Gaseous and Particulate Products from the Atmospheric Ozonolysis of a Biogenic Hydrocarbon, Sabinene

Abstract

Environmental Context. Volatile organic compounds (VOCs) are a source of ozone and secondary organic aerosols, which have significant effects in the lower troposphere and on human health. The emission rate of VOCs from plants exceeds anthropogenic emissions by a factor of ten. In order to understand how these plant-derived compounds influence global ozone budgets, studies into the atmospheric reactions of these compounds are needed. This study investigates the ozonolysis of sabinene, a VOC abundantly emitted by trees in Europe. Abstract. This work investigates both the gaseous and particulate phase products from the ozonolysis of sabinene in smog chamber experiments. The gaseous phase was analyzed in situ by FTIR. The particulate phase was analyzed after sampling with a supercritical fluid extraction technique directly coupled to gas chromatography and mass spectrometry (SFE-GC-MS) and to an in situ derivatization method. Sabinaketone, formaldehyde, and formic acid have been detected in the gaseous phase. More than 30 products have been observed in the secondary organic aerosol formed from sabinene oxidation and among them 10 have been identified as compounds containing carbonyl, hydroxyl and carboxyl groups. Hypotheses concerning reaction formation pathways have been proposed for each identified product in gaseous and particulate phases.