CV Hilkka Timonen

Hilkka Timonen

Title Senior Research Scientist


Postal address Finnish Meteorological Institute, PL 503, FIN-00101 Helsinki, Finland

Street address Erik Palménin aukio 1, Helsinki

Phone number +358-50-3802864

Fields of expertise

  • Atmospheric aerosols
  • Secondary aerosol formation
  • Organic aerosols, especially water-soluble organic fraction
  • Aerosol mass spectrometry
  • Emissions measurements


  • Academy of Finland/ PARMAT, Particulate matter in mines and mining environments
  • Smart and clean foundation/HAQT: Helsinki Air Quality Testbed
  • TEKES/NEWGAS: New technologies for gas combustion emissions (NewGas)
  • TEKES/TAQIITA: Traffic and air quality in India: technologies and attitudes
  • TEKES/Citizer: Services for effective decision making and environmental resilience
  • Interreg/Envisum; Environmental Impact of Low Emission Shipping: Measurements and Modelling Strategies

University and other degrees

  • Docent (Aerosol physics/aerosol composition analysis), Tampere University of Technology, 1.7.2016
  • Ph.D in physics, University of Helsinki 2011
  • M.Sc. in chemistry, University of Eastern Finland

Previous professional appointments

  • Visiting scientist at VTT Technical Research centre, 01.10.-31.12.2016
  • Post-doctoral scientist at University of Washington, USA, 2011 – 2013
  • Research scientist at Finnish Meteorological institute, Helsinki, Finland 2004 – 2011
  • Researcher at Disperse Technologies plc., UK, 2001-2002
  • Teaching assistant at University of Helsinki, 2000-2001

List of publications

•         kuula, J., Mäkelä, T., Hillamo, R., and Timonen, H.: Response Characterization of an Inexpensive Aerosol Sensor, Sensors, 17, 2915, 10.3390/s17122915, 2017.

•         Amanatidis, S., Ntziachristos, L., Karjalainen, P., Saukko, E., Simonen, P., Kuittinen, N., Aakko-Saksa, P., Timonen, H., Rönkkö, T. and Keskinen, J.: Comparative performance of a thermal denuder and a catalytic stripper in sampling laboratory and marine exhaust aerosols, Accepted to AST, AST-MS-2017-153.R1.

•         Saarikoski, S., Teinilä, K., Timonen, H., Aurela, M., Laaksovirta, T., Reyes, F., Vásques, Y., Oyola, P., Artaxo, P., Pennanen, A., Junttila, S., Linnainmaa, M., Salonen, R., Hillamo, R. Particulate matter characteristics, dynamics and sources in an underground mine. Aerosol Sci. Technol., 2017, DOI: 10.1080/02786826.2017.1384788.

•         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.

•         Alanen, J., Simonen, P., Saarikoski, S., Timonen, H., Kangasniemi, O., Saukko, E., Hillamo, R., Lehtoranta, K., Murtonen, T., Vesala, H., Keskinen, J., and Rönkkö, T.: Comparison of primary and secondary particle formation from natural gas engine exhaust and of their volatility characteristics, Atmos. Chem. Phys., 17, 8739-8755,, 2017

•         S. Saarikoski, H. Timonen, S. Carbone, H. Kuuluvainen, J. V. Niemi, A. Kousa, T. Rönkkö, D. Worsnop, R. Hillamo and L. Pirjola. Investigating the chemical species in submicron particles emitted by city buses, Aerosol Science and Technology, 51:3, 317-329, DOI:10.1080/02786826.2016.1261992, 2017.

•         Lehtoranta, K., Murtonen, T., Vesala, H., Koponen, P., Alanen, J., Simonen, P., Rönkkö, T., Timonen, H., Saarikoski, S., Maunula, T., Kallinen, K., and Korhonen, S.: Natural Gas Engine Emission Reduction by Catalysts, Emission Control Science and Technology, 10.1007/s40825-016-0057-8, 2016.

