【摘要】 为探讨华北地区秋冬季重污染过程PM_2.5（细颗粒物）中PAHs（多环芳烃）的污染水平、分布特征及来源,分别采集2018年11月17日—2019年1月19日德州市和北京市PM_2.5样品利用气相色谱-质谱法测量两个站点6次重污染过程中26种PAHs浓度水平,分析PAHs污染特征、分子组成分布及其来源,并利用毒性当量因子估算了PAHs毒性.结果表明:①6次重污染过程中德州站点∑₂₆PAHs浓度为62～191 ng/m³北京站点为61～129 ng/m³.②单位质量PM_2.5中PAHs的浓度北京站点更高.③两个站点PAHs分子组成分布较为一致,萘、蒽、芴等低分子量的PAHs浓度较低,高分子量PAHs浓度较高,浓度最高的分别为苯并[b]荧蒽、苯并[a]芘、苯并[a]蒽和甲基荧蒽等.④特征比值结果显示,PAHs来源包括柴油车尾气、燃煤和生物质燃烧,德州站点受生物质燃烧影响更为显著.⑤毒性当量计算结果表明,德州站点毒性当量浓度（TEQ）高于北京站点,6次重污染过程中两个站点PAHs的TEQ平均值在6.5～17.2 ng/m³之间,低于国内其他一些地区,但苯并[a]芘的浓度在5.2～13.1 ng/m³之间,超过了GB 3095—2012《环境空气质量标准》日均值的标准限值（2.5 ng/m³）,对人体健康存在潜在危害.研究显示:秋冬季重污染过程中北京站点单位质量PM_2.5中PAHs的浓度较高,两个点位PAHs分子组成分布特征及来源较为相似且均对人体健康存在潜在危害;应进一步加强对PAHs浓度水平的控制这不仅有利于持续改善PM_2.5污染,也有助于减轻人体潜在的健康风险.更多还原

【Abstract】 Particulate PAHs are of significant concern due to their carcinogenic and mutagenic properties.In order to investigate the characteristics and sources of particulate PAHs during heavy pollution episodes,PM_2.5 samples were collected in Beijing and Dezhou in the North China Plain from November 17^th,2018 to January 19^th,2019.26 species of PAHs in PM_2.5 during six heavy pollution episodes were measured by gas chromatography-mass spectrometer（GC-MS）.The results showed that:（1） The total concentration of PAHs during six heavy pollution episodes ranged from 62 to 191 ng/m³ in Dezhou,and from 61 to 129 ng/m³ in Beijing.（2） The ratios of ∑₂₆ PAHs/PM_2.5were higher in Beijing,although PM_2.5 concentrations were lower.（3） The dominant components of PAHs were benzo [b]fluoranthene,benzo [a] pyrene（Bap）,benzo [a] anthracene,methyl-fluoranthene and retene,accounting for about 50% of ∑₂₆ PAHs.（4） The diagnostic ratios indicated vehicle exhaust,coal combustion and biomass burning were the main sources of PAHs at both sites.A more obvious influence of biomass burning in Dezhou was found via a tracer-based approach and using the ratio of PAHs to levoglucosan in fresh biomass burning aerosols.（5） The Bap toxic equivalent concentrations（TEQ） were 6.5-17.2 ng/m3,with higher values in Dezhou than those in Beijing.The BaP concentration ranged from 5.2 to 13.1 ng/m³ and exceeded BaP standard（24 h average:2.5 ng/m³） in China（Ambient Air Quality Standard,GB 3095-2012）,indicating a potential hazardous effect on human health.The studies have shown that both sites have similar distribution characteristics and sources,while the enrichment ratios of ∑₂₆ PAHs/PM_2.5 in Beijing were higher.PAHs emission control needs to be further strengthened to reduce the risk of human exposure to heavy pollution episodes and the PM_2.5pollution levels.更多还原