A case study on estimation of dry deposition of sulfur and nitrogen compounds by inferential method

In order to estimate dry deposition, deposition velocity calculation and co ncentration measurement were carried out in Niigata, Japan. Deposition velo cities of SO2 and HNO3 for some surfaces such as coniferous forest, deciduo us forest, agricultural land, and water were calculated taking into account diurnal variations of meteorological elements using routine meteorological data. Deposition velocities of fine and coarse aerosols were also estimate d respectively. Concentrations of SO2, HNO3, sulfate and nitrate in fine an d coarse aerosols respectively were measured from July to December in 1998 using filter pack and denuder methods. The results indicate that HNO3 dry d eposition for the high aerodynamic roughness surfaces such as forests is qu ite large. It is suggested that sulfate and nitrate aerosols depositions as well as the gases depositions should be taken into account to estimate dry deposition of sulfur and nitrogen compounds. It is also indicated that dry depositions of sulfur and nitrogen compounds are. unable to ignore compare d with their wet depositions.