Atmos. Chem. Phys. Discuss., 9, 2195-2222, 2009
© Author(s) 2009. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
An investigation of nucleation events in a coastal urban environment in the Southern Hemisphere
J. F. Mejía and L. Morawska
International Laboratory of Air Quality and Health, Queensland University of Technology, 2 George Street, Brisbane, QLD 4001, Australia

Abstract. 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 (N14−30) 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 NO2 concentrations during the events. SO2 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.

Citation: Mejía, J. F. and Morawska, L.: An investigation of nucleation events in a coastal urban environment in the Southern Hemisphere, Atmos. Chem. Phys. Discuss., 9, 2195-2222, doi:10.5194/acpd-9-2195-2009, 2009.
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