Road dust is an important source to airborne particles in the Nordic countries. It consists of wear products from road pavement, tyres, brakes, traction sand, salt and dust dragged in from adjacent unbound roads or deposited from nearby or long distance dust sources, like building sites and farmland. The cold climate in the Nordic countries enhances the formation of road dust compared to most European countries, since it promotes the use of studded tyres, which abrades the road surfaces, and winter maintenance where dust forming material is added to the road surfaces.

The NORDUST II project has aimed to enhance knowledge about road dust emissions through extensive investigations, including laboratory and field studies, measurements, modeling, and future scenarios. An initial work package summarized current knowledge on mitigating road dust emissions. It found that dust binding solutions are most effective during acute dust episodes, while sweeping is beneficial on a seasonal basis. Preventive measures during autumn and winter can reduce airborne dust in spring. A core component of the project was experimental parameterization of processes in the NORTRIP emissions model. Studies revealed that vehicle weight and speed significantly influence particulate matter (PM) emissions, with heavier vehicles and higher speeds increasing emissions. The type of tire and road surface properties also play crucial roles.Experiments showed that winter sand is quickly crushed into finer fractions when driven over, but only a small portion of the sand mass is crushed. Coarse particles are removed more efficiently than finer particles at low speeds, but all particles are removed at speeds above 20 km/h. A field test in Linköping, Sweden, examined the removal of the dust binder CMA by traffic. Results indicated that the NORTRIP model could largely replicate the impact of traffic migration on CMA concentrations.