The impact of jet fans layout on the CO concentration distribution inside tunnel for the congestion scenario

Abstract

Air pollution inside tunnel has attracting more people’s attention in China. The occurrence of traffic accident in the rush hours would cause widespread traffic congestion inside tunnel. This may further lead to accumulation of air pollutants near the accident location. To analyze the accumulative effect, the air velocity and CO concentration under different jet fans layout are predicted by use of the multi-segments model. The results show that the occurrence of the accident does influence the spatial-temporal distributions of air velocity and CO concentration. After the accident, air velocity in the congestion region drops significantly and CO concentration jumps downstream the accident location. For a traffic accident-induced congestion scenario, increasing the jet fans in the upstream area is more effective to dilute the air pollutants inside tunnel.