Exploring the variation of black and brown carbon during COVID-19 lockdown in megacity Wuhan and its surrounding cities, China

Qinglu Wang; Lili Wang; Minghui Tao; Nan Chen; Yali Lei; Yang Sun; Jinyuan Xin; Tingting Li; Jingxiang Zhou; Jingda Liu; Dongsheng Ji; Yuesi Wang

doi:10.1016/j.scitotenv.2021.148226

Exploring the variation of black and brown carbon during COVID-19 lockdown in megacity Wuhan and its surrounding cities, China

Sci Total Environ. 2021 Oct 15:791:148226. doi: 10.1016/j.scitotenv.2021.148226. Epub 2021 Jun 4.

Authors

Qinglu Wang¹, Lili Wang², Minghui Tao³, Nan Chen⁴, Yali Lei⁵, Yang Sun⁶, Jinyuan Xin¹, Tingting Li⁷, Jingxiang Zhou¹, Jingda Liu⁸, Dongsheng Ji¹, Yuesi Wang⁹

Affiliations

¹ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: wll@mail.iap.ac.cn.
³ Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China.
⁴ The Ecology and Environment Monitoring Center of Hubei Province, Wuhan 430070, China.
⁵ Key Lab of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai 200241, China.
⁶ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Atmospheric Sciences of Huainan, Institute of Atmospheric Physics, Chinese Academy of Sciences, Huainan 232000, China.
⁷ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China.
⁸ College of Atmospheric Physics, Nanjing University of Information Science & Technology, Nanjing 210044, China.
⁹ State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.

Abstract

Absorbing carbonaceous aerosols, i.e. black and brown carbon (BC and BrC), affected heavily on climate change, regional air quality and human health. The nationwide lockdown measures in 2020 were performed to against the COVID-19 outbreak, which could provide an important opportunity to understand their variations on light absorption, concentrations, sources and formation mechanism of carbonaceous aerosols. The BC concentration in Wuhan megacity (WH) was 1.9 μg m^-3 during lockdown, which was 24% lower than those in the medium-sized cities and 26% higher than those in small city; in addition, 39% and 16-23% reductions occurred compared with the same periods in 2019 in WH and other cities, respectively. Fossil fuels from vehicles and industries were the major contributors to BC; and compared with other periods, minimum contribution (64-86%) mainly from fossil fuel to BC occurred during the lockdown in all cities. Secondary BrC (BrCsec) played a major role in the BrC light absorption, accounting for 65-77% in WH during different periods. BrCsec was promoted under high humidity, and decreased through the photobleaching of chromophores under higher Ox. Generally, the lockdown measures reduced the BC concentrations significantly; however, the variation of BrCsec was slight.

Keywords: Black carbon; Brown carbon; COVID-19; Light absorption.

MeSH terms

COVID-19*
Carbon / analysis
China
Cities
Communicable Disease Control
Environmental Monitoring
Humans
SARS-CoV-2
Soot / analysis*

Substances

Soot
Carbon