ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-9-2195-2009 An investigation of nucleation events in a coastal urban environment in the Southern Hemisphere Mejía J. F. 1 Morawska L. 1 International Laboratory of Air Quality and Health, Queensland University of Technology, 2 George Street, Brisbane, QLD 4001, Australia 23 01 2009 9 1 2195 2222 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-discuss.net/9/2195/2009/acpd-9-2195-2009.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/9/2195/2009/acpd-9-2195-2009.pdf

The occurrence of and conditions favourable to nucleation were investigated at an industrial and commercial coastal location in Brisbane, Australia during five different campaigns covering a total period of 13 months. To identify potential nucleation events, the difference in number concentration in the size range 14–30 nm (<i>N</i><sub>14&minus;30</sub>) between consecutive observations was calculated using first-order differencing. The data showed that nucleation events were a rare occurrence, and that in the absence of nucleation the particle number was dominated by particles in the range 30–300 nm. In many instances, total particle concentration declined during nucleation. There was no clear pattern in change in NO and NO<sub>2</sub> concentrations during the events. SO<sub>2</sub> concentration, in the majority of cases, declined during nucleation but there were exceptions. Most events took place in summer, followed by winter and then spring, and no events were observed for the autumn campaigns. The events were associated with sea breeze and long-range transport. Roadside emissions, in contrast, did not contribute to nucleation, probably due to the predominance of particles in the range 50–100 nm associated with these emissions.

 References 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. Charlson, R. J., Schwartz, S. E., Hales, J. M., Cess, R. D., Coakley Jr., J. A., Hansen, J. E., and Hofmann, D. J.: Climate forcing by anthropogenic aerosols, Science, 255, 423–430, 1992. Curtius, J.: Nucleation of atmospheric aerosols, Physique, 7, 1027–1045, 2006. Easter, R. C. and Peters, L. K.: Binary homogeneous nucleation: Temperature and relative humidity fluctuations, nonlinearity, and aspects of new particle production in the atmosphere, J. Appl. Meteorol., 33, 775–784, 1990. Friedlander, S. K., Koch, W., and Main, H. H.: Scavenging of a coagulating fine aerosol by a coarse particle model, J. Aerosol Sci., 22, 1–8, 1991. Hitchins, J., Morawska, L., Wolff, R., and Gilbert, D.: Concentrations of submicrometre particles from vehicle emissions near a major road, Atmos. Environ., 34, 51–59, 2000. Hobbs, P. V. (Ed.): Cloud interactions, in: Aerosol-cloud-climate interactions, San Diego, California, Academic Press, 233~pp., 1993. Jeong, C.-H., Hopke, P. K., Chalupa, D., and Utell, M.: Characteristics of Nucleation and Growth Events of Ultrafine Particles Measured in Rochester, NY, Environ. Sci. Technol., 37, 1933–1940, 2004. Kerminen, V. M., Lehtinen, K. J., Anttila, T., and Kulmala, M.: Dynamics of atmospheric nucleation mode particles: a time scale analysis, Tellus~B, 56(2), 135–146, 2004. Kim, J., Yoon, S.-C., Kim, S.-W., Brechtel, F., Jefferson, A., Dutton, E. G., Bower, K. N., Cliff, S., and Schauer, J. J.: Chemical apportionment of shortwave direct aerosol radiative forcing at the Gosan super-site, Korea during ACE-Asia, Atmos. Environ., 40, 6718–6729, 2006. Kulmala, M., Maso, M. D., Makela, J. M., Pirjola, L., Vakeva, M., Aalto, P., Miikkulainen, P., Hameri, K., and O'Dowd, C. D.: On the formation, growth and composition of nucleation mode particles, Tellus~B, 53(4), 479–490, 2001. Kulmala, M., Vehkamaki, H., Petaja, 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, 2004. Lee, S.