Yang Yi, Han Li-Yuan, Liu Huan-Wu, Lei Ying, Li Yi, Xu Hui-Ning
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Huan Jing Ke Xue. 2020 Feb 8;41(2):743-749. doi: 10.13227/j.hjkx.201907073.
Fluorescence characteristics and sources of dissolved organic matter (DOM) in snowfall in Xi'an were studied by three-dimensional fluorescence spectroscopy, parallel factor analysis, and backward trajectory model, which provided a data basis for the analysis of the chemical composition and source of atmospheric organic pollutants. Results show that the DOC content of DOM was 0.88-10.92 mg·L. DOM mainly contained humus-like, fulvic acid-like, tryptophan-like, and tyrosine-like substances. The fluorescence intensity and the summed intensities of these substances exhibited significant positive correlations with the DOC and UV (<0.01). The fluorescence index (FI), biological source index (BIX), and humic index (HIX) values of DOM during snowfall were 1.50-1.75, 0.87-1.25, and 1.11-1.97, respectively. FI was positively correlated with BIX and negatively correlated with HIX (<0.05). During snowfall, the air mass transmission trajectories included the local transmission, long-distance transmission starting from Xinjiang (through Gansu and Ningxia), and medium-distance transmissions starting from Inner Mongolia (through Ningxia) and Shandong (via Henan), accounting for 38.78%, 24.04%, 19.87%, and 17.31% of the total, respectively. This indicates that the content or relative content of the DOM contained in the precipitation can be characterized by fluorescence intensities and their sums of the humic-like, fulvic acid-like, tryptophan-like, and tyrosine-like tyrosine. The DOM in snowfall had both biological and terrestrial characteristics, and belonged to a self-generated source with the newly produced organic matter or matter with stronger self-source characteristics. Local transmission had the most significant contribution to the source of snowfall DOM.
利用三维荧光光谱、平行因子分析和后向轨迹模型研究了西安市降雪过程中溶解有机物（DOM）的荧光特性和来源，为分析大气有机污染物的化学组成和来源提供了数据依据。结果表明，DOM的DOC含量为0.88～10.92mg·L。DOM主要包含类腐殖质、类富里酸、类色氨酸和类酪氨酸物质。这些物质的荧光强度及其总和强度与DOC和UV呈显著正相关（<0.01）。降雪期间DOM的荧光指数（FI）、生物源指数（BIX）和腐殖化指数（HIX）值分别为1.50～1.75、0.87～1.25和1.11～1.97。FI与BIX呈正相关，与HIX呈负相关（<0.05）。降雪期间，气团传输轨迹包括本地传输、从新疆出发（经甘肃和宁夏）的远距离传输以及从内蒙古出发（经宁夏）和山东出发（经河南）的中距离传输，分别占总数的38.78%、24.04%、19.87%和17.31%。这表明，降水中所含DOM的含量或相对含量可以通过类腐殖质、类富里酸、类色氨酸和类酪氨酸的荧光强度及其总和来表征。降雪过程中的DOM具有生物和陆源特征，属于自生源，具有新产生的有机物或自源特征较强的物质。本地传输对降雪DOM的来源贡献最为显著。
