This EPA model is a steady-state Gaussian plume model which can be used to assess pollutant concentrations from a wide variety of sources associated with an industrial source complex. This model can account for settling and dry deposition of particulates, downwash, area, line, and volume sources, plume rise as a function of downwind distance, separation of point sources, and limited terrain adjustment. ISC is designed to calculate the average seasonal and/or annual ground level concentration or total deposition from multiple continuous point, volume, and/or areas sources. Provision is made for special discrete, X, Y receptor points that may correspond to sampler sites, points of maxima, or special points of interest. Sources can be positioned anywhere relative to the grid system. For the short term model, input requires hourly surface weather data from the preprocessor program RAMMET, which provides hourly stability class, wind direction, wind speed, temperature, and mixing height.