摘要
为探讨不同交通状况下大气颗粒物中二■英(PCDD/Fs)的污染特征以及评估交通限行对大气颗粒物中二■英(PCDD/Fs)变化趋势的影响,在中国地质大学(北京)东门使用中流量采样器对大气颗粒物PM10和TSP样品进行了连续同步采集,应用同位素稀释高分辨率气相色谱/高分辨率质谱(HRGC/HRMS)联用法和US EPA 1613B标准方法,检测分析了北京市交通限行期间以及交通限行前后等不同交通状况下大气颗粒物TSP和PM10中17种2,3,7,8-氯取代PCDD/Fs浓度及其变化特征,结果显示,PCDD/Fs在TSP中的浓度和毒性当量(TEQ)分别是交通限行前2117 fg·m-3(120.85 fg I-TEQ·m-3)、限行期间550 fg·m-3(25.26 fg I-TEQ·m-3),在PM10中的浓度(毒性当量)分别是交通限行前2045 fg·m-3(112.87 fg I-TEQ·m-3)、限行期间484 fg·m-3(19.67 fg I-TEQ·m-3)、限行结束后1572 fg·m-3(81.06 fg I-TEQ·m-3). PCDDs浓度远低于PCDFs,体现了典型'热源'特征,除OCDF外,PCDDs和PCDF同族体浓度变化趋势表现为随着取代氯原子个数的增加而增大,PCDD/Fs主要附着在PM10中,占TSP中总浓度的87%—97%,平均92%.交通限行期间PCDD/Fs污染水平明显降低,临时交通流控制措施是PCDD/Fs降低的主要因素.当前的研究结果力求为评价交通源对大气环境中PCDD/Fs的影响以及交通限行对PCDD/Fs的削减贡献提供支撑.
Atmospheric particles(PM10,TSP)with different traffic conditions sampling were carried out simultaneously in Beijing with middle-volume active sampler at the east gate of China University of Geosciences(CUGB)to investigate the concentrations,congener profiles and estimate the effect of traffic restriction on variation trends of Polychlorinated dibenzo-p-dioxins(PCDDs)and Polychlorinated dibenzofurans(PCDFs),seventeen 2,3,7,8-substitituted congeners of PCDD/Fs were determined using high resolution gas chromatography/high resolution mass spectrometry(HRGC/HRMS)based on US EPA 1613 B method.The concentrations and I-TEQs of PCDD/Fs were respectively 2045 fg·m-3(112.87 fg I-TEQ·m-3)(before traffic restriction),484 fg·m-3(19.67 fg I-TEQ·m-3)(during traffic restriction)and 1572 pg·m-3(81.06 fg I-TEQ·m-3)(after traffic restriction)for PM10,the concentrations and I-TEQs were 2117 fg·m-3(120.85 fg I-TEQ·m-3)(before traffic restriction)and 550 fg·m-3(25.26 fg I-TEQ·m-3)(during traffic restriction)for PCDD/Fs in TSP.The homologue profiles for PCDDs concentrations presented were obviously lower than those of PCDFs,which was classified as thermal source pollution profiles,both the PCDD and PCDF concentrations increased with the increasing levels of chlorination with the exception of OCDF,by contrasting the PM10 and TSP results,an apparent trend was found with higher PCDD/F concentrations in PM10,which accounted for 87%—97%of the total PCDD/F concentrations in TSP,with an average contribution of 92%.The levels of PCDD/Fs during traffic resteriction were significantly lower than that in normal traffic situation,which was attributed to the reduction of traffic flow as well as the increase of fleet speed during the Beijing Olympics.The results from present study provides further aid in evaluating the impact of vehicle as PCDD/Fs emission sources to ambient air,and further to assess the effectiveness of vehicle restriction measures in reducing atmospheric PCDD/Fs.
作者
孙俊玲
王鹏焱
张庆华
SUN Junling;WANG Pengyan;ZHANG Qinghua(Shandong Vehicle Emission Administration Center,Jinan,250101,China;Hainan Normal University,Haikou,571158,China;State Key Laboratory of Environmental Chemistry and Ecotoxicology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China)
出处
《环境化学》
CAS
CSCD
北大核心
2019年第7期1582-1589,共8页
Environmental Chemistry
基金
国家自然科学基金(91743206,21777186,41676183)资助~~
关键词
二■英
TSP
PM10
交通限行
北京大气
PCDD/Fs
atmospheric TSP
atmospheric PM10
vehicle restriction
Beijing air
