Humic-like substances (HULIS), the most ubiquitous class of water-soluble organic compounds in the atmosphere could enhance the generation of reactive oxygen species (ROS), and play a significant role in impacting aerosol chemistry and health effects. In this study, twenty-three PM2.5 samples were collected in the atmosphere of suburban Shanghai from November 29 to December 17, 2015, and March 17 to April 30, 2016, during haze and non-haze days. The mean concentrations of HULIS in spring both in haze and non-haze days (2.34 ± 0.70 µg/m3 and 1.94 ± 0.88 µg/m3) were relatively higher than in that of winter (1.93 ± 0.95 µg/m3 and 1.31 ± 0.28 µg/m3). The ammonium, sulfate, and nitrate are the dominant ionic species in both winter and spring during haze days in suburban Shanghai. Correlation results revealed that HULIS formation was highly associated with the biomass burning (K) and secondary aerosols formation (SIA: NH4+, SO42−, NO3−) and also well-correlated with F− and ca.2+ ions, crustal elements (Al and Fe) and anthropogenic pollution metals (As, Se, Rb, Sr, and Pb), suggesting that HULIS-C formation might be from biomass burning and secondary aerosol processes and also mixed formation (marine, crustal and industrial emissions) sources. From the coinciding results of the clustering analysis and weighted-CWT model, the principal potential source regions were the short transports from the Yangtze River Delta (YRD) regions, local regions, marine areas (the Bohai Sea, the Yellow Sea, the East China Sea) and also the long-range transports from northwestern in those seasons.

中文翻译：

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雾霾天和非雾霾天上海郊区PM2.5中HULIS-C的来源及其与微量金属、离子种类的关系

腐殖质类物质 (HULIS) 是大气中最普遍的一类水溶性有机化合物，可以增强活性氧 (ROS) 的产生，并在影响气溶胶化学和健康影响方面发挥重要作用。本研究于2015年11月29日至12月17日和2016年3月17日至4月30日，在雾霾天和非雾霾天期间，在上海郊区的大气中收集了23个PM2.5样本。春季雾霾天和非雾霾天 HULIS 的平均浓度（2.34 ± 0.70 µg/m3 和 1.94 ± 0.88 µg/m3）相对高于冬季（1.93 ± 0.95 µg/m3 和 1.31 ± 0.28 µg） /立方米）。在上海郊区的雾霾天，铵、硫酸盐和硝酸盐是冬春季的主要离子种类。相关性结果表明，HULIS 的形成与生物质燃烧 (K) 和二次气溶胶的形成 (SIA: NH4+, SO42−, NO3−) 高度相关，也与 F− 和 ca.2+ 离子、地壳元素 (Al和 Fe）和人为污染金属（As、Se、Rb、Sr 和 Pb），表明 HULIS-C 的形成可能来自生物质燃烧和二次气溶胶过程以及混合形成（海洋、地壳和工业排放）来源。从聚类分析和加权CWT模型的一致结果来看，主要的潜在源区是来自长江三角洲（YRD）地区、局地地区、海域（渤海、黄海、华东）的短程运输。海）以及这些季节从西北部的远程运输。