New indoor carpet as an adsorptive reservoir for volatile organic compounds

Carpet is generally recognized as a source of volatile organic compounds (VOCs) in indoor air. However, carpet systems can also serve as adsorptive sinks with the potential for reductions in peak VOC concentrations and subsequent re-emission of VOCs over prolonged periods of time. A series of experiments involving eight VOCs, several carpet systems, and environmental conditions were completed using a set of parallel chambers to characterize the sorptive interaction between VOCs and carpet. A linear adsorption/desorption model was observed to be appropriate for short-term sorption events. New carpet fibers treated with stain protection generally accounted for only a small fraction of mass sorbed to carpet. Most of the sorbed mass was accounted for by either the underlying pad (cushion) or a combination of the pad and structural backing. Equilibrium partition coefficients were observed to be correlated to chemical vapor pressure and octanol-air partition coefficient. Variations in relative humidity (RH) had a significant effect on the degree of sorption for a highly soluble VOC (2-propanol). However, RH had little apparent effect on other VOCs. Inlet concentrations generally had little effect on sorption.