An investigation was carried out in the design of a CO2 cleaner system for removing excessive CO2 from indoor polluted air with a randomly packed column by using aqueous solutions of monoethanolamine (MEA) and diethanolamine (DEA). Experiments were conducted within an MEA concentration of 0.02-0.50 kmol/m(3) and a DEA concentration of 0.10-0.50 kmol/m(3) at 25 degreesC. The effective gas-liquid interfacial area a(v) of the packed column, which was determined by using dilute CO2 absorption into aqueous solutions of sodium hydroxide, was well corrected by an equation as a function of gas flow rate G. A theoretical model based on Danckwerts' theory of surface renewal was proposed. The investigation shows that MEA and DEA are both effective absorbents to remove excessive CO2 from indoor polluted air, while the former exceeds the latter in efficiency, and that both the concentration of alkanolamimes and the gas flow rate greatly affect the CO2 removal efficiency. Besides, with an increase of the concentration of alkanolamines and a decrease of the gas flow rate, the CO2 removal efficiency will be remarkably improved.