... carbon, photocatalyst, cold catalyst, nano silver to make HEPA filters. It has the function to purify and absorb the odor ... toxic, harmless, no sensitive reaction. Application:1). Central air conditioner, air HFPA purifier, air cleaner, auto cabin, Fragrance machine etc.2). Medical ... particles with size over 0.3um, which is the ideal air filters. The materials of HEPA can be classified five types: ...