Impact of Covid-19 lockdown on PM 10, SO 2 and NO 2 concentrations in Sale City (Morocco)
Impact of Covid-19 lockdown on PM 10, SO 2 and NO 2 concentrations in Sale City (Morocco)
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DOI：
10.1016/j.scitotenv.2020.139541
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发表时间：
2020-09-15
影响因子：
9.8
通讯作者：
Krombi, M'hamed
中科院分区：
文献类型：
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作者：
Otmani, Anas;Benchrif, Abdelfettah;Krombi, M'hamed
2020年3月2日，摩洛哥首次报告了新冠肺炎。此后，为了防止其传播，摩洛哥政府宣布进入卫生紧急状态。采取了一系列迅速而严格的反措施，包括封锁城市、限制人口流动和禁止几乎所有可避免的活动。在本研究中，我们试图评估的一些空气污染物（主要是PM10，NO2和SO2）在萨莱市（西北摩洛哥）在封锁措施的水平的变化。在此背景下，于COVID-19封城期之前及期间持续测量PM10、SO2及NO2。由于采取了安全措施和控制行动，车辆尾气和工业生产的排放量大大减少，这有助于降低所研究污染物的浓度。结果显示，封城前与封城期间录得的PM10、SO2及NO2浓度分别相差75%、49%及96%。PM10浓度的降低幅度远小于NO2。使用HYSPLIT模型的三维气团后向轨迹表明，与封锁相关的PM10本地减排的好处被远距离传输的气溶胶的贡献所淹没。此外，这两个时期的气团反向轨迹和气象也存在显着差异。
Covid-19 was first reported in Morocco on March 2, 2020. Since then, to prevent its propagation, the Moroccan government declared a state of health emergency. A set of rapid and strict countermeasures have taken, including locking down cities, limiting population's mobility and prohibiting almost all avoidable activities. In the present study, we attempted to evaluate the changes in levels of some air pollutants (mainly PM10, NO2and SO2) in Salé city (North-Western Morocco) during the lockdown measures. In this context, a continuous measurement of PM10, SO2and NO2was carried before and during the Covid-19 lockdown period. As a consequence of the security measures and control actions undertaken, the emissions from vehicle exhaust and industrial production were significantly reduced, which contribute to the decrease in the concentrations of the studied pollutants. The obtained results showed that the difference between the concentrations recorded before and during the lockdown period were respectively 75%, 49% and 96% for PM10, SO2and NO2. PM10levels were much less reduced than NO2. The three-dimensional air mass backward trajectories, using the HYSPLIT model, demonstrated the benefits of PM10local emission reductions related to the lockdown were overwhelmed by the contribution of long-range transported aerosols outside areas. In addition, noteworthy differences in the air mass back trajectories and the meteorology between these two periods were evidenced.