References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-8-655-2008

Variation and balance of positive air ion concentrations in a boreal forest

Hõrrak

¹ Aalto

P. P.

² Salm

¹ Komsaare

¹ Tammet

¹ Mäkelä

J. M.

³ Laakso

² Kulmala

Institute of Physics, University of Tartu, 18 Ülikooli St., 50090 Tartu, Estonia

Department of Physical Sciences, Division of Atmospheric Sciences P.O. Box 64, 00014 University of Helsinki, Finland

Tampere University of Technology, Institute of Physics, P.O. Box 692, 33101, Tampere, Finland

12 02 2008

8 3 655 675

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.

This article is available from http://www.atmos-chem-phys.net/8/655/2008/acp-8-655-2008.html

The full text article is available as a PDF file from http://www.atmos-chem-phys.net/8/655/2008/acp-8-655-2008.pdf

Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were discriminated as small ions (charged molecular aggregates of the diameter of less than 2.5 nm), intermediate ions (charged aerosol particles of the diameter of 2.5–8 nm), and large ions (charged aerosol particles of the diameter of 8–20 nm). Statistical characteristics of the ion concentrations and the parameters of ion balance in the atmosphere are presented separately for the nucleation event days and non-event days. In the steady state, the ionization rate is balanced with the loss of small ions, which is expressed as the product of the small ion concentration and the ion sink rate. The widely known sinks of small ions are the recombination with small ions of opposite polarity and attachment to aerosol particles. The dependence of small ion concentration on the concentration of aerosol particles was investigated applying a model of the bipolar diffusion charging of particles by small ions. When the periods of relative humidity above 95% and wind speed less than 0.6 m s−1 were excluded, then the small ion concentration and the theoretically calculated small ion sink rate were closely negatively correlated (correlation coefficient −87%). However, an extra ion loss term of the same magnitude as the ion loss onto aerosol particles is needed for a quantitative explanation of the observations. This term is presumably due to the small ion deposition on coniferous forest. The hygroscopic growth correction of the measured aerosol particle size distributions was also found to be necessary for the proper estimation of the ion sink rate. In the case of nucleation burst events, the concentration of small positive ions followed the general balance equation, no extra ion loss in addition to the deposition on coniferous forest was detected, and the hypothesis of the conversion of ions into particles in the process of ion-induced nucleation was not proved. The estimated average ionization rate of the air at the Hyytiälä station in early spring, when the ground was partly covered with snow, was about 6 ion pairs cm−3 s−1. The study of the charging state of nanometer aerosol particles (diameter 2.5–8 nm) in the atmosphere revealed a strong correlation (correlation coefficient 88%) between the concentrations of particles neutralized in the aerosol spectrometer and naturally positively charged particles (air ions) during nucleation bursts. The charged fraction of particles varied from 3% to 6% in accordance with the hypothesis that the particles are quasi-steady state charged.

References 1

Aalto, P., Hämeri, K., Becker, E., Weber, R., Salm, J., Mäkelä, J. M., Hoell, C., O'Dowd, C. D., Karlsson, H., Hansson, H.-C., Väkevä, M., Koponen, I., Buzorius, G., and Kulmala, M.: Physical characterization of aerosol particles during nucleation events, Tellus, 53B, 344–258, 2001.

Beig, G. and Brasseur, G. P.: Model of tropospheric ion composition: A first attempt, J. Geophys. Res., 105, 22 671–22 684, 2000.

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.

Birmili, W., Schwirn, K., Nowak, A., Petäjä, T., Rose, D., Hämeri, K., Aalto, P., Wiedensohler, A., Kulmala, M., and Boy, M.: Hygroscopic growth of particle number size distributions at the atmospheric research station Hyytiälä, Finland, Report Series in Aerosol Science (Helsinki), 81A, 62–67, 2006.

Chalmers, J. A.: Atmospheric Electricity, Pergamon Press, Oxford, London, 1967.

Dolezalek, H.: The atmospheric electric fog effect, Rev. Geophys., 1(2), 231–282, 1963.

Eisele, F. L. and Tanner, D. J.: Identification of ions in continental air, J. Geophys. Res., 95, 20 539–20 550, 1990.

