1. A real-world assessment of urban bus transport in Isfahan, Iran was conducted to analyze emission performance and fuel consumption.
2. The study found that poor urban development significantly affects bus emissions and fuel consumption, and after-treatment systems may have unexpected functionalities in different situations.
3. Per-passenger emission factors and fuel consumption rates are more than halved by a 1.5 T increase in passenger loads, and Euro IV buses with DPFs had better per-passenger/accumulated emission performance and fuel consumption than others.
The article provides a comprehensive real-world assessment of the driving behavior, emission performance, and fuel consumption of urban buses in Isfahan, Iran. The study highlights the impact of poor urban development on bus emissions and fuel consumption and suggests that Bus Rapid Transit (BRT) could be a wise alternative for reducing bus emissions.
The article presents several interesting findings, such as the strong correlation between speed and HC FBEFs reduction by over 70% with increasing 30 km/h in bus speed. The study also shows that idling status contributes over 70%, 50%, 30%, and 30% to NOx, CO2, HC emission, and FC of the studied fleet, respectively. Additionally, Euro IV buses with DPFs had better per-passenger/accumulated emission performance and fuel consumption than others.
However, the article has some potential biases and limitations. For instance, it only focuses on one city in the Middle East, which limits its generalizability to other cities or regions. Moreover, the study does not consider other factors that could affect bus emissions such as weather conditions or road infrastructure.
Additionally, while the article acknowledges different technologies such as SCR devices or DOCs to decrease environmental drawbacks of diesel engines, it does not explore their limitations or potential risks associated with their use. Furthermore, there is no discussion about alternative fuels or electric buses that could significantly reduce bus emissions.
Overall, while the article provides valuable insights into urban bus transport in Isfahan and highlights some important factors affecting bus emissions and fuel consumption rates; it has some limitations regarding its generalizability to other regions or cities worldwide. It also lacks a comprehensive discussion about alternative solutions to reduce bus emissions beyond BRT systems or after-treatment systems for diesel engines.