南京市大气细颗粒物(PM_(2.5))中硝基多环芳烃污染特征与风险评估

Pollution Characteristics and Risk Assessment of Nitro Polycyclic Aromatic Hydrocarbons in PM_(2.5) of Nanjing,China

硝基多环芳烃是大气细颗粒物中具有致癌效应的一类重要污染物,为探明硝基多环芳烃污染特征与来源,采集南京市14个大气细颗粒样品,利用气相色谱-质谱联用仪(GC-MS)测定硝基多环芳烃浓度,进行分布特征分析,来源识别和健康风险评估.结果表明,南京市大气细颗粒物中2,8-二硝基二苯并噻吩(743 pg·m^(-3))、2,7-二硝基芴(331 pg·m^(-3))、9-硝基蒽(326pg·m^(-3))、3-硝基荧蒽(217 pg·m^(-3))和1,8-二硝基芘(193 pg·m^(-3))为主要的硝基多环芳烃;硝基多环芳烃检出浓度具有明显的季节变化,冬季最高(3082 pg·m^(-3)),秋季其次(1553 pg·m^(-3)),春季最低(1218 pg·m^(-3)).南京市大气细颗粒物中硝基多环芳烃主要来自多环芳烃大气光氧化反应与生物质燃烧,二次生成是硝基多环芳烃的重要来源.当前南京PM_(2.5)中硝基多环芳烃的致癌风险可控,二硝基多环芳烃是致癌风险的主要来源.

Nitro polycyclic aromatic hydrocarbons(NPAHs)are important pollutants with carcinogenic effects present in PM_(2.5).To analyze the pollution characteristics and sources of NPAHs,14 samples of PM_(2.5)were collected in Nanjing from November 2017 to March 2018.The results showed that,2,8-dinitrodibenzothiophene(743 pg·m^(-3)),2,7-dinitrofluorene(331 pg·m^(-3)),9-nitroanthracene(326 pg·m^(-3)),3-nitrofluoranthene(217 pg·m^(-3)),and 1,8-dinitropyrene(193 pg·m^(-3))were dominant,and the detection concentrations notably varied between seasons;the highest concentrations occurred in winter(3082 pg·m^(-3))followed by autumn(1553 pg·m^(-3))and spring(1218 pg·m^(-3)).The ratio of nitrofluoranthene and 1-nitropyrene concentrations,and 9-nitroanthracene and 1-nitropyrene concentrations,indicated that the main sources of NPAHs in the PM_(2.5)of Nanjing were photooxidation of polycyclic aromatic hydrocarbons and biomass burning.NPAHs were more typically associated with smaller particles,which further indicated that secondary formation is an important source.The current carcinogenic risk of NPAHs in PM_(2.5)in Nanjing is controllable,and dinitro-polycyclic aromatic hydrocarbons represent the highest level of risk.The data presented in this study provide important baseline information that can inform the management of risks associated with NPAHs in PM_(2.5)in Nanjing.