Negative ion LED night light lons are produced when electrons collide with molecules in the air. Those with negative charge are called negative ions.Our health is based on the air,and negative ions are callde"vitamin of the air"Negative ions are odorless, tasteless and invisible molecules. Although they exist everywhere in nature,we can not see them with our eyes. The photo-synthesis of plants and waterfalls produces a great amount of negative ions. That is why people feel refreshed during thundering wet weather, in the forest or under a waterfall.