This book describes the optical properties of atmospheric aerosols observed over different locations in East Africa, which are considered significant to the Earth's radiation budget and climate change. Various sources and properties of aerosols are characterized utilizing remotely sensed ground- and satellite-based long-term observations combined with numerical computations and simulations. The basic principles of Sun photometer and various satellite measurements especially MODerate resolution Imaging Spectro-radiometer (MODIS), Multi-angle Imaging Spectro-Radiometer (MISR), and Ozone Monitoring Instrument (OMI) are illustrated. The background methodology and the physical explanations are clarified to the best of our knowledge. Multiple data sets are utilized to study the climatological aspects of various aerosol properties and their association with potential impact factors, including regional meteorology. The results presented in this book forms a basis for regional climate change studies which is a subset to global climate change, and could increase the accuracy of climate model simulations over this unique and less explored region in Africa.