Production of Volatile Organic Compounds by Ozone Oxidation Chemistry at the South China Sea Surface Microlayer

Abstract

Ozone (O3) oxidation chemistry on proxy compounds of the sea surface microlayer (SML) generates volatile organic compounds (VOCs) in the atmosphere. To shed light on the proposed significance of this chemistry, we investigated the formation of VOCs through heterogeneous chemistry of O3 (100 ppb) with authentic SML collected from 10 sites in the South China Sea using a reactor coupled to proton transfer reaction–time of flight–mass spectrometry (PTR–TOF–MS) and subsequently identified by off-line techniques. On the basis of the semi-quantitative data of the identified compounds, we estimated the production rates of acetone, acetaldehyde, propanal, hexanal, heptanal, octanal, and nonanal, which correspond to the experimental conditions applied in this study. These results provide a significant update to our understanding of abiotic formation of VOCs in the marine atmosphere, which should be considered in future model studies to properly evaluate the VOC contribution of ozone heterogeneous chemistry with the SML.