The dry deposition of Pb, Zn, and Cd containing particles from the atmosphere was studied by comparing theory with experiment for two types of surfaces: first, smooth flat teflon plates mounted on a smooth building roof and, second, fields of Avena fatua, wild oat grass, about 50 cm tall. Gravitational sedimentation controlled the dry deposition of these trace metals on flat surfaces, while inertial impaction was the controlling mechanism for the vegetated surfaces. Convective diffusion to the grassy surfaces controlled the deposition of particles smaller than 0.1μ (condensation nuclei) over the grassy fields: this mechanism contributed little to total trace metal deposition. Theories for these three mechanisms were then used to construct a plot of depositon velocity versus particle diameter for Avena. The model incorporates a novel two-step deposition process: eddy diffusion and sedimentation from the atmosphere to the grassy field followed by filtration by the grass elements. The results of the calculations compared well with literature data for the total lead deposition on fields of Avena. Brownian diffusion was negligible, while impaction on the plant elements was responsible for nearly all of the depositon. Of these particles, about one-fourth were brought from the atmosphere into the canopy by sedimentation: wind eddy transport was responsible for the remaining fraction.