Ozone profile retrievals from TROPOMI: Implication for the variation of tropospheric ozone during the outbreak of COVID-19 in China

Fei Zhao; Cheng Liu; Zhaonan Cai; Xiong Liu; Juseon Bak; Jae Kim; Qihou Hu; Congzi Xia; Chengxin Zhang; Youwen Sun; Wei Wang; Jianguo Liu

doi:10.1016/j.scitotenv.2020.142886

Ozone profile retrievals from TROPOMI: Implication for the variation of tropospheric ozone during the outbreak of COVID-19 in China

Sci Total Environ. 2021 Apr 10:764:142886. doi: 10.1016/j.scitotenv.2020.142886. Epub 2020 Oct 13.

Authors

Fei Zhao¹, Cheng Liu², Zhaonan Cai³, Xiong Liu⁴, Juseon Bak⁴, Jae Kim⁵, Qihou Hu⁶, Congzi Xia⁷, Chengxin Zhang⁷, Youwen Sun⁶, Wei Wang⁶, Jianguo Liu⁶

Affiliations

¹ Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China.
² Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230026, China; Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, China; Anhui Province Key Laboratory of Polar Environment and Global Change, University of Science and Technology of China, Hefei 230026, China. Electronic address: chliu81@ustc.edu.cn.
³ Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. Electronic address: caizhaonan@mail.iap.ac.cn.
⁴ Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, United States.
⁵ Pusan National University, Busan, Republic of Korea.
⁶ Key Lab of Environmental Optics & Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China.
⁷ School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.

Abstract

During the outbreak of the coronavirus disease 2019 (COVID-19) in China in January and February 2020, production and living activities were drastically reduced to impede the spread of the virus, which also caused a strong reduction of the emission of primary pollutants. However, as a major species of secondary air pollutant, tropospheric ozone did not reduce synchronously, but instead rose in some region. Furthermore, higher concentrations of ozone may potentially promote the rates of COVID-19 infections, causing extra risk to human health. Thus, the variation of ozone should be evaluated widely. This paper presents ozone profiles and tropospheric ozone columns from ultraviolet radiances detected by TROPOospheric Monitoring Instrument (TROPOMI) onboard Sentinel 5 Precursor (S5P) satellite based on the principle of optimal estimation method. We compare our TROPOMI retrievals with global ozonesonde observations, Fourier Transform Spectrometry (FTS) observation at Hefei (117.17°E, 31.7°N) and Global Positioning System (GPS) ozonesonde sensor (GPSO₃) ozonesonde profiles at Beijing (116.46°E, 39.80°N). The integrated Tropospheric Ozone Column (TOC) and Stratospheric Ozone Column (SOC) show excellent agreement with validation data. We use the retrieved TOC combining with tropospheric vertical column density (TVCD) of NO₂ and HCHO from TROPOMI to assess the changes of tropospheric ozone during the outbreak of COVID-19 in China. Although NO₂ TVCD decreased by 63%, the retrieved TOC over east China increase by 10% from the 20-day averaged before the lockdown on January 23, 2020 to 20-day averaged after it. Because the production of ozone in winter is controlled by volatile organic compounds (VOCs) indicated by monitored HCHO, which did not present evident change during the lockdown, the production of ozone did not decrease significantly. Besides, the decrease of NO_x emission weakened the titration of ozone, causing an increase of ozone.

Keywords: COVID-19; Lockdown; Ozone profile retrievals; Soft calibration; TROPOMI.

MeSH terms

Air Pollutants* / analysis
Beijing
COVID-19*
China / epidemiology
Communicable Disease Control
Disease Outbreaks
Environmental Monitoring
Humans
Ozone* / analysis
SARS-CoV-2

Substances

Air Pollutants
Ozone