Froyd, K. D. and Lovejoy, E. R.: Experimental thermodynamics of cluster ions composed of H2SO4 and H2O. 1. Positive ions, J. Phys. Chem. A, 107, 9800–9811, 2003a.

Froyd, K. D. and Lovejoy, E. R.: Experimental thermodynamics of cluster ions composed of H2SO4 and H2O. 2. Measurements and ab initio structures of negative ions, J. Phys. Chem. A, 107, 9812–9824, 2003b.

Fuchs, N. A. and Sutugin, A. G.: High-dispersed aerosols, in: Topics in Current Aerosol Research, edited by: Hidy, G. M. and Brock, J. R., vol. 2, pp. 1–60, Pergamon, Oxford, 1971.

Hanson, D. R. and Eisele, F. L.: Measurement of prenucleation molecular clusters in the NH3, H2SO4, H2O system, J. Geophys. Res., 107(D12), 4158, doi:10.1029/2001JD001100, 2002.

Hari, P. and Kulmala, M.: Station for Measuring Ecosystem–Atmosphere Relations (SMEAR II), Boreal Environ. Res., 10, 315–322, 2005.

Hatakka, J., Paatero, J., Viisanen, Y., and Mattsson, R.: Variations of external radiation due to meteorological and hydrological factors in central Finland, Radiochemistry, 40(6), 515–519, MAIK Nauka/ Interperiodica Publishing, 1998.

Hensen, A. and van der Hage, J. C. H.: Parametrization of cosmic radiation at sea level, J. Geophys. Res., 99, 10 693–10 695, 1994.

Hirsikko, A., Laakso, L, Hõrrak, U., Aalto, P. P., Kerminen, V.-M., and Kulmala, M.: Annual and size dependent variation of growth rates and ion concentrations in boreal forest, Boreal Env. Res., 10, 357–369, 2005.

Hoppel, W. A.: Ion-aerosol attachment coefficients, ion depletion, and the charge distribution on aerosols, J. Geophys. Res., 90, 5917–5923, 1985.

Hoppel, W. A. and Frick, G. M.: Ion-aerosol attachment coefficients and the steady-state charge distribution on aerosols in a bipolar ion environment, Aerosol Sci. Technol., 5, 1–21, 1986.

Hoppel, W. A. and Frick, G. M.: The nonequilibrium character of the aerosol charge distributions produced by neutralizers, Aerosol Sci. Technol., 12, 471–496, 1990.

Hoppel, W. A., Anderson, R. V., and Willett, J. C.: Atmospheric electricity in the planetary boundary layer, In: The Earth's Electrical Environment, National Academy Press, Washington, D.C., 149–165, 1986.

Hoppel, W. A., Frick, G. M., Fitzgerald, J. W., and Larson, R. E.: Marine boundary layer measurements of new particle formation and the effects nonprecipitating clouds have on aerosol size distribution, J. Geophys. Res., 99, 14 443–14 459, 1994.

Hõrrak, U., Salm, J., and Tammet, H.: Bursts of intermediate ions in atmospheric air, J. Geophys. Res., 103, 13 909–13 915, 1998a.

Hõrrak, U., Mirme, A., Salm, J., Tamm, E., and Tammet, H.: Air ion measurements as a source of information about atmospheric aerosols, Atmos. Res., 46, 233–242, 1998b.

Hõrrak, U., Salm, J., and Tammet, H.: Statistical characterization of air ion mobility spectra at Tahkuse Observatory: Classification of air ions, J. Geophys. Res., 105, 9291–9302, 2000.

Hõrrak, U., Aalto, P., Salm, J., and Kulmala, M.: Characterization of air ions during nucleation events in boreal forest air, Report Series in Aerosol Science (Helsinki), 59, 196–201, 2003a.

Hõrrak, U., Salm, J., and Tammet, H.: Diurnal variation in the concentration of air ions of different mobility classes at a rural area, J. Geophys. Res., 108(D20), 4653, doi:10.1029/2002JD003240, 2003b.

