SEASONAL-CHANGES IN THE DISTRIBUTION OF DICARBOXYLIC-ACIDS IN THE URBAN ATMOSPHERE
SEASONAL-CHANGES IN THE DISTRIBUTION OF DICARBOXYLIC-ACIDS IN THE URBAN ATMOSPHERE
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DOI：
10.1021/es00047a033
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发表时间：
1993-10-01
影响因子：
11.4
通讯作者：
IKUSHIMA, K
中科院分区：
文献类型：
--
作者：
KAWAMURA, K;IKUSHIMA, K
1988-1989年，采用毛细管气相色谱和气相色谱-质谱联用技术，对东京大气气溶胶中的低分子量二元羧酸进行了研究。在气溶胶中检测到一系列同源的C2-C-10二羧酸，包括直链饱和、不饱和、支链和羟基化物质。二酸的分子分布表明，草酸（C2）是整个四季中最丰富的，其次是C3和C4二酸：C2二酸占总二酸浓度的37- 69%。具有更多碳数的二酸不太丰富，尽管C6和C9二酸相对丰富。二酸的总浓度范围为90至1370 ng m-3，相当于总气溶胶质量的0.06- 1.1%。它们相对于气溶胶质量的浓度呈季节性变化趋势，8月份最高。气溶胶总碳归一化的C2-C4二酸碳也表现出强烈的季节性变化，在夏季达到最大值，并与氧化剂浓度呈正相关。有趣的是，较低的二酸显示出较高的相关系数值（例如，对于草酸，r = 0.80），表明优先产生低分子量二羧酸，尤其是C2二酸。可能的反应机制进行了讨论，在有关的优先积累的低二元酸在大气中。
Low molecular weight dicarboxylic acids have been studied in the urban aerosol samples collected from Tokyo atmosphere in 1988-1989, by using a capillary GC and GC-MS method employing a dibutyl ester derivatization technique. A homologous series of C2-C-10 dicarboxylic acids were detected in the aerosols, including straight-chain saturated, unsaturated, branched-chain, and hydroxylated species. Molecular distributions of the diacids demonstrated that oxalic (C2) acid was the most abundant throughout the four seasons, followed by C3 and C4 diacids: the C2 diacid comprised 37-69 % of the total diacid concentrations. The diacids with more carbon numbers were less abundant, although C6 and C9 diacids were relatively abundant. Total concentrations of the diacids ranged from 90 to 1370 ng m-3, which correspond to 0.06-1.1 % of the total aerosol mass. Their concentrations relative to aerosol mass showed a seasonal trend with a maximum in August. The C2-C4 diacid carbon normalized by aerosol total carbon also showed a strong seasonal change with a maximum in the summer and indicated a positive correlation with oxidant concentrations. Interestingly, lower diacids showed higher values for correlation coefficient (e.g., r = 0.80 for oxalic acid), suggesting a preferential production of low molecular weight dicarboxylic acids, especially, C2 diacid. Possible reaction mechanisms are discussed in relation to the preferential accumulation of lower diacids in the atmosphere.