A204-05
Composition and Properties of Indoor Organic Films: Cooking, Cleaning, and Long-term Aging.

Tuesday, 15 December 2020: 19:29
Virtual
Rachel E O'Brien1, Hannah Przelomski2, Ying Li3, Kristian Kiland4, Gloria Ge2, Julia Mesawich2, Allan K Bertram5 and Manabu Shiraiwa6, (1)College of William and Mary, Chemistry, Williamsburg, VA, United States, (2)College of William and Mary, Williamsburg, United States, (3)IAP Insititute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China, (4)University of British Columbia, Vancouver, Canada, (5)University of British Columbia, Department of Chemistry, Vancouver, BC, Canada, (6)Max-Planck-Institut für Chemie, Mainz, Germany
Recorded Presentation
Abstract:
Indoor areas have large surface area to volume ratios, increasing the importance of the material on surfaces for chemical reactions and partitioning of semi-volatile organic compounds (SVOCs). Many indoor surfaces become coated in an organic film which may play important roles in these processes. Previous work has investigated the composition of SVOCs in surface films, but less is known about lower volatility material that may be present and may act as a longer-term base coating. Current models are limited to using octanol as the organic film to estimate SVOC partitioning, but this may not accurately model the chemical and physical properties of these films. In addition, understanding the sources for lower volatility organic material in these films will improve our ability to model both partitioning and film growth in different indoor areas. Here, the chemical composition of lower volatility material found on surfaces in kitchens and living areas is characterized using both ultra-high resolution mass spectrometry (UHR-MS) and offline-Aerosol Mass Spectrometry (AMS). The average molecular weight for a film formed over three weeks in an actively used kitchen is large, around 900 Daltons, with an average carbon number of 50. The viscosity of this film is being measured and modeled to provide a better understanding of how chemical composition relates to physical properties in this type of indoor organic film. For regularly cleaned surfaces, the composition is very different and chemicals consistent with the lower volatility fraction of commercial cleaning products are observed. These chemical residuals remain on the surface after cleaning and may serve as a starting organic layer for SVOC film growth on cleaned indoor surfaces. Characterizing the chemical and the corresponding physical properties of organic films in different indoor environments is important to improving our ability to model how emitted SVOCs partition indoors.
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