【摘要】 水溶性有机氮（WSON）在大气化学和气候变化中具有重要作用,目前鲜有针对WSON粒径分布的研究。本研究利用大流量采样器在2014年9月至2015年7月期间采集了广州市各个季节PM₁₀中不同粒径段（<0.49μm、0.49～0.95μm、0.95～1.5μm、1.5～3.0μm、3.0～7.2μm、7.2～10μm）大气颗粒物样品共100个,分析了其中的水溶性总氮（WSTN）、WSON以及水溶性无机氮（WSIN）含量。结果表明,各个粒径段中WSON的浓度呈现相似的季节变化特征,秋、冬季较高,春、夏季较低。WSON主要分布在细颗粒物上,PM₃中WSON的季节平均浓度在1.15～2.62μg/m³范围内,占PM₁₀中WSON总量的63%～71%。WSON的粒径分布呈现单峰分布,主要富集在0.49～1.5μm粒径段。主成分分析/绝对主成分得分（PCA/APCS）分析表明,<0.49μm颗粒物上的WSON主要来源于本地化石燃料的燃烧排放;0.49～0.95μm颗粒物的WSON主要来源于建筑扬尘和光化学氧化二次生成过程;0.95～1.5μm颗粒物的WSON主要来源于光化学氧化二次生成过程。研究结果增加了目前对于WSON粒径分布特征和来源的认识。更多还原

【Abstract】 Water-soluble organic nitrogen（WSON）plays an important role in atmospheric chemistry and climatic change.However,few studies have focused on WSON in size-segregated particles.In this study,size-segregated particle samples in the size ranges of<0.49μm,0.49–0.95μm,0.95–1.5μm,1.5–3.0μm,3.0–7.2μm,7.2–10μm were collected in Guangzhou,China from September 2014 to July 2015 by a high-volume sampler.Samples were analyzed for water-soluble total nitrogen（WSTN）,WSON and and water-soluble inorganic ions（WSIN）.The concentrations of WSON in each size range showed a similar seasonal trend with higher concentrations in autumn and winter and lower concentrations in spring and summer.The seasonal average concentrations of WSON in PM₃ ranged from 1.15 to 2.62μg/m³,contributing to 63%–71%of the WSON in PM₁₀.The concentrations of WSON in particles<3μm exhibited a unimodal distribution in four seasons,enriching in the 0.49–0.95μm particles.The principal component analysis（PCA）/absolute principal component scores（APCS）analysis showed that WSON can be mainly attributed to the burning of local fossil fuels in particles<0.49μm,to construction dust and photochemical oxidation leading to its secondary formation in 0.49–0.95μm particles;and to photochemical oxidation leading to secondary formation alone in 0.95–1.5μm particles.Our research improves our understanding of the environmental geochemical processes of organic nitrogen compounds.更多还原