新冠疫情对我国NO2排放影响的时空分析

基于高分辨率的TROPOMI数据,分析了我国疫情爆发期的NO₂空间分布情况,同时对比了疫情同比期和环比期不同地区的变化情况.分析表明,全国范围内NO₂柱浓度的同比下降率和环比下降率分别为40.46%和50.09%,经济发达且人口稠密的城市群,排放量下降较为显著,其中江苏、河南、山东、浙江等NO₂历史排放较高的省份受疫情影响更大.湖北省疫情期的NO₂柱浓度绝对值(1.63×10¹⁵molec/cm²)在中东部省份属于最低位水平,同比和环比下降率也均在50%以上.相对来说,武汉、孝感等周边城市的影响远大于十堰、恩施等西部山区.地基国控站点的NO₂质量浓度也显示了与卫星观测较一致的空间分布和变化趋势,证明了采用“自上而下”的遥感手段,可以对不同区域的大气污染排放强度和社会经济活动水平进行快速评估.

Spatiotemporal analysis on the impact of COVID-19 pandemic on NO2 emission in China

Based on the high-resolution TROPOMI data, this paper analyzed the spatial distribution of NO₂ column density during the COVID-19 outbreaking period in China, and revealed the spatial variations in the NO₂ changes during the year-on-year and month-on-month COVID-19 pandemic. The analysis showed that during the pandemic, the nationwide decline in NO₂ column density compared to the NO₂ level during the same period in 2019 (year-on-year) and during one-month before (month-on-month) the pandemic reached 40.46% and 50.09%, respectively. The economically developed and populous urban agglomerations had a significant decrease in emissions. Specifically, provinces with high historical NO₂ emissions, including Jiangsu, Henan, Shandong, Zhejiang, etc., were more affected by the epidemic. Hubei showed the lowest NO₂ column density (1.63×10¹⁵molec/cm²) during the epidemic period among the central and eastern provinces, with the NO₂ decrease compared to the NO₂ level during the same period in 2019 and during one-month before the pandemic greater than 50%. Regarding different cities in Hubei, the influence of the COVID-19 pandemic on the surrounding cities, e.g. Wuhan and Xiaogan, was much greater than that on the western mountainous cities, e.g. Shiyan and Enshi. The measurements of NO₂ concentration at the ground-based national air quality monitoring stations also showed a consistent spatiotemporal trend with satellite observations, indicating that the "top-down" remote sensing method can efficiently reflects the intensity of air pollution emissions and the level of socio-economic activities in different regions.