EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Halogens enhance haze pollution in China

Qinyi Li1, Xiao Fu2,3, Xiang Peng2, Weihao Wang2, Alba Badia4, Rafael P. Fernandez1,5, Carlos A. Cuevas1, Yujing Mu6, Jianmin Chen7, Jose L. Jimenez8, Tao Wang2, and Alfonso Saiz-Lopez1
Qinyi Li et al.
  • 1Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Madrid 28006, Spain (
  • 2Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China
  • 3Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
  • 4Institute of Environmental Science and Technology (ICTA), Universitat Autònoma de Barcelona (UAB), Barcelona 08193, Spain
  • 5Institute for Interdisciplinary Science (ICB), National Research Council (CONICET), FCEN-UNCuyo, Mendoza M5502JMA, Argentina
  • 6Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
  • 7Department of Environmental Science and Engineering, Fudan University, Institute of Atmospheric Sciences, Shanghai 200433, China
  • 8Cooperative Institute for Research in Environmental Sciences and Department of Chemistry, University of Colorado, Boulder, CO 80309, USA

Severe and persistent haze events in northern China, characterized by high loading of fine aerosol especially of secondary origin, negatively impact human health and the welfare of ecosystems. However, current knowledge cannot fully explain the formation of this haze pollution. Despite field observations of elevated levels of reactive halogen species (e.g., BrCl, ClNO2, Cl2, HBr) at several sites in China, the influence of halogens (particularly bromine) on haze pollution is largely unknown. Here, for the first time, we compile an emission inventory of anthropogenic bromine and quantify the collective impact of halogens on haze pollution in northern China. We utilize a regional model (WRF-Chem), revised to incorporate updated halogen chemistry and anthropogenic chlorine and bromine emissions and validated by measurements of atmospheric pollutants and halogens, to show that halogens enhance the loading of fine aerosol in northern China (on average by 21%) and especially its secondary components (~130% for secondary organic aerosol and ~20% for sulfate, nitrate, and ammonium aerosols). Such a significant increase is attributed to the enhancement of atmospheric oxidants (OH, HO2, O3, NO3, Cl, and Br) by halogen chemistry, with a significant contribution from previously unconsidered bromine. These results show that higher recognition of the impact of anthropogenic halogens shall be given in haze pollution research and air quality regulation.

How to cite: Li, Q., Fu, X., Peng, X., Wang, W., Badia, A., Fernandez, R. P., Cuevas, C. A., Mu, Y., Chen, J., Jimenez, J. L., Wang, T., and Saiz-Lopez, A.: Halogens enhance haze pollution in China, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4097,, 2022.