Ions in Nature
Ions are particles that are created whenever energy is moved in the atmosphere. Energy can be transferred through sources like thunderstorms, sunlight and radiation levels in soil. Positive ions are usually abundant in the atmosphere just before a thunderstorm, when the air is often humid and oppressive. According to The Ionizer website, this can lead to sensitivity in people who suffer from asthma and allergies. Negative ions, in contrast, are usually found in places people find relaxing and comforting, such as waterfalls and mountains.
Ions in Buildings
The interiors of buildings usually have very low levels of negative ions. This is because negative ions lose their energy once they combine with other contaminants in the air, which causes them to fall to the ground. Television screens and certain types of synthetic materials present in households also reduce levels of negative ions and can create substantial amounts of positive ions.
Standard air purifiers operate by extracting polluted air from the atmosphere. The corrupt air is then cleaned through a filter and sent back into the room. A standard purifier, however, cannot remove all the contaminants in the air. Each time the air particles pass through the purifier, they become cleaner, but contaminants are still present in the air the machine ejects. More expensive, powerful air purifiers can remove additional contaminants, but these machines can be very noisy and can use substantial amounts of energy. The purifier will also require regular cleaning as dust and debris can block up the filter and cause it to work less efficiently.
A room ionizer works by generating a cloud of negative ions, which move out into the room and bind with air pollution, caused by dust, smoke and pollen. These tiny air particles can aggravate existing allergies and lead to breathing difficulties. The negative ions bind with these particles by passing on their static charge. The particles then become heavier, causing them to drop to the ground or nearest surface. Once the particles fall, they can easily be swept up and removed from the atmosphere for good.
Corona Discharge Method
Most air ionizers use a method of delivery known as corona discharge to propel negative ions into the atmosphere. A single needle -- or, in some cases, multiple needles -- is charged with a high voltage current. The electrons created by the flow of electricity are then passed down the needle toward the tip. The electrons come closer together as they move, due to the tapered shape of the needle. Electrons naturally repel each other, so eventually they leap off the needle tip into the atmosphere, bind to air molecules and create negative ions.