Aerosol Hygroscopicity during the Haze Red-Alert Period in December 2016 at a Rural Site of the North China Plain

作     者：Xuefei QI Junying SUN Lu ZHANG Xiaojing SHEN Xiaoye ZHANG Yangmei ZHANG Yaqiang WANG Haochi CHE Zhouxiang ZHANG Junting ZHONG Kaiyan TAN Huarong ZHAO Sanxue REN 

作者机构：State Key Laboratory of Severe Weather、Key Laboratory of Atmospheric Chemistry of China Meteorological Administration Chinese Academy of Meteorological Sciences Beijing 100081 Integrated Ecological-Meteorological Observation and Experimental Station Chinese Academy of Meteorological Sciences Beijing 100081 

出 版 物：《Journal of Meteorological Research》 (气象学报（英文版）)

年 卷 期：2018年第32卷第1期

页      面：38-48页

核心收录：

学科分类：07[理学] 070602[理学-大气物理学与大气环境] 0706[理学-大气科学] 

基　　金：Supported by the National Key Project of Ministry of Science and Technology of China(2016YFC0203305 and 2016YFC0203306) National Natural Science Foundation of China(41475118 and 41675129) Chinese Academy of Meteorological Sciences Basic Research Fund(2017Z011,2016Z001,and 2016Y004) 

主　　题：aerosol hygroscopicity scattering enhancement factor chemical composition 

摘      要：A humidification system was deployed to measure aerosol hygroscopicity at a rural site of the North China Plain during the haze red-alert period 17–22 December 2016. The aerosol scattering coefficients under dry [relative humidity（RH） 〈 30%] and wet（RH in the range of 40%–85%） conditions were simultaneously measured at wavelengths of450, 550, and 700 nm. It is found that the aerosol scattering coefficient and backscattering coefficient increased by only 29% and 10%, respectively when RH went up from 40% to 80%, while the hemispheric backscatter fraction went down by 14%, implying that the aerosol hygroscopicity represented by the aerosol scattering enhancement factor f（RH） is relatively low and RH exerted little effects on the aerosol light scattering in this case. The scattering enhancement factors do not show significant differences at the three wavelengths, only with an approximate 2% variation, suggesting that the aerosol hygroscopicity is independent of the wavelength. Aerosol hygroscopicity is highly dependent on the aerosol chemical composition. When there is a large mass fraction of inorganics and a small mass fraction of organic matter, f（RH） reaches a high value. The fraction of NO3^- was strongly correlated with the aerosol scattering coefficient at RH = 80%, which suggests that NO3^- played an important role in aerosol hygroscopic growth during the heavy pollution period.