References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-6-5549-2006

Using discriminant analysis as a nucleation event classification method

Mikkonen

¹ Lehtinen

K. E. J.

¹ ² Hamed

¹ Joutsensaari

³ Facchini

M. C.

⁴ Laaksonen

Department of Physics, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland

Finnish meteorological institute, Kuopio Unit, P.O. Box 1627, 70210 Kuopio, Finland

Department of Environmental Sciences, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland

Istituto di Scienze dell'Atmosfera e del Clima – CNR, Italy Via Gobetti 101, 40 129 Bologna, Italy

11 12 2006

6 12 5549 5557

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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The full text article is available as a PDF file from http://www.atmos-chem-phys.net/6/5549/2006/acp-6-5549-2006.pdf

More than three years of measurements of aerosol size-distribution and different gas and meteorological parameters made in Po Valley, Italy were analysed for this study to examine which of the meteorological and trace gas variables effect on the emergence of nucleation events. As the analysis method, we used discriminant analysis with non-parametric Epanechnikov kernel, included in non-parametric density estimation method. The best classification result in our data was reached with the combination of relative humidity, ozone concentration and a third degree polynomial of radiation. RH appeared to have a preventing effect on the new particle formation whereas the effects of O3 and radiation were more conductive. The concentration of SO2 and NO2 also appeared to have significant effect on the emergence of nucleation events but because of the great amount of missing observations, we had to exclude them from the final analysis.

References 1

Birmili, W. , Berresheim, H., Plass-Dülmer, C., Elste, T., Gilge, S., Wiedensohler, A., and Uhrner, U.: The Hohenpeissenberg aerosol formation experiment (HAFEX): a long-term study including size-resolved aerosol, H2SO4, OH, and monoterpenes measurements, Atmos. Chem. Phys., 3, 361–376, 2003.

Boy, M. and Kulmala, M.: Nucleation events in the continental boundary layer: influence of physical and meteorological parameters, Atmos. Chem. Phys., 2, 1–16, 2002.

Dal Maso, M., Kulmala, M., Riipinen, I., Wagner, R., Hussein, T., Aalto, P. P., and Lehtinen, K. E. J.: Formation and growth of fresh atmospheric aerosols: eight years of aerosol size distribution data from SMEAR II, Hyytiälä, Finland, Boreal Environ. Res., 10, 323–336, 2005.

Hamed, A., Joutsensaari, J., Mikkonen, S., Sogacheva, L., Dal Maso, M., Kulmala, M., Cavalli, F., Fuzzi, S., Facchini, M. C., Decesari, S., Mircea, M., and Laaksonen, A.: Nucleation and growth of new particles in Po Valley, Italy, Atmos. Chem. Phys. Discuss., 6, 9603–9653, 2006.

Hyvönen, S., Junninen, H., Laakso, L., Dal Maso, M., Grönholm, T, Bonn, B., Keronen, P., Aalto, P., Hiltunen, V., Pohja, T., Launiainen, S., Hari, P., Mannila, H., and Kulmala, M.: A look at aerosol formation using data mining techniques, Atmos. Chem. Phys., 5, 3345–3356, 2005.

Efron, B. and Tibshirani, R.: An Introduction to the Bootstrap, London Chapman and Hall, 1993.

Epanechnikov, V. A.: Nonparametric estimation of a multidimensional probability density. Theory Probab. Appl., 14, 153–158, 1969.

Kulmala, M., Kerminen, V.-M., Anttila, T., Laaksonen, A., and O'Dowd, C.: Organic aerosol formation via sulphate cluster activation, J. Geophys. Res., 109, D04205, doi:10.1029/2003JD003961, 2004a.

Kulmala, M., Vehkamäki, H., Petäjä, T., Dal Maso, M., Lauri, A., Kerminen, V.-M., Birmili, W., and McMurry, P.: Formation and growth rates of ultrafine atmospheric particles: a review of observations, J. Aerosol Sci., 35, 143–176, doi:10.1016/j.jaerosci.2003.10.003, 2004b.

Morrison, D. F.: Multivariate Statistical Methods, Belmont CA: Thomson/Brooks/Cole, 2005.

O'Dowd, C. D., Aalto, P., Hämeri, K., Kulmala, M., and Hoffman, T.: Atmospheric particles from organic vapours, Nature, 416, 497–498, doi: 10.1038/416497a, 2002.

Mäkelä, J., Dal Maso, M., Pirjola, L., Keronen, P., Laakso, L., Kulmala, M., and Laaksonen, A.: Characteristics of the atmospheric particle formation events observed at a boreal forest site in southern Finland, Boreal Environ. Res., 5, 299–313, 2000.

Rodríguez, S., Van Dingenen R., Putaud, J.-P., Martins-Dos Santos, S., and Roselli D.: Nucleation and growth of new particles in the rural atmosphere of Northern Italy–relationship to air quality monitoring. Atmospheric environment, 39(36), 6734–6746, doi:10.1016/j.atmosenv.2005.07.036, 2005.

SAS Institute Inc.: SAS/STAT User's Guide, Version 9.1, SAS Publishing, 2004.

Woo, K. S., Chen, D. R., Pui, D. Y. H., and McMurry, P. H.: Measurement of Atlanta aerosol size distributions: Observations of ultrafine particle events, Aerosol Sci. Technol., 34, 75–87, doi:10.1080/02786820120056, 2001.