This project is a field study of fluxes of atmospheric aerosol to grass using micrometeorological techniques and high frequency aerosol measurements. Aerosol size spectra consisting of optical measurements of particle concentration from a high flow rate sensor and wind velocity data from sonic anemometry will be collected from field towers for determining turbulent fluxes using eddy correlation. Fluxes estimates will also be derived from vertical profiles of aerosol concentration. Uncertainties associated with aerosol counting statistics and the effect of hygroscopic growth on aerosol fluxes will be investigated. The primary goal of this project is the determination of the aerosol deposition velocity (flux/concentration) as a function of diameter, friction velocity, and stability. These flux measurements will help determine the key physical and chemical process controlling the fate of aerosols, and aid in the parameterization of aerosol removal in regional and global models.