AN INVESTIGATION OF AEROSOL MICROSTRUCTURE ON VISUAL AIR-QUALITY

Visibility modeling requires a proper description of the optical properties of atmospheric pollutants and an accurate simulation of the physical processes of light propagation in the atmosphere. The objectives of this paper are to study the effects of various microstructures of atmospheric particles on their optical properties (such as extinction coefficient, probability of scattering, and scattering phase matrix) and consequential influence on the computation of path radiance and contrast. Mie computations are performed, in which the physical characteristics (e.g. size distribution, solubility, and mixture) of particles and the atmospheric conditions (e.g. moisture) are allowed to vary. A plane-parallel multiple scattering radiation model, utilizing the methods of doubling and adding, is then used to assess the impact of atmospheric pollutants on visibility and visual air quality. The results of this study demonstrate the dependence of sky radiance not only on the aerosol extinction coefficient but on the phase matrix and environmental conditions as well. These results are presented in sky color maps which are created using truecolor imagery.