Nowadays, with the development of people's health and environmental awareness, the air anion has been used as an important standard for air quality and environment evaluation.People will feel relaxed and happy when they are in the environment of waterfalls, sea or forest. There is a very important reason is that the air is rich in anions.
Anion fiber is a functional fiber which can release negative ions, and it has important applications in the field of environmental protection and health care. In the 21st century,the anion textile has been arouse more attention, and its market develop prospects are very broad .
In the natural state, each molecule was tested neutral overall. But under the sufficient energy radiation effect of ultraviolet light, cosmic rays, lightning, and other trace elements, the air molecules will lose part of the electrons rotating around the nucleus. The escaped electrons were called free electron with a negative charge. After the atomic losing or gaining electrons, it will form charged particles which were called ions. It will form air negative ions after the escaping free electrons combine with other neutral gas molecules. These molecules which were missed an electron with a positive charge, and we call it a positive ion or cation.
As the ions have short life in the air, there have been ions were balanced out, and continue to have new ions. Therefore,the concentration of positive and negative ions in the air constantly changing, maintaining a dynamic balance. As shown in Figure l is the structure of water anion [H30+(H20)7-]in the air.
Positive and negative ions in the air were divided into large, medium and small ions in accordance with the size of the mobility. The small particle of the negative oxygen ions have good biological activity, and they can get through the blood brain barrier into the body exerting their biological effects. According to the US EPA measurement laboratory,the smaller the particle size, the higher the activity, and the more natural diffusion distance away.