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Σ _(12)NPAHs质量浓度在2. 06～37. 14ng·m^(-3)之间,其中基于能源产业的宝丰采样点冬、夏季采样期Σ _(12)NPAHs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Σ _(12)NPAHs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Σ _(12)NPAHs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Σ _(12)NPAHs浓度水平的空间差异.两个采样点PM_(2.5)中Σ _(12)NPAHs浓度的夜昼比表明,夏季Σ _(12)NPAHs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Σ _(12)NPAHs/Σ _(16)PAHs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Σ _5NPAHs的呼吸暴露肺癌风险,结果表明,宝丰采样点PM_(2.5)中Σ _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.
Atmospheric PM2.5 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 Σ 12NPAHs in PM2.5 ranged from 2.06 ng·m3 to 37.14ng·m-3 at the Ningdong Energy and Chemical Industry Base.The average concentrations of Σ 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 Σ 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 Σ 12NPAHs in PM2.5 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 Σ 12NPAHs in PM2.5 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,Σ 12NPAHs/Σ-(16)PAHs ratios were calculated to identify the potential sources of NPAHs across the city.The results indicated tha 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 Σ 5NPAHs were assessed based on the BaP equivalent toxicity factor.The results showed that the lung cancer risk values of Σ 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 PM2.5-bound NPAHs.
作者
刘攀亮
剧媛丽
毛潇萱
黄韬
高宏
马建民
LIU Pan-liang;JU Yuan-li;MAO Xiao-xuan;HUANG Tao;GAO Hong;MA Jian-min(Key Laboratory for Environmental Pollution Prediction and Control,Gansu Province,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China;Shijiazhuang Banknote Printing Co.,Ltd.,Shijiazhuang 050031,China;Collegeof Urban and Environmental Sciences,Peking University,Beijing 100871,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2019年第6期2556-2564,共9页
Environmental Science
基金
国家重点研发计划项目(2017YFC0212002)
国家自然科学基金项目(41671460)
甘肃省民生科技计划项目(1503FCMA003)
中央高校基本科研业务费专项(lzujbky-2017-it100)
关键词
宁东能源化工基地
PM2.5
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
Ningdong energy and chemical industry base
PM2.5
nitrated polycyclic aromatic hydrocarbons(NPAHs)
atmospheric pollution characteristics
source appointment
lung cancer risk derived from inhalation exposure
