Black carbon concentrations in California vehicles and estimation of in-vehicle diesel exhaust particulate matter exposures
Black carbon concentrations in California vehicles and estimation of in-vehicle diesel exhaust particulate matter exposures
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DOI：
10.1016/j.atmosenv.2004.04.026
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发表时间：
2004-08-01
影响因子：
5
通讯作者：
Rodes, CE
中科院分区：
文献类型：
--
作者：
Fruin, SA;Winer, AM;Rodes, CE
这项研究评估了车内暴露于黑碳（BC）作为柴油颗粒物（CO2）暴露的指标。在洛杉矶和萨克拉门托的高速公路和动脉环路上行驶的车辆内进行了大约50小时的实时Aethalometer BC测量。录像带的司机的看法被转录记录的交通状况，车辆跟随，和车辆乘员的意见，这些结果进行了测试，其关联与BC浓度。当直接跟随柴油动力车辆时，车内的BC浓度最高，特别是那些排气管位置较低的车辆。最低的BC浓度是在跟随汽油动力的客车汽车时观察到的，平均而言与不跟随任何车辆没有什么不同。由于柴油车在实地研究中被过度采样，结果并不能代表现实世界的驾驶。为了计算代表性的接触量，针对每种道路类型和拥堵程度，按所跟随的车辆类型对车内BC浓度进行了分组。然后，这些分组被随机重新采样，与每种条件下全州车辆行驶里程（VMT）的比例成比例。在柴油车之后花费的大约6%的时间导致了23%的车内BC暴露，而剩余的暴露是由于道路BC浓度升高。在洛杉矶和海湾地区，车内BC暴露平均为6 mug m（-3），这是交通拥堵最严重的地区，也是该州VMT的主要地区。全州平均车内BC暴露量为4 mug m-3，对应于7-23 mug m-3的碳浓度，这取决于Aethalometer对元素碳（EC）的反应和碳中EC的分数。在全州人口的基础上，车内对总体暴露的贡献约为总暴露的30%至55%。因此，尽管在车辆中的时间平均只有1.5小时/天（-1），但车辆可能是总体暴露的最重要微环境。(C)2004爱思唯尔有限公司保留所有权利。
This research assessed in-vehicle exposures to black carbon (BC) as an indicator of diesel particulate matter (DPM) exposures. Approximately 50 h of real-time Aethalometer BC measurements were made inside vehicles driven on freeway and arterial loops in Los Angeles and Sacramento. Video tapes of the driver's view were transcribed to record the traffic conditions, vehicles followed, and vehicle occupant observations, and these results were tested for their associations with BC concentration. In-vehicle BC concentrations were highest when directly following diesel-powered vehicles, particularly those with low exhaust pipe locations. The lowest BC concentrations were observed while following gasoline-powered passenger cars, on average no different than not following any vehicle. Because diesel vehicles were over-sampled in the field study, results were not representative of real-world driving. To calculate representative exposures, in-vehicle BC concentrations were grouped by the type of vehicle followed, for each road type and congestion level. These groupings were then re-sampled stochastically, in proportion to the fraction of statewide vehicle miles traveled (VMT) under each of those conditions. The approximately 6% of time spent following diesel vehicles led to 23% of the in-vehicle BC exposure, while the remaining exposure was due to elevated roadway BC concentrations. In-vehicle BC exposures averaged 6 mug m(-3) in Los Angeles and the Bay Area, the regions with the highest congestion and the majority of the state's VMT. The statewide average in-vehicle BC exposure was 4 mug m(-3), corresponding to DPM concentrations of 7-23 mug m-3, depending on the Aethalometer response to elemental carbon (EC) and the EC fraction of the DPM. In-vehicle contributions to overall DPM exposures ranged from approximately 30% to 55% of total DPM exposure on a statewide population basis. Thus, although time spent in vehicles was only 1.5 h day(-1) on average, vehicles may be the most important microenvironment for overall DPM exposure. (C) 2004 Elsevier Ltd. All rights reserved.