Abstract View
Measuring and Modeling the Behavior of VOCs on Indoor Wood Surfaces
ANNA ZIOLA, Paul Ziemann, University of Colorado Boulder
Abstract Number: 364
Working Group: Indoor Aerosols
Abstract
The average person spends nearly 90% of their lifetime indoors, but we know very little about the chemical and physical processes that impact volatile organic compounds (VOCs) in indoor environments. Perhaps most importantly, we do not fully understand how VOCs interact with surfaces indoors. This makes it difficult to predict and model the behavior of VOCs in rooms with a variety of surfaces, all with different properties and compositions. By measuring the interactions of VOCs with individual surfaces, data can be obtained for improving indoor models and for gaining insight into where VOCs are coming from and going. To study VOC interactions with wood surfaces specifically, we have conducted experiments in which air containing selected VOCs was flown through an uncoated or varnish-coated (umbrella term for any wood coating) wood tube, creating a chromatography-like apparatus where VOCs interact with and equilibrate with the tube surface before they are detected with an iodide chemical ionization mass spectrometer. We then calculated surface absorptive capacities and diffusion coefficients using a model to fit the VOC time profiles. An attenuated total reflectance-Fourier transform infrared spectrometer was also used to measure diffusion coefficients for VOCs in thin varnish films. These experiments have shown that the behavior of VOCs indoors relies less on the identity of the wood and more on the identity of the varnish. Shellac, one of the varnishes studied, has little interaction with carboxylic acid VOCs and is a relatively small VOC sink. Conversely, lacquer, a widely used varnish, has a much higher absorptive capacity than shellac and absorbs a relatively large fraction of the VOCs that contact the surface. The absorptive capacities and diffusion coefficients measured in these experiments can be incorporated into larger indoor air models to predict the fate and behavior of VOCs in various indoor spaces.