Sýkora Ivan, Holý Karol, Ješkovský Miroslav, Müllerová Monika, Bulko Martin, Povinec Pavel P
Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
Department of Nuclear Physics and Biophysics, Faculty of Mathematics, Physics and Informatics, Comenius University, SK-84248, Bratislava, Slovakia.
J Environ Radioact. 2017 Jan;166(Pt 1):27-35. doi: 10.1016/j.jenvrad.2016.03.004. Epub 2016 Mar 24.
Variations of aerosol radionuclides (2001-2015) in the ground-level air in Bratislava (Slovakia) showed Be maxima in spring/early summer and minima in winter, however, an inverse trend was observed for Pb, Cs and K. A decreasing amplitude and splitting of summer maxima for Be in the last years has been found. A temporal behavior of the Be/Pb activity ratio showed higher levels during warm seasons due to vertical convection of air masses from higher altitudes. The Cs 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 average Cs concentrations during 2009-2014 were almost constant, disturbed only by the Fukushima accident in 2011. The increased atmospheric Cs and K levels observed during the autumn-winter season may be due to surface soil resuspension, biomass burning and radionuclide transport by winds. Seasonal variations of Rn 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 of Rn has been larger than that of Pb. The Pb/Rn 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 the Rn 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 the Pb/Rn method to be 4.5 ± 0.9 days.
斯洛伐克布拉迪斯拉发地面空气中气溶胶放射性核素的变化（2001 - 2015年）显示，铍在春季/初夏达到最大值，冬季达到最小值，然而，铅、铯和钾则呈现相反趋势。近年来发现铍的夏季最大值的振幅减小且出现分裂。由于来自较高海拔气团的垂直对流，铍/铅活度比的时间行为在温暖季节呈现较高水平。2003年至2010年期间地表空气中铯的活度浓度以1.9±0.3年的有效半衰期下降。2009 - 2014年期间铯的年平均浓度几乎保持不变，仅在2011年受福岛事故干扰。秋冬季节观测到的大气中铯和钾水平升高可能是由于地表土壤再悬浮、生物质燃烧以及风对放射性核素的传输。发现氡活度浓度存在季节性变化，在秋末和冬季达到最大值，春季达到最小值。氡年均变化过程的变异性大于铅。铅/氡活度比在冬末和春季最高，而从6月到12月几乎保持恒定。春季月份更强烈的大气混合导致氡活度浓度下降，而大气中的气溶胶成分主要在秋冬季节受到影响。使用铅/氡方法计算得出气溶胶在大气中的平均停留时间为4.5±0.9天。
