| Title: | An observation approach in evaluation of ozone production to precursor changes during the COVID-19 lockdown |
| Author(s): | Qi J; Mo Z; Yuan B; Huang S; Huangfu Y; Wang Z; Li X; Yang S; Wang W; Zhao Y; Wang X; Wang W; Liu K; Shao M; |
| Address: | "Institute for Environmental and Climate Research, Jinan University, Guangzhou, 511443, China. Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou, 511443, China. Multiphase Chemistry Department, Max Planck Institute for Chemistry, Mainz, 55128, Germany. Bureau of Ecology and Environment of Dongguan, Dongguan, 523099, China" |
| DOI: | 10.1016/j.atmosenv.2021.118618 |
| ISSN/ISBN: | 1352-2310 (Print) 1352-2310 (Electronic) 1352-2310 (Linking) |
| Abstract: | "The increase of surface ozone during the Corona Virus Disease 2019 (COVID-19) lockdown in China has aroused great concern. In this study, we combine 1.5 years of measurements for ozone, volatile organic compounds (VOCs), and nitrogen oxide (NO(X)) at four sites to investigate the effect of COVID-19 lockdown on surface ozone in Dongguan, an industrial city in southern China. We show that the average concentrations of NO(X) and VOCs decreased by 70%-77% and 54%-68% during the lockdown compared to pre-lockdown, respectively. Based on the source apportionment of VOCs, the contribution of industrial solvent use reduced significantly (86%-94%) during the lockdown, and climbed back slowly along with the re-opening of the industry after lockdown. A slight increase in mean ozone concentration (3%-14%) was observed during the lockdown. The rise of ozone was the combined effect of substantial increase at night (58%-91%) and small reduction in the daytime (1%-17%). These conflicting observations in ozone response between day and night to emission change call for a more detailed approach to diagnostic ozone production response with precursor changes, rather than directly comparing absolute concentrations. We propose that the ratio of daily Ox (i.e. ozone + NO(2)) enhancement to solar radiation can provide a diagnostic parameter for ozone production response during the lockdown period. Smaller ratio of daily O(X) (ozone + NO(2)) enhancement to solar radiation during the lockdown were observed from the long-term measurements in Dongguan, suggesting significantly weakened photochemistry during the lockdown successfully reduces local ozone production. Our proposed approach can provide an evaluation of ozone production response to precursor changes from restrictions of social activities during COVID-19 epidemic and also other regional air quality abatement measures (e.g. public mega-events) around the globe" |
| Keywords: | COVID-19 lockdown Nox Ozone Solar radiation VOCs; |
| Notes: | "PubMed-not-MEDLINEQi, Jipeng Mo, Ziwei Yuan, Bin Huang, Shan Huangfu, Yibo Wang, Zelong Li, Xiaobing Yang, Suxia Wang, Wenjie Zhao, Yiming Wang, Xuemei Wang, Weiwen Liu, Kexuan Shao, Min eng England 2021/07/20 Atmos Environ (1994). 2021 Oct 1; 262:118618. doi: 10.1016/j.atmosenv.2021.118618. Epub 2021 Jul 14" |
