北极Alert地区有机气溶胶的分子组成及来源贡献

Molecular Composition and Source Apportionment of Organic Aerosols at Alert in the High Arctic

北极地区大气气溶胶的来源及有机分子组成的研究相对较少。本文通过采集Alert地区从冬季到夏季的气溶胶样品,利用气相色谱仪以及气相色谱-质谱(GC-MS)联用仪研究其有机分子组成及季节性变化趋势。结果表明,所检测到的有机化合物总浓度范围为18.3～109ng m-3,其中二元酸的浓度最高。α-蒎烯来源的二次有机碳(SOC)含量高于β-石竹烯来源的SOC;它们比异戊二烯来源的SOC高数倍。SOC明显高于生物质燃烧和真菌孢子来源的有机碳。本研究表明,北极地区气溶胶的分子组成与中低纬度地区有显著差异;并且,夏季北冰洋向大气释放有机质的贡献也不能被忽视。

Little is known about sources and organic molecular compositions of the Arctic aerosol.In this study,aerosol samples collected at Alert were investigated using gas chromatography and gas chromatography/mass spectrometry.Concentrations of the total identified organics range from 18.3 to 109 ng m-3,and dicarboxylic acids,which accounts for half of the total identified organics,is the predominant class.Using a tracer-based method,the estimated secondary organic carbon（SOC） from the oxidation of α-pinene is higher than that of β-caryophyllene;both of them are several times higher than that of isoprene-derived SOC.This pattern is different from those reported in atmospheric aerosols collected from other locations around the world,indicating a unique emission of biogenic volatile organic compounds from vegetations in the Arctic region,nevertheless,the emission of VOCs from the open Arctic ocean can not be exclued in summer.In addition,our results also show that biogenic SOC is more abundant than those of primary sources such as the emissions from biomass burning and fungal spores in the high Arctic.