•         Simonen, P., Saukko, E., Karjalainen, P., Timonen, H., Bloss, M., Aakko-Saksa, P., Rönkkö, T., Keskinen, J., and Dal Maso, M.: A New Oxidation Flow Reactor for Measuring Secondary Aerosol Formation of Rapidly Changing Emission Sources, Atmos. Meas. Tech., 10, 1519-1537,, 2017.

•         Timonen, H., Karjalainen, P., Saukko, E., Saarikoski, S., Aakko-Saksa, P., Simonen, P., Murtonen, T., Dal Maso, M., Kuuluvainen, H., Ahlberg, E., Svenningsson, B., Pagels, J., Brune, W. H., Keskinen, J., Worsnop, D. R., Hillamo, R., and Rönkkö, T.: Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle, Atmos. Chem. Phys., 17, 5311-5329,, 2017.

•         Ntziachristos, L., Saukko, E., Lehtoranta, K., Rönkkö, T., Timonen, H., Simonen, P., Karjalainen, P., Keskinen, J.: Particle Emissions Characterization from a Medium-Speed Marine Diesel Engine with two Fuels at Different Sampling Conditions, Fuel,186, 456-465, 2016., DOI: 10.1016/j.fuel.2016.08.091.

•         Timonen, H., Cubison, M., Aurela, M., Brus, D., Lihavainen, H., Hillamo, R., Canagaratna, M., Nekat, B., Weller, R., Worsnop, D., and Saarikoski, S.: Applications and limitations of constrained high-resolution peak fitting on low resolving power mass spectra from the ToF-ACSM, Atmos. Meas. Tech., 9, 3263-3281, doi:10.5194/amt-9-3263-2016, 2016.

•         Petäjä, T., O'Connor, E, Moisseev, D., Sinclair, V.A., Manninen, A.J, Väänänen, R.,von Lerber, A., Thornton, J., Nicoll, K., Petersen, W., Chandrasekar, V., Smith, J., Winkler, P., Krüger, O., Hakola, H., Timonen, H., Brus, D., Laurila, T., Asmi, E., Riekkola, M-L., Mona, L., Massoli, P., Engelmann, R., Komppula, M., Wang, J., Kuang, C., Bäck, J., Virtanen, A., Levula, J., Ritsche, M. and Hickmon, N.: BAECC A field campaign to elucidate the impact of Biogenic Aerosols on Clouds and Climate", Bulletin of the American Meteorological Society, BAMS-D-14-00199, 2016.

•         Karjalainen, P., Timonen, H., Saukko, E., Kuuluvainen, H., Saarikoski, S., Aakko-Saksa, P., Murtonen, T., Bloss, M., Dal Maso, M., Simonen, P., Ahlberg, E., Svenningsson, B., Brune, W. H., Hillamo, R., Keskinen, J., and Rönkkö, T.: Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car, Atmos. Chem. Phys., 16, 8559-8570, doi:10.5194/acp-16-8559-2016, 2016.

•         Carbone, S., Onasch, T., Saarikoski, S., Timonen, H., Saarnio, K., Sueper, D., Rönkkö, T., Pirjola, L., Häyrinen, A., Worsnop, D., and Hillamo, R.: Characterization of trace metals on soot aerosol particles with the SP-AMS: detection and quantification, Atmos. Meas. Tech., 8, 4803-4815, 2016.

•         Pirjola, L., Dittrich, A., Niemi, J.V.,  Saarikoski, S., Timonen, H., Kuuluvainen, H., Kousa, A.,   Rönkkö, T. and Hillamo, R. Physical and chemical characterization of real-world particle number and mass emissions from city buses in Finland, accepted to EST, 2015.

