| 西安市降雪中DOM荧光特性和来源分析 |
| 摘要点击 2770 全文点击 1132 投稿时间：2019-07-08 修订日期：2019-09-29 |
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| 中文关键词 降雪 溶解性有机物 荧光特性 平行因子分析 后向轨迹模型 来源 |
| 英文关键词 snowfall dissolved organic matter fluorescence characteristics parallel factor analysis backward trajectory model source |
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| 中文摘要 |
| 利用三维荧光光谱、平行因子分析模型和后向轨迹模型等，分析西安市降雪中溶解性有机物（DOM）的荧光特性和来源，研究结果可为大气有机污染物的化学组成和来源分析提供数据基础.结果表明，降雪DOM的DOC含量为0.88~10.92 mg·L-1，主要含有类腐殖质、类富里酸、类色氨酸和类酪氨酸，它们荧光强度及其总和与DOC和UV254呈显著正相关（P<0.01）.降雪过程中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，且FI与BIX和HIX分别呈正相关和负相关（P<0.05）.降雪期间气团传输轨迹包括：本地源、起始于新疆（途经甘肃、宁夏）的长距离传输、起始于内蒙古（途经宁夏）和山东（途经河南）的中距离传输，分别占总量的38.78%、24.04%、19.87%和17.31%.结果也表明，可利用代表类腐殖质、类富里酸、类色氨酸和类酪氨酸荧光峰的荧光强度与其总和表征降水中DOM的含量或相对含量，降雪中DOM兼具生物源和陆源，属于自生来源且有机质为新近产生或具有较强自源特征，本地源对降雪DOM的来源贡献最为显著. |
| 英文摘要 |
| 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-1. 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 UV254 (P<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 (P<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. |
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