New indoor carpet as an adsorptive reservoir for volatile organic compounds

Carpet is generally recognized as a source of volatile organic compounds (V OCs) in indoor air. However, carpet systems can also serve as adsorptive si nks with the potential for reductions in peak VOC concentrations and subseq uent re-emission of VOCs over prolonged periods of time. A series of experi ments involving eight VOCs, several carpet systems, and environmental condi tions were completed using a set of parallel chambers to characterize the s orptive interaction between VOCs and carpet. A linear adsorption/desorption model was observed to be appropriate for short-term sorption events. New c arpet fibers treated with stain protection generally accounted for only a s mall fraction of mass sorbed to carpet. Most of the sorbed mass was account ed for by either the underlying pad (cushion) or a combination of the pad a nd structural backing. Equilibrium partition coefficients were observed to be correlated to chemical vapor pressure and octanol-air partition coeffici ent. Variations in relative humidity (RH) had a significant effect on the d egree of sorption for a highly soluble VOC (2-propanol). However, RH had li ttle apparent effect on other VOCs. Inlet concentrations generally had litt le effect on sorption.