Study on the Relationship between Traffic State and Pollutant Emissions in Highway Tunnel

Considering the influence of the state of motor vehicle traffic on the pollutant emission concentration in highway tunnel, the single vehicle pollutant emission factor model of highway tunnels is established. The emission concentration of nitrogen oxides (NOx) and hydrocarbons (HC) is predicted by the proposed model based on the Taihu Lake Tunnel’s traffic data; then verified by the traffic simulation software VISSIM. The results show that the concentration of NOx and HC in the tunnel will increase with traffic volume, the concentration of NOx will increase as speed increases, and the concentration of HC will decrease as speed increases. Finally, the accuracy of the model is verified by applying actual data from the Taihu Lake Tunnel. The model correctly reflects the relationship between traffic conditions and pollutant emissions in highway tunnels and provides decision support for the management and control of highway tunnels.