Abstract for presentation at 14th IUAPPA World Congress

In many countries road tunnels have proven to be a viable solution in solving many highway traffic problems, including traffic congestion through built up areas in cities and topographical constraints in mountainous countries. However, the beneficial effects of incorporating tunnels as solutions in traffic flow problems must be weighed up against the potential adverse effects of air exhaust emissions from vehicles, both in-tunnel and ambient air quality effects on the surrounding community. Various systems can be applied to upgrade the quality of the environment around tunnels and roads by making use of technologies such as movement and control, purification, and control and measurement. Air exhaust emissions can be substantially reduced by a correctly designed ventilation system and a variety of other methods including tall ventilation exhaust stacks, filter dust collector systems, electrostatic precipitators or denitrification or a ventilation control and measurement system based on the traffic volume and the polluted conditions in a tunnel at any point in time. The effective dispersion, dilution and achievement of satisfactory ground level concentrations of key air quality parameters (CO,NO₂ and particulates)for these exhaust gases is essential to ensure non-negative health effects on the surrounding community.
The paper will identify and discuss the types and character of air emissions, controls, the efficiency of the various control measures and estimated costs of some systems.
Progress has been made in the field of emission treatment technology and viable
technologies are now available to remove suspended particles, nitrogen dioxide, some
portion of other oxides of nitrogen, and hydrocarbon vapours from road tunnel exhaust
air.
Keywords: road tunnels, air quality effects, air exhaust emissions, ventilation exhaust stacks, filter dust collector systems, electrostatic precipitators, denitrification, efficiency, costs