The disk contains a microcomputer model (IBM-PC or compatible) to estimate indoor air quality in a multiroom building. The model treats each room as a well mixed chemical reactor that can contain pollutant sources and sinks. HVAC (heating, ventilating and air conditioning) systems, air cleaners, interroom air flows and air exchange with the outdoor are included in the model. The model is menu driven. Data entry is handled with a fill-in-the-form interface. Model predictions are in good agreement with experimental data. Software Description: The program is written in the BASIC programming language for implementation on an IBM-PC/XT or compatible equipment, using MS DOS 2.1 or better operating system. The system has 512K of memory. A graphics adapter and monitor are required to display the graphics output from the model.