... the filtration hole. Active carbon series product can adsorb various of venomous gas (formaldehyde, benzene, dimethylbenzene, ammonia, chlorine, carbon monoxide, ... method. 2. It belongs to physics adsorption, needn't energy sources, will not produce secondary pollution. 3. Besides the strong ... site, industrial estate and so on. 4. The position of placing it should not be too high. 5. When you ...