Atmospheric sulfate and nitrate: Distribution, formation and deposition

Understanding the dry deposition process for ambient sulfate and nitrate is important because of the effect of the deposited material on the acidity of water bodies. In this study, sulfate and nitrate dry deposition fluxes were measured using a smooth, greased surface with a sharp leading edge. The ambient mass concentration in the size range between 0.1 and 100 ;The measured fluxes compared well with calculated fluxes using the measured ambient particulate mass data and deposition velocities obtained from the Sehmel and Hodgson model. 99% of the dry deposition fluxes for both sulfate and nitrate were shown to be due to coarse particles (;The size distribution for the total mass varied with wind speed and direction. The average size distribution of total mass for nineteen samples was trimodal with peaks at 0.43, 6.75 and 28.58 ;The mass size distribution of sulfate and nitrate between the fine and coarse particulate modes were evaluated as a function of temperature. The concentration of fine particulate nitrate (;The following evaluation were performed to determined the possible form of sulfate and nitrate in the fine and coarse fraction: (1) Ion balances demonstrated that the possible forms of sulfate and nitrate in the fine fraction were ammonium sulfate, (...