EC-01. Determining and Modeling the Behavior of VOCs on Indoor Wood Surfaces

Abstract
Even though the average person spends nearly 90% of their lifetime indoors, we know very little about the chemical and physical processes of volatile organic compounds (VOCs) in indoor environments, where there are a variety of surfaces that VOCs can interact with. Without understanding how VOCs interact with individual surfaces, it is difficult to predict and model the behavior of molecules in a room that may have a dozen different surfaces, all with varying properties and compositions. By isolating the VOC behavior with individual surfaces, like wood, indoor models can be improved and give better insight into sources and sinks of VOCs. To understand these processes with wood surfaces, we have used an iodide chemical ionization mass spectrometer (I-CIMS) and an attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer in tandem with an iterative model to understand how carboxylic acids, prominent organic molecules found indoors, interact with a variety of wood species and varnishes. These experiments have shown that the behavior of indoor VOCs rely more on the identity of the varnish and less on the identity of the wood species. Shellac, an evaporative finish varnish, has little interaction with carboxylic acids and is a relatively small sink for VOCs. Lacquer, a widely used varnish, on the other hand, has a much higher absorptive capacity and is a significant VOC sink, absorbing and equilibrating with volatile carboxylic acids that contact the surface.