Daytime SO2 chemistry on ubiquitous urban surfaces as a source of organic sulfur compounds in ambient air

Huifan Deng; Pascale S J Lakey; Yiqun Wang; Pan Li; Jinli Xu; Hongwei Pang; Jiangping Liu; Xin Xu; Xue Li; Xinming Wang; Yuzhong Zhang; Manabu Shiraiwa; Sasho Gligorovski

doi:10.1126/sciadv.abq6830

Daytime SO₂ chemistry on ubiquitous urban surfaces as a source of organic sulfur compounds in ambient air

Sci Adv. 2022 Sep 30;8(39):eabq6830. doi: 10.1126/sciadv.abq6830. Epub 2022 Sep 28.

Authors

Huifan Deng^{1

2

3

4}, Pascale S J Lakey⁵, Yiqun Wang^{1

4}, Pan Li^{1

4}, Jinli Xu^{1

4}, Hongwei Pang¹, Jiangping Liu¹, Xin Xu⁶, Xue Li^{6

7

8}, Xinming Wang^{1

2

3}, Yuzhong Zhang⁹, Manabu Shiraiwa⁵, Sasho Gligorovski^{1

2

3}

Affiliations

¹ State Key Laboratory of Organic Geochemistry and Guangdong Provincial Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510 640, China.
² Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China.
³ Chinese Academy of Science, Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
⁴ University of Chinese Academy of Sciences, Beijing, China.
⁵ Department of Chemistry, University of California, Irvine, Irvine, CA 92687-2025, USA.
⁶ Institute of Mass Spectrometry and Atmospheric Environment, Jinan University, Guangzhou 510632, China.
⁷ Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air Pollution, Guangzhou 510632, China.
⁸ Guangdong-Hongkong-Macau Joint Laboratory of Collaborative Innovation for Environmental Quality, Guangzhou 510632, China.
⁹ Key Laboratory of Coastal Environment and Resources of Zhejiang Province, School of Engineering, Westlake University, Hangzhou 310024, China.

Abstract

The reactions of sulfur dioxide (SO₂) with surface-bound compounds on atmospheric aerosols lead to the formation of organic sulfur (OS) compounds, thereby affecting the air quality and climate. Here, we show that the heterogeneous reaction of SO₂ with authentic urban grime under near-ultraviolet sunlight irradiation leads to a large suite of various organic compounds including OS released in the gas phase. Calculations indicate that at the core area of Guangzhou, building surface uptake of SO₂ is 15 times larger than uptake of SO₂ on aerosol surfaces, yielding ~20 ng m^-3 of OS that represents an important fraction of the observed OS compounds (60 to 200 ng m^-3) in ambient aerosols of Chinese megacities. This chemical pathway occurring during daytime can contribute to the observed fraction of OS compounds in aerosols and improve the understanding of haze formation and urban air pollution.