The main objectives of ESAC II are the following: (1) Extend and improve the important existing Belgian contribution in atmospheric research started in the 50s, recognized internationally. (2) Investigate the chemistry of the atmosphere, to detect and understand its evolution, mainly with experimental means. Special attention will be paid to the evolution of the ozone layer and chemical species and processes with an impact on climate changes. (3) Support the Belgian policies and decisions regarding the Amendments to: - the Montreal Protocol on Substances that deplete the Ozone Layer; - the Kyoto Protocol on Greenhouse Gases (GHG) emissions.