Rogak Steven N, Green Sheldon I, Pott Ute
a Department of Mechanical Engineering , University of British Columbia , Vancouver , British Columbia , Canada.
J Air Waste Manag Assoc. 1998 Jun;48(6):545-552. doi: 10.1080/10473289.1998.10463707.
Pollutant measurements in traffic tunnels have been used to estimate motor-vehicle emissions for several decades. The objective in this type of study is to use the traffic tunnel as a tool for characterizing motor vehicles rather than seeking a tunnel design with acceptably low pollutant concentrations. In the past, very simple aerodynamic models have been used to relate measured concentrations to vehicle emissions. Typically, it is assumed that velocities and concentrations are uniform across the tunnel cross section. In the present work, a vehicle emitting a known amount of sulfur hexafluoride (SF) was driven repeatedly through a 730-m-long traffic tunnel in Vancouver, Canada. Comparing the measured SF concentrations to the known emission rates, it is possible to directly assess the accuracy of the simple tunnel aerodynamic models typically used to interpret tunnel data. Correction factors derived from this procedure were then applied to measurements of carbon monoxide and other pollutants to obtain gram-per-kilometer emission factors for vehicles. Although the specific correction factors measured here are valid only for the tunnel tested, the magnitude of the factors (up to two or more) suggests that the phenomena observed here should be considered when interpreting data from other tunnels.
几十年来，交通隧道中的污染物测量一直被用于估算机动车排放。这类研究的目的是将交通隧道用作表征机动车的工具，而非寻求污染物浓度低至可接受水平的隧道设计。过去，人们使用非常简单的空气动力学模型来关联测量浓度与车辆排放。通常假定整个隧道横截面上的速度和浓度是均匀的。在当前工作中，一辆排放已知量六氟化硫（SF）的车辆在加拿大温哥华一条730米长的交通隧道中反复行驶。将测量的SF浓度与已知排放率进行比较，就可以直接评估通常用于解释隧道数据的简单隧道空气动力学模型的准确性。然后，将从该过程得出的校正因子应用于一氧化碳和其他污染物的测量，以获得车辆每公里的克排放因子。尽管此处测量的特定校正因子仅对测试的隧道有效，但这些因子的量级（高达两倍或更多）表明，在解释来自其他隧道的数据时应考虑此处观察到的现象。
