European Commission Joint Research Centre Ispra, Institute for Energy, Sustainable Transport Unit, 21027 Ispra (VA), Italy.
Anal Chim Acta. 2012 Mar 2;717:28-38. doi: 10.1016/j.aca.2011.12.029. Epub 2011 Dec 23.
Two-stroke mopeds are a popular and convenient mean of transport in particular in the highly populated cities. These vehicles can emit potentially toxic gaseous and aerosol pollutants due to their engine technology. The legislative measurements of moped emissions are based on offline methods; however, the online characterization of gas and particulate phases offers great possibilities to understand aerosol formation mechanism and to adapt future emission standards. The purpose of this work was to study the emission behavior of two mopeds complying with different European emission standards (EURO-1 and EURO-2). A sophisticated set of online analyzers was applied to simultaneously monitor the gas phase and particulate phase of exhaust on a real time basis. The gaseous emission was analyzed with a high resolution Fourier transform infrared spectrometer (FTIR; nitrogen species) and a resonance-enhanced multiphoton ionization time-of-flight mass spectrometer (REMPI-ToF-MS; polycyclic aromatic hydrocarbons: PAH), whereas the particulate phase was chemically characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS; organic, nitrate and chloride aerosol) and a multiangle absorption photometer (MAAP; black carbon). The physical characterization of the aerosol was carried out with a condensation particle counter (CPC; particle number concentration) and a fast mobility particle sizer (FMPS; size distribution in real time). In order to extract underlying correlation between gas and solid emissions, principal component analysis was applied to the comprehensive online dataset. Multivariate analysis highlighted the considerable effect of the exhaust temperature on the particles and heavy PAH emissions. The results showed that the after-treatment used to comply with the latest EURO-2 emission standard may be responsible for the production of more potentially harmful particles compared to the EURO-1 moped emissions.
二冲程轻便摩托车在人口稠密的城市中是一种很受欢迎且便捷的交通工具。由于其发动机技术，这类车辆会排放出具有潜在毒性的气态和气溶胶污染物。轻便摩托车排放的立法测量是基于离线方法的；然而，对气体和颗粒相的在线特性描述提供了很大的可能性，可以帮助我们理解气溶胶的形成机制，并适应未来的排放标准。本工作的目的是研究两辆符合不同欧洲排放标准（EURO-1 和 EURO-2）的轻便摩托车的排放行为。一套复杂的在线分析器被应用于实时地同时监测废气的气相和颗粒相。气态排放通过高分辨率傅里叶变换红外光谱仪（FTIR；氮物种）和共振增强多光子电离飞行时间质谱仪（REMPI-ToF-MS；多环芳烃：PAH）进行分析，而颗粒相则通过高分辨率飞行时间气溶胶质谱仪（HR-ToF-AMS；有机、硝酸盐和氯化物气溶胶）和多角度吸收光度计（MAAP；黑碳）进行化学特性分析。气溶胶的物理特性通过凝聚粒子计数器（CPC；粒子数浓度）和快速迁移率粒子粒径仪（FMPS；实时的粒径分布）进行测量。为了提取气体和固体排放之间的潜在相关性，应用主成分分析对综合在线数据集进行了分析。多元分析突出了排气温度对颗粒和重质 PAH 排放的显著影响。结果表明，为了符合最新的 EURO-2 排放标准而采用的后处理技术可能会导致比 EURO-1 轻便摩托车排放更多潜在有害的颗粒。
