中文关键词宁东能源化工基地PM_2.5硝基多环芳烃(NPAH)大气污染特征来源分析呼吸暴露肺癌风险 英文关键词Ningdong energy and chemical industry basePM_2.5nitrated polycyclic aromatic hydrocarbons (NPAHs)atmospheric pollution characteristicssource appointmentlung cancer risk derived from inhalation exposure

作者	单位	E-mail
刘攀亮	兰州大学资源环境学院, 甘肃省环境污染预警与控制重点实验室, 兰州 730000	liupl15@lzu.edu.cn
剧媛丽	石家庄印钞有限公司, 石家庄 050031
毛潇萱	兰州大学资源环境学院, 甘肃省环境污染预警与控制重点实验室, 兰州 730000
黄韬	兰州大学资源环境学院, 甘肃省环境污染预警与控制重点实验室, 兰州 730000
高宏	兰州大学资源环境学院, 甘肃省环境污染预警与控制重点实验室, 兰州 730000	honggao@lzu.edu.cn
马建民	兰州大学资源环境学院, 甘肃省环境污染预警与控制重点实验室, 兰州 730000 北京大学城市与环境学院, 北京 100871

中文摘要 利用大气主动采样技术对宁东能源化工基地大气PM_2.5中硝基多环芳烃（NPAHs）的污染特征、一次排放和二次形成源贡献及呼吸暴露风险进行了观测研究.结果表明，宁东能源化工基地大气PM_2.5中∑₁₂NPAHs质量浓度在2.06~37.14 ng·m^-3之间，其中基于能源产业的宝丰采样点冬、夏季采样期∑₁₂NPAHs的平均质量浓度分别为（25.57±5.76）ng·m^-3和（6.22±1.74）ng·m^-3.以化工、电力产业为主的英力特采样点冬、夏季∑₁₂NPAHs平均质量浓度分别为（7.13±1.44）ng·m^-3和（2.58±0.39）ng·m^-3，两采样点均表现出冬季高于夏季的季节特征，推测为冬季取暖造成较高的NPAHs一次排放所致.宝丰采样点∑₁₂NPAHs浓度水平明显高于英力特，可能与宝丰的煤炭开采及焦炭生产的能源产业较化工产业造成更高的NPAHs一次排放相关，因而造成了∑₁₂NPAHs浓度水平的空间差异.两个采样点PM_2.5中∑₁₂NPAHs浓度的夜昼比表明，夏季∑₁₂NPAHs浓度日间明显高于夜间而冬季则相反，表明夏季日间较夜间存在更活跃的大气光化学反应，较夜间贡献更多二次形成的NPAHs.NPAHs族谱特征的时空差异表现为：宝丰和英力特采样点冬夏季均以一次排放标识物2N-FLO和6N-CHR为主要占比，其中宝丰采样点冬季2N-FLO和6N-CHR总占比为46%，夏季为73%，英力特采样点冬季总占为59%，夏季为55%.但英力特采样点夏季二次形成的标识物3N-PHE浓度占比较宝丰更高，表明基于化工产业的英力特较宝丰存在更高的前体物排放，由此贡献更多二次形成的NPAHs.本研究还借助∑₁₂NPAHs/∑₁₆PAHs比值对NPAHs可能的来源贡献进行了分析研究，结果表明宁东能源化工基地夏季较高的温度促进了PAHs的降解以及NPAHs的二次形成，较冬季贡献更多二次形成源的NPAHs.基于BaP等效毒性因子评价法估算了PM_2.5中∑₅NPAHs的呼吸暴露肺癌风险，结果表明，宝丰采样点PM_2.5中∑₅NPAHs的肺癌风险值冬季为（3.06×10^-5±1.36×10^-5），夏季为（1.79×10^-5±0.80×10^-5），英力特采样点冬季为（2.85×10^-5±1.20×10^-5），夏季为（1.86×10^-5±0.83×10^-5）.宝丰和英力特肺癌风险值均高于Cal/EPA规定的1.00×10^-5的限值，表明宁东能源化工基地人群存在一定程度的大气PM_2.5中NPAHs呼吸暴露肺癌风险. 英文摘要 Atmospheric PM_2.5 samples were collected by using the active sampling method to investigate the pollution characteristics of nitrated polycyclic aromatic hydrocarbons (NPAHs) at the Ningdong Energy and Chemical Industry Base, Northwest China. Furthermore, the primary sources and the contributions of secondary formation sources as well as the inhalation exposure risks were identified. The main results were as follows. The concentration levels of ∑₁₂NPAHs in PM_2.5 ranged from 2.06 ng·m^-3 to 37.14 ng·m^-3 at the Ningdong Energy and Chemical Industry Base. The average concentrations of ∑₁₂NPAHs were (25.57±5.76) ng·m^-3 in winter and (6.22±1.74) ng·m^-3 in summer for the Baofeng sampling site associated with the energy industry. The average concentrations of ∑₁₂NPAHs were (7.13±1.44) ng·m^-3 in winter and (2.58±0.39) ng·m^-3 in summer for the Yinglite sampling site associated with chemical and electricity industries. The levels of ∑₁₂NPAHs in PM_2.5 were higher in winter than those in summer because of the increased heating in winter. Atmospheric pollution levels of NPAHs at the Baofeng sampling site were generally higher than those at the Yinglite sampling because of the higher primary NPAHs emissions from coal mining and coke production in Baofeng compared with those from the chemical industry in Yinglite. The calculated nocturnal/diurnal ratios revealed that the concentrations of ∑₁₂NPAHs in PM_2.5 during the summer season were higher in the daytime than those in the nighttime, but the opposite trend occurred in winter, thus indicating that secondary formation processes made more contributions to NPAHs during summer in the daytime. The congener profiles of NPAHs were mainly composed of primary emission markers such as 2-nitrofluorene (2N-FLO) and 6-nitrochrysene (6N-CHR), which were the predominant ones in winter and summer for both the Baofeng and Yinglite sampling sites. Total proportions of 2N-FLO and 6N-CHR were 46% in winter and 73% in summer for Baofeng and 59% in winter and 55% in summer for Yinglite, respectively. Meanwhile, 3N-PHE, which is a marker compound of secondary formation processes, accounted for a higher percentage in summer especially at Yinglite. This finding revealed that the chemical production at Yinglite was associated with higher precursor emissions than that of Baofeng, and thus, more NPAHs were derived from secondary formation processes. Moreover, ∑₁₂NPAHs/∑₁₆PAHs ratios were calculated to identify the potential sources of NPAHs across the city. The results indicated that higher environmental temperatures in summer promoted the degradation of PAHs and secondary formation of NPAHs, and thus, secondary formation contributed more to NPAHs in summer than in winter. Furthermore, lung cancer risks induced by inhalation exposures to ∑₅NPAHs were assessed based on the BaP equivalent toxicity factor. The results showed that the lung cancer risk values of ∑₅NPAHs were (3.06×10^-5±1.36×10^-5) in winter and (1.79×10^-5±0.80×10^-5) in summer for the Baofeng sampling site, while the risk values were (2.85×10^-5±1.20×10^-5) in winter and (1.86×10^-5±0.83×10^-5) in summer for the Yinglite sampling site. Notably, the lung cancer risk values in our study for both sampling sites were higher than the standard limit value (1.00×10^-5) of the California Environmental Protection Agency, which indicates that the local population at the Ningdong Energy and Chemical Industry Base has been subjected to potentially elevated lung cancer risks due to inhalation exposures to PM_2.5-bound NPAHs.

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