Describes a research project involving instrumenting a variable air volume (VAV) building on the campus of the University of Missouri-Rolla with indoor air quality (IAQ) measuring devices in order to investigate methods of ventilation control on VAV systems, to modify the building control system to achieve ventilation control, and to observe and analyse IAQ before and after system changes. The IAQ measuring devices include a total volatile organic matter sensor, a real time dust sensor and CO2 sensors. Additionally, methods of controlling outside air on a VAV building were studied using a computer simulation. Illustrates schematically the VAV system and the equipment layout and a control scheme for economiser controlled ventilation. Presents the findings for ventilation control and of IAQ measurements with and without direct ventilation control. Concludes that with relatively simple and inexpensive hardware modifications, outside air ventilation control is achievable on present VAV buildings that currently do not have direct ventilation control schemes.