Assessment of Alternative Ventilation Schemes at Public Transport Interchange

Document Type

Journal Article

Publication Date


Subject Area

operations - traffic, infrastructure - vehicle, infrastructure - interchange/transfer, economics - appraisal/evaluation, organisation - management, mode - pedestrian


Waiting areas, Ventilation systems, Vehicle exhaust, Transportation control measures, Transit centers, Traffic, Smoke, Smog control, Simulation, Rush hour, Pedestrian bridges, Peak hour traffic, Hong Kong (China), Footbridges, Foot bridges, Fluid dynamics, Exhaust gases, Exhaust emissions, Evaluation and assessment, Emission control, Computer simulation, Automobile exhaust, Air quality management, Air quality, Air pollution control, Air pollution, Air pollutants


The provision of mechanical ventilation in a semi-confined public transport interchange is mandatory in Hong Kong. The authority recommends the general use of low-level-supply and high-level-exhaust airflow schemes that different from the traditional ventilation concept in that low-level emitted vehicle pollutants are best removed at source. Analyses of air quality at typical public transport interchange environments are conducted for the two airflow schemes. The computational fluid dynamics simulations are generalized by studying light and heavy traffic conditions with adjusted ventilation rates to match the change in vehicle emission levels to examine pollutant concentrations at passenger waiting areas and the elevated footbridges. While the conventional high-level-supply and low-level-exhaust scheme could perform better during light traffic loads, the difference diminishes with increased traffic loads during peak hours. On the other hand, the high-level exhaust scheme has an advantage of serving as a smoke extraction system during a fire outbreak.


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