研究报告
周志刚,胡芳伟,鲍宗炜,毛文文,冯加良.兰溪市PM2.5中有机物的组成特征、季节变化及来源研究[J].环境科学学报,2018,38(6):2253-2261
兰溪市PM2.5中有机物的组成特征、季节变化及来源研究
- Study on the composition characteristics, seasonal variation and sources of organic matter in PM2.5 in Lanxi
- 基金项目：兰溪市环保局PM2.5源解析项目（No.dscg-lx2015095-129）；国家自然科学基金项目（No.41473088）
- 作者
- 单位
- 周志刚
- 浙江省兰溪市环境保护监测站, 兰溪 321100
- 胡芳伟
- 浙江省兰溪市环境保护监测站, 兰溪 321100
- 鲍宗炜
- 浙江省兰溪市环境保护监测站, 兰溪 321100
- 毛文文
- 上海大学环境与化学工程学院, 上海 200444
- 冯加良
- 上海大学环境与化学工程学院, 上海 200444
- 摘要：为更好地理解我国中小城市地区大气细颗粒物的污染特征，利用大流量采样器采集了浙江中部典型内陆城市-兰溪市近郊和市区两个站点2016年四个季节的PM2.5样品，测定了碳质气溶胶的含量，利用气相色谱/质谱联用仪（GC/MS）分析了正构烷烃、藿烷、多环芳烃和长链脂肪酸等弱极性有机物的组成.结果表明，兰溪PM2.5中有机碳的年均浓度为9.7 μg·m-3，有机物中正构烷烃、藿烷、多环芳烃和脂肪酸的年均浓度分别为40.8、2.0 、21.0和168 ng·m-3.同系物分布特征表明，化石燃料燃烧是兰溪PM2.5中正构烷烃的主要来源，但植物蜡也有重要贡献；藿烷的组成及其季节变化显示兰溪PM2.5中的藿烷主要来源于机动车排放，但冬季存在明显的燃煤贡献；基于BeP/（BeP+BaP）、IcdP/（IcdP+BgP）等特征比值分析，兰溪PM2.5中的多环芳烃主要来源于机动车尾气和煤炭/生物质燃烧的混合贡献，冬季燃煤贡献较高；兰溪夏季多环芳烃的老化程度较低，表明兰溪夏季PM2.5以本地排放新鲜颗粒为主，外来输送的影响较小；脂肪酸的浓度和组成说明餐饮排放对市区PM2.5的影响较大.研究结果为大气PM2.5的来源解析提供了重要的基础信息.
- Abstract：In order to better understand the characteristics of fine particles in small and medium cities in China, the PM2.5 samples for four seasons in 2016 were collected simultaneously with high-volume samplers at one urban site and one suburb site in Lanxi, a representative inland city in Zhejiang Province. The concentrations of carbonaceous aerosols in the collected samples were measured, and the concentrations and distributions of some weak-polar organics including n-alkanes, hopanes, polycyclic aromatic hydrocarbons (PAHs) and n-fatty acids were analyzed with GC-MS. The results showed that the annual averaged concentration of organic carbon in PM2.5 in Lanxi was 9.7 μg·m-3, and the annual averaged concentrations of n-alkanes, hopanes, PAHs and n-fatty acids were 40.8, 2.0, 21.0 and 168 ng·m-3 respectively. The homologues distributions indicated that the fossil fuel usage was the main source of n-alkanes in PM2.5 in Lanxi, though plant wax also had important contribution. The hopanes composition and seasonal variation suggested that vehicle emission was main source of the hopanes in PM2.5 in Lanxi, while obvious contribution from coal combustion could be found in winter. Based on the analysis of the diagnostic ratios of PAHs, such as BeP/(BeP+BaP) and IcdP/(IcdP+BgP), the PAHs in PM2.5 in Lanxi was from mixed sources of vehicle emission and coal/biomass burning, while the higher contribution from coal/biomass burning in winter. The aging degree of PAHs in summer was lower than expected, indicating that the PM2.5 was mainly from local emission sources and the contribution of transported particles was relatively low in Lanxi. The concentration and distribution of n-fatty acids approved that cooking emission had stronger impact to the PM2.5 level in the downtown area of Lanxi. This study provided important information for the source apportionment of PM2.5 in Lanxi and other cities.
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