We are talking about bench top ionizers, ion bars, ionizer air guns, overhead ionizers and Spot Ionizers.
Proper grounding procedures can efficiently neutralise charges on conductors, but only ionisation can eliminate harmful charges on isolated conductors and insulative materials such as plastics.
To ensure a ESD safe working environment it is imperative to control all static charges. Not all products and tools can be make conductive or semi conductive. Therefore air ionisation can control the level of the static charge actively, preventing ESD damage.
Air ionisation is the most effective method of eliminating static charges on non-conductive materials and isolated conductors. Air ionisers generate large quantities of positive and negative ions in the surrounding atmosphere, which serve as mobile carriers of charge into the air. As ions flow through the air, they are attracted to oppositely charged particles and surfaces. Neutralization of charged surfaces can be rapidly achieved through the process.
Air ionisation may be formed using electrical ionisers, which generate ions in a process known as corona discharge. Electrical ionisers generate air ions through this process by intensifying an electric field around a sharp point until it overcomes the dielectric strength of the surrounding air. Negative corona occurs when electrons are flowing from the electrode into the surrounding air. Positive corona occurs as result of the flow of electrons from the air molecules into the electrode.