珠三角典型地区大气细颗粒物中有机物质的化学组成研究

本文主要利用热解-气相色谱质谱联用技术(Py-GC/MS)对珠三角典型区域的大气颗粒物的化学特征进行研究,讨论了不同地区样品的化学和来源组成。结果显示,不同样品热解产物的组成具有一定的类似性。这些化合物均以脂肪烃(24. 6%～52. 2%)、脂肪酸(5. 0%～43. 6%)、芳香化合物(14. 7%～36. 3%)为主,另外还包括苯酚类化合物(0. 68%～11. 5%)、呋喃类化合物(0. 26%～5. 86%)、含N化合物(4. 80%～10. 2%)和含S化合物(NA～0. 67%)等,表明这些样品主要由芳香碳和脂肪链结构组成,连接有含氧、氮等杂原子基团。同时不同地区的气溶胶样品的热解产物也具有一定的差异性,反映了气溶胶中有机质的组成、来源是有差异的,如从化样品中植物来源贡献是最多的,其次是珠海,广州最少。另外不同季节采集的气溶胶样品的热解产物也表现出一定的差异性,一般情况下夏季样品中生物质来源贡献更多,而冬季样品中则是老化的气溶胶更多。

Chemical Characteristics of Organic Material in Atmospheric Fine Particles in the Pearl River Delta

In this study, the chemical characteristics of fine particles collected in different regions of the Pearl River Delta (PRD) were studied with the pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), and chemical compositions and sources of these fine particles were discussed. The results showed that the pyrolysis products of fine particles obtained in different sites and seasons were quite similar, mainly contain aliphatic hydrocarbons (24.6%-52.2%), fatty acids (5.0%-43.6%) and aromatic compounds (14.7%-36.3%) with minor contents of phenolic compounds (0.68%-11.5%), furans (0.26%-5.86%), N-containing compounds (4.8%-10.2%) and S-containing compounds (NA-0.67%). These data suggested that these organic particulate samples are mainly composed of aromatic and aliphatic structures, connected with oxygen, nitrogen and other heteroatom groups. However, differences, which may reflect the differences in chemical composition and source of these organic aerosols, were also founded among of the pyrolysis products of aerosol samples collected in different sites, for example, aerosol samples in the Conghua site exhibited the highest plant-derived characteristics, followed by Zhuhai samples and then Guangzhou samples. In addition, differences were also identified for aerosol samples collected in summer or winter, the pyrolysis products of summer samples usually contained relative high content of plant-derived contributions, while the winter samples contained more aging aerosol components.