Photochemical trajectory modeling of ozone concentrations in Hong Kong

In this study, tropical cyclones over the East and South China Seas were found to be the most predominant weather conditions associated with the occurrence of high ozone (O3) episodes in Hong Kong in 2005-2009. A photochemical trajectory model coupled with Master Chemical Mechanism (MCM) was adapted to simulate the O3concentrations during two O3pollution episodes. The results agreed well with the observed data. A representative backward air mass trajectory was used to determine the contribution of each volatile organic compound (VOC) to the O3levels. After taking into account both reactivity and mass emission of each VOC, 10 species were found to be the key O3precursors in Hong Kong. Further analysis identified solvent related products accounting for 70% of the modeled O3concentration in Hong Kong. The results highlight the importance of considering together reactivity and source sector emissions in developing targeted VOC reduction for O3abatement strategies.