Experimental and Parameterization Method for Evaluation of Dry Deposition of S Compounds to Natural Surfaces

This paper deals with parameterization method based on meteorological parameters for calculation of dry deposition of S compounds on natural surface (leaf of Cassia siamea) and direct measurement method. A scheme based on meteorological parameters has been evolved to calculate the dry deposition theoretically and a computer program has been developed. Experimentally dry deposition flux of S on leaf of Cassia siamea was measured by exposing the leaf surfaces on non-dewy, non-foggy and non rainy days and washing the leaf surfaces with deionised water and samples were analyzed by Dionex Dx-500 Ion Chromatograph. Atmospheric concentration of SO₂ was 3.54±1.41 μg m^-3 and particulate SO4^2- was 2.72±1.15 μg m^-3. Theoretically obtained dry deposition velocity of SO₂ and SO4^2- are 0.32 cm s^-1 and 0.75cm s^-1, respectively. The calculated deposition of S as total sulphate (gaseous SO₂ and particulate SO4^2-) to Cassia leaf was 2.05±0.78mg m^-2 d^-1 and experimentally obtained dry deposition of S as sulphate was 1.07±1.35 mg m^-2 d^-1. The experimentally and theoretically obtained mean values for S as SO4^2- are comparable