The (mid-visible) aerosol optical depth (‘aod’) is probably the most important optical property to quantify atmospheric aerosol. When observing aerosol from space retrievals have been developed mainly to provide data for this property. However, influenced by sensor and algorithm capabilities, individual satellite retrievals have regional and seasonal strengths and weaknesses (to a point that no reliable retrieval is possible). In order to provide a superior product, in terms of accuracy and global coverage, over that of any individual retrieval, regional and seasonal advantages of available global satellite data-sets are combined to a recommended data-set. The necessary retrieval assessment is based on quality ground remote sensing by AERONET. Recommended composites will be discussed and presented for the mid-visible aerosol optical depth (representing aerosol amount) and for the Angstrom parameter which describes the spectral dependence of the visible aerosol optical depth (representing aerosol size).