Modelling of Transient Emissions and Concentrations from Traffic in Street Canyons

INTRODUCTION In the EU 5 framework project DECADE (2001-2003) a new methodology has been developed to calculate in detail the engine power required to drive a given vehicle over any particular route. It includes the rapidly changing (transient) demands placed on the engine, an area that has proved an obstacle to accurate simulations in the past. Together with the associated speed profiles, the actual power demands allow a detailed calculation of emissions and ambient air concentrations in street canyons. This makes the methodology a valuable tool for detailed assessments of the ambient air quality impact of e.g. street design (traffic lights, road bumps, busy crossings), driving patterns, driving behaviour and fleet composition.