Distributions of Polycyclic Aromatic Hydrocarbons, Aromatic Ketones, Carboxylic Acids, and Trace Metals in Arctic Aerosols: Long-Range Atmospheric Transport, Photochemical Degradation/Production at Polar Sunrise.
Distributions of Polycyclic Aromatic Hydrocarbons, Aromatic Ketones, Carboxylic Acids, and Trace Metals in Arctic Aerosols: Long-Range Atmospheric Transport, Photochemical Degradation/Production at Polar Sunrise.
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DOI：
10.1021/acs.est.7b01644
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发表时间：
2017-08
影响因子：
11.4
通讯作者：
D. K. Singh;K. Kawamura;Ayako Yanase;L. Barrie
中科院分区：
文献类型：
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作者：
D. K. Singh;K. Kawamura;Ayako Yanase;L. Barrie
研究了加拿大北极高地气溶胶中芳香酸、芳香酮、多环芳烃(PAHs)和痕量金属的分布、相关性和来源解析。检测到19种多环芳烃，包括少量的含硫杂环多环芳烃(二苯并噻吩类)和主要的6种致癌多环芳烃，其中荧蒽所占比例较高，其次是苯并[k]荧菲、芘和大黄烯。然而，在春季阳光充足的时候，它们的浓度可能由于光化学分解而显著下降。在3月中旬至4月中旬的极地日出期间，苯并[a]芘/苯并[e]芘的比值显著下降，并在4月下旬至5月以后进一步减小。这些结果表明，北极地区输送的多环芳烃在极地日出时会受到强烈的光化学降解。虽然芳香酮在春季减少，但在极地日出过程中，苯甲酸和邻苯二甲酸等一些芳香酸的浓度增加，这表明芳香烃被氧化生成芳香酸。然而，多环芳烃并不是低分子量二酸(如草酸)的主要来源，草酸主要在极地日出时在北极大气中形成，因为多环芳烃的丰度比低分子二元酸少1至2个数量级。解释了痕量金属与有机物的相关性、来源以及痕量过渡金属的可能作用。
The distributions, correlations, and source apportionment of aromatic acids, aromatic ketones, polycyclic aromatic hydrocarbons (PAHs), and trace metals were studied in Canadian high Arctic aerosols. Nineteen PAHs including minor sulfur-containing heterocyclic PAH (dibenzothiophene) and major 6 carcinogenic PAHs were detected with a high proportion of fluoranthene followed by benzo[k]fluoranthene, pyrene, and chrysene. However, in the sunlit period of spring, their concentrations significantly declined likely due to photochemical decomposition. During the polar sunrise from mid-March to mid-April, benzo[a]pyrene to benzo[e]pyrene ratios significantly dropped, and the ratios diminished further from late April to May onward. These results suggest that PAHs transported over the Arctic are subjected to strong photochemical degradation at polar sunrise. Although aromatic ketones decreased in spring, concentrations of some aromatic acids such as benzoic and phthalic acids increased during the course of polar sunrise, suggesting that aromatic hydrocarbons are oxidized to result in aromatic acids. However, PAHs do not act as the major source for low molecular weight (LMW) diacids such as oxalic acid that are largely formed at polar sunrise in the arctic atmosphere because PAHs are 1 to 2 orders of magnitude less abundant than LMW diacids. Correlations of trace metals with organics, their sources, and the possible role of trace transition metals are explained.