Numerical modeling is performed to predict airflow patterns, thermal comfort, and ventilation air distribution within an open office space. This analysis is conducted to examine the ability of a three-dimensional airflow simulation model to predict the performance of a linear diffuser and to assess the impact of several parameters on performance. The airflow within a single cubicle within a mechanically ventilated open office area is modeled numerically using the program EXACT3. The airflow patterns, temperature distributions and local age of air are calculated for different air exchange rates, interior partition locations and discharge angles of the supply air, using a threedimensional, turbulent flow finite difference model. Thermal comfort within the space is described by the Air Diffusion Performance Index (ADPI), and ventilation effectiveness is determined with a simulated tracer gas measurement of the local age of air.