Zeng Jinghai, Wang Can
State Key Joint Laboratory of Environment Simulation and Pollution Control (SKLESPC), School of Environment, Tsinghua University, Beijing 100084, China.
Department of Atmospheric Environment (Atmospheric Environment Administration of the Beijing-Tianjin-Hebei Region and Surrounding Areas), Ministry of Ecology and Environment, Beijing 100005, China.
Resour Conserv Recycl. 2022 Jun;181:106223. doi: 10.1016/j.resconrec.2022.106223. Epub 2022 Feb 9.
Previous studies have evaluated the impact of lockdown measures on air quality during the COVID-19 pandemic in China, but few have focused on the temporal characteristics and spatial heterogeneity of the impact across all 337 prefecture cities. In this study, we estimated the impact of the lockdown measures on air quality in each of 337 cities using the Regression Discontinuity in Time method. There was a short-term influence from January 24th to March 31th in 2020. The 337 cities could be divided into six categories showing different response and resilience patterns to the epidemic. Fine particulate matter (PM) in 89.5% of the cities was sensitive to the lockdown measures. The change of air pollutants showed high spatial heterogeneity. The provinces with a greater than 20% reduction in PM and PM and greater than 40% reduction in NO during the impact period were mainly concentrated southeast of the "Hu Line". Compared to the no-pandemic scenario, the national annual average concentration of PM, NO, PM, SO, and CO in 2020 were decreased by 6.3%, 10.6%, 7.4%, 9.0%, and 12.5%, respectively, while that of O increased by 1.1%.This result indicates that 2020 can still be used as a baseline for setting and allocating air improvement targets for the next five years.
以往的研究评估了中国新冠疫情期间封锁措施对空气质量的影响，但很少有研究关注全国337个地级市影响的时间特征和空间异质性。在本研究中，我们使用时间回归断点法估计了封锁措施对337个城市中每个城市空气质量的影响。2020年1月24日至3月31日存在短期影响。这337个城市可分为六类，显示出对疫情不同的应对和恢复模式。89.5%的城市细颗粒物（PM）对封锁措施敏感。空气污染物的变化呈现出高度的空间异质性。在影响期内，PM和PM下降幅度大于20%、NO下降幅度大于40%的省份主要集中在“胡焕庸线”东南部。与无疫情情景相比，2020年全国PM、NO、PM、SO和CO的年均浓度分别下降了6.3%、10.6%、7.4%、9.0%和12.5%，而O的年均浓度增加了1.1%。这一结果表明，2020年仍可作为设定和分配未来五年空气质量改善目标的基线。
