This paper summarises the development and principal results of fifty years of research on aerosols in the marine atmosphere at Mace Head Atmospheric Research Station on the west coast of Ireland. It concentrates on the sources. physico-chemical properties, number and mass concentrations, size range, volatility and chemical composition of aerosols in different air masses. it also examines optical properties of the aerosols and their long-range transport. (c) 2008 Published by Elsevier B.V.