Odor control using hollow fiber membrane modules has been investigated both theoretically, and experimentally. First, a mathematical model for the odor gas removal from gas streams in hollow fiber membrane modules was developed, with which the effects of the liquid flow rate and the reactant concentration in solution on the odor removal were studied As a result, a criterion to determine the optimum liquid flow rate and reactant concentration required for the odor removal was established. Second, experimental studies on the odor removal, that is, H2S removal from N-2 streams in PVDF hollow fiber membrane modules were carried out. The results indicate that H2S with low concentrations can be removed from gas streams effectively and economically, and a very high removal rate could be expected. All the experimental data can be estimated satisfactorily with the presented mathematical model. Finally, application of the hollow fiber membrane module fitted in air conditioners for the indoor air purification was explored and a quick graphic method for designing the membrane module was presented. (c) 2005 American Institute of Chemical Engineers.