-H., Reeves, J. M., Wilson, J. C., Hunton, D. E., Viggiano, A. A., Miller, T. M., Ballenthin, J. O., and Lait, L. R.: Particle formation by ion nucleation in the upper tropospher and lower stratosphere, Science, 301, 1886–1889, 2003. Lee, Y.-G., Lee, H.-W., Kim, M.-S., Choi, C. Y., and Kim, J.: Characteristics of particle formation events in the coastal region of Korea in 2005, Atmos. Environ., 42, 3729–3739, 2008. Nilsson, E. D. and Kulmala, M.: The potential for atmospheric mixing processes to enhance the binary nucleation rate, J. Geophys. Res., 103, 1381–1389, 1998. O'Dowd, C. D., McFiggans, G., Creasey, D. J., Pirjola, L., Hoell, C., Smith, M. H., Allan, B. J., Plane, J. M. C., Heard, D. E., Lee, J. D., Pilling, M. J., and Kulmala, M.: On the photochemical production of new particles in the coastal boundary layer, Geophys. Res. Lett., 26, 1707–1710, 1999. O'Dowd, C. D., Yoon, Y. J., Junkerman, W., Aalto, P., Kulmala, M., Lihavainen, H., and Viisanen, Y.: Airborne measurements of nucleation mode particles I: coastal nucleation and growth rates, Atmos. Chem. Phys., 7, 1491–1501, 2007. O'Dowd, C. D., Hämeri, K., Mäkelä, J., Väkeva, M., Aalto, P., de Leeuw, G. K., Gerard J., Becker, E., Hansson, H.-C., Allen, A. G., Harrison, R. M., Berresheim, H., Kleefeld, C., Geever, M., Jennings, S. G., and Kulmala, M.: Coastal new particle formation: environmental conditions and aerosol physicochemical characteristics during nucleation bursts, J. Geophys. Res., 107, PAR12.1–PAR12.17, 2002 Pirjola, L., O'Dowd, C. D., Brooks, I. M., and Kulmala, M.: Can new particle formation occur in the clean marine boundary layer?, J. Geophys. Res., 105, 26 531–26 546, 2000. Qian, S., Sakurai, H., and McMurry, P. H.: Characteristics of regional nucleation events in urban East St. Louis, Atmos. Environ., 41, 4119–4127, 2007. Spracklen, D. V., Carslaw, K. S., Kulmala, M., Kerminen, V.-M., Mann, G. W., and Sihto, S.-L.: The contribution of boundary layer nucleation events to total particle concentrations on regional and global scales, Atmos. Chem. Phys., 6, 5631–5648, 2006. Stanier, C. O., Khlystov, A. Y., and Pandis, S. N.: Nucleation Events During the Pittsburgh Air Quality Study: Description and Relation to Key Meteorological, Gas Phase, and Aerosol Parameters, Aerosol. Sci. TECH., 38, 253–264, 2004. Stern, D. I.: Global sulfur emissions from 1850 to 2000, Chemosphere, 58, 163–175, 2005. Tunved, P., Hansson, H.-C., Kulmala, M., Aalto, P., Viisanen, Y., Karlsson, H., Kristensson, A., Swietlicki, E., Dal Maso, M., Ström, J., and Komppula, M.: One year boundary layer aerosol size distribution data from five nordic background stations, Atmos. Chem. Phys., 3, 2183–2205, 2003. Vaattovaara, P., Huttunen, P. E., Yoon, Y. J., Joutsensaari, J., Lehtinen, K. E. J., O'Dowd, C. D., and Laaksonen, A.: The composition of nucleation and Aitken modes particles during coastal nucleation events: evidence for marine secondary organic contribution, Atmos. Chem. Phys., 6, 4601–4616, 2006. Wehner, B. and Wiedensohler, A.: Long term measurements of submicrometer urban aerosols: statistical analysis for correlations with meteorological conditions and trace gases, Atmos. Chem. Phys., 3, 867–879, 2003. Woo, K. S., Chen, D. R., Pui, D. Y. H., and McMurry, P. H.: Measurement of Atlanta Aerosol Size Distributions: Observation of ultrafine particle events, Aerosol Sci. Technol., 34, 75–87, 2001. Zhang, Q., Stanier, C. O., Canagaratna, M. R., Jayne, J. T., Worsnop, D. R., Pandis, S. N., and Jimenez, J. L.: Insights into the Chemistry of New Particle Formation and Growth Events in Pittsburgh Based on Aerosol Mass Spectrometry, Environ. Sci. Technol., 38, 4797–4809, 2004.