Atmospheric Particle Hygroscopicity and the Influence by Oxidation State of Organic Aerosols in Urban Beijing  

作　　者：Sinan Zhang Xiaojing Shen Junying Sun Yangmei Zhang Xiaoye Zhang Can Xia Xinyao Hu Junting Zhong Jialing Wang Shuo Liu 

机构地区：[1]State Key Laboratory of Severe Weather&Key Laboratory of Atmospheric Chemistry of CMA,Chinese Academy of Meteorological Sciences,Beijing 100081,China [2]School of Atmospheric Physics,Nanjing University of Information Science&Technology,Nanjing 210044,China

出　　处：《Journal of Environmental Sciences》2023年第2期544-556,共13页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.42075082,41875147,42090031);the S&T Development Fund of CAMS (No.2020KJ001),Basic Research Fund of CAMS (No.2020Z002);the Innovation and Development Program of CMA (No.CXFZ2021Z089)

摘　　要：A hygroscopic tandem differentialmobility analyser(H-TDMA)was used to observe the sizeresolved hygroscopic characteristics of submicron particles in January and April 2018 in urban Beijing.The probability distribution of the hygroscopic growth factor(HGF-PDF)in winter and spring usually showed a bimodal pattern,with more hygroscopic mode(MH)being more dominant.The seasonal variation in particle hygroscopicity was related to the origin of air mass,which received polluted southerly air masses in spring and clean northwesterly air masses in winter.Particles showed stronger hygroscopic behaviour during heavy pollution episodes(HPEs)with elevated concentrations of secondary aerosols,especially higher mass fraction of nitrate,which were indicated using the PM2.5(particulate matter with diameter below 2.5μm)mass concentration normalised by CO mass concentration.The hygroscopic parameter(κ)values were calculated using H-TDMA(κhtdma)and chemical composition(κchem).The closure study showed thatκchem was overestimated in winter afternoon when compared withκhtdma,because the organic particle hygroscopic parameter(κorg)was overestimated in the calculations.It was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol(HOA)with a weak water uptake ability.A positive relationship was observed betweenκorg and the ratio of oxygenated organic aerosol(OOA)and HOA,thereby indicating that the strong oxidation state enhanced the hygroscopicity of the particles.This study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity,which is of great significance for understanding the pollution formation mechanism in the North China Plain.

关 键 词：H-TDMA Hygroscopic parameter (κ) Organic AEROSOLS Oxidation state HEAVY pollution EPISODE (HPE) 

分 类 号：X513[环境科学与工程—环境工程]