Vapor isotopic evidence for the worsening of winter air quality by anthropogenic combustion-derived water
Meng Xing, Weiguo Liu, Xia Li, Weijian Zhou, Qiyuan Wang, Jie Tian, Xiaofei Li, Xuexi Tie, Guohui Li, Junji Cao, Huiming Bao, Zhisheng An
Abstract
Significance Water vapor emitted from anthropogenic combustion for winter heating in northern China may exacerbate air pollution. This hypothesis is of considerable scientific and environmental interest. We conducted a multiyear sampling campaign of air vapor isotope compositions and associated atmospheric data from the city of Xi’an, located in an enclosed basin in northwestern China. We found that the fraction of combustion-derived water vapor increases with increasing relative humidity and with the concentration of particulate matter with an aerodynamic diameter less than 2.5 μm in polluted conditions based on field observation, isotopic analysis, and numerical simulation. Our results demonstrated that combustion-derived water is nontrivial when considering energy policy for improving air quality.