Loskot Jan, Jezbera Daniel, Nalezinková Martina, Šmejkalová Adéla Holubová, Fernandes Danilo, Komárek Jan
Department of Physics, Faculty of Science, University of Hradec Králové, Rokitanského 62, Hradec Králové, 500 03, Czech Republic.
Department of Biology, Faculty of Science, University of Hradec Králové, Rokitanského 62, Hradec Králové, 500 03, Czech Republic.
Sci Rep. 2024 Dec 30;14(1):32002. doi: 10.1038/s41598-024-83603-0.
In late March to early April 2024, an unusually high amount of sand dust was wind-blown to Europe from the Sahara Desert. Most of mainland Europe was affected by these sand dust particles. As a result, Central Europe experienced an exceptionally high increase in air pollution. In this work, the impact of this Saharan dust event on PM characteristics in an urban and a natural locality in the Czech Republic was investigated. PM concentrations during the Saharan dust event were about 6-8 times higher than under normal atmospheric conditions, exceeding WHO guidelines by up to 2 times. Terrain and altitude may have influenced the local concentrations of Saharan dust. Airborne dust collected before and during the Saharan dust event was then studied using scanning electron microscopy combined with energy-dispersive spectroscopy. These methods were employed to determine the sizes and elemental compositions of the individual dust particles. Further, X-ray diffraction analysis was carried out to reveal the mineralogical composition of the collected dust. Surprisingly, the particle size distribution was not significantly affected by the windblown Saharan dust, but its dependency on the sampling locality was revealed. It may be explained by the different altitudes of the sampling localities, as coarse particles are more susceptible to gravitational pull while fine particles tend to remain suspended at higher altitudes. The dominant mineral in the Saharan dust was calcite, which substantially altered the local PM composition. The studied Saharan dust originated from a natural area, as the amount of anthropogenic pollutants detected was negligible. Notably, its carbon content was lower compared with the usual local PM. The elevated PM concentrations appear to be the most relevant risk associated with this Saharan dust event in Central Europe. The transported dust originated from the northern/north-western Sahara - probably from the Atlas region - which was verified by a backward trajectory analysis of air masses using the HYSPLIT model.
2024年3月下旬至4月初，异常大量的沙尘从撒哈拉沙漠被风吹到欧洲。欧洲大陆大部分地区都受到了这些沙尘颗粒的影响。结果，中欧的空气污染异常大幅增加。在这项工作中，研究了此次撒哈拉沙尘事件对捷克共和国一个城市地区和一个自然地区颗粒物特征的影响。撒哈拉沙尘事件期间的颗粒物浓度比正常大气条件下高出约6至8倍，超过世界卫生组织指南多达2倍。地形和海拔可能影响了当地撒哈拉沙尘的浓度。然后，使用扫描电子显微镜结合能量色散光谱对撒哈拉沙尘事件之前和期间收集的空气传播沙尘进行了研究。这些方法用于确定单个沙尘颗粒的大小和元素组成。此外，还进行了X射线衍射分析以揭示收集到的沙尘的矿物组成。令人惊讶的是，粒径分布并未受到吹入的撒哈拉沙尘的显著影响，但揭示了其对采样地点的依赖性。这可能是由于采样地点的海拔不同，因为粗颗粒更容易受到重力作用，而细颗粒往往在较高海拔处保持悬浮状态。撒哈拉沙尘中的主要矿物是方解石，这极大地改变了当地的颗粒物组成。所研究的撒哈拉沙尘源自自然区域，因为检测到的人为污染物数量可以忽略不计。值得注意的是，与当地通常的颗粒物相比，其碳含量较低。颗粒物浓度升高似乎是中欧此次撒哈拉沙尘事件最相关的风险。输送来的沙尘源自撒哈拉沙漠北部/西北部——可能来自阿特拉斯地区——这通过使用HYSPLIT模型对气团进行后向轨迹分析得到了验证。
