Abstract: The invention relates to a light-pipe system for conducting/distributing light and air, which can also purify indoor air, particularly in a building, or the like. The light-pipe system includes a light-pipe for conducting light and having a clear top dome mounted at the top of the light-pipe to let in sunlight but keep out dust, rain and UV. An emitter fitted to the bottom of light-pipe improves the light distribution into the room, and a ventilation stack laid around the light-pipe coaxially/or non-coaxially, and a photocatalyst film (e.g. Nanometer TiO2) coated on the outer surface of the emitter for purifying indoor air under the illumination of light from light-pipe. The air and light are conducted separately along two different transport paths. The light-pipe system can provide illumination, ventilation and air purification simultaneously. The light source may be daylight, artificial light, light storage material or a mixture of them. Air can be moved naturally and/or is transported mechanically.