Organic Geochemical Studies of Polar Aerosols : Long distance transport and photochemical transformation of natural and anthropogenic materials

1987年7月至1988年6月在阿勒特采集的北极气溶胶样品中测定了低分子量二羧酸（C2-C11）的同系物。草酸（C2）被认为是占主导地位的物种，其次是丙二酸（C3）或琥珀酸（C4）。在极地日出的时候，北极霾气溶胶中的某些二羧酸比之前黑暗的冬季多5到20倍。此外，它们还与以溴颗粒为标志的对流层臭氧消耗事件相关。本文首次报道了极地大气中的二羧酸同系物，并讨论了这些有机酸的形成与中纬度地区大气中污染物前体物质的光化学氧化有关，同时还研究了在昭和站收集的南极气溶胶中的水溶性有机化合物。还测定了总碳和总氮。琥珀酸（C4）或草酸（C2）被发现作为主要的二酸物种，其次是壬二酸（C9），己二酸（C6）或丙二酸（C3）。总二酸的浓度范围为5.9-88 ngm-3，平均值为29 ngm-3。在夏季样本中观察到最高浓度，琥珀酸占主导地位（61.5 ngm-3），其中包括ca。70%的总二酸和占3.5%的总气溶胶碳（1020 ngm-3）。琥珀酸（C4）可能是由4-氧代羧酸的光氧化产生的，4-氧代羧酸作为不饱和脂肪酸光氧化的中间体存在于大气中。这些结果表明，南极有机气溶胶来源于海洋来源的脂类，并在很大程度上通过光化学氧化转化。ω-氧代羧酸（C2-C9，0.36 -3.0 ngm-3）在夏季样品中也显示出最高浓度，再次表明南极和南大洋大气中的次级产物。

Homologous series of low molecular weight dicarboxylic acids (C2-C11) have been measured in the arctic aerosol samples collected from July 1987 to June 1988 in Alert. Oxalic acid (C2) was found as the dominant species followed by malonic (C3) or succinic (C4) acid. At the time of polar sunrise, certain dicarboxylic acids in arctic haze aerosols became 5 to 20 times more abundant than in the preceding dark winter months. Furthermore, they are correlated with tropospheric ozone depletion events marked by particulate bromine. Here, we report, for the first time, homologous series of dicarboxylic acids in the polar atmosphere and discuss the formation of these organic acids in terms of photochemical oxidation of pollutant precursors that reach the Arctic by long range atmospheric transport from midlatitudes.Antarctic aerosols collected at Syowa Station were also studied for water soluble organic compounds. Total carbon and nitrogen were also determined. Succinic (C4) or oxalic (C2) acid was found as the dominant diacid species followed by azelaic (C9), adipic (C6) or malonic (C3) acid. Concentration range of the total diacids was 5.9-88 ngm-3 with an average of 29 ngm-3. Highest concentrations were observed in the summer sample with a predominance of succinic acid (61.5 ngm-3), which comprised of ca. 70% of the total diacids and accounted for 3.5% of total aerosol carbon (1020 ngm-3). The succinic acid (C4) is likely produced by photooxidation fo 4-oxocarboxylic acids, which are present in the atmosphere as intermediates of the photooxidation of unsaturated fatty acids. These results indicate that the antarctic organic aerosols originate from marine-derived lipids and are transformed largely by photochemical oxidations. w-Oxocarboxylic acids (C2-C9,0.36-3.0 ngm-3) also showed the highest concentration in the summer sample, again suggesting a secondarily production in the atmosphere of the Antarctic and Southern Oceans.