This compact and lightweight ionizer can be mounted on a wall or shelf, as well as easily transported for field service use. An active feedback, auto-balancing circuit ensures and maintains the unit's ion balance despite variations in line voltage, air speed, or emitter electrode condition. A replaceable emitter cassette minimizes downtime by easily sliding out for cleaning and replacement. A LO/OFF/HI fan speed selector switch adjusts airflow from 60 to 77 CFM. Other features include a “clean-me” flashing indicator, visual/audible maintenance alarm, and a ground jack for personal grounding. Operates on 120VAC and comes with a power cord, grounded metal case, removable back grill, air filter screen, and NIST-traceable Certificate of Calibration.