title: Measurement and three-dimensional modeling of airflow and pollutant dispersion in an undersea traffic tunnel.
abstract: Airflow and pollutant dispersion in a cross-harbor traffic tunnel were experimentally and numerically studied. Concentrations of the gaseous pollutants CO, NOx, and total hydrocarbons (THC) at three axial locations in the tunnel, together with traffic flow rate, traffic speed, and types of vehicle were measured. Three-dimensional (3D) turbulent flow and dispersion of air pollutants in the tunnel were modeled and solved numerically using the finite volume method. Traffic emissions were modeled accordingly as banded line sources along the tunnel floor. The results reveal that cross-sectional concentrations are nonuniformly distributed and that concentrations rise with downstream distance. The piston effect of vehicles alone can provide 9-23% dilution of air pollutants in the tunnel, compounded to a 23-74% dilution effect according to the ventilation condition.
authors.affiliation: Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan, Republic of China. shin@mail.nsysu.edu.tw
authors.forename: K S
authors.initials: KS
authors.lastname: Chen
authors.forename: Chung-Yi
authors.initials: CY
authors.lastname: Chung
authors.forename: S W
authors.initials: SW
authors.lastname: Wang
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods; D005160:Facility Design and Construction; D008838:Microcomputers; D008962:Models, Theoretical; D014186:Transportation; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions