An unexpected large continental source of reactive bromine and chlorine with significant impact on wintertime air quality

Xiang Peng, Weihao Wang, Men Xia, Hui Chen, A. R. Ravishankara, Qinyi Li, Alfonso Saiz-Lopez, Pengfei Liu, Fei Zhang, Chenglong Zhang, Likun Xue, Xinfeng Wang, Christian George, Jinhe Wang, Yujing Mu, Jianmin Chen, Tao Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

13 Citations (Scopus)


Halogen atoms affect the budget of ozone and the fate of pollutants such as hydrocarbons and mercury. Yet their sources and significances in polluted continental regions are poorly understood. Here we report the observation of unprecedented levels (averaging at 60 parts per trillion) of bromine chloride (BrCl) at a mid-latitude site in North China during winter. Widespread coal burning in rural households and a photo-assisted process were the primary source of BrCl and other bromine gases. BrCl contributed about 55% of both bromine and chlorine atoms. The halogen atoms increased the abundance of 'conventional' tropospheric oxidants (OH, HO2 and RO2) by 26%-73%, and enhanced oxidation of hydrocarbon by nearly a factor of two and the net ozone production by 55%. Our study reveals the significant role of reactive halogen in winter atmospheric chemistry and the deterioration of air quality in continental regions where uncontrolled coal combustion is prevalent.

Original languageEnglish
Article numbernwaa304
JournalNational Science Review
Issue number7
Publication statusPublished - Jul 2021


  • air pollution
  • BrCl
  • coal burning
  • North China
  • oxidation
  • reactive halogen

ASJC Scopus subject areas

  • General

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