北京市大兴区夏季大气中醛酮类化合物的污染水平、来源及影响  

The pollution levels,sources and impact of atmospheric carbonyls in summer of Daxing District,Beijing

作　　者：李元昭 李少华[1] 张成龙[2,3,4] 王亚飞[5] 刘鹏飞 薛朝阳[2,4] 刘成堂 刘俊锋[2,3,4] 张圆圆 牟玉静 LI Yuanzhao;LI Shaohua;ZHANG Chenglong;WANG Yafei;LIU Pengfei;XUE Chaoyang;LIU Chengtang;LIU Junfeng(Institute of Resources and Environment,Henan Polytechnic University,Jiaozuo,454003,China;Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing,100085,China;Center for Excellence in Regional Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen,361021,China;University of Chinese Academy of Sciences,Beijing,100049,China;School of Mechanical Engineering,Beijing Institute of Petrochemical Technology,Beijing,102617,China)

机构地区：[1]河南理工大学资源环境学院,焦作454003 [2]中国科学院生态环境研究中心,北京100085 [3]中国科学院区域大气环境研究卓越创新中心,厦门361021 [4]中国科学院大学,北京100049 [5]北京石油化工学院机械工程学院,北京102617

出　　处：《环境化学》2021年第7期1999-2015,共17页Environmental Chemistry

基　　金：国家重点研发计划(2017YFF0108301,2016YFC1400601-3);国家自然科学基金(41727805,21876186)资助.

摘　　要：本研究采用2,4-二硝基苯肼(DNPH)涂敷硅胶柱于2018年8月至9月在北京市大兴区开展了为期32 d的大气醛酮类化合物样品采集,并利用高效液相色谱对采集样品中醛酮类化合物进行了定量分析。大兴区大气中共检测出10种醛酮类化合物,体积分数总平均值为(5.68±4.25)×10^(−9),其中甲醛、丙酮和乙醛的体积分数分别为(3.31±2.44)×10^(−9),(1.31±1.23)×10^(−9)和(0.89±0.77)×10^(−9),占醛酮类化合物总体积分数的83.89%。醛酮类化合物与CO和NOx的平均浓度日变化趋势十分相似,均呈现夜晚高白天低的日变化特征,表明燃烧源和汽车尾气可能是大兴区大气醛酮类化合物的重要来源。分别以CO和O3作为一次和二次来源的示踪物,采用多元线性回归的分析方法对大气中醛酮类化合物进行了来源分析,结果表明:大兴区甲醛和乙醛主要来自一次来源,分别占其总来源的82.02%和74.45%,而一次来源对丙酮贡献仅为42.04%。基于光化学辐射通量测定,计算了甲醛、乙醛和丙酮的光解速率及其对过氧自由基的贡献,发现这三种主要醛酮化合物在污染天的光解速率以及过氧自由基的产生速率相对清洁天可提高3—5倍,从而促进了NO向NO2转化以及O3的形成。Atmospheric carbonyl compounds(carbonyls)were sampled by using silica cartridges that were pre-coated with 2,4-dinitrophenylhydrazine(DNPH)at a semi-urban site in Daxing district,Beijing,from August to September 2018.The carbonyls concentrations were quantified through measurements of hydrazones formed from the reactions of carbonyls with the DNPH by using a high-performance liquid chromatography(HPLC)equipped with UV detector.Ten carbonyls in the samples were identified and quantified with a total mean volume concentration of(5.68±4.25)×10^(−9).The mean volume concentrations of formaldehyde,acetaldehyde and acetone were(3.31±2.44)×10^(−9),(1.31±1.23)×10^(−9)和(0.89±0.77)×10^(−9),respectively,accounting for 83.89%of the total mean volume concentration.The diurnal variation trends of formaldehyde,acetaldehyde and acetone with relatively high concentrations at night and minimal concentrations around noontime were very similar to those of CO and NOx,indicating that combustion source and automobile exhaust might be their important sources.The sources of the carbonyls were further quantitatively analyzed by using a multiple linear regression method with CO as the tracer of primary source and O3 as the secondary sources.The results showed that formaldehyde and acetaldehyde mainly came from the primary sources,accounting for 82.02%and 74.45%of the total sources,respectively,while the contribution of the primary sources to acetone was only 42.04%.The photolysis rates of formaldehyde,acetaldehyde and acetone as well as their contributions to peroxide free radicals were calculated based on the photochemical radiation flux measurement.The photolysis rates of the three main carbonyls and the production rates of the peroxide free radicals were found to increase by 3—5 times in polluted days in comparison with clean days,and thus the conversion rate of NO to NO2 would be greatly accelerated in pollution days to promote formation of O3.

关 键 词：醛酮类化合物 北京市 光解速率 大气氧化性 臭氧生成潜势 

分 类 号：X51[环境科学与工程—环境工程]