Department of Physics, University of Cordoba, 14071, Córdoba, Spain.
Energy Engineering Department, University of the Basque Country, 48013, Bilbao, Spain.
J Environ Radioact. 2024 Sep;278:107494. doi: 10.1016/j.jenvrad.2024.107494. Epub 2024 Jul 6.
One of the main factors that affect urban air quality is meteorology. The objective of this study is to understand and characterise the influence that "Galerna" (GL) (an abrupt westerly change over the northern coast of Spain) has on the daily variability of the air quality over Bilbao city (northern Spain). A total of 46 one-day periods from 2009 to 2019 during which GL have been analysed. Radon observations at the Bilbao city radiological station were used because radon is a suitable atmospheric tracer by which to assess and characterise air quality dynamics. The cluster analysis of these periods revealed that increases in radon concentrations, mainly in the afternoon, are associated with the occurrence of GL, but that, this increase in the daily variability of radon concentrations in Bilbao is not reflected in all these GL periods. This variability in the impact of the GL scenario on radon concentrations is associated with the location of Bilbao: along the Nervion valley and 16 km from the coast. The analysis of three GL periods using 10-min surface meteorological and radon data showed an anomalous increase in radon with the arrival of maritime winds, which is associated with the process of a progressive accumulation of radon concentrations over the coastal area in the previous days, and the displacement of these air masses inland owing to the development of the GL event. Our results consequently identify the impact of GL on urban air quality in the afternoon, along with the fact that the complex layout of this coastal area, with the presence of valleys and mountains, favours the formation of reservoir layers above the coastal and valley areas, thus influencing on daily variability of air pollution concentrations. These increases in radon concentrations do not present a significant impact on human health.
影响城市空气质量的一个主要因素是气象条件。本研究的目的是了解和描述“Galerna”（GL）（西班牙北部海岸的一次突然西风变化）对毕尔巴鄂市（西班牙北部）空气质量日变化的影响。共分析了 2009 年至 2019 年期间的 46 个为期一天的时间段，其中出现了 GL。毕尔巴鄂市辐射站的氡观测被用来评估和描述空气质量动态，因为氡是一种合适的大气示踪剂。这些时期的聚类分析表明，氡浓度的增加，主要是在下午，与 GL 的发生有关，但这种在毕尔巴鄂市氡浓度日变化的增加并不反映在所有这些 GL 时期。这种 GL 情景对氡浓度影响的可变性与毕尔巴鄂市的位置有关：沿着内尔维翁山谷，距离海岸 16 公里。使用 10 分钟的地面气象和氡数据对三个 GL 时期的分析表明，随着海风的到来，氡异常增加，这与前几天沿海地区氡浓度逐渐积累的过程有关，以及由于 GL 事件的发展，这些空气团向内陆移动。因此，我们的结果确定了 GL 对下午城市空气质量的影响，以及该沿海地区复杂的布局，存在山谷和山脉，有利于在沿海和山谷地区上方形成储层层，从而影响空气污染浓度的日变化。这些氡浓度的增加对人体健康没有显著影响。
