authors.lastname: Tschiersch
authors.forename: E
authors.initials: E
authors.lastname: Karg
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D002940:Circadian Rhythm; D005858:Germany; D011886:Radon / Q000032:analysis* / Q000378:metabolism*; D011891:Rain; D012621:Seasons; D013997:Time Factors
chemical_list: D000396:Air Pollutants, Radioactive; D011886:Radon