Halogens Enhance Haze Pollution in China

LI, QINYI; FU, XIAO; PENG, XIANG; WANG, WEIHAO; BADIA, ALBA; FERNANDEZ, RAFAEL P.; CUEVAS, CARLOS A.; MU, YUJING; CHEN, JIANMIN; JIMENEZ, JOSE L.; WANG, TAO; SAIZ-LOPEZ, ALFONSO

ENVIRONMENTAL SCIENCE & TECHNOLOGY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2021 vol. 55 p. 13625 - 13637

0013-936X

Severe and persistent haze events in northern China, characterizedby high loading offine aerosol especially of secondary origin, negatively impacthuman health and the welfare of ecosystems. However, current knowledge cannotfully explain the formation of this haze pollution. Despitefield observations ofelevated levels of reactive halogen species (e.g., BrCl, ClNO2,Cl2, HBr) at severalsites in China, the influence of halogens (particularly bromine) on haze pollutionis largely unknown. Here, for thefirst time, we compile an emission inventory ofanthropogenic bromine and quantify the collective impact of halogens on hazepollution in northern China. We utilize a regional model (WRF-Chem), revised toincorporate updated halogen chemistry and anthropogenic chlorine and bromineemissions and validated by measurements of atmospheric pollutants and halogens,to show that halogens enhance the loading offine aerosol in northern China (onaverage by 21%) and especially its secondary components (∼130% for secondaryorganic aerosol and∼20% for sulfate, nitrate, and ammonium aerosols). Such asignificant 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 ofanthropogenic halogens shall be given in haze pollution research and air quality regulation.