How Ionisers Work

How an Ioniser Works

Negative ions can be be produced by copying any of the ways that Nature makes them – with ultra violet rays (by using UV lamps), from radioactive sources or using foaming water (in fact a bathroom shower provides a plentiful supply!) But in most cases it is either too dangerous, too expensive or just impractical for everyday purposes. For this reason most manufacturers use a method called “corona discharge” which is similar to lightning. A high voltage (but at extremely limited current, for safety) is applied to one or more sharp needles.

What we call electricity is a flow of individual “particles” called electrons. And it’s these eIectrons which are used to make negative ions. The ionisers’ internal circuit pushes the electricity (lots of electrons) down the needles towards their tip. The nearer they get to the point, the closer the electrons become sqeezed together. Electrons naturally repel each other so, as they reach the tip, the pressure between them builds up. When it becomes too much they’re “pushed off”, onto the nearest passing air molecule, turning it into a negative ion.

By carefully adjusting the voltage levels, the needle profile and the various materials used, this process can be made very efficient.

Out in the air, negative ions once again repel each other, so they are driven from the needles as a gentle breeze, then form a dense, invisible “cloud” in front of the ionizer, which spreads in all directions out into the room.

Air ions have two qualities:

  • They are beneficial to health by being inhaled and absorbed into the body. (oxygen ions in particular)
  • They are also very efficient air cleaners, particularly of the smaller-sized and more hazardous particles.

Ions leaving the ionizer are small, high velocity ones. These are found to be most beneficial to health. If they collide with particles of smoke or pollution near the ionizer, they pass on their “static” charge. This particle is then strongly attracted to the nearest “earthed” surface. (which could be a wall or the shelf on which the ionizer is placed – so make sure it is washable!) Out into the room the ions naturally begin to slow down. As they drift, pollutants such as dust, pollen, cigarette smoke and even vapourised substances like aerosol propellants and car fumes are attracted to and cluster around the ions. This has the effect of making the ion grow in size. There comes a point where it is too heavy to be carried in the air, so it falls to the ground. The ability of an ioniser to remove these very fine particles from the air makes it extremely valuable for health. Studies indicate that the smaller the particle, the harder it is for our immune systems to cope with.

So ionisers have a “double action” effect. They excel at removing microscopic particles – the most harmful – and at the same time they restore a “vitality” to the air – which our bodies appear to need for their everyday functioning.

A very important point to be aware of, is: A badly designed ioniser often produces ozone, and with it nitrous oxide. These are toxic substances and can cause respiratory difficulties and stinging eyes (often the very things they were purchased to alleviate). WHO (World Health Organization) guidelines, say that the maximum acceptable level of ozone is 0.1ppm (parts per million). So when purchasing, make sure it is from a reputable company. (We have tested some cheap models in the past, and they really are unpleasant to use).

Tests on our Astrid Ionisers have found “no detectable ozone”.