Dynamic Traffic Routing for Air Quality Enhancement During Urban Environmental Crises

This study introduces an air quality-aware traffic re-routing scheme designed to minimise vehicle emissions in highly polluted urban areas during environmental crises. Tested in two scenarios, a building fire and a smog episode near a train station, the scheme employs an ‘emission sensitivity factor’ ($\Delta$) to adjust re-routing costs based on normalised air quality index (AQI) data and vehicle emission profiles. Results indicate that selecting an optimal $\Delta$ can reduce ${\text{NO}}_x$ concentrations by 15% and improve AQI by 10% in targeted areas without adversely affecting traffic performance. Key traffic metrics such as average vehicle duration, waiting time, and speed remained largely unchanged (under 2% variation), demonstrating a balance between traffic efficiency and air quality improvement. The findings highlight the potential for integrating dynamic AQI data into urban traffic management systems, offering valuable insights for urban planners and policymakers aiming to reduce pollution exposure while maintaining optimal traffic flow.