PROGRESS TOWARDS TRAFFIC INDUCED ROAD DUST AND SALT EMISSION MODELLING: MODEL DEVELOPMENT WITHIN NORTRIP

Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Modelling these emissions is a challenging task as they are sensitive to environmental factors such as road surface moisture as well as road maintenance activities (salting and sanding) and tyre and vehicle types. The ability to model these emissions is desirable as this provides the potential for more effective road management, improved assessment of mitigation strategies for reducing emissions and can help quantify the impact of salting and sanding activities. These are all important applications relevant to the European AQ Directive. The Nordic based project NORTRIP is building upon existing road dust emission models, combined with field and laboratory measurements, to develop a more comprehensive and generalised process based model description of the non-exhaust emissions, with emphasis on the contribution of road wear, salt and sand to the emissions. In this paper we present the current status of the modelling, briefly describing the processes and their parameterisations. The performance of the model is illustrated using two example applications from Norway and Sweden and future developments are discussed.