Hõrrak, U., Tammet, H., Aalto, P. P., and Kulmala, M.: Charge distribution on nanometer aerosol particles in the atmosphere during nucleation burst events, J. Aerosol Sci., 35, S299–S300, 2004a.

Hõrrak, U., Tammet, H., Aalto, P. P., and Kulmala, M.: Study of air ions and nanometer particles in the atmosphere during nucleation burst events, Report Series in Aerosol Science (Helsinki), 71A, 184–189, 2004b.

Hämeri, K., Väkevä, M., Aalto, P. P., Kulmala, M., Swietlicki, E., Zhou, J., Seidl, W., Becker, E., and O'Dowd, C. D.: Hygroscopic and CCN properties of aerosol particles in boreal forests, Tellus, 53B, 359–379, 2001.

Iida, K., Stolzenburg, M., McMurry, P., Dunn, M. J., Smith, J. N., Eisele, F., and Keady, P.: Contribution of ion-induced nucleation to new particle formation: Methodology and its application to atmospheric observations in Boulder, Colorado, J. Geophys. Res., 111, D23201, doi:10.1029/2006JD007167, 2006.

Isra\"el, H.: Atmospheric Electricity, Vol I, Israel Program for Scientific Translations, Jerusalem, 1970.

Isra\"el, H.: Atmospheric Electricity, Vol II, Israel Program for Scientific Translations, Jerusalem, 1973.

Kim, T. O., Adachi, M., Okuyama, K., and Seinfeld, J. H.: Experimental measurement of competitive ion-induced and binary homogeneous nucleation in SO2/H2O/N2 mixtures, Aerosol Sci. Technol., 26, 527–543, 1997.

Kim, T. O., Ishida, T., Adachi, M., Okuyama, K., and Seinfeld, J. H.: Nanometer-sized particle formation from NH3/SO2/H2O/air mixtures by ionizing irradiation, Aerosol Sci. Technol., 29, 111–125, 1998.

Korhonen, P., Kulmala, M., Laaksonen, A., Viisanen, Y., McGraw, R., and Seinfeld, J.: Ternary nucleation of H2SO4, NH3 and H2O in the atmosphere, J. Geophys. Res., 104, 26 349–26 353, 1999.

Kulmala, M., Pirjola, L., and Mäkelä, J. M.: Stable sulphate clusters as a source of new atmospheric particles, Nature, 404, 66–69, 2000.

Kulmala, M., Hämeri, K., Aalto, P. P., Mäkelä, J. M., Pirjola, L., Nilsson, E. D., Buzorius, G., Rannik,Ü., Dal Maso, M., Seidl, W., Hoffman, T., Janson, R., Hansson, H.-C., Viisanen, Y., Laaksonen, A., and O'Dowd, C. D.: Overview of the international project on biogenic aerosol formation in the boreal forest (BIOFOR), Tellus, 53B, 324–343, 2001a.

Kulmala, M., Dal Maso, M., Mäkelä, J. M., Pirjola, L., Väkevä, M., Aalto, P. P., Miikkulainen, P., Hämeri, K., and O'Dowd, C. D.: On the formation, growth and composition of nucleation mode particles, Tellus, 53B, 479–490, 2001b.

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

Kulmala, M., Laakso, L., Lehtinen, K. E. J., Riipinen, I., Dal Maso, M., Anttila, T., Kerminen, V.-M., Hõrrak, U., Vana, M., and Tammet,~H.: Initial steps of aerosol growth, Atmos. Chem. Phys., 4, 2553–2560, 2004b.

Laakso L., Mäkelä, J. M., Pirjola, L., and Kulmala, M.: Model studies on ion-induced nucleation in the atmosphere, J. Geophys. Res., 107(D20), 4427, doi:10.1029/2002JD002140, 2002.

Laakso, L., Petäjä, T., Lehtinen, K. E. J., Kulmala, M., Paatero, J., Hõrrak, U., Tammet, H., and Joutsensaari, J.: Ion production rate in a boreal forest based on ion, particle and radiation measurements, Atmos. Chem. Phys., 4, 1933–1943, 2004a.

