... , ultra-fine particle size, large anion release. Powders at roomtemperature for anion release 20000-30000 pcs/ cm3, with the negative ion ... per day required about 13 billion negative ions, and our room, offices, can only provide about 2000000000 anions, such a huge ... is a very useful and far-infrared radiation material, suitable for the body to absorb the best of the far-infrared ...