Negative ion generators or ionizers are electronic air cleaners that disperse negatively-charged air molecules, "called ions" into the air. The ion molecule has an extra electron that detaches and then reattaches to a dust molecule, giving it a charge. The negatively charged dust molecule then sticks to the nearest surface or object available. This new molecule must be removed from walls, ceilings, floors or furniture, or it can detach and become airborne again.
These ions are often produced with ultraviolet light. Electronic air cleaners use high voltage to create ions. Ozone and nitrogen oxide are toxic chemicals, which are often created in the process. Ozone, a known lung irritant, reacts to chemicals found in household cleaning products, paints, polishes, carpets and linoleum. These chemical reactions create harmful byproducts that can exacerbate allergies, asthma and lung disease. The EPA states that "relatively low amounts (of ozone) can cause chest pain, coughing, shortness of breath, and, throat irritation."
Comtech Research and HealthGlow make ionizers.