冬季积雪期燃煤排放的人为氯对大气 ClNO₂ 的贡献

Nitrous pentoxide (N₂O₅) and nitryl chloride (ClNO₂) are recognized as crucial reactive nitrogen species in the polluted troposphere. ClNO₂ serves as a precursor to highly reactive chlorine radicals, influencing atmospheric oxidation processes. This study conducted long-term field observations of N₂O₅ and ClNO₂, coupled with the CAMx three-dimensional numerical model, to examine ClNO₂ concentration variations during the snow cover period in the Beijing-Tianjin-Hebei and Northeast regions. Research findings indicated that the BT09 scheme outperformed the YU20 scheme in simulating ClNO₂ concentrations. This discrepancy might be attributed to the formation of ice films on aerosol surfaces during snow cover, altering aerosol water content and consequently affecting γN₂O₅ and φClNO₂. Annual emissions of HCl, PCl, and Cl₂, primary anthropogenic chlorine species emitted during coal combustion, were substantial, totaling 180.53 Gg, 20.51 Gg and 7.29 Gg, respectively. Under snow cover conditions, the increase in temperature in coastal urban areas led to an increase in liquid water on the surface of snow particles, enhancing N₂O₅ hydrolysis. Incorporating anthropogenic chlorine emissions from coal combustion alongside heterogeneous N₂O₅ chemical processes on surfaces markedly improved ClNO₂ simulation accuracy, emphasizing the decisive influence of anthropogenic chlorine emissions on regional ClNO₂ concentrations. This study provides essential scientific foundations for a comprehensive understanding of atmospheric oxidation and the development of control strategies.