Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/65733
Title: Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air
Authors: Lui, KH
Ho, SSH
Louie, PKK
Chan, CS
Lee, SC 
Hu, D
Chan, PW
Lee, JCW
Ho, KF
Keywords: Ambient air
Carbonyl
Correlation analysis
Seasonal variation
Source apportionment analysis
Issue Date: 2017
Publisher: Pergamon Press
Source: Atmospheric environment, 2017, v. 152, p. 51-60 How to cite?
Journal: Atmospheric environment 
Abstract: Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012–2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT < TC < YL) reflect location characteristics (urban > rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).
URI: http://hdl.handle.net/10397/65733
ISSN: 1352-2310
EISSN: 1873-2844
DOI: 10.1016/j.atmosenv.2016.12.004
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