[en] 1 - Description of problem or function: DWNWND estimates the atmospheric concentration and deposition of material downwind from its point of release by the Gaussian plume atmospheric dispersion model. 2 - Method of solution: The model uses empirically determined dispersion factors for different release heights and meteorological and terrain conditions. The user may specify any of eight different sets of dispersion parameters: Pasquill-Gifford, Briggs-Smith, Briggs, Klug, Brookhaven, St. Louis, Juelich (50 m release height), and Juelich (100 m release height). Using the selected dispersion para- meters, ground-level normalized exposure estimates are made at any specified downwind distance for the plume centerline and for the 22.5 degree sector average. Computed values may be corrected for plume depletion due to deposition and for plume settling due to gravitational fall