New particle formation and growth at a suburban site and a background site in Hong Kong.

Autor: Lyu XP; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong; Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University, Hong Kong., Guo H; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong; Research Institute for Sustainable Urban Development, The Hong Kong Polytechnic University, Hong Kong. Electronic address: ceguohai@polyu.edu.hk., Cheng HR; Department of Environmental Engineering, School of Resource and Environmental Sciences, Wuhan University, Wuhan, China. Electronic address: chenghr@whu.edu.cn., Wang DW; State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2018 Feb; Vol. 193, pp. 664-674. Date of Electronic Publication: 2017 Nov 14.
DOI: 10.1016/j.chemosphere.2017.11.060
Abstrakt: Atmospheric nanoparticles have great impacts on human health and global climate change. The number concentrations and size distributions of nanoparticles in the size range of 5.5-350.4 nm were detected at a background site and a suburban site in Hong Kong from summer to winter in 2011 and in autumn of 2013, respectively. Significantly higher particle number concentrations in all modes were observed at the suburban site (p < 0.05) during the sampling periods, possibly due to stronger primary emissions/regional transport and more intensive new particle formation (NPF). Particle number concentrations were much enhanced under northerly winds at both sites, resulting from regional transport of Aitken and accumulation mode particles, enhanced local NPF and occasionally low condensation sink. NPF was mainly limited by the precursors of condensable vapors and oxidative capacity of the atmosphere at the background site and the suburban site, respectively. In most cases, the formation rate of 5.5 nm particles was a function of sulfuric acid vapor to the power of 1.32 ± 0.34 at the background site and 0.81 ± 0.31 at the suburban site, abiding by the cluster activation theory. However, ozonolysis of monoterpenes (particularly α-pinene) might also drive NPF, particularly in the afternoon. These reactions also contributed to the growth of nucleation mode particles, which was largely explained by sulfuric acid vapor (73.6 ± 10% at the background site and 60.4 ± 9.8% at the suburban site). In contrast, the oxidations of isoprene, β-pinene and aromatics (particularly xylenes and trimethylbenzenes) were found to participate in the growth of Aitken mode particles.
(Copyright © 2017 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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