scholarly journals Modeling C1 -C4 Alkyl Nitrate Photochemistry and Their Impacts on O3 Production in Urban and Suburban Environments of Hong Kong

2017 ◽  
Vol 122 (19) ◽  
pp. 10,539-10,556 ◽  
Author(s):  
X. P. Lyu ◽  
H. Guo ◽  
N. Wang ◽  
I. J. Simpson ◽  
H. R. Cheng ◽  
...  
Keyword(s):  
Hong Kong ◽  
Alkyl Nitrate

scholarly journals New insight into the spatiotemporal variability and source apportionments of C<sub>1</sub>–C<sub>4</sub> alkyl nitrates in Hong Kong

2016 ◽  
Vol 16 (13) ◽  
pp. 8141-8156 ◽  
Author(s):  
Zhenhao Ling ◽  
Hai Guo ◽  
Isobel Jane Simpson ◽  
Sandra Maria Saunders ◽  
Sean Ho Man Lam ◽  
...  
Keyword(s):  
Hong Kong ◽  
Biomass Burning ◽  
Spatiotemporal Variability ◽  
Urban Site ◽  
Mesoscale Circulation ◽  
Peroxy Radicals ◽  
Alkyl Nitrates ◽  
Regional Transport ◽  
Secondary Formation ◽  
Alkyl Nitrate

Abstract. C1–C4 alkyl nitrates (RONO2) were measured concurrently at a mountain site, Tai Mo Shan (TMS), and an urban site, Tsuen Wan (TW), at the base of the same mountain in Hong Kong from September to November 2010. Although the levels of parent hydrocarbons were much lower at TMS (p  <  0.05), similar alkyl nitrate levels were found at both sites regardless of the elevation difference, suggesting various source contributions of alkyl nitrates at the two sites. Prior to using a positive matrix factorization (PMF) model, the data at TW were divided into "meso" and "non-meso" scenarios for the investigation of source apportionments with the influence of mesoscale circulation and regional transport, respectively. Secondary formation was the prominent contributor of alkyl nitrates in the meso scenario (60 ± 2 %, 60.2 ± 1.2 pptv), followed by biomass burning and oceanic emissions, while biomass burning and secondary formation made comparable contributions to alkyl nitrates in the non-meso scenario, highlighting the strong emissions of biomass burning in the inland Pearl River delta (PRD) region. In contrast to TW, the alkyl nitrate levels measured at TMS mainly resulted from the photooxidation of the parent hydrocarbons at TW during mesoscale circulation, i.e., valley breezes, corresponding to 52–86 % of the alkyl nitrate levels at TMS. Furthermore, regional transport from the inland PRD region made significant contributions to the levels of alkyl nitrates (∼  58–82 %) at TMS in the non-meso scenario, resulting in similar levels of alkyl nitrates observed at the two sites. The simulation of secondary formation pathways using a photochemical box model found that the reaction of alkyl peroxy radicals (RO2) with nitric oxide (NO) dominated the formation of RONO2 at both sites, and the formation of alkyl nitrates contributed negatively to O3 production, with average reduction rates of 4.1 and 4.7 pptv pptv−1 at TMS and TW, respectively.

Verocytotoxin-producing Escherichia coli infection: The Hong Kong experience

1998 ◽  
Vol 13 (11-s4) ◽  
pp. S289-S293 ◽  
Author(s):  
SSY WONG ◽  
WC YAM ◽  
PHM LEUNG ◽  
PCY WOO ◽  
KY YUEN
Keyword(s):  
Escherichia Coli ◽  
Hong Kong ◽  
Escherichia Coli Infection

Abstracts of the Annual Scientific Meeting of the College of Surgeons of Hong Kong 20-21 May 2000

2000 ◽  
Vol 4 (2) ◽  
pp. A5-A5
Author(s):  
P.B.S. Lai ◽  
W.Y. Lau ◽  
S.S.M. Ng ◽  
P.T. Chui ◽  
K.L. Leung ◽  
...  
Keyword(s):  
Hong Kong ◽  
Scientific Meeting ◽  
Annual Scientific ◽  
Annual Scientific Meeting
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