Discovered more than 100 years ago, Negative Air Ions, also known as NAIs, are created when a negatively charged electron attaches to an Oxygen molecule. Oxygen molecules in their natural state have no charge. When they join then, this creates a negatively charged oxygen molecule while the electron is attached. A microscopic film of water surrounding that Oxygen molecule will prevent the electron from leaving. This creates a permanently negative charged Oxygen molecule, that we call NAI.
NAIs help electrically charge up airborne particles with static causing them to become sticky to nearby surfaces. As they stick to walls or the ground, the particles are removed from the air and not inhaled into our lungs. Greater concentrations of NAIs are more effective in cleaning and refreshing air.