State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Vehicle Emission Control Center of Ministry of Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
State Environmental Protection Key Laboratory of Vehicle Emission Control and Simulation, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Vehicle Emission Control Center of Ministry of Ecology and Environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Sci Total Environ. 2021 Nov 1;793:148380. doi: 10.1016/j.scitotenv.2021.148380. Epub 2021 Jun 16.
Characterized by a high frequency of use, harsh working environments, poor maintenance, and low levels of emission controls, rural vehicles (RVs) are becoming an important source of air pollution. Our study used a portable emission measurement system (PEMS) to test the real-world emissions of 35 RVs on provincial, rural, and farm roads. The results show that high emission rates of carbon monoxide (CO) and hydrocarbons (HC) mainly occurred when accelerating at low speeds. However, high levels of nitrogen oxides (NO) were emitted during high-speed acceleration. The particulate number (PN) of emissions was higher when the RVs were accelerating. According to the overall test results, the vehicle specific power (VSP) on the provincial road mostly ranged within (0, 3], accounting for 68.80% of the total. The VSP on rural and farm roads was concentrated within (0, 2] kW·ton, accounting for 67.09% and 76.64% of the total, respectively. We defined 14 bins based on the distribution of the VSP values and calculated the average emission rate of each bin. By comparing the average emission rate among the bins, we found that within Bins 1-7 (VSP < 0 kW·ton), CO, HC, and NO emissions slowly increased as the VSP increased. In Bins 8-13 (VSP ≥ 0 kW·ton), the average emission rates of four pollutants increased as the VSP increased. However, all pollutants decreased in Bin 14 (VSP ≥ 6 kW·ton). We built a microscopic emission model according to the VSP distribution characteristics of RVs on different road types. We compared the measured and simulated emission factors and found that our emission model can greatly simulate the HC, NOx and PN emission factors of RVs.
以高使用频率、恶劣的工作环境、差的维护和低排放控制水平为特征，农村车辆（RV）正成为空气污染的一个重要来源。我们的研究使用便携式排放测量系统（PEMS）测试了 35 辆 RV 在省级、农村和农场道路上的实际排放情况。结果表明，一氧化碳（CO）和碳氢化合物（HC）的高排放率主要发生在低速加速时。然而，在高速加速时会排放出高水平的氮氧化物（NO）。排放的颗粒数（PN）在 RV 加速时较高。根据整体测试结果，省级道路上的车辆特定功率（VSP）主要在（0,3]范围内，占总数的 68.80%。农村和农场道路上的 VSP 集中在（0,2]kW·ton 范围内，分别占总数的 67.09%和 76.64%。我们根据 VSP 值的分布定义了 14 个 bin，并计算了每个 bin 的平均排放率。通过比较 bin 之间的平均排放率，我们发现在 VSP<0kW·ton 的 Bin 1-7 中，随着 VSP 的增加，CO、HC 和 NO 的排放缓慢增加。在 VSP≥0kW·ton 的 Bin 8-13 中，随着 VSP 的增加，四种污染物的平均排放率都有所增加。然而，在 VSP≥6kW·ton 的 Bin 14 中，所有污染物都减少了。根据不同道路类型上 RV 的 VSP 分布特征，我们建立了微观排放模型。我们比较了测量和模拟的排放因子，发现我们的排放模型可以很好地模拟 RV 的 HC、NOx 和 PN 排放因子。
