Science news archive

« Back

Traffic is a major source of atmospheric nanocluster aerosol

Traffic is a major source of atmospheric nanocluster aerosol

Measurements of NCA were conducted in both laboratory and in ambient environment. For instance, in a semiurban roadside environment, the NCA represented 20–54% of the total particle number concentration in ambient air.

The observed NCA concentrations varied significantly depending on the traffic rate and wind direction. Interestingly, these emissions were not associated with all vehicles.

These NCA emissions directly affect particle concentrations and human exposure to nanosized aerosol in urban areas, and potentially may act as nanosized condensation nuclei for the condensation of atmospheric low-volatile organic compounds. New results can be further utilized in FMI air quality and climate models.says research scientist Hilkka Timonen.

Article about NCA can be found from PNAS: Research was done in tight co-operation between Tampere University of Technology, Finnish Meteorological institute, Helsinki Region Environmental Services Authority, Metropolia university of applied sciences and  ja Turku university of applied sciences. Research was funded by Tekes, Academy of Finland, Cleen Oy, Dinex Ecocat Oy, Neste Oyj, AGCO Power, Ab Nanol Technologies Oy and Strategic Research Council.

For more information:

Senior Research Scientist Hilkka Timonen,

Reference: Rönkkö, T., Kuuluvainen, H., Karjalainen, P., Keskinen, J., Hillamo, R., Niemi, J. V., Pirjola, L., Timonen, H. J., Saarikoski, S., Saukko, E., Järvinen, A., Silvennoinen, H., Rostedt, A., Olin, M., Yli-Ojanperä, J., Nousiainen, P., Kousa, A., and Dal Maso, M.: Traffic is a major source of atmospheric nanocluster aerosol, Proceedings of the National Academy of Sciences, 201700830, 10.1073/pnas.1700830114, 2017


The Finnish Meteorological Institute is a leading expert in meteorology, air quality, climate change, earth observation, marine and arctic research areas. FMI is in a unique position to study various themes of climate change in the Northern context.


High-quality observational data and research is utilized to develop services to benefit our everyday life. Visible examples are improvement of weather forecasts, development of new expert and warning services as well as applications of the newest research results.