段乐君,袁自冰,沙青娥,王梦雷,刘学辉,刘元向,郝钰琦,郑君瑜.不同排放标准下机动车挥发性有机化合物排放特征趋势研究[J].环境科学学报,2021,41(4):1239-1249
不同排放标准下机动车挥发性有机化合物排放特征趋势研究
- Investigation on the trend of emission characteristics of volatile organic compounds from motor vehicle exhaust under different emission standards
- 基金项目：国家重点研发计划（No.2016YFC0202201）
- 段乐君
- 华南理工大学环境与能源学院, 广州 510006
- 袁自冰
- 华南理工大学环境与能源学院, 广州 510006
- 沙青娥
- 暨南大学环境与气候研究院, 广州 511443
- 王梦雷
- 华南理工大学环境与能源学院, 广州 510006
- 刘学辉
- 华南理工大学环境与能源学院, 广州 510006
- 刘元向
- 华南理工大学环境与能源学院, 广州 510006
- 郝钰琦
- 华南理工大学环境与能源学院, 广州 510006
- 郑君瑜
- 暨南大学环境与气候研究院, 广州 511443
- 摘要：针对机动车挥发性有机物（VOCs）排放特征研究中缺乏含氧VOCs（OVOCs）覆盖、缺乏最新国VI排放标准特征识别等问题，本研究选取了涵盖国I~国VI不同排放标准的轻型汽油车和国Ⅲ~国Ⅴ柴油车为研究对象进行底盘测功机测试，采用SUMMA罐和DNPH管采样相结合的方法，探究了不同排放标准下机动车尾气中VOCs排放特征的变化趋势及启动方式对VOCs排放特征的影响.结果表明，不同排放标准的轻型汽油车尾气组成呈现较大差异.随着排放标准的升级，烷烃、烯炔烃和芳香烃的质量比例逐渐减少，OVOCs逐渐增加，国Ⅰ~国IV轻型汽油车排放以烷烃和芳香烃为主，国V~国Ⅵ轻型汽油车排放以OVOCs为主.国VI轻型汽油车中OVOCs占比高达58.0%，其中，甲醛、乙醛和丙酮合计占47.3%.不同排放标准的柴油车尾气中VOCs均以OVOCs和烯炔烃为主，占79.0%~83.0%.此外，冷启动是机动车尾气VOCs排放的主要阶段，此阶段的VOCs排放因子显著高于热启动，但随着排放标准升级，柴油车在启动阶段的VOCs排放降幅仅有约40%，显著小于全工况排放降幅（77.5%），表明柴油车启动过程对VOCs排放贡献随排放标准升级逐步加大.本研究凸显了在我国机动车排放标准不断升级的背景下VOCs排放的重要性，需要在制定机动车VOCs排放控制策略中重点关注柴油车尾气中烯炔烃和汽油车尾气中OVOCs减排.
- Abstract：In view of the lacks of Oxygenated volatile organic compounds (OVOCs) and VOCs emission characteristics from motor vehicles with the latest China VI emission standard. In this study, fleet of light-duty gasoline vehicles spanning emission standards from China I to VI and diesel vehicles with China Ⅲ- China Ⅴ emission standards were selected to carry out the chassis dynamometer test. SUMMA canisters and DNPH cartridges were collectively used for sample analysis to identify the trends of VOCs (including OVOCs) emission characteristics from motor vehicles under different emission standards and to explore the impacts of starting styles on the VOCs emissions. Huge differences in the compositions of gasoline vehicles exhausts were found under different emission standards. With the upgrading of emission standards, the mass fractions of alkanes, alkenes and aromatics gradually reduced and OVOCs increased. Alkanes and aromatics occupied the VOCs emissions from China I-IV gasoline vehicles, while OVOCs were the dominant species in VOCs emissions from China V-VI vehicles, especially China VI vehicles with the OVOCs fraction of 58.0%, in which formaldehyde, acetaldehyde and acetone had the fraction of 47.3%. OVOCs and alkenes were the main components for diesel vehicle exhaust under different emission standards, ranging from 79.0% to 83.0%. Additionally, vehicles had more VOCs emissions during cold start, and the emission factor was much higher than that of hot start. However, the reduction magnitude of VOCs from the starting stage was only around 40%, much lower than that of 77.5% for the entire sampling period with the increasing emission standards. This indicated that the emission contributions from the starting period became much greater with the newer emission standard. This study highlighted the importance of VOCs with the continuous upgrading of emission standards in China. More attention should be paid on OVOCs for light-duty vehicles and alkenes for diesel vehicles when formulating effective control strategies to reduce VOCs emissions from motor vehicles.
