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Nocturnal new particle formation events in urban environments

Citation

Salimi, F and Rahman, MM and Clifford, S and Ristovski, Z and Morawska, L, Nocturnal new particle formation events in urban environments, Atmospheric Chemistry and Physics, 17, (1) pp. 521-530. ISSN 1680-7316 (2017) [Refereed Article]


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Copyright Statement

Copyright 2017 Authors. Licenced under Creative Commons Attribution 3.0 Unported (CC BY 3.0) https://creativecommons.org/licenses/by/3.0/

DOI: doi:10.5194/acp-17-521-2017

Abstract

Few studies have investigated nocturnal new particle formation (NPF) events, and none of them were conducted in urban environments. Nocturnal NPF can potentially be a significant source of particles in urban areas, and studying them would improve our understanding of nucleation mechanisms. To address this, our study was conducted in an urban environment to investigate the physical characteristics of NPF events, with a particular focus on nocturnal events and the differences between them and the daytime NPF events. Particle number size distribution (PNSD) was measured for 2 weeks at each of 25 sites across an urban environment. A new method was proposed to automatically categorise NPF events based on growth rate (GR) in order to remove the bias related to the manual procedure. Out of 219 observed events, 118 and 101 were categorised into class I and II respectively and 73 happened during the nighttime which included more than 30% of the events. GR and condensation sink (CS) were calculated and a slight negative relationship between GR and CS was observed. Nocturnal events displayed higher GRs compared to daylight ones which were on average about 10%. Back trajectory analysis was also conducted to estimate the locations of the sources of daylight and nocturnal precursors. While the precursors related to daylight events originated from different locations with no particular pattern, back-trajectory analysis showed many air masses associated with nocturnal NPF events were transported from over the ocean. Overall, nocturnal NPF events were found to be a significant source of particles in the studied environment with different physical characteristics and/or sources compared to daylight events.

Item Details

Item Type:Refereed Article
Keywords:new particle formation events, NPF, nocturnal NPF, urban environments
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Atmospheric Dynamics
Objective Division:Health
Objective Group:Public Health (excl. Specific Population Health)
Objective Field:Environmental Health
Author:Salimi, F (Dr Farhad Salimi)
ID Code:124380
Year Published:2017
Web of Science® Times Cited:8
Deposited By:Menzies Institute for Medical Research
Deposited On:2018-02-20
Last Modified:2018-07-20
Downloads:8 View Download Statistics

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