Li Haiyan, Zhang Qi, Jiang Wenqing, Collier Sonya, Sun Yele, Zhang Qiang, He Kebin
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Department of Environmental Toxicology, University of California, Davis, CA 95616, USA.
Department of Environmental Toxicology, University of California, Davis, CA 95616, USA.
Sci Total Environ. 2021 Mar 1;758:143970. doi: 10.1016/j.scitotenv.2020.143970. Epub 2020 Dec 2.
Water-soluble organic aerosol (WSOA) in fine particles (PM) collected during wintertime in a polluted city (Handan) in Northern China was characterized using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (AMS). Through comparing with real-time measurements from a collocated Aerosol Chemical Speciation Monitor (ACSM), we determined that WSOA on average accounts for 29% of total organic aerosol (OA) mass and correlates tightly with secondary organic aerosol (SOA; Pearson's r = 0.95). The mass spectra of WSOA closely resemble those of ambient SOA, but also show obvious influences from coal combustion and biomass burning. Positive matrix factorization (PMF) analysis of the WSOA mass spectra resolved a water-soluble coal combustion OA (WS-CCOA; O/C = 0.17), a water-soluble biomass burning OA (WS-BBOA; O/C = 0.32), and a water-soluble oxygenated OA (WS-OOA; O/C = 0.89), which account for 10.3%, 29.3% and 60.4% of the total WSOA mass, respectively. The water-solubility of the OA factors was estimated by comparing the offline AMS analysis results with the ambient ACSM measurements. OOA has the highest water-solubility of 49%, consistent with increased hygroscopicity of oxidized organics induced by atmospheric aging processes. In contrast, CCOA is the least water soluble, containing 17% WS-CCOA. The distinct characteristics of WSOA from different sources extend our knowledge of the complex aerosol chemistry in the polluted atmosphere of Northern China and the water-solubility analysis may help us to understand better aerosol hygroscopicity and its effects on radiative forcing in this region.
利用高分辨率飞行时间气溶胶质谱仪（AMS）对中国北方污染城市（邯郸）冬季采集的细颗粒物（PM）中的水溶性有机气溶胶（WSOA）进行了表征。通过与并置的气溶胶化学形态监测仪（ACSM）的实时测量结果进行比较，我们确定WSOA平均占总有机气溶胶（OA）质量的29%，并且与二次有机气溶胶（SOA；皮尔逊相关系数r = 0.95）紧密相关。WSOA的质谱与环境SOA的质谱非常相似，但也显示出受煤炭燃烧和生物质燃烧的明显影响。对WSOA质谱进行的正矩阵因子分解（PMF）分析解析出一种水溶性煤炭燃烧有机气溶胶（WS-CCOA；O/C = 0.17）、一种水溶性生物质燃烧有机气溶胶（WS-BBOA；O/C = 0.32）和一种水溶性氧化有机气溶胶（WS-OOA；O/C = 0.89），它们分别占WSOA总质量的10.3%、29.3%和60.4%。通过将离线AMS分析结果与环境ACSM测量结果进行比较，估算了OA因子的水溶性。OOA的水溶性最高，为49%，这与大气老化过程导致的氧化有机物吸湿性增加相一致。相比之下，CCOA的水溶性最低，其中水溶性煤炭燃烧有机气溶胶占17%。来自不同来源的WSOA的独特特征扩展了我们对中国北方污染大气中复杂气溶胶化学的认识，并且水溶性分析可能有助于我们更好地理解该地区气溶胶的吸湿性及其对辐射强迫的影响。
