[ACG42-P03] Carbon isotopic characterization of organic aerosols in tropical marine atmosphere at the Maïdo high-altitude observatory, Reunion Island
Keywords:Marine atmospheric organic aerosol, OVOCs, Tropical marine atmosphere, Halogen chemistry
To improve our knowledge on the role of tropical oceans in the formation of atmospheric organic aerosols, size-segregated aerosol sampling was conducted for the first time at the Maïdo observatory (2,200m a.s.l) in Reunion Island in the Indian Ocean. The aerosol measurements were made during the Oxygenated Compounds in the Tropical Atmosphere–Variability and Exchanges (OCTAVE) project in March-June 2018, with integrated approach combining in situ/off-line measurements, satellite retrievals, and modelling. Stable carbon isotopic compositions together with molecular characterization of organic aerosols showed clear seasonal changes with significant contribution of marine sources to the observed aerosols in March when the microbial activity in sea surface was most active in that oceanic region. The effect of the changes in conditions of marine boundary layer and free troposphere on the observed organic aerosols are also discussed.