Impacts of oxygenated organic compounds on photochemical air pollution in coastal Hong Kong

Oxygenated organic compounds are key reactive pollutants that significant impact air quality and human health. They play critical roles in tropospheric photochemistry and oxidation capacity, profoundly influencing radical cycling and O3 formation. Despite their importance, the precise quantification of these compounds remain a significant challenging. Here we present a comprehensive field study of volatile organic compounds (VOCs) and oxygenated VOCs in the coastal atmosphere of Hong Kong, employing a combination of real-time online mass spectrometry and offline sampling methods. The measurements revealed the substantial abundance of OVOCs and their significant contributions (~50%) to photochemical reactivity and O3 formation potential. Further observation-based modeling analysis were performed to quantify the impacts of these reactive organic species on photochemistry and the formation of secondary pollutants. The results demonstrated that the OVOCs related reactions can contribute to 30-65% of peroxy radical formation and recycling, thereby enhancing daytime O3 formation. This highlights the pivotal role of OVOCs in photochemical pollution and air quality. Our results provide quantitative insights into the formation and impacts of oxygenated reactive organics, highlighting their pivotal roles in photochemical pollution and air quality. These findings are essential for improving air quality models and developing effective pollution control strategies, particularly in coastal urban environments.