ISC3 (Industrial Source Complex) model is a popular steady-state Gaussian plume model which can be used to assess pollutant concentrations from a wide variety of sources associated with an industrial complex. This model can account for the following: * Point, area, line, and volume sources * Settling and dry deposition of particles * Downwash * Separation of point sources * Limited terrain adjustment ISC3 operates in both long-term and short-term modes. The screening version of ISC3 is SCREEN3.