•         Alanen, J., Saukko, E., Lehtoranta, L., Murtonen, T., Timonen, H., Hillamo, R., Karjalainen, P., Kuuluvainen, H., Harra, J., Keskinen, J., Rönkkö, T.: The formation and physical properties of the particle emissions from a natural gas engine, Fuel, 162, 155-161, doi:10.1016/j.fuel.2015.09.003.

•         Timonen, H., Aurela, M., Carbone, S., Saarnio, K., Frey, A., Saarikoski, S., Teinilä, K., Kulmala, M. and Hillamo, R. 2014, Seasonal and diurnal changes in inorganic ions, carbonaceous matter and mass in ambient aerosol particles at an urban, background area. Boreal Env. Res. 19 (suppl. B): 71–86.

•         Saarnio, K., Frey, A., Niemi, J.V., Timonen, H., Rönkkö, T., Karjalainen, P., Vestenius, M., Teinilä, K., Pirjola, L., Niemelä, V., Keskinen, J., Häyrinen, A., and Hillamo R. (2014) Chemical composition and size of particles in emissions of a coal-fired power plant with flue gas desulfurization. J. Aerosol Sci., 73, 14-26, 10.1016/j.jaerosci.2014.03.004.

•         Carbone S., Aurela M., Saarnio K., Saarikoski S., Timonen H., Frey A., Sueper D., Ulbrich I.M., Jimenez J.L., Kulmala M., Worsnop D.R. , Hillamo R.E. (2014), Wintertime Aerosol Chemistry in Sub-Arctic Urban Air, Aerosol Science and Technology, 48(3), 313-323, doi:10.1080/02786826.2013.875115.

•         Timonen, H., Ambrose, J. L., and Jaffe, D. A.: Oxidation of elemental Hg in anthropogenic and marine airmasses, Atmos. Chem. Phys., 13, 2827-2836, doi:10.5194/acp-13-2827-2013, 2013.

•         Timonen, H., Wigder, N., and Jaffe, D. A.: Influence of background particulate matter (PM) on urban air quality in the Pacific Northwest, J. Environ. Manage., 129, 333-340, 2013.

•         Smith, D. J., Timonen, H.J., Jaffe, D.A., Griffin, D.W., Birmele, M.N., Perry, K.D., Ward, P.D., Roberts, M.S.: Intercontinental Dispersal of Bacteria and Archaea in Transpacific Winds. Appl. Environ. Microb., 79, 1134-1139, DOI:10.1128/AEM.03029-12, 2013.

•         Timonen, H., Carbone, S., Aurela, M., Saarnio, K., Saarikoski, S., Ng., N.L., Canagaratna, M., Kulmala, M., Kerminen, V.-M., Worsnop, D., and Hillamo, R. 2013. Characteristics, sources and water-solubility of ambient submicron organic aerosol in springtime in Helsinki, Finland,  J. Aerosol Sci., 51, 61-77. j.jaerosci.2012.06.005.

•         Saarnio K., Niemi J.V., Saarikoski S., Aurela M., Timonen H., Teinilä K., Myllynen M., Frey A., Lamberg H., Jokiniemi J., and Hillamo R. (2012) Using monosaccharide anhydrides to estimate the impact of wood combustion on fine particles in the Helsinki Metropolitan Area. Boreal Env. Res. 17, 163–183

•         Saarnio K., Teinilä K., Saarikoski S., Carbone S., Gilardoni S., Timonen H., Aurela M., and Hillamo R. (2013) Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS). Atmos. Meas. Tech. 6, 2839–2849, doi:10.5194/amt-6-2839-2013

•         Kerminen, V.-M., Niemi, J. V., Timonen, H., Aurela, M., Frey, A., Carbone, S., Saarikoski, S., Teinilä, K., Hakkarainen, J., Tamminen, J., Vira, J., Prank, M., Sofiev, M., and Hillamo, R. 2011: Characterization of a volcanic ash episode in southern Finland caused by the Grimsvötn eruption in Iceland in May 2011, Atmos. Chem. Phys., 11, 12227-12239.