Laakso, L., Anttila, T., Lehtinen, K. E. J., Aalto, P. P., Kulmala, M., Hõrrak, U., Paatero, J., Hanke, M., and Arnold, F.: Kinetic nucleation and ions in boreal forest particle formation events, Atmos. Chem. Phys., 4, 2353–2366, 2004b.

Lovejoy, E., Curtius, J., and Froyd, K.: Atmospheric ion-induced nucleation of sulfuric acid and water, J. Geophys. Res., 109, doi:10.1029/2003JD004460, 2004.

Luts, A. and Parts, T.-E.: Evolution of negative small air ions at two different temperatures, J. Atmos. Solar-Terr. Phys., 64, 763–774, 2002.

Mäkelä, J. M., Dal Maso, M., Pirjola, L., Keronen, P., Laakso, L., Kulmala, M., and Laaksonen, A.: Characteristics of the aerosol particle formation events observed at a boreal forest site in southern Finland, Boreal Environ. Res., 4, 299–313, 2000.

Mäkelä, J. M., Salm, J., Smirnov, V. V., Koponen, I., Paatero, J., and Pronin, A. A.: Electrical charging state of fine and ultrafine particles in boreal forest air, J. Aerosol Sci., 32, S149–S150, 2001a.

Mäkelä, J. M., Yli-Koivisto, S., Hiltunen, V., Seidl, W., Swietlicki, E., Teinilä , K., Sillanpää, M., Koponen, I. K., Paatero, J., Rosman, K., and Hämeri, K.: Chemical composition of aerosol during particle formation events in Boreal forest, Tellus, 53B, 380–393, 2001b.

Mäkelä, J. M., Salm, J., Smirnov, V. V., Koponen, I., Paatero, J., and Pronin, A. A.: Measurements of the mobility distribution of air ions as a source of information for the study of aerosol generation, In: Proceedings of 12th International Conference on Atmospheric Electricity, 2003, Versailles, 793–796, 2003.

Nadykto, A. and Yu, F.: Uptake of neutral polar vapour molecules by charged particles: Enhancement due to dipole-charge interaction, J. Geophy. Res., 108(D23), 4717, doi:10.1029/2003JD003664, 2003.

Nagato, K. and Ogawa, T.: Evolution of tropospheric ions observed by an ion mobility spectrometer with a drift tube, J. Geophys. Res. 103, 13 917–13 925, 1998.

Napari, I., Kulmala, M., and Vehkamäki, H.: Ternary nucleation of inorganic acids, ammonia, and water, J. Chem. Phys., 117, 8418–8425, 2002.

Nilsson, E. D., Paatero, J., and Boy, M.: Effects of air masses and synoptic weather on aerosol formation in the continental boundary layer, Tellus, 53B, 462–478, 2001a.

Nilsson, E. D., Rannik, Ü., Buzorius, G., O'Dowd, C., Boy, M., Paatero J., and Laakso, L.: Effects of the continental boundary layer evolution, convection, turbulence and entrainment on aerosol formation, Tellus, 53B, 441–461, 2001b.

Parts, T.-E. and Luts, A.: Observed and simulated effects of certain pollutants on small air ion spectra: I. Positive ions, Atmos. Environ., 38, 1283–1289, 2004.

Penttinen, L., Paatero, J., Viisanen, Y., and Kulmala, M.: Seasonal and diurnal variation of airbone radon-222 at Hyytiälä, Finland, Report Series in Aerosol Science (Helsinki), 59, 79–82, 2003.

Porstendörfer, J.: Properties and behaviour of radon and thoron and their decay products in the air, J. Aerosol Sci., 25, 219–263, 1994.

Raes, F. and Janssens, A.: Ion-induced aerosol formation in a H2O-H2SO4 system. I. Extension of the classical theory and search for experimental evidence, J. Aerosol Sci., 16, 217–227, 1985.

Raes, F. and Van Dingenen, R.: Simulation of condensation and cloud condensation nuclei from biogenic SO2 in the remote marine boundary layer, J. Geophys. Res., 97, 12 901–12 912, 1992.

Ramamurthi, M., Strydom, R., Hopke, P. K., and Holub, R. F.: Nanometer and ultrafine aerosols from radon radiolysis, J. Aerosol Sci., 24, 393–407, 1993.

