An air flow monitoring and control system with reduced false alarms includes an alarm sensor for monitoring air flow in a fume hood or the like, set to provide a warning if air flow drops below a predetermined amount. A local controller monitors the alarm, and disables it when the hood is set to reduced air flow, whether by a local timer or by command of a central control system. Optionally, the controller itself can operate a variable speed drive to reduce air flow on a timed basis, and the controller can communicate with facility management through a dialer or the Internet, or can interface with a central control for the facility through a facility bus.