Suspended particles in the atmosphere (aerosol) emitted by natural and anthropogenic activities effect climate, air quality and health. Black carbon (BC), optically absorbing form of carbonaceous aerosols, emitted by various combustion processes reduce the incoming solar radiation and causes heating of the particles and local warming of the boundary layer of the atmosphere. Recently, BC has been used as an indicator of exposure to diesel soot, which has been classified as a toxic air contaminant and a suspected carcinogen. BC is responsible for change in surface albedo and the single scattering albedo (SSA). The SSA determines the degree of absorption and is a very important parameter in term of their radiative effects. Generally, for non dust aerosol SSA decreases with wavelength and for dust aerosols increases with wavelength. One of the most important properties of aerosols is the aerosol optical depth (AOD) helps in deriving information of the optical properties and size distribution of the particles. AOD value is used to estimate aerosol radiative forcing. The largest contribution to global annual average AOD (0.12 at 550 nm) is from natural (58%), fossil fuel (26%) and biomass burning (16%). Aerosols impact climate by modifying cloud properties. Aerosols in the range of 0.3 to 1 µm in diameter reduce visibility and it below 0.1 µm get deposited in the lung and causes several respiratory problems.