Faculty of Engineering, University of the Basque Country UPV/EHU, 48013 Bilbao, Spain.
Int J Environ Res Public Health. 2021 Oct 20;18(21):11042. doi: 10.3390/ijerph182111042.
The impact of the lockdown, during the period from March to June in 2020, upon the air quality of the Basque Country in northern Spain is analyzed. The evaluation accounts for the meteorology of the period. Daily and sub-daily analysis of aerosol and ozone records show that the territory was repeatedly affected by episodes of pollutants from outer regions. Three episodes of PM and ten of PM were caused by transported anthropogenic European sulfates, African dust, and wildland fires. The region, with a varied orographic climatology, shows high and diverse industrial activity. Urban and interurban road traffic of the region decreased by 49% and 53%, respectively, whereas industrial activity showed a lower reduction of 20%. Consequently, the average concentrations of NO in the cities during the period fell to 12.4 µg·m (-45%). Ozone showed up to five exceedances of the WHOAQG for the daily maximum 8-h average in both rural and urban sites, associated with transport through France and the Bay of Biscay, under periods of European blocking anticyclones. However, averages showed a moderate decrease (-11%) in rural environments, in line with the precursor reductions, and disparate changes in the cities, which reproduced the weekend effect of their historical records. The PM decreased less than expected (-10% and -21%, in the urban and rural environments, respectively), probably caused by the modest decrease of industrial activity around urban sites and favorable meteorology for secondary aerosol formation, which could also influence the lower changes observed in the PM (-1% and +3% at the urban and rural sites, respectively). Consequently, in a future low NOx traffic emission scenario, the inter-regional PM and ozone control will require actions across various sectors, including the industry and common pollution control strategies.
分析了 2020 年 3 月至 6 月期间封锁措施对西班牙北部巴斯克地区空气质量的影响。该评估考虑了该时期的气象条件。气溶胶和臭氧记录的日和亚日分析表明，该地区多次受到来自外部地区污染物的影响。有三个 PM 事件和十个 PM 事件是由传输的人为欧洲硫酸盐、非洲尘埃和野火引起的。该地区拥有多样的地形气候，拥有高且多样的工业活动。该地区城市和城乡间道路交通量分别减少了 49%和 53%，而工业活动的降幅较小，为 20%。因此，在此期间城市中 NO 的平均浓度下降到 12.4 µg·m（-45%）。臭氧在农村和城市站点的日最大 8 小时平均浓度中出现了多达五次超过世界卫生组织空气质量准则的情况，这与在欧洲阻塞反气旋期间通过法国和比斯开湾的传输有关。然而，平均值显示农村环境中出现适度下降（-11%），与前体物减少相一致，而城市中的变化则有所不同，复制了其历史记录的周末效应。PM 的减少低于预期（城市和农村环境分别减少了 10%和 21%），这可能是由于城市周围工业活动的适度减少和有利于二次气溶胶形成的有利气象条件造成的，这也可能影响到 PM 观察到的较小变化（城市和农村站点分别减少了 1%和增加了 3%）。因此，在未来低氮氧化物交通排放情景下，跨区域 PM 和臭氧控制将需要各部门采取行动，包括工业和共同的污染控制策略。
