Middela Mounisai Siddartha, Mahesh Srinath, McNabola Aonghus, Smith William, Timoney David, Ekhtiari Ali, Fowler Ben, Willis Paul, Rose Rebecca, Wareham Jasmine, Walker Hannah, Ghosh Bidisha
Department of Civil, Structural and Environmental Engineering, School of Engineering, Trinity College Dublin, Dublin, Ireland.
Delft University of Technology, Delft, the Netherlands.
Environ Pollut. 2024 Mar 1;344:123241. doi: 10.1016/j.envpol.2023.123241. Epub 2024 Jan 8.
Assessing real-world emissions from buses and taxis is vital to comprehend their impact on urban air quality. Such vehicles differ significantly from the majority of the fleet owing to their higher mileage rates. However, few studies have focused on specifically assessing the emissions from this segment of the vehicle fleet. In this context, this study evaluated the real-world emissions of nitrogen oxides (NO) from in-use buses and taxis in Dublin, Ireland, using crossroad remote sensing technology. The remote sensing system was deployed at strategic locations throughout the city to capture on-road emissions from passing vehicles. The collected data included vehicle related information such as emission standard, make, and mileage, and pollutants including NO. Based on this data, analysis was aimed to understand the impact of Euro emission standard, ambient temperature, mileage, and make of the vehicle on NO emissions. The results reveal that the average emissions from taxis reduce by 37% from Euro 5 to Euro 6b, and average emissions from Euro 6 buses are 87% lower compared to Euro 5. The trends in emission factors (EFs) of buses and taxis were similar during summer and winter sampling. Moreover, on comparing the emissions from the top five taxi manufacturers, different trends in the emission factors were observed. Finally, the study found that the effect of vehicle mileage on emissions was unclear for both buses and taxis. In any case, these findings provide valuable insights into the real-world emission performance of the existing fleet of buses and taxis in Dublin and highlight the need for targeted measures to reduce emissions from these vehicles. The results can assist policymakers and urban planners in formulating evidence-based strategies to improve air quality in Dublin and other cities facing similar challenges.
评估公交车和出租车的实际排放量对于理解它们对城市空气质量的影响至关重要。由于这些车辆的行驶里程较高，它们与大多数车队有显著差异。然而，很少有研究专门关注评估这部分车辆的排放量。在此背景下，本研究使用十字路口遥感技术评估了爱尔兰都柏林在用公交车和出租车的氮氧化物（NO）实际排放量。遥感系统部署在城市的战略位置，以捕捉过往车辆的道路排放量。收集的数据包括车辆相关信息，如排放标准、品牌和里程，以及污染物，包括NO。基于这些数据，分析旨在了解欧洲排放标准、环境温度、里程和车辆品牌对NO排放的影响。结果显示，出租车的平均排放量从欧5标准到欧6b标准降低了37%，与欧5标准相比，欧6公交车的平均排放量降低了87%。公交车和出租车的排放因子（EFs）在夏季和冬季采样期间趋势相似。此外，在比较前五名出租车制造商的排放量时，观察到排放因子的不同趋势。最后，研究发现车辆里程对公交车和出租车排放量的影响尚不清楚。无论如何，这些发现为都柏林现有公交车和出租车车队的实际排放性能提供了有价值的见解，并突出了采取针对性措施减少这些车辆排放的必要性。研究结果可协助政策制定者和城市规划者制定基于证据的战略，以改善都柏林及面临类似挑战的其他城市的空气质量。
