Vehicular emissions and air quality assessment in roadway tunnels: The Salim Slam tunnel

Vehicle emissions constitute a serious environmental concern particularly in confined spaces such as tunnels and underground parking garages. These emissions are characterized with the presence of various pollutants, which, at high concentrations, can cause adverse health effects. This paper presents an assessment of vehicle-induced emissions and air quality in a heavily traveled tunnel located in urban metropolitan Beirut. For this purpose, common modeling theories were reviewed, relevant air quality standards were defined, existing conditions were characterized, an air-sampling program was implemented, and mathematical modeling to simulate field measurements was conducted. Impact significance was evaluated by comparing measured and simulated pollutant concentrations with air quality standards. Model simulations were also used to evaluate vehicle-induced pollutant emission factors. Finally, mitigation measures are proposed to insure proper air quality management inside the tunnel.