Vertical variations of optical characteristics of atmospheric aerosol (air turbidities and logarithmic gradients oi intensities) at altitudes between 20 and 150 km were obtained by twilight photometry carried out between 1942 and 1993 at the Abastumani Astrophysical Observatory in Georgia. The reported data include periods of increased volcanic and meteor activities. Also shown are air turbidity curves for different latitudes obtained in 1974 soon after the eruption of Fuego; these were derived from photographs of the earth＇s sunlit limb from the spacecraft Soyuz 16. A combined curve of vertical aerosol distribution typical of the middle atmosphere is presented.