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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:  http://www.pnas.org/content/early/2017/06/26/1700830114. 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, hilkka.timonen@fmi.fi

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


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FMI researchers produce some 300 publications annually, the majority of them in international scientific journals. Research results are also published in FMI´ss own publications series. FMI`s own series are:

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All publications from 2016 onwards can be found on Helda.