Potential Effect of Halogens on Atmospheric Oxidation and Air Quality in China

Qinyi Li, Alba Badia, Tao Wang, Golam Sarwar, Xiao Fu, Li Zhang, Qiang Zhang, Jimmy Fung, Carlos A. Cuevas, Shanshan Wang, Bin Zhou, Alfonso Saiz-Lopez

Research output: Journal article publicationJournal articleAcademic researchpeer-review

33 Citations (Scopus)


Air pollution has been a hazard in China over recent decades threatening the health of half a billion people. Much effort has been devoted to mitigating air pollution in China leading to a significant reduction in primary pollutants emissions from 2013 to 2017, while a continuously worsening trend of surface ozone (O3, a secondary pollutant and greenhouse gas) was observed over the same period. Atmospheric oxidation, dominated by daytime reactions involving hydroxyl radicals (OH), is the critical process to convert freshly-emitted compounds into secondary pollutants, and is underestimated in current models of China's air pollution. Halogens (chlorine, bromine, and iodine) are known to profoundly influence oxidation chemistry in the marine environment; however, their impact on atmospheric oxidation and air pollution in China is unknown. In the present study, we report for the first time that halogens substantially enhance the total atmospheric oxidation capacity in polluted areas of China, typically 10% to 20% (up to 87% in winter) and mainly by significantly increasing OH level. The enhanced oxidation along the coast is driven by oceanic emissions, and that over the inland areas by anthropogenic emission. The extent and seasonality of halogen impact are largely explained by the dynamics of Asian monsoon, location and intensity of halogen emissions, and O3 formation regime. The omission of halogen emissions and chemistry may lead to significant errors in historical re-assessments and future projections of the evolution of atmospheric oxidation in polluted regions.

Original languageEnglish
Article numbere2019JD032058
JournalJournal of Geophysical Research: Atmospheres
Issue number9
Publication statusPublished - 16 May 2020


  • air qualityS
  • China
  • oxidation
  • reactive halogen
  • WRF-Chem

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology


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