Air quality control system

The present invention is a system for controlling the quality of air in a building. The system includes a sensor disposed for sensing the air quality in a building. Upon a sensing of an air quality problem, the system issues a command to draw in additional outside air into the building to alleviate the problem. The issuing of such command can be made conditional on a measurement of outside air temperature. The flow of additional outside air may be limited or avoided altogether where drawing in additional outside air would adversely affect the inside air temperature. Additional air can be drawn into a building, for example, by opening an economizer, activating a fan system, or by increasing a pressure setpoint in a supply air duct.