Revisiting the levels of Aerosol Optical Depth in south-southeast Asia, Europe and USA amid the COVID-19 pandemic using satellite observations.
Revisiting the levels of Aerosol Optical Depth in south-southeast Asia, Europe and USA amid the COVID-19 pandemic using satellite observations.
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利用卫星观测重新研究新冠肺炎大流行期间南亚、东南亚、欧洲和美国的气溶胶光学厚度水平。
DOI：
10.1016/j.envres.2020.110514
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发表时间：
2021-03
影响因子：
8.3
通讯作者：
Sreekesh S
中科院分区：
文献类型：
--
作者：
Acharya P;Barik G;Gayen BK;Bar S;Maiti A;Sarkar A;Ghosh S;De SK;Sreekesh S
几十年来，世界各国都在处理空气质量问题，这是由于它们的生产模式和能源使用。2019冠状病毒病爆发为大流行病，全球经济随之停摆，首次为实时实验提供了基础，以研究地球仪减排对空气污染问题的影响。本研究涉及气溶胶光学厚度（AOD）的变化，这是空气污染的标志，因为冠状病毒大流行导致全球经济关闭。该研究考虑了南亚和东南亚（SSEA）、欧洲和美国因冠状病毒大流行而延长封锁期的国家。分析了封锁前（2017-2019年）和封锁期间（2020年）的中分辨率成像光谱仪（MODIS）的每日气溶胶光学厚度（AOD）和臭氧监测仪器（OMI）传感器的对流层NO2和SO2柱密度，包括风速（WS）和相对湿度（RH）等气象数据。采用Wilcoxon符号配对秩检验对封锁期间的平均AOD、NO2和SO2与封锁前的平均值进行统计比较。使用AERONET数据估计了MODIS导出的AOD的准确性，包括由于锁定而导致的AOD的变化模式。利用气溶胶光学厚度（AOD）、NO2和SO2的周距平数据，分析了各国在不同时间点实施限制措施时气溶胶负荷的时空变化。此外，随机森林为基础的回归（RF）模型被用来检查的影响，气象和排放参数的空间变化的AOD。在封锁期间，东南亚、欧洲及美国大部分地区的气溶胶光学厚度均大幅下降（-20%）。然而，在SSEA的东南部、欧洲的西部和美国地区获得了AOD增加的集群（30-60%）。在这些地区的大多数地区，NO2的减少量高达20- 40%，而SO2的排放量增加了30%。周距平具有明显的时空变化。在高相对湿度和低相对湿度条件下，在垂直向下气流的辅助下，我们发现了新粒子形成的证据。RF模型显示了一个可区分的排放和气象因素的相对重要性，这些地区之间的AOD的空间变异性。我们的研究结果表明，持续的封锁可能会为空气污染提供临时解决方案;然而，为了应对持续的空气质量问题，它需要转向更清洁的生产和能源模式。因此，这项研究的结果倡导在全球范围内制定替代能源政策。由于实施封城措施，东南亚、欧洲及美国大部分地区的AOD减少至20%。在封锁期间，NO2减少了20- 40%，而SO2在大多数地区增加了30%。SO2、WS和RH之间的复杂相互作用通过形成新的颗粒而导致高的AOD。在美国封锁期间，SO2浓度与居民流动性之间存在显著相关性。使用随机森林回归的排放和气象因素对AOD的可分辨的影响。
The countries around the world are dealing with air quality issues for decades due to their mode of production and energy usages. The outbreak of COVID-19 as a pandemic and consequent global economic shutdown, for the first time, provided a base for the real-time experiment of the effect of reduced emissions across the globe in abetting the air pollution issue. The present study dealt with the changes in Aerosol Optical Depth (AOD), a marker of air pollution, because of global economic shutdown due to the coronavirus pandemic. The study considered the countries in south and south-east Asia (SSEA), Europe and the USA for their extended period of lockdown due to coronavirus pandemic. Daily Aerosol Optical Depth (AOD) from Moderate-resolution imaging spectroradiometer (MODIS) and tropospheric column density of NO2 and SO2 from Ozone monitoring instrument (OMI) sensors, including meteorological data such as wind speed (WS) and relative humidity (RH) were analyzed during the pre-lockdown (2017–2019) and lockdown periods (2020). The average AOD, NO2 and SO2 during the lockdown period were statistically compared with their pre-lockdown average using Wilcoxon-signed-paired-rank test. The accuracy of the MODIS-derived AOD, including the changing pattern of AOD due to lockdown was estimated using AERONET data. The weekly anomaly of AOD, NO2 and SO2 was used for analyzing the space-time variation of aerosol load as restrictions were imposed by the concerned countries at the different points of time. Additionally, a random forest-based regression (RF) model was used to examine the effects of meteorological and emission parameters on the spatial variation of AOD. A significant reduction of AOD (−20%) was obtained for majority of the areas in SSEA, Europe and USA during the lockdown period. Yet, the clusters of increased AOD (30–60%) was obtained in the south-east part of SSEA, the western part of Europe and US regions. NO2 reductions were measured up to 20–40%, while SO2 emission increased up to 30% for a majority of areas in these regions. A notable space-time variation was observed in weekly anomaly. We found the evidence of the formation of new particles for causing high AOD under high RH and low WS, aided by the downward vertical wind flow. The RF model showed a distinguishable relative importance of emission and meteorological factors among these regions to account for the spatial variability of AOD. Our findings suggest that the continued lockdown might provide a temporary solution to air pollution; however, to combat persistent air quality issues, it needs switching over to the cleaner mode of production and energy. The findings of this study, thus, advocated for alternative energy policy at the global scale. AOD reduced to 20% in majority of the areas in SSEA, Europe and USA due to lockdown measures. NO2 reduction was measured up to 20–40%, while SO2 increased up to 30% for majority of the areas during lockdown. A complex interaction among SO2, WS and RH leads to high AOD by forming new particles. Significant correlation was found between SO2 concentration and residential mobility during lockdown period for USA. A distinguishable influence on AOD was obtained for emission and meteorological factors using random forest regression.
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DOI：
10.1016/s0140-6736(17)30505-6
发表时间：
2017-05-13
期刊：
Lancet (London, England)
影响因子：
--
作者：
Cohen AJ;Brauer M;Burnett R;Anderson HR;Frostad J;Estep K;Balakrishnan K;Brunekreef B;Dandona L;Dandona R;Feigin V;Freedman G;Hubbell B;Jobling A;Kan H;Knibbs L;Liu Y;Martin R;Morawska L;Pope CA 3rd;Shin H;Straif K;Shaddick G;Thomas M;van Dingenen R;van Donkelaar A;Vos T;Murray CJL;Forouzanfar MH
通讯作者：
Forouzanfar MH
影响因子：
3.8
作者：
Irie, H.;Boersma, K. F.;Wang, Z. F.
通讯作者：
Wang, Z. F.
影响因子：
9.8
作者：
Abdullah, Samsuri;Abu Mansor, Amalina;Ramly, Zamzam Tuah Ahmad
通讯作者：
Ramly, Zamzam Tuah Ahmad
影响因子：
9.8
作者：
Collivignarelli, Maria Cristina;Abba, Alessandro;Miino, Marco Carnevale
通讯作者：
Miino, Marco Carnevale
影响因子：
6.3
作者：
Hilboll, A.;Richter, A.;Burrows, J. P.
通讯作者：
Burrows, J. P.