Zhang Junke, Li Huan, Chen Luyao, Huang Xiaojuan, Zhang Wei, Zhao Rui
Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 611756, China.
Plateau Atmosphere and Environment Key Laboratory of Sichuan Province, School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu, 610225, China.
Atmos Environ (1994). 2022 Jan 1;268:118844. doi: 10.1016/j.atmosenv.2021.118844. Epub 2021 Nov 9.
In order to investigate the effects of the Coronavirus Disease 2019 (COVID-19) lockdown on air quality in cities in southwest China, a single particle aerosol mass spectrometer (SPAMS) and other online equipments were used to measure the air pollution in Chengdu, one of the megacities in this area, before and during the lockdown period. It was found that the concentrations of fine particulate matter (PM), nitric oxide (NO), nitrogen dioxide (NO), sulfur dioxide (SO) and carbon monoxide (CO) decreased by 38.6%, 77.5%, 47.0%, 35.1% and 14.1%, respectively, while the concentration of ozone (O) increased by 57.5% from the time before to the time during lockdown. All particles collected during the study period could be divided into eight categories: biomass burning (BB), coal combustion (CC), vehicle emissions (VE), cooking emissions (CE), Dust, K-nitrate (K-NO), K-sulfate (K-SO) and K-sulfate-nitrate (K-SN) particles, and their contributions changed significantly after the beginning of lockdown. Compared to before lockdown, the contribution of VE particles experienced the largest reduction (by 14.9%), whereas the contributions of BB and CE particles increased by 7.0% and 7.3%, respectively, during the lockdown period. Regional transmission was critical for pollution formation before lockdown, whereas the pollution that occurred during the lockdown period was caused mainly by locally emitted particles (such as VE, CE and BB particles). Weighted potential source contribution function (WPSCF) analysis further verified and emphasized the difference in the contribution of regional transmission for pollution formation before and during lockdown. In addition, the potential source area and intensity of the particles emitted from different sources or formation mechanisms were quite different.
为了调查2019年冠状病毒病（COVID-19）封锁措施对中国西南部城市空气质量的影响，在封锁期之前和期间，使用单颗粒气溶胶质谱仪（SPAMS）及其他在线设备对该地区特大城市之一成都的空气污染进行了测量。研究发现，细颗粒物（PM）、一氧化氮（NO）、二氧化氮（NO₂）、二氧化硫（SO₂）和一氧化碳（CO）的浓度分别下降了38.6%、77.5%、47.0%、35.1%和14.1%，而臭氧（O₃）的浓度从封锁前到封锁期间上升了57.5%。研究期间收集的所有颗粒物可分为八类：生物质燃烧（BB）、煤炭燃烧（CC）、车辆排放（VE）、烹饪排放（CE）、扬尘、硝酸钾（K-NO₃）、硫酸钾（K-SO₄）和硫酸硝酸钾（K-SN）颗粒，封锁开始后它们的贡献发生了显著变化。与封锁前相比，VE颗粒的贡献下降幅度最大（下降了14.9%），而在封锁期间，BB和CE颗粒的贡献分别增加了7.0%和7.3%。封锁前区域传输对污染形成至关重要，而封锁期间出现的污染主要由本地排放的颗粒物（如VE、CE和BB颗粒）造成。加权潜在源贡献函数（WPSCF）分析进一步验证并强调了封锁前后区域传输对污染形成贡献的差异。此外，不同来源或形成机制排放的颗粒物的潜在源区和强度差异很大。
