Everything is constituted of atom, and atom is also constituted of many basic particles. Simply stated, the proton and the neutron compound the center of an atom (nucleus), and many particles with the minus electricity are around it outside. The minus electricity-charged particles are the main characters to the chemical reactions, and the sources of the electricity charged by the substance and the generation of electricity power, also the major force in the communication of the nutrition and excrement inside the biosphere. The minus electricity-charged particles are well-known “Electrons”.
Because of the balance between the electrons (negatively-charged) and protons (positively-charged), atoms are in the state of uncharged neutral. But when atom (or molecule) is in the affect of the energies like mechanism, light, electricity, chemical, it may lose or gain electron, hence will be positively or negatively charged. The positively-charged atom (molecule) is called the “Positive Ion”; and the negatively-charged atom (molecule) is called the “Negative Ion”.
In the aerosphere we are living, because of all the effect by natural phenomenon including Cosmic Ray, Ultraviolet Ray, Radioactive Substance, Thermal energy, Thunder, Lightning, Wind and Waterfall, the positive and negative ions will continuously being generated and disappeared, keep it in a lively balance state.
In the forest, mountain or waterfall, because of the high density of the negative ions, the air is pure and clean, and people will feel refreshing. On the other hand, in the crowded and heavy-polluted areas, the density of negative ions will be way down, and the unbalance between positive and negative ions will occur, causing uneasy feelings or even diseases.