The Indoor Air Quality model developed in this study involves the application of chemical engineering principles to the movement and potential control of volatile substances in buildings. The model incorporates the surface interactions of volatile organic compounds (VOCs) with interior materials. Sorption parameters estimated in a test chamber are then applied to an actual test house in Kuwait as an example building. Model parameters including source emission rates, removal rates by adsorption and surface emission rates by desorption, together with their relationships with air movement in the chamber, have been studied. Adsorption and desorption rate constants for four VOCs have been obtained using polyacrylonitrile, polyester and cotton textiles that are usually present in living room carpets, sofas and curtains of actual houses. The adsorption isotherms obtained by thermogravimetric analysis reveal that Henry's law can be used as an approximate isotherm for VOC concentrations in air below 1000 mg m(-3). The linear adsorption rate constants (based on bare fibre areas) for the tested fibre materials ranged from 0.02 to 7.3 m h(-1) and the linear desorption rate constants ranged from 0.001 to 17.8 h(-1). The model developed in this study predicts concentration profiles that fit very well with the concentrations measured in an actual test house located in Kuwait, providing good prediction of ways of improving air quality inside buildings in all locations.