Simultaneous determination of gas and particle dry deposition onto conditioned surrogate surfaces

Aerodynamically designed surrogate surfaces were used to determine the rela tive importance of gaseous (SO2, HNO3, NH3) and particulate species (SO42-, NO3-, NH4+, Ca2+) in the dry deposition flux. For 11 sampling periods, we measured the deposition fluxes, ambient gaseous concentrations, size distri butions of atmospheric aerosols and some meteorological parameters in Uji. The dry deposition of the gas to a nearly perfect sink was calculated by su btracting the greased surface flux from the total deposition flux to both t he greased and reagent impregnated (or water) surface. It was found that th e gas phase deposition contributed significantly more (60-93%) than the par ticulate phase to overall deposition of sulfur and nitrogen compounds. The dry deposition velocities of the species were also calculated using the dep osition fluxes and the measured ambient concentrations. Comparisons were ma de between the measured and modeled particulate deposition flux.