气候变化领域集成服务门户(CCPortal): Insights into the significant increase in ozone during COVID-19 in a typical urban city of China

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DOI	10.5194/acp-22-4853-2022
	Insights into the significant increase in ozone during COVID-19 in a typical urban city of China
	Zhang, Kun; Liu, Zhiqiang; Zhang, Xiaojuan; Li, Qing; Jensen, Andrew; Tan, Wen; Huang, Ling; Wang, Yangjun; de Gouw, Joost; Li, Li
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	4853
结束页码	4866
卷号	22 期号:7 页码:14
英文摘要	The outbreak of COVID-19 promoted strict restrictions to human activities in China, which led to a dramatic decrease in most air pollutant concentrations (e.g., PM2.5, PM10, NOx, SO2 and CO). However, an obvious increase in ozone (O-3) concentrations was found during the lockdown period in most urban areas of China. In this study, we conducted field measurements targeting ozone and its key precursors by utilizing a novel proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) in Changzhou, which is representative of the Yangtze River Delta (YRD) city cluster of China. We further applied the integrated methodology including machine learning, an observation-based model (OBM) and sensitivity analysis to obtain insights into the reasons causing the obvious increase in ozone. Major findings include the following: (1) by deweathered calculation, we found changes in precursor emissions contributed 1.46 ppbv to the increase in the observed O-3 during the full-lockdown period in 2020, while meteorology constrained 3.0 ppbv of O-3 in the full-lockdown period of 2019. (2) By using an OBM, we found that although a significant reduction in O-3 precursors was observed during the full-lockdown period, the photochemical formation of O-3 was stronger than that during the pre-lockdown period. (3) The NOx /VOC ratio dropped dramatically from 1.84 during the pre-lockdown to 0.79 in the full-lockdown period, which switched O-3 formation from a VOC-limited regime to the boundary of a NOx- and VOC-limited regime. Additionally, box model results suggested that the decrease in the NOx /VOC ratio during the full-lockdown period could increase the mean O-3 by 2.4 ppbv. Results of this study give insights into the relationship between O-3 and its precursors in urban area and demonstrate reasons for the obvious increase in O-3 in most urban areas of China during the COVID-19 lockdown period. This study also underlines the necessity of controlling anthropogenic oxygenated volatile organic compounds (OVOCs), alkenes and aromatics in the sustained campaign of reducing O-3 pollution in China.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000782152800001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273891
作者单位	Shanghai University; Shanghai University; University of Colorado System; University of Colorado Boulder; University of Colorado System; University of Colorado Boulder; TOFWERK AG
推荐引用方式 GB/T 7714	Zhang, Kun,Liu, Zhiqiang,Zhang, Xiaojuan,et al. Insights into the significant increase in ozone during COVID-19 in a typical urban city of China[J],2022,22(7):14.
APA	Zhang, Kun.,Liu, Zhiqiang.,Zhang, Xiaojuan.,Li, Qing.,Jensen, Andrew.,...&Li, Li.(2022).Insights into the significant increase in ozone during COVID-19 in a typical urban city of China.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(7),14.
MLA	Zhang, Kun,et al."Insights into the significant increase in ozone during COVID-19 in a typical urban city of China".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.7(2022):14.