A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air
https://orcid.org/0000-0002-1238-238X
AbstractGas-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).
HighlightsFormaldehyde (HCHO) and acetaldehyde together contribute >70% to total carbonyls.Strong correlation between the two compounds implies same source.Rural area with low vehicular emissions shows lowest primary HCHO contribution.Highest primary source signal in winter due to direct emissions at low temperature.Acetone not reported due to DNPH cartridge shows negative biases in measurement.
Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air
https://orcid.org/0000-0002-1238-238X
AbstractGas-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).
HighlightsFormaldehyde (HCHO) and acetaldehyde together contribute >70% to total carbonyls.Strong correlation between the two compounds implies same source.Rural area with low vehicular emissions shows lowest primary HCHO contribution.Highest primary source signal in winter due to direct emissions at low temperature.Acetone not reported due to DNPH cartridge shows negative biases in measurement.
Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air
https://orcid.org/0000-0002-1238-238X
AbstractGas-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).
HighlightsFormaldehyde (HCHO) and acetaldehyde together contribute >70% to total carbonyls.Strong correlation between the two compounds implies same source.Rural area with low vehicular emissions shows lowest primary HCHO contribution.Highest primary source signal in winter due to direct emissions at low temperature.Acetone not reported due to DNPH cartridge shows negative biases in measurement.
Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air
Lui, K.H. (author) / Ho, Steven Sai Hang (author) / Louie, Peter K.K. (author) / Chan, C.S. (author) / Lee, S.C. (author) / Hu, Di (author) / Chan, P.W. (author) / Lee, Jeffrey Chi Wai (author) / Ho, K.F. (author)
Atmospheric Environment ; 152 ; 51-60
2016-12-02
10 pages
Article (Journal)
Electronic Resource
English
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