ACSOE (Atmosphere Chemistry Studies in the Oceanic Environment) - OXIdising Capacity of the Ocean Atmosphere (OXICOA). ACSOE, which took place between 1995 and 2000, is a UK Natural Environment Research Council (NERC) Thematic Research Programme to investigate the chemistry of the lower atmosphere (0 - 12 km) over the oceans. The studies aimed to bring about a clearer understanding of natural processes in the remote marine atmosphere, and how these processes are affected by atmospheric pollution originating from the continents. This information is vital in understanding regional and global-scale changes in atmospheric chemistry and climate. The principal Investigator of ACSOE was Prof Stuart Penkett of University of East Anglia. The project had three consortia of UK institutes and universities, each of which focused on a different scientific topic: OXICOA (OXIdising Capacity of the Ocean Atmosphere), MAGE (Marine Aerosol and Gas Exchange) and ACE (Aerosol Characterisation Experiment). OXICOA was a study of oxidant, radical and related gas-phase chemistry in the clean and moderately polluted marine atmosphere.