Understanding room air and air contaminant distribution is essential to the design of a ventilation system and the control of room thermal and air quality conditions. The objectives of the proposal are: (1) Investigate the regional airflow characteristic of a realistic ventilated room, especially with obstructions, with heat sources, with both obstructions and heat sources, and under low turbulence airflow conditions. (2) Develop a method for scaling among different sized rooms. (3) Evaluate and improve existing numerical simulation models to predict the air and air contaminant distribution in ventilated rooms under realistic situations. (4) Provide experimental data for the analysis and evaluation of theoretically-based models of room air and air contaminant distribution in ventilated rooms.