This paper will describe a dispersion model that more accurately predicts downwind concentrations of particulate from agricultural operations. The model currently approved for use by the EPA (ISC Screen3) and the proposed model, Classical Gaussian Dispersion (CGD), are based upon the Gaussian diffusion equations. A simulation program was written to develop an equation that could be used to calculate longer time averages. The CGD model incorporates this equation. With the use of this equation the one-hour and 24-hour average concentrations can be calculated once the 10-minute concentration is obtained. A procedure has also been developed to assist in the validation of the CGD model. This procedure was used to compare actual measured concentrations to predicted concentrations from the CGD and ISC. The ultimate goal of this project is to have the CGD model approved by EPA Region VI for future use in the regulation of air pollution from agricultural operations.