采用高效阴离子交换色谱-脉冲安培检测技术(HPAEC-PAD)对柳州市春、秋、冬3个季节大气PM2.5中的糖类进行测定,分析了PM2.5和总糖类物质的浓度水平和分布特征,并探讨其指示意义.结果表明,柳州市PM2.5、总糖类物质浓度水平季节分布规律相似,均呈现冬季高于春季和秋季、秋季最低的污染特征.且3个季节总糖类物质的含量水平有显著性差异,3个监测点空间上总糖类物质的含量水平无显著性差异.总糖类物质中左旋葡聚糖占比基本超过80%,左旋葡聚糖及其异构体与总糖具有明显的相关性,表明左旋葡聚糖及其异构体能较好代表总糖类物质.柳州市PM2.5中左旋葡聚糖/甘露聚糖(L/M)、左旋葡聚糖/(甘露聚糖+半乳聚糖)[L/(M+G)]均值为10.4±2.3和8.6±2.1,结合本地的农业和林业生产情况,判断柳州市大气PM_(2.5)中的生物质燃烧源主要来源于软木和作物残渣的混合贡献.
In this paper, the technology of high performance anion exchange chromatography-pulsed amperometric detection(HPAEC-PAD) was used to measure the carbohydrates in the atmospheric particulates during three seasons(spring, autumn and winter) in Liuzhou, to study the levels, distribution characteristics and sources of carbohydrates. The results show that, the concentrations of PM2.5 and the total carbohydrates are higher than that in spring and autumn, with lowest values in autumn and similar seasonal distribution patterns. Also, there is a significant difference in the level of total carbohydrates content during three seasons, but the difference between three monitoring sites is of no significance in space. Levoglucosan makes up almost more than 80% of total carbohydrates. There is obvious relationship between levoglucosan, its isomers and the total carbohydrates, suggesting that levoglucosan and its isomers can represent the total carbohydrates well. The average ratios of levoglucosan/mannosan(L/M) and levoglucosan/(mannosan+galactosan) [L/(M+G)] are 10.4±2.3 and 8.6±2.1, respectively. Considering with the local agriculture and forestry production situations, it can be initially inferred that the mixture of cork and crop residues are the main biomass combustion sources in the PM2.5 of Liuzhou.