State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring, China National Environmental Monitoring Centre, Bejing 100012, China.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China; School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310000, China.
Environ Int. 2022 Sep;167:107421. doi: 10.1016/j.envint.2022.107421. Epub 2022 Jul 16.
Aromatic compounds, including many polycyclic aromatic hydrocarbons (PAHs), are suspected carcinogens and may originate from different sources. To investigate the impact of anthropogenic emission reductions on unknown aromatic compounds in particulate matter, we collected samples during the pre-COVID period in 2020, the COVID-19 lockdown period in 2020, and the same period as the lockdown in 2019. Besides the 16 PAHs, other aromatic compounds were analyzed by Fourier transform ion cyclotron resonance mass spectrometry and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. Four main compound classes were identified: CH, CHO, CHNO, and CHOS. Hierarchical cluster analysis showed the aromatic compounds varied during the different periods. Compared with before the pandemic, the relative abundances of aromatic compounds with low degrees of unsaturation and long alkyl chains (e.g., alkylbenzenes) increased. These compounds probably mainly arose from fossil fuel combustion and petrochemical industry emissions. The CHO compounds, which were dominated by those with high degrees of oxidation, might originate from secondary organic aerosols. Aromatic aldehydes (e.g., cyclamen aldehyde) and benzoates (e.g., 2-ethylhexyl benzoate) probably with high toxicity deserve more attention. During lockdown, nitro derivatives of condensed PAHs were the main CHNO compounds, and the numbers of homologs decreased perhaps because of significant reductions in NO and PAHs. CHOS compounds with long carbon chains and low degrees of unsaturation were predominant and the numbers of homologs increased. Five compounds (e.g. 1,3-dimethyl pyrene) were predicted to possibly exhibit persistent and bio-accumulated by EPI Suite model, which need further research. The results provide insight on aromatic compounds and their source appointment in atmospheric particulate matter.
芳香族化合物，包括许多多环芳烃（PAHs），被怀疑是致癌物质，可能来自不同的来源。为了研究人为减排对颗粒物中未知芳香族化合物的影响，我们在 2020 年新冠疫情前、2020 年疫情封锁期间和 2019 年同期封锁期间采集了样本。除了 16 种 PAHs 外，还通过傅里叶变换离子回旋共振质谱和全二维气相色谱-飞行时间质谱分析了其他芳香族化合物。鉴定出了 4 种主要的化合物类别：CH、CHO、CHNO 和 CHOS。层次聚类分析表明，不同时期芳香族化合物的分布有所不同。与大流行前相比，低不饱和度和长烷基链（如烷基苯）的芳香族化合物的相对丰度增加。这些化合物可能主要来自化石燃料燃烧和石化工业排放。CHO 化合物，主要由高度氧化的化合物组成，可能来自二次有机气溶胶。具有高毒性的芳香族醛（如仙客来醛）和苯甲酸酯（如 2-乙基己基苯甲酸酯）值得更多关注。在封锁期间，稠合 PAHs 的硝基衍生物是主要的 CHNO 化合物，同系物数量减少，可能是因为 NO 和 PAHs 的显著减少。长链和低不饱和度的 CHOS 化合物占主导地位，同系物数量增加。EPI Suite 模型预测有 5 种化合物（如 1,3-二甲基苝）可能具有持久性和生物累积性，需要进一步研究。研究结果为大气颗粒物中的芳香族化合物及其来源提供了深入了解。