Reischl, G. P., Mäkelä, J. M., Karch, R., and Necid, J.: Bipolar charging of ultrafine particles in the size range below 10 nm, J. Aerosol Sci., 27, 931–949, 1996.

Svenningsson, B., Rissler, J., Swietlicki, E., Mircea, M., Bilde, M., Facchini, M. C., Decesari, S., Fuzzi, S., Zhou, J., Mønster, J., and Rosenørn, T.: Hygroscopic growth and critical supersaturations for mixed aerosol particles of inorganic and organic compounds of atmospheric relevance, Atmos. Chem. Phys., 6, 1937–1952, 2006.

Tamm, E., Hõrrak, U., Mirme, A., and Vana, M.: On the charge distribution on atmospheric nanoparticles, J. Aerosol Sci., 32, S347–S348, 2001.

Tammet, H.: The aspiration method for the determination of atmospheric ion-spectra, Israel Program for Scientific Translations, Jerusalem, 1970.

Tammet, H.: Aerosol electrical density: Interpretation and principles of measurement, Report Series in Aerosol Science (Helsinki), 19, 128–133, 1991.

Tammet, H. and Kimmel, V.: Electrostatic deposition of radon daughter clusters on the trees, J. Aerosol Sci., 29, S473–S474, 1998.

Tammet, H., Kimmel, V., and Israelsson, S.: Effect of atmospheric electricity on dry deposition of airborne particles from atmosphere, Atmos. Environ., 35, 3413–3419, 2001.

Tammet, H., Hõrrak, U., Laakso, L., and Kulmala, M.: Factors of air ion balance in a coniferous forest according to measurements in Hyytiälä, Finland, Atmos. Chem. Phys., 6, 3377–3390, 2006.

Tunved, P., Hansson, H.-C., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., Kristensson, A., Swietlicki, E., Dal Maso, M., Strom, J., and Komppula, M.: One year boundary layer aerosol size distribution data from five nordic background stations, Atmos. Chem. Phys., 3, 2183–2205, 2003.

Vesala, T., Haataja, J., Aalto, P., Altimir, N., Buzorius, G., Garam, E., Hämeri, K., Ilvesniemi, H., Jokinen, V., Keronen, P., Lahti, T., Markkanen, T., Mäkelä, J.M., Nikinmaa, E., Palmroth, S., Palva, L., Pohja, T., Pumpanen, J., Rannik, Ü., Siivola, E., Ylitalo, H., Hari, P., and Kulmala, M.: Long-term field measurements of atmosphere-surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol physics and atmospheric chemistry, Trends in Heat, Mass and Momentum Transfer, 4, 17–35, 1998.

Wex, H., Kiselev, A., Stratmann, F., Zoboki, J., and Brechtel, F.: Measured and modeled equilibrium sizes of NaCl and (NH$_4)_2$SO4 particles at relative humidities up to 99.1%, J. Geophys. Res., 110, D21212, doi:10.1029/2004JD005507, 2005.

Wilhelm, S., Eichkorn, S., Wiedner, D., Pirjola, L., and Arnold, F.: Ion-induced aerosol formation: new insights from laboratory measurements of mixed cluster ions HSO$^-_4$(H2SO$_4)_a$(H2O)$_w$ and H$^+$(H2SO$_4)_a$(H2O)$_w$, Atmos. Environ., 38, 1735–1744, 2004.

Yu, F. and Turco, R. P.: Ultrafine aerosol formation via ion-mediated nucleation, Geophys. Res. Lett., 27, 883–886, 2000.

Yu, F. and Turco, R. P.: From molecular clusters to nanoparticles: Role of ambient ionization in tropospheric aerosol formation, J. Geophys. Res., 106, 4797–4814, 2001.

Zhou, J., Swietlicki, E., Berg, O. H., Aalto, P. P., Hämeri, K., Nilsson, E. D., and Leck, C.: Hygroscopic properties of aerosol particles over the central Arctic Ocean during summer, J. Geophys. Res., 106, 32 111–32 123, 2001.