This book focuses on the optical properties of atmospheric aerosols, their diurnal and seasonal variations that have been observed at Kannur (11.9oN, 75.4oE, 5 m ASL). This work has been carried out with the ground based measurements by using a sun photometer. Measurement of aerosol mass loading and chemical analysis for identifying and quantifying various inorganic chemical species gives more insight to formulate a model suited for this region. The results were quite positive in climate models to study the impact of aerosols on the atmospheric radiation balance. The results of the chemical analysis conducted for aerosols of size ...