Atmos. Chem. Phys. Discuss., 11, 32965-32992, 2011
© Author(s) 2011. This work is distributed
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Influence of medium range transport of particles from nucleation burst on particle number concentration within the urban airshed
H. C. Cheung1, L. Morawska1, Z. D. Ristovski1, and D. Wainwright2
1International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD 4001, Australia
2Queensland Department of Environmental Resource and Management, Brisbane, Australia

Abstract. Elevated particle number concentration (PNC) observed during nucleation events could make a significant contribution to the total particle load and thus air pollution in urban environments. Therefore, a field measurement study of PNC was conducted to investigate the temporal and spatial variations of PNC within the urban airshed of Brisbane, Australia. PNC was monitored at urban (QUT), roadside (WOO) and semi-urban (ROC) areas around the Brisbane region during 2009. The results showed that morning traffic exhaust emissions were the main contributor to high PNCs at QUT and WOO which contributed 5.5% and 5.1 5 during the week, respectively, with a less significant contribution on weekends. PNC peaks were observed around noon, which correlated with the highest solar radiation levels at all three stations, thus suggesting that high PNC levels were likely to be associated with new particle formation caused by photochemical reactions. Wind rose plots showed relatively higher PNC for the NE direction, which was associated with industrial pollution, accounting for 12%, 9% and 14% of overall PNC at QUT, WOO and ROC, respectively. Although there was no significant correlation between PNC at each station, the variation of PNC was well correlated among three stations during regional nucleation events. In addition, PNC at ROC was significantly influenced by upwind urban pollution during the nucleation burst events, with the average enrichment factor of 15.4. This study provides an insight into the influence of regional nucleation events on PNC in the Brisbane region and is the first study to quantify the effect of urban pollution on semi-urban PNC through the nucleation events.

Citation: Cheung, H. C., Morawska, L., Ristovski, Z. D., and Wainwright, D.: Influence of medium range transport of particles from nucleation burst on particle number concentration within the urban airshed, Atmos. Chem. Phys. Discuss., 11, 32965-32992, doi:10.5194/acpd-11-32965-2011, 2011.
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