Air quality has become a topic of concern in the planning, design and operation process of road tunnels.

This is a state-of-the-art report on the knowledge and regulations in the field of road traffic impact on air quality. It also provides a detailed description of air quality optimization at tunnel portals, pollution dispersion from air tunnels, chimneys and openings.

A diagnosis is made on the type and performance of the various measures and technologies to reduce the level of pollutant emissions in tunnels.

The report is complemented by nine case studies, a description of the health impact of the various air pollutants potentially present in the air and an introduction to dispersion models for the design of ventilation systems.