New particle formation and growth at a remote, sub-tropical coastal location
Author:
Modini R. L.,Ristovski Z. D.,Johnson G. R.,He C.,Surawski N.,Morawska L.,Suni T.,Kulmala M.
Abstract
Abstract. A month-long intensive measurement campaign was conducted in March/April 2007 at Agnes Water, a remote coastal site just south of the Great Barrier Reef on the east coast of Australia. Particle and ion size distributions were continuously measured during the campaign. Coastal nucleation events were observed in clean, marine air masses coming from the south-east on 65% of the days. The events usually began at ~10:00 local time and lasted for 1–4 h. They were characterised by the appearance of a nucleation mode with a peak diameter of ~10 nm. The freshly nucleated particles grew within 1–4 h up to sizes of 20–50 nm. The events occurred when solar intensity was high (~1000 W m−2) and RH was low (~60%). Interestingly, the events were not related to tide height. The volatile and hygroscopic properties of freshly nucleated particles (17–22.5 nm), simultaneously measured with a volatility-hygroscopicity-tandem differential mobility analyser (VH-TDMA), were used to infer chemical composition. The majority of the volume of these particles was attributed to internally mixed sulphate and organic components. After ruling out coagulation as a source of significant particle growth, we conclude that the condensation of sulphate and/or organic vapours was most likely responsible for driving particle growth during the nucleation events. We cannot make any direct conclusions regarding the chemical species that participated in the initial particle nucleation. However, we suggest that nucleation may have resulted from the photo-oxidation products of unknown sulphur or organic vapours emitted from the waters of Hervey Bay, or from the formation of DMS-derived sulphate clusters over the open ocean that were activated to observable particles by condensable vapours emitted from the nutrient rich waters around Fraser Island or Hervey Bay. Furthermore, a unique and particularly strong nucleation event was observed during northerly wind. The event began early one morning (08:00) and lasted almost the entire day resulting in the production of a large number of ~80 nm particles (average modal concentration during the event was 3200 cm−3). The Great Barrier Reef was the most likely source of precursor vapours responsible for this event.
Publisher
Copernicus GmbH
Reference52 articles.
1. Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., Aalto, P. P., Kulmala, M., Hyötyläinen, T., Cavalli, F., and Laaksonen, A.: Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer, Atmos. Chem. Phys., 6, 315–327, 2006. 2. Baron, P. A. and Willeke, K.: Aerosol Measurement - Principles, Techniques, and Applications (2nd Edition), John Wiley & Sons, New York, 2001. 3. Bates, T. S., Kapustin, V. N., Quinn, P. K., Covert, D. S., Coffman, D. J., Mari, C., Durkee, P. A., De Bruyn, W. J., and Saltzman, E. S.: Processes controlling the distribution of aerosol particles in the lower marine boundary layer during the First Aerosol Characterization Experiment (ACE 1), J. Geophys. Res., 103, 16369–16383, 1998. 4. Bigg, E. K. and Turvey, D. E.: Sources of atmospheric particles over Australia, Atmos. Env., 12, 1643–1655, 1978. 5. Broadbent, A. D. and Jones, G. B.: DMS and DMSP in mucus ropes, coral mucus, surface films and sediment pore waters from coral reefs in the Great Barrier Reef, Mar. Freshw. Res., 55, 849–855, 2004.
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