Cheng Yuan, Li Shao-Meng, Liggio John, Hayden Katherine, Han Yuemei, Stroud Craig, Chan Tak, Poitras Marie-Josée
Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada.
Air Quality Research Division, Environment and Climate Change Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada.
Environ Pollut. 2017 Nov;230:72-80. doi: 10.1016/j.envpol.2017.06.014. Epub 2017 Jun 22.
Semivolatile organic compounds (SVOCs) represent a dominant category of secondary organic aerosol precursors that are increasingly included in air quality models. In the present study, an experimental system was developed and applied to a light-duty diesel engine to determine the emission factors of particulate SVOCs (pSVOCs) and nonvolatile particulate matter (PM) components at dilution ratios representative of ambient conditions. The engine was tested under three steady-state operation modes, using ultra-low-sulfur diesel (ULSD), three types of pure biodiesels and their blends with ULSD. For ULSD, the contribution of pSVOCs to total particulate organic matter (POM) mass in the engine exhaust ranged between 21 and 85%. Evaporation of pSVOCs from the diesel particles during dilution led to decreases in the hydrogen to carbon ratio of POM and the PM number emission factor of the particles. Substituting biodiesels for ULSD could increase pSVOCs emissions but brought on large reductions in black carbon (BC) emissions. Among the biodiesels tested, tallow/used cooking oil (UCO) biodiesel showed advantages over soybean and canola biodiesels in terms of both pSVOCs and nonvolatile PM emissions. It is noteworthy that PM properties, such as particle size and BC mass fraction, differed substantially between emissions from conventional diesel and biodiesels.
半挥发性有机化合物（SVOCs）是二次有机气溶胶前体的主要类别，空气质量模型中越来越多地纳入了这类物质。在本研究中，开发了一种实验系统，并将其应用于一台轻型柴油发动机，以确定在代表环境条件的稀释比下颗粒态SVOCs（pSVOCs）和非挥发性颗粒物（PM）成分的排放因子。该发动机在三种稳态运行模式下进行测试，使用超低硫柴油（ULSD）、三种纯生物柴油及其与ULSD的混合物。对于ULSD，pSVOCs在发动机尾气中对总颗粒有机物（POM）质量的贡献在21%至85%之间。稀释过程中柴油颗粒中pSVOCs的蒸发导致POM的氢碳比以及颗粒的PM数量排放因子降低。用生物柴油替代ULSD会增加pSVOCs排放，但会大幅降低黑碳（BC）排放。在所测试的生物柴油中，牛油/废食用油（UCO）生物柴油在pSVOCs和非挥发性PM排放方面比大豆和油菜籽生物柴油更具优势。值得注意的是，传统柴油和生物柴油排放的PM特性，如粒径和BC质量分数，有很大差异。
