For each positive and negative ion, its life is short, usually only for tens of minutes. The amount of negative ions in the air is affected by the special conditions of the geographical conditions. Parks, suburbs, fields, beaches, lakes, waterfalls, and forests are more abundant. Therefore, when people enter these sites, they are fresh, comfortable and refreshed. Entering the noisy crowded crowd, or entering the air-conditioned room, makes people feel stuffy, poor breathing and so on. Generally speaking, people need about 13 billion negative ions per day, while our living room, office, environment and so on, can only provide about 1 - 2 billion. This huge contrast between supply and demand, often lead to pneumonia, tracheitis respiratory diseases. Negative air ions are often expelled from air conditioning systems for central heating and air conditioning. Synthetic fiber, carpet with positive charge, easy to absorb negative ions. Both steel and fiberboard absorb negative ions. The air anion can active oxygen reduction from atmospheric pollutants, nitrogen oxides and cigarettes produced (oxygen free radicals), reduce the damage of active oxygen on the human body; and a positively charged air dust without charge after deposition, thereby purifying air. Negative ions can not only contribute to the body of vitamin synthesis and storage, strengthen and activate the physiological activities of the human body, so it is also called "air vitamin", think of it like food like vitamins, has a very important effect on the human body and other biological life activities, such as after the thunderstorm, the increase of negative ions in air. People feel comfortable. While in the air conditioning room, because of the negative ions in the air after a series of air conditioning purification and ventilation pipe after long almost disappeared, in which people stay for a long time will feel chest tightness, dizziness, fatigue, decreased work efficiency and health status, known as the "air conditioning syndrome". In the medical field, anion is recognized as an effective means of killing bacteria and purifying the air. The mechanism is that the negative ions combine with bacteria to make the bacteria change in structure or transfer of energy, leading to bacterial death, and finally sink to the ground. Medical research shows that the negative particles in the air can increase the oxygen content in the blood, which is beneficial to the blood oxygen transportation, absorption and utilization. It can promote the metabolism of the human body, improve the immune capacity of the human body, enhance the muscle energy of the human body, and regulate the function balance of the body. According to the textual research, negative ions can inhibit, relieve and assist the treatment of more than 30 kinds of diseases in 7 systems of human body, especially the health care effect of human body.