title: Long-term variations of radionuclides in the Bratislava air.
abstract: Variations of aerosol radionuclides (2001-2015) in the ground-level air in Bratislava (Slovakia) showed7Be maxima in spring/early summer and minima in winter, however, an inverse trend was observed for210Pb,137Cs and40K. A decreasing amplitude and splitting of summer maxima for7Be in the last years has been found. A temporal behavior of the7Be/210Pb activity ratio showed higher levels during warm seasons due to vertical convection of air masses from higher altitudes. The137Cs activity concentration in the surface air between 2003 and 2010 was decreasing with an effective half-life of 1.9 ± 0.3 years. The yearly average137Cs concentrations during 2009-2014 were almost constant, disturbed only by the Fukushima accident in 2011. The increased atmospheric137Cs and40K levels observed during the autumn-winter season may be due to surface soil resuspension, biomass burning and radionuclide transport by winds. Seasonal variations of222Rn activity concentrations were found with maxima at the end of autumn and in winter, and minima in spring. The variability of the average annual course of222Rn has been larger than that of210Pb. The210Pb/222Rn activity ratio was highest at the end of winter and in the spring, while from June to December remained nearly constant. More intensive atmospheric mixing in spring months caused a decrease in the222Rn activity concentration, while the aerosol component of the atmosphere has been affected mainly during the autumn and winter seasons. The mean residence time of aerosols in the atmosphere was calculated using the210Pb/222Rn method to be 4.5 ± 0.9 days.
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Sýkora
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
authors.forename: Karol
authors.initials: K
authors.lastname: Holý
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Ješkovský
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
authors.forename: Monika
authors.initials: M
authors.lastname: Müllerová
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
authors.forename: Martin
authors.initials: M
authors.lastname: Bulko
authors.affiliation: Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia. Electronic address: Povinec@fmph.uniba.sk.
authors.forename: Pavel P
authors.initials: PP
authors.lastname: Povinec
mesh_terms: D000336:Aerosols / Q000032:analysis; D000396:Air Pollutants, Radioactive / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D006207:Half-Life; D011834:Radiation Monitoring; D012621:Seasons; D018154:Slovakia
chemical_list: D000336:Aerosols; D000396:Air Pollutants, Radioactive
keywords: Aerosols; Atmospheric radioactivity; Chernobyl accident; Fukushima accident; Global fallout; Radionuclides