•         Aurela, M., Saarikoski, S., Timonen, H., Aalto, P., Keronen, P., Saarnio, K., Teinilä, K., Kulmala, M. and Hillamo, R. 2011: Carbonaceous aerosol at a forested and an urban background sites in Southern Finland, Atmos. Environ., Vol. 45, 7, 1394-1401.

•         Timonen, H., Aurela, M., Carbone, S., Saarnio, K., Saarikoski, S., Mäkelä, T., Worsnop, D. R., Kulmala, M., Kerminen, V. -M. and Hillamo, R. 2010: Chemical characterization of the water-soluble fraction of ambient aerosols measured with two high-resolution devices PILS-TOC-IC and AMS, Atmos. Meas. Tech., 3, 1-12.

•         Saarnio, K., Teinilä, K., Aurela, M., Timonen, H., Hillamo, R. (2010): High-performance anion-exchange chromatography–mass spectrometry method for determination of levoglucosan, mannosan, and galactosan in atmospheric fine particulate matter, Anal. Bioanal. Chem. 398, 2253-2264. DOI: 10.1007/s00216-010-4151-4.

•         Saarnio, K., Aurela, M., Timonen, H., Saarikoski, S., Teinilä, K., Mäkelä, T., Sofiev, M., Koskinen, J., Aalto, P., Kulmala, M. and Hillamo R. 2010: Fine particles in fresh smoke plumes from boreal forest-fires, Sci. Tot. Environ., 408, 12,  2527-2542.

•         Asmi, E., Frey, A., Virkkula, A., Ehn, M., Manninen, H. E., Timonen, H., Tolonen-Kivimäki, O., Aurela, M., Hillamo, R., and Kulmala, M. 2010: Hygroscopicity and chemical composition of Antarctic sub-micrometre aerosol particles and observations of new particle formation, Atmos. Chem. Phys., 10, 4253-4271.

•         Frey, A. K., Tissari, J., Saarnio, K. M., Timonen, H. J., Tolonen-Kivimäki, O., Aurela, M. A., Saarikoski, S. K., Makkonen, U., Hytönen, K., Jokiniemi, J., Salonen, R. O. & Hillamo, R. E. J. 2009: Chemical composition and mass size distribution of fine particulate matter emitted by a small masonry heater, Boreal Env. Res. 14, 255–271.

•         Timonen, H. J., Saarikoski, S. K., Aurela, M. A., Saarnio, K. M. and Hillamo, R. E. J. 2008: Water-soluble organic carbon in urban aerosol: concentrations, size distributions and contribution to particulate matter, Boreal Env. Res. 13, 335–346.

•         Timonen, H., Saarikoski, S., Tolonen-Kivimäki, O., Aurela, M., Saarnio, K., Petäjä, T., Aalto, P.P., Kulmala, M., Pakkanen, T., and Hillamo, R. 2008: Size distributions, sources and source areas of water-soluble organic carbon in urban background air, Atmos. Chem. Phys., 8, 5635–5647.

•         Saarikoski, S., Timonen, H., Saarnio, K., Aurela, M., Järvi, L., Keronen, P., Kerminen, V.-M., and Hillamo, R. 2008: Sources of organic carbon in fine particulate matter in northern European urban air, Atmos. Chem. Phys., 8, 6281-6295.

•         Saarikoski, S., Sillanpää, M., Sofiev, M., Timonen, H., Saarnio, K., Teinilä, K., Karppinen, A., Kukkonen, J., Hillamo, R. 2007: Chemical composition of aerosols during a major biomass burning episode over northern Europe in spring 2006: Experimental and modeling assessments, Atmos. Environ. 41, 3577-3589.

•         Holopainen, H., Alvila, L., Pakkanen T. T. 2003: Determination of the formaldehyde-to-phenol molar ratios of resol resins by infrared spectroscopy and multivariate analysis, J Appl Polym Sci, 89, 3582-3586.