Lough Glynis C, Christensen Charles G, Schauer James J, Tortorelli James, Mani Erin, Lawson Douglas R, Clark Nigel N, Gabele Peter A
Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI 53706, USA.
J Air Waste Manag Assoc. 2007 Oct;57(10):1190-9. doi: 10.3155/1047-3289.57.10.1190.
As part of the Gasoline/Diesel PM Split Study, relatively large fleets of gasoline vehicles and diesel vehicles were tested on a chassis dynamometer to develop chemical source profiles for source attribution of atmospheric particulate matter in California's South Coast Air Basin. Gasoline vehicles were tested in cold-start and warm-start conditions, and diesel vehicles were tested through several driving cycles. Tailpipe emissions of particulate matter were analyzed for organic tracer compounds, including hopanes, steranes, and polycyclic aromatic hydrocarbons. Large intervehicle variation was seen in emission rate and composition, and results were averaged to examine the impacts of vehicle ages, weight classes, and driving cycles on the variation. Average profiles, weighted by mass emission rate, had much lower uncertainty than that associated with intervehicle variation. Mass emission rates and elemental carbon/organic carbon (EC/OC) ratios for gasoline vehicle age classes were influenced most by use of cold-start or warm-start driving cycle (factor of 2-7). Individual smoker vehicles had a large range of mass and EC/OC (factors of 40 and 625, respectively). Gasoline vehicle age averages, data on vehicle ages and miles traveled in the area, and several assumptions about smoker contributions were used to create emissions profiles representative of on-road vehicle fleets in the Los Angeles area in 2001. In the representative gasoline fleet profiles, variation was further reduced, with cold-start or warm-start and the representation of smoker vehicles making a difference of approximately a factor of two in mass emission rate and EC/OC. Diesel vehicle profiles were created on the basis of vehicle age, weight class, and driving cycle. Mass emission rate and EC/OC for diesel averages were influenced by vehicle age (factor of 2-5), weight class (factor of 2-7), and driving cycle (factor of 10-20). Absolute and relative emissions of molecular marker compounds showed levels of variation similar to those of mass and EC/OC.
作为汽油/柴油颗粒物排放源解析研究的一部分，在底盘测功机上对数量相对较多的汽油车和柴油车车队进行了测试，以建立化学源排放清单，用于加利福尼亚州南海岸空气盆地大气颗粒物的源解析。汽油车在冷启动和热启动条件下进行了测试，柴油车则通过多个驾驶循环进行了测试。对尾气排放的颗粒物进行了有机示踪化合物分析，包括藿烷、甾烷和多环芳烃。不同车辆之间在排放速率和成分上存在很大差异，对结果进行了平均处理，以研究车辆年龄、重量等级和驾驶循环对这种差异的影响。按质量排放速率加权的平均排放清单的不确定性远低于车辆间差异带来的不确定性。汽油车不同年龄组的质量排放速率和元素碳/有机碳（EC/OC）比值受冷启动或热启动驾驶循环的影响最大（相差2至7倍）。个别高排放车辆的质量和EC/OC范围很大（分别相差40倍和625倍）。利用汽油车年龄平均值、该地区车辆年龄和行驶里程数据以及关于高排放车辆贡献的若干假设，创建了代表2001年洛杉矶地区道路车辆车队的排放清单。在代表性汽油车队排放清单中，差异进一步减小，冷启动或热启动以及高排放车辆的占比在质量排放速率和EC/OC方面造成了约两倍的差异。柴油车排放清单是根据车辆年龄、重量等级和驾驶循环创建的。柴油车平均质量排放速率和EC/OC受车辆年龄（相差2至5倍）、重量等级（相差2至7倍）和驾驶循环（相差10至20倍）的影响。分子标志物化合物的绝对和相对排放量显示出与质量和EC/OC类似的变化水平。
