Emissions of size-segregated aerosols from on-road vehicles in the Caldecott Tunnel
Emissions of size-segregated aerosols from on-road vehicles in the Caldecott Tunnel
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DOI：
10.1021/es0015545
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发表时间：
2001-11-01
影响因子：
11.4
通讯作者：
Cass, GR
中科院分区：
文献类型：
--
作者：
Allen, JO;Mayo, PR;Cass, GR
研究人员测量了37500辆汽车穿过位于旧金山湾区的Calclecott隧道的两个孔时，加州正在使用的车辆排放的颗粒物。使用微孔级联冲击器和基于过滤器的采样器来确定颗粒化学成分作为粒度的函数。车队的氨排放也被测量了。报告了气溶胶质量、有机碳、元素碳、硫酸盐离子、硝酸盐离子和铵离子以及13种元素的浓度。颗粒质量分布在粒径范围0.1 ~ 0.18 μ m气动直径（D-a）内达到峰值。在所有粒径范围内，元素碳和有机质是颗粒质量的最大组成部分。研究的Caldecott隧道包括一个承载轻型车辆的隧道和一个承载轻型和重型混合车辆的隧道。根据在两个孔中进行的实验，对100%轻型和100%重型车队的颗粒物排放的大小分布和化学成分进行了估计。重型车辆在燃烧的燃料中每公斤碳排放1285 +/- 237毫克细颗粒物（D-a < 1.9毫克）（相当于每公里行驶约430 +/- 79毫克）。轻型车辆在燃烧的燃料中排放的碳含量低于85 +/- 6毫克/千克（相当于每公里行驶的碳含量低于约5.5 +/- 0.4毫克）。据测量，在Caldecott隧道中燃烧的汽油当量燃料中，气相氨的排放量分别为194和267毫克/升。氨气的排放是由于使用了3种催化剂的汽车和燃料丰富的汽车造成的。
Particulate matter emissions from the California in-use vehicle fleet were measured as 37 500 vehicles traveled through two bores of the Calclecott Tunnel located in the San Francisco Bay area. Microorifice cascade impactors and filter-based samplers were used to determine the particle chemical composition as a function of particle size. Ammonia emissions from the vehicle fleet were measured as well. Concentrations of aerosol mass, organic carbon, elemental carbon, sulfate ion, nitrate ion, and ammonium ion, as well as 13 elements are reported. The particle mass distribution peaks in the particle size range 0.1-0.18 mum aerodynamic diameter (D-a). Elemental carbon and organic matter were the largest components of particle mass in all the size ranges studied. The Caldecott Tunnel bores studied include one which carries light-duty vehicle traffic and one which carries a mixture of light- and heavy-duty vehicle traffic. From experiments conducted in both bores, estimates are made of the size distribution and chemical composition of particulate matter emissions extrapolated to the 100% light-duty and 100% heavy-duty vehicle fleets. The heavy-duty vehicle fleet emitted 1285 +/- 237 mg of fine particulate matter (D-a < 1.9 mum)/kg of C contained in the fuel burned (corresponding to approximately 430 +/- 79 mg/km driven). Light-duty vehicles emitted less than 85 +/- 6 mg/ kg of C in the fuel burned (corresponding to less than approximately 5.5 +/- 0.4 mg/km driven). Emissions of gasphase ammonia in the Caldecott Tunnel were measured to be 194 and 267 mg/L of gasoline-equivalent fuel burned in the tunnel. The ammonia emissions are attributed to automobiles that were equipped with 3-way catalysts and operating fuel rich.