A structured methodology to calculate traffic emissions inventories for city centres

This study presents a methodology to estimate traffic emissions inventories for the case of city centres. It deals with the problem in a structured manner, identifying the sources and the formats of the input data as well as labelling the steps needed to perform the calculation. It describes a method to calculate the total mileage driven around the city using the concept of mileage per zone. Although the methodology employs a classical approach through the use of emission factors developed for mean speeds, it also discusses the possibility of applying these factors to instantaneous speeds. Finally, the study focuses on the influence of two critical factors: time resolution and the estimate of the total mileage. In both cases, the results indicate that the assumptions made are adequate and yield accurate results. The methodology has been applied to the city of Madrid as an example.