Quantifying the Sorptive Properties of Carpets with Regards to Indoor VOCs Through High-Resolution Chemical Ionization Mass Spectrometry

Abstract:

While carpet is the largest single component of the U.S. flooring industry, accounting for roughly half of all sales, interactions between carpets and volatile organic compounds (VOCs) found in indoor air are not well understood. Carpets are mostly made of synthetic polymers, with a heavy emphasis on nylon and polyester, and their twisted, looped fibers provide a large surface area and volume for absorption. Many studies have shown that carpets emit hundreds of compounds on their own, and that carpets take up ozone and emit harmful aldehydes in the process. Indeed persistent ‘new carpet smell’ is perhaps the simplest indicator that carpets impact indoor air quality. A recent study demonstrated the high sorptive capacity of paint with regards to VOCs, suggesting that paint can serve as a large reservoir of VOCs in buildings. Likewise, studies of tubing materials show that VOCs will readily partition in and out of polymers. We extend these studies by exposing raw carpet materials and authentic carpet samples to a series of homologous VOCs in a flow reactor, and employ a high-resolution Vocus PTR-TOF and CIMS to monitor the VOC concentrations in real time. Using the same absorptive partitioning models as the tubing and paint studies, we are able to quantify the sorptive capacity of each carpet material or sample. We have found that raw nylon and polyester uptake VOCs as much as FEP (fluorinated ethylene propylene) Teflon and PEEK (polyether ether ketone), and that carpet samples uptake even more. Using the derived sorbing capacities, we estimate the role of carpets in indoor air quality as reservoirs of VOCs.