2024

Gustafsson, Mats; Blomqvist, Göran; Järlskog, Ida; Svensson, Nina; Kulovuori, Sami; Rolstad Denby, Bruce; Grøtting Wærsted, Eivind; Stojilikovic, Ana; Karvosenoja, Niko; Grythe, Henrik; Yttri, Karl-Espen; Thorsteinsson, Throstur; Johansson, Christer; Norman, Michael; Engardt, Magnuz; Josefsson, Anton

The NORDUST II project has aimed to enhance knowledge about road dust emissions through extensive inves-tigations, 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 re-vealed 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, exam-ined 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. A 16% reduction in PM10 concentrations was observed with dust binding. The project also explored the correlation between road dust load and PM concentrations in the air, noting that dust load is typically lower in wheel tracks due to higher suspension forces. Studies found that tire wear particles have a unimodal size distribution, with a peak between 1 µm and 4 µm, making them a significant source of microplastics. Future scenarios with increased shares of electric vehicles (EVs) in Stockholm, Hel-sinki, and Trondheim were modeled. Heavier EVs increase non-exhaust emissions, particularly if the use of studded tires remains constant. Reducing studded tire use can, however, lead to lower emissions. Initial tests in Iceland characterized road dust load, showing patterns similar to other Nordic countries. The NORTRIP model was used to assess the impact of mitigation measures on particulate matter pollution in Rey-kjavik. The NORTRIP model has been refined through various studies and applied to analyze future scenarios and mitigation measures. The model's parameters have been adjusted for better accuracy and have been used to evaluate the impact of changes in the vehicle fleet. The NORDUST II project has significantly advanced the understanding of road dust emissions and effective mitigation strategies. It has developed tools for modeling and predicting future emissions under various sce-narios, focusing on the parameterization of emissions, the impact of vehicles and tires, and the effects of elec-trification.