Air Pollution Scenario over China during COVID-19
Air Pollution Scenario over China during COVID-19
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DOI：
10.3390/rs12132100
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发表时间：
2020-07-01
期刊：
影响因子：
5
通讯作者：
Qiu, Zhongfeng
中科院分区：
文献类型：
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作者：
Nichol, Janet E.;Bilal, Muhammad;Qiu, Zhongfeng
2019年11月至2020年4月的COVID-19期间，中国前所未有的经济放缓本应减少雾霾城市的污染。然而，中分辨率成像光谱仪（MODIS）卫星反演的气溶胶光学厚度（AOD）显示，与前一个冬季相比，京津冀（BHT）地区和东北、华中大部分地区气溶胶浓度明显增加。来自地面监测站的细颗粒物（PM2. 5）数据显示，北京在2020年1月至2月期间增加了19. 5%，而天津则没有减少。在2020年3月和4月，出现了一个不同的空间模式，在中国大陆的50%以上地区观察到非常高的AOD水平，包括西北和西南的周边地区。与此同时，臭氧监测仪（OMI）卫星获得的NO2浓度在中国各地急剧下降。北京和中国各地PM2.5的增加而NO2的减少可能是由于二次颗粒物的产生增加。当氮氧化物的减少导致臭氧形成增加时，就会形成这些物质，从而增加大气的氧化能力。地面空气质量数据显示，二零二零年二月及三月期间，精细模式气溶胶的数量增加，以及在COVID-19封城期间雾霾事件期间，PM2. 5、相对湿度（RH）和臭氧水平增加，为这一解释提供了支持。反向轨迹表明，影响华北和华东工业中心的气团的起源是本地的。造成大气颗粒物增加的其他因素可能包括周边地区膨胀的工业生产，以补偿主要人口和工业中心的损失，以及低风速。对COVID-19关闭导致的异常大气条件的卫星监测可以加强对烟雾形成的了解，并试图控制它。
The unprecedented slowdown in China during the COVID-19 period of November 2019 to April 2020 should have reduced pollution in smog-laden cities. However, moderate resolution imaging spectrometer (MODIS) satellite retrievals of aerosol optical depth (AOD) show a marked increase in aerosols over the Beijing-Tianjin-Hebei (BHT) region and most of Northeast and Central China, compared with the previous winter. Fine particulate (PM2.5) data from ground monitoring stations show an increase of 19.5% in Beijing during January and February 2020, and no reduction for Tianjin. In March and April 2020, a different spatial pattern emerges, with very high AOD levels observed over 50% of the Chinese mainland, and including peripheral regions in the northwest and southwest. At the same time, ozone monitoring instrument (OMI) satellite-derived NO2 concentrations fell drastically across China. The increase in PM2.5 while NO2 decreased in BTH and across China is likely due to enhanced production of secondary particulates. These are formed when reductions in NOx result in increased ozone formation, thus increasing the oxidizing capacity of the atmosphere. Support for this explanation is provided by ground level air quality data showing increased volume of fine mode aerosols throughout February and March 2020, and increased levels of PM2.5, relative humidity (RH), and ozone during haze episodes in the COVID-19 lockdown period. Backward trajectories show the origin of air masses affecting industrial centers of North and East China to be local. Other contributors to increased atmospheric particulates may include inflated industrial production in peripheral regions to compensate loss in the main population and industrial centers, and low wind speeds. Satellite monitoring of the extraordinary atmospheric conditions resulting from the COVID-19 shutdown could enhance understanding of smog formation and attempts to control it.