New particle formation and growth at a remote, sub-tropical coastal location


Autoria(s): Modini, Robin L.; Ristovski, Zoran; Johnson, Graham R.; He, Congrong; Surawski, Nicholas; Morawska, Lidia; Suni, Tanji; Kulmala, Markku
Data(s)

2009

Resumo

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 hrs. 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 hrs 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.

Formato

application/pdf

Identificador

http://eprints.qut.edu.au/25831/

Publicador

Copernicus GmbH

Relação

http://eprints.qut.edu.au/25831/1/c25831.pdf

DOI:10.5194/acp-9-7607-2009

Modini, Robin L., Ristovski, Zoran, Johnson, Graham R., He, Congrong, Surawski, Nicholas, Morawska, Lidia, Suni, Tanji, & Kulmala, Markku (2009) New particle formation and growth at a remote, sub-tropical coastal location. Atmospheric Chemistry and Physics Discussions, 9(19), pp. 7607-7621.

Direitos

Copyright 2009 The authors.

This work is distributed under the Creative Commons Attribution 3.0 License.

Fonte

Faculty of Science and Technology

Palavras-Chave #029999 Physical Sciences not elsewhere classified #039901 Environmental Chemistry (incl. Atmospheric Chemistry) #020203 Particle Physics #040101 Atmospheric Aerosols #particle size distributions #ion size distributions #new particle formation #coastal nucleation
Tipo

Journal Article