... the filtration hole. Active carbon series product can adsorb various of venomous gas (formaldehyde, benzene, dimethylbenzene, ammonia, chlorine, carbon monoxide, ... . 3. This product is not suitable to put in high density, big grain pollution area, such as building site, industrial estate ... and so on. 4. The position of placing it should not be too high. 5. When you ...