To ensure enough specific surface area (the proportion of volume to surface area) to be effective in micro- world, the diameter of TiO2 must be controlled under nanometer. According to the reports by Scientific American in 2002, the general crystallization of TiO2 is between 20~250nm, which is not effective. In fact, TiO2 will work only if its diameter is under 7nm. It is because in 3-D space, the smaller the particles’ diameters are, the closer they will line, and the increase of specific surface area will cause more sensitive reaction. The average diameter of TiO2 in ARC-FLASH Photocatalyst is under 7nm, which could result in a rather big specific surface area, and a high effectiveness per unit.