Radiative forcing of aerosols is much more difficult to estimate than that of well-mixed gases due to the large spatial variability of aerosols and the lack of an adequate database on their radiative properties. In this paper, the optical depth, scattering coefficient, absorption coefficient, extinction coefficient and single scattering albedo were modeled using Optical Properties of Aerosols and Clouds (OPAC) by slightly altering the number densities of soot at visible wavelengths range of 0.25-1.00 mm for eight different relative humidities (RHs) (0, 50, 70, 80, 90, 95, 98 and 99%). The data obtained was used to estimate the radiative forcing (RF). The RF was observed to increase at all RHs given rise to positive RF when compared, as we moved from the first to the third models reflecting the dominance of warming effect. There are no noticeable changes in the scattering coefficient and extinction coefficient due to high percentage of volume mix ratio and mass mix ratio of water soluble when compared to the soot components; however, the single scattering albedo decreases with RHs attributing to a more absorbing aerosol. The regression analysis of the Ångström exponents and curvature which helps to determine the sizes of atmospheric particles was done using SPSS 16.0 Software, the analysis reveals the presence of fine mode particles.
