Phuleria Harish C, Geller Michael D, Fine Philip M, Sioutas Constantinos
Department of Civil and Environmental Engineering, University of Southern California, Los Angeles, California 90089, USA.
Environ Sci Technol. 2006 Jul 1;40(13):4109-18. doi: 10.1021/es052186d.
Individual organic compounds found in particulate emissions from vehicles have proven useful in source apportionment of ambient particulate matter. Species of interest include the hopanes, originating in lube oil, and selected PAHs generated via combustion. Most efforts to date have focused on emissions and apportionment PM10 or PM2.5 However, examining how these compounds are segregated by particle size in both emissions and ambient samples will help efforts to apportion size-resolved PM, especially ultrafine particles which have been shown to be more potent toxicologically. To this end, high volume size-resolved (coarse, accumulation, and ultrafine) PM samples were collected inside the Caldecott tunnel in Orinda, California to determine the relative emission factors for these compounds in different size ranges. Sampling occurred in two bores, one off-limits to heavy-duty diesel vehicles, which allows determination of the different emissions profiles for diesel and gasoline vehicles. Although tunnel measurements do not measure emissions over a full engine duty cycle, they do provide an average emissions profile over thousands of vehicles that can be considered characteristic of "freeway" emissions. Results include size-fractionated emission rates for hopanes, PAHs, elemental carbon, and other potential organic markers apportioned to diesel and gasoline vehicles. The results are compared to previously conducted PM2.5 emissions testing using dynamometer facilities and othertunnel environments.
已证明，车辆颗粒物排放中发现的个别有机化合物在环境颗粒物的源解析中很有用。感兴趣的物种包括源自润滑油的藿烷，以及通过燃烧产生的选定多环芳烃。迄今为止，大多数工作都集中在排放和PM10或PM2.5的源解析上。然而，研究这些化合物在排放和环境样品中如何按粒径分离，将有助于对粒径分辨的颗粒物进行源解析，尤其是超细颗粒物，已证明其在毒理学上更具毒性。为此，在加利福尼亚州奥林达的卡尔德科特隧道内采集了大量按粒径分辨（粗颗粒部分、积聚部分和超细颗粒部分）的颗粒物样本，以确定这些化合物在不同粒径范围内的相对排放因子。采样在两个钻孔中进行，其中一个钻孔禁止重型柴油车辆通行，这使得能够确定柴油车和汽油车的不同排放特征。尽管隧道测量不能测量整个发动机工作循环的排放，但它们确实提供了数千辆车的平均排放特征，可被视为“高速公路”排放的特征。结果包括分配给柴油车和汽油车的藿烷、多环芳烃、元素碳和其他潜在有机标志物的粒径分级排放率。将结果与之前使用测功机设施和其他隧道环境进行的PM2.5排放测试进行比较。
