Institute of Chemical Process Fundamentals, Czech Academy of Sciences, Rozvojová 1/135, 165 02, Prague 6, Czech Republic; Chubu Institute for Advanced Studies, Chubu University, 1200 Matsumoto-cho, Kasugai, 487-8501, Japan.
Chubu Institute for Advanced Studies, Chubu University, 1200 Matsumoto-cho, Kasugai, 487-8501, Japan.
Chemosphere. 2023 Oct;337:139393. doi: 10.1016/j.chemosphere.2023.139393. Epub 2023 Jul 1.
Isotopic analysis of specific compounds in aerosols can be a useful tool when studying atmospheric processes. Here, we present the results of stable carbon isotope ratio (δC) measurements performed on a one-year set (n = 96, Sep. 2013-Aug. 2014) of dicarboxylic acids and related compounds in PM at a rural Central European background site, Košetice (Czech Republic). The most C enriched acid was oxalic (C, annual average = -16.6 ± 5.0‰) followed by malonic (C, avg. = -19.9 ± 6.6‰) and succinic (C, avg. = -21.3 ± 4.6‰) acids. Thus, δC values decreased with an increase in carbon numbers. Azelaic acid (C, avg. = -27.2 ± 3.6‰) was found to be the least C enriched. A comparison of δC of dicarboxylic acids from other background sites, especially in Asia, shows similar values to those from the European site. This comparison also showed that C is more C enriched at background sites than at urban ones. In general, we did not observe significant seasonal differences in δC values of dicarboxylic acids at the Central European station. We observed statistically significant differences (p value < 0.05) between winter and summer δC values solely for C, glyoxylic acid (ωC), glutaric acid (C) and suberic acid (C). The only significant correlations between δC of C and δC of C were found in spring and summer, suggesting that the oxidation of C to C is significant in these months with a strong contribution from biogenic aerosols. The strongest season-independent annual correlation was observed in δC values between C and C, the two dominant dicarboxylic acids. Therefore, C appears to be the main intermediate precursor of C throughout the whole year.
在研究大气过程时，对气溶胶中特定化合物的同位素分析可能是一种有用的工具。在这里，我们介绍了在中欧农村背景站点 Košetice（捷克共和国）进行的为期一年（2013 年 9 月至 2014 年 8 月，n=96）的大气气溶胶中二羧酸和相关化合物的稳定碳同位素比（δC）测量结果。最富含碳的酸是草酸（C，年均值为-16.6±5.0‰），其次是丙二酸（C，平均值为-19.9±6.6‰）和琥珀酸（C，平均值为-21.3±4.6‰）。因此，δC 值随着碳数的增加而降低。发现壬二酸（C，平均值为-27.2±3.6‰）是最不含碳的酸。与其他背景站点（尤其是亚洲）的二羧酸的 δC 值进行比较表明，它们与欧洲站点的类似。这种比较还表明，背景站点的 C 比城市站点的 C 更丰富。总的来说，我们没有在中欧站观察到二羧酸 δC 值的显著季节性差异。我们仅在冬季和夏季观察到 δC 值存在统计学上的显著差异（p 值<0.05），分别为 C、乙醛酸（ωC）、戊二酸（C）和乌头酸（C）。仅在春季和夏季发现 C 的 δC 值与 C 的 δC 值之间存在显著相关性，表明 C 氧化为 C 是这些月份的重要过程，其中生物气溶胶的贡献很大。在 C 和 C 之间的 δC 值中观察到最强的与季节无关的年度相关性，这两种是主要的二羧酸。因此，C 似乎是整个一年中 C 的主要中间前体。
