Theoretical and observational study to estimate the contribution of natural and anthropogenic aerosols, the tiny suspended particles in the air, to the perturbation of Earth?s radiation budget is described in this book. This book contains six chapters, starting with a brief introduction about the properties of aerosols and their role in climate. Ground-based measurement techniques for investigating the basic aerosol properties are described in the second chapter. The changes in aerosol properties due to dust storms, fog, long-range transport of anthropogenic aerosols and also the seasonal variation of background and urban aerosols over semi-arid region in India are discussed in third and fourth chapters. Quantification of the perturbation of radiation budget due to aerosols with detail description regarding the computation of aerosol radiative forcing constitutes the fifth chapter. Finally, the contribution of natural and anthropogenic aerosols on radiation budget is given in the last chapter along with a description of the estimation process and a discussion on the seasonal variation of their contributions over background region and urban region in India is also presented.