Organic matter contributes substantially to the atmospheric particulate matters in earth’s atmosphere. A wide range of techniques aiming at measuring the physical and chemical properties of particulate matters have revealed remarkable insights about the formation and evolution of particulate organic matters. Kinetic models provide a unique perspective and unravel information that is difficult or impossible to obtain otherwise. In this dissertation, kinetic models are utilized to probe some key aspects regarding the formation and evolution of organic aerosols in different atmospheric systems, and with some focus on Hong Kong, a densely populated region in the south of China. Secondary organic formation (SOA) from widely identified volatile organic precursors (isoprene, monoterpenes and a...[ Read more ]

Organic matter contributes substantially to the atmospheric particulate matters in earth’s atmosphere. A wide range of techniques aiming at measuring the physical and chemical properties of particulate matters have revealed remarkable insights about the formation and evolution of particulate organic matters. Kinetic models provide a unique perspective and unravel information that is difficult or impossible to obtain otherwise. In this dissertation, kinetic models are utilized to probe some key aspects regarding the formation and evolution of organic aerosols in different atmospheric systems, and with some focus on Hong Kong, a densely populated region in the south of China. Secondary organic formation (SOA) from widely identified volatile organic precursors (isoprene, monoterpenes and aromatics) are modeled and evaluated using tracer-based measurements, and the sensitivities (e.g. on NO_x and VOCs) are examined. Located in the tropical latitude, Hong Kong is feather with high humidity all year around and the ambient aerosols are expected to be rich in liquid water content. The aqueous-particle processes are unique and quite different from cloud processes. The potential contribution of aqueous-particle processes in SOA formation in ambient Hong Kong is investigated using an observation-based model, based on most updated aqueous-phase mechanism that is relevant to aqueous-particle conditions. Glyoxal, emitted by a wide range of anthropogenic and natural processes, are highly water-soluble yet its behavior in aqueous-particles remain highly uncertain. Controlled chamber experiments (PSI, Switzerland) combined with a kinetic model were conducted to investigate the reactive uptake of glyoxal on ammonium seeds and the kinetic behavior in the aerosol system under humid conditions. Finally, a method has been developed to estimate the effective degradation of particulate semi-volatile organic compounds using ambient data, and the application of this method to estimate the effective degradation of hopanes in ambient Hong Kong.