Vehicle emissions in congestion: Comparison of work zone, rush hour and free-flow conditions
Vehicle emissions in congestion: Comparison of work zone, rush hour and free-flow conditions
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DOI：
10.1016/j.atmosenv.2011.01.030
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发表时间：
2011-04-01
影响因子：
5
通讯作者：
Dion, Francois
中科院分区：
文献类型：
--
作者：
Zhang, Kai;Batterman, Stuart;Dion, Francois
交通拥堵经常发生在高峰时段和工作区，并且是车辆排放和空气质量影响的重要原因。本研究估算了工作区和高峰时段拥堵情况下轻型和重型车辆（LDV、HDV）的车辆排放量，并将其与畅通交通条件下的排放量进行了比较。现场实验收集了典型工作日沿高速公路路段的每秒车辆速度和加速度数据，该路段经历了高峰时段和工作区拥堵。收集到的数据经过平滑处理后用于综合模态排放模型 (CMEM)，以生成逐秒的排放量。对于LDV而言，以g mi(-1)车辆(-1)表示时，碳氢化合物(HC)、一氧化碳(CO)和氮氧化物(NOx)的最高排放率出现在交通从畅通状态变为拥堵状态的过渡期间，反之亦然；最低的比率发生在低速工作区拥堵期间。然而，最高的燃料消耗率和最高的二氧化碳（CO2）排放量出现在工作区拥堵时，而最低的燃料消耗率和二氧化碳排放量出现在高峰时段拥堵时。在链路或排放密度的基础上（例如，g mi(-1) s(-1)），高峰时段拥堵的排放率和燃料消耗率最高。 HDV 的结果有所不同，因为工作区拥堵与最高的 HC 排放量相关。 CO和CO2的油耗最高，而不同交通条件下NOx的排放率相似。然而，从排放密度来看，高峰时段拥堵再次与 CO、NOx 和 CO2（但不是 HC）的最高排放量相关。拥堵和自由流动条件之间的差异凸显了在排放、暴露和健康风险评估以及交通规划中考虑拥堵的重要性。 (C) 2011 Elsevier Ltd. 保留所有权利。
Traffic congestion frequently occurs during rush hour periods and in work zones, and can account for a significant share of vehicle emissions and air quality impacts. This study estimates vehicle emissions from light- and heavy-duty vehicles (LDVs, HDVs) in work zone and rush hour congestion, which are compared to emissions under free-flow traffic conditions. Field experiments collected second-by-second vehicle speed and acceleration data on typical weekdays along a freeway segment that experienced both rush hour and work zone congestion. The collected data were smoothed and used in the Comprehensive Modal Emissions Model (CMEM) to generate second-by-second emissions. For LDVs and when expressed as g mi(-1) vehicle(-1), the highest emission rates of hydrocarbons (HC), carbon monoxide (CO) and nitrogen oxide (NOx) occurred during the transitional period when traffic changed from free-flow to congested conditions and vice-versa; the lowest rates occurred during low speed work zone congestion periods. However, the highest fuel consumption rates and the highest carbon dioxide (CO2) emissions occurred under work zone congestion, while the lowest fuel consumption and CO2 emissions occurred with rush hour congestion. On a link or emission density basis (e.g., g mi(-1) s(-1)), rush hour congestion had the highest emission and fuel consumption rates. Results for HDVs differed in that work zone congestion was associated with the highest emissions of HC. CO and CO2, and the highest fuel consumption, while NOx emission rates under the different traffic conditions were similar. On an emission density basis, however, the rush hour congestion again was associated with the highest emissions of CO, NOx and CO2 (but not HC). The differences between congestion and free-flow conditions highlight the importance of accounting for congestion in emission, exposure and health risk evaluations, as well as transportation planning. (C) 2011 Elsevier Ltd. All rights reserved.