AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Using Aerosol Principles to Advance Exposure Science: Development of a Better Understanding of the Roles of Water and Water-Soluble Gases on Indoor Surface Chemistry and Indoor Air Composition
MARC WEBB, Sara Duncan, Liyong Cui, Joanna Atkin, Jason Surratt, Barbara Turpin, University of North Carolina at Chapel Hill
Abstract Number: 130 Working Group: Indoor Aerosols
Abstract Surfaces play an important role in indoor chemistry, where surface area-to-volume ratios are greater than 3 m2/m3, orders of magnitude greater than typical of ambient aerosols. Even though “dampness” is a substantial issue in buildings, little is known about the hygroscopicity and water content of indoor surfaces, the concentrations and composition of water-soluble gases, the effects of liquid water on indoor surface chemistry, and the subsequent effects of that chemistry on exposure. However, even a 5 nm water film on indoor surfaces (assuming 20 m2/m3 of surface in a 300-m3 home) will provide more than 1000 times the volume of liquid water as is found in aerosols outdoors. Since the resulting aqueous solutions will be highly concentrated, aqueous surface chemistry on authentic indoor surfaces may mimic aqueous aerosol chemistry.
In this work, we provide results to date and outline future plans to study the effects of RH on indoor surface chemistry, including controlled experiments with authentic indoor surfaces. A custom parallel plate flow reactor designed to hold soiled/oxidized indoor surface materials and a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) are used to measure reactive uptake of water-soluble organic compounds (e.g., hydroperoxides) and uptake of water at 5%, 50%, and 80% relative humidity (RH) on authentic surfaces. Changes in surface film functionality due to hydration, oxidation and reactive uptake are monitored in other experiments by Raman microscopy. Surface films will also be characterized by ultra-high resolution electrospray ionization QTOF-MS. This work is designed to provide quantitative constraints for indoor modeling that will ultimately improve our understanding of the impact of “dampness” on indoor exposures.