长春秋季细颗粒物中有机气溶胶组成特征及来源

Molecular Composition and Source Apportionment of Fine Organic Aerosols in Autumn in Changchun

利用大流量采样器采集了长春城郊2016年10月至2016年11月大气细颗粒物(PM2.5)样品共40套,分析了颗粒物中的有机碳(OC)、元素碳(EC)以及非极性有机化合物(主要包括正构烷烃、多环芳烃以及藿烷类化合物)和生物质燃烧标志物左旋葡聚糖的质量浓度,并用分子标记物、特征比值及主成分分析-多元线性回归(PCA-MLR)模型等方法探讨了有机气溶胶的主要来源.结果表明,观测期间PM2.5的平均质量浓度为(79. 0±55. 7)μg·m^-3,OC和EC的平均质量浓度分别为(20. 7±15. 6)μg·m^-3和(2. 2±1. 1)μg·m^-3,分别占PM2.5的26. 2%和2. 8%.所测非极性有机化合物的总平均浓度为(186. 3±104. 5) ng·m^-3,浓度高低顺序为正构烷烃[(101. 3±67. 0) ng·m^-3]>多环芳烃[(81. 4±46. 0) ng·m^-3]>藿烷类化合物[(3. 8±1. 9) ng·m^-3,其主要来源包括煤燃烧源、生物质燃烧源以及交通源.主成分分析-多元线性回归模型得出该地区有机气溶胶主要排放源的相对贡献依次是煤燃烧源(47. 0%)、生物质燃烧源(42. 6%)和交通源(10. 4%).本研究结果可为我国东北地区有机气溶胶污染防控提供科学依据.

Organic aerosols have attracted increasing attention recently due to their significant contribution to fine particles (PM2.5)and their complex components and sources. In this study,a total of 40 PM2.5 samples were collected simultaneously with high-volume samplers in Changchun from 16th Oct to 29th Nov 2016. Organic carbon(OC),elemental carbon(EC),non-polar organic compounds including n-alkanes,polycyclic aromatic hydrocarbons (PAHs),and hopanes,and levoglucosan in atmospheric fine particles were analyzed. The main sources of organic aerosols were identified by molecular markers,diagnostic ratios,and a principal component analysis-multiple liner regression(PCA-MLR) model. The results showed that the average mass concentration of PM2.5 was(79.0 ±55.7)μg·m^-3,and the averaged OC and EC mass concentrations were( 20. 7 ± 15. 6)μg·m^-3 and( 2. 2 ± 1. 1)μg·m^-3,which accounted for 26. 2% and 2. 8% of PM2.5,respectively. The total average concentration of the tested non-polar organic compounds was( 186. 3 ± 104. 5) ng·m^-3 and,in descending order,this was composed of n-alkane( 101. 3 ± 67. 0) ng·m^-3,polycyclic aromatic hydrocarbons( 81. 4 ± 46. 0) ng·m^-3,hopanes( 3. 8 ± 1. 9) ng·m^-3. The PCA-MLR model results showed that the relative contributions of the main sources of organic aerosols were coal combustion( 47. 0%),biomass burning(42. 6%),and traffic emission( 10. 4%).