An air ioniser is a device which some claim can improve the health of human beings.

There are two types of air ionisers.

The first type creates small amounts of ozone, which is relatively harmless to humans. The ozone generated is highly toxic to air-borne bacteria, and will destroy or kill these often infectious organisms when they come into close contact with the generated ozone.

Proponents claim that a closed room ionised by a low energy ioniser offers improved health benefits because the concentration of infectious organisms is reduced compared to a non-ionised room. However, the benefits of this practice are regularly debated and argued. It can also be seen that an ionized room that is rarely visited or exposed to outside contaminates - should in theory be a less contaminated room.

The second type of air ioniser purifies air by generating negative ions. Negative ions occur natually near waterfalls and after heavy thunderstorms and have the effect of cleaning the air. The negative ions are attracted to positively charged dust and smoke particles. These new heavier combined particles then fall out of the air leaving purified air.

The use of negative ions continues to be a more accepted mainstream therapy in Eastern Europe and the Far East than in Western Europe or the United States. Although problems with nosocomial infections (hospital acquired "super-bugs") have led the National Health Service (NHS) in the UK to do extensive research into the effect of negative ions on this area of hygiene. The results were very positive(see article in The New Scientist [1] ). Recent SARS outbreaks have fuelled the desire for personal ionisers in the far east and in Japan everything from toothbrushes to fridges and washing machines have negative ions generators in them.