THESIS
2016
xxvi, 239 pages : illustrations (some color) ; 30 cm
Abstract
Hong Kong is one of the world’s most densely populated cities and has long suffered from air
pollution. This work discusses the first high resolution aerosol mass spectrometer (HR-AMS)
measurements of submicron particulate matter (PM
1) composition at a typical urban location in
Hong Kong. Measurements were carried out in spring and summer 2013 at street level in a district
with mainly commercial and residential activities. Primary goals of this study are the
characterization and differentiation of important aerosol sources in the urban inner-city
environment and their varying importance at different time scales including diurnal patterns,
seasonal characteristics and changes with air mass origin.
Total non-refractory PM
1 at the roadside was vastly dominated by organic constituen...[
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Hong Kong is one of the world’s most densely populated cities and has long suffered from air
pollution. This work discusses the first high resolution aerosol mass spectrometer (HR-AMS)
measurements of submicron particulate matter (PM
1) composition at a typical urban location in
Hong Kong. Measurements were carried out in spring and summer 2013 at street level in a district
with mainly commercial and residential activities. Primary goals of this study are the
characterization and differentiation of important aerosol sources in the urban inner-city
environment and their varying importance at different time scales including diurnal patterns,
seasonal characteristics and changes with air mass origin.
Total non-refractory PM
1 at the roadside was vastly dominated by organic constituents with
primary organic aerosol from cooking and traffic found to be dominant. Findings were
corroborated by additional measurements including wind rose analysis, traffic data, EC/OC data
and gas phase species. The relationship of traffic-related organics and elemental carbon
concentrations with traffic count data was studied in detail to evaluate the contributions of different
broad engine types (gasoline, diesel, LPG) to roadside particulate matter concentrations. Cooking
contributions in organic aerosol were assessed directly for the first time in Hong Kong and
exceeded those related to vehicles although traffic was still the major PM
1 source when elemental
carbon (EC) was included. Influences of traffic and cooking-related emissions on particle size
distributions were examined. Secondary organic aerosol albeit at smaller contribution was
consistently abundant. Episodic pollution events and their relation to various meteorological
conditions, including land-sea-breeze conditions and typhoon-outflow circulations, and their
effects on different inorganic and organic species were assessed. Regional transport, wet chemistry
and photochemistry varyingly contributed to high particulate matter events. Elemental analysis of
high-resolution mass spectra revealed that data alignment in the van Krevelen diagram was mostly
related to different mixing of organic aerosol sources.
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