AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Methods for the Quantification and Identification of Alkenes on Indoor Surfaces
BENJAMIN DEMING, Paul Ziemann, University of Colorado
Abstract Number: 716 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract The deposition and accumulation of aerosols and gases to surfaces can lead to the formation of surface films. These films are believed to be ubiquitous indoors, where they can act as sinks for semi-volatile organic compounds (SVOCs), reactors for condensed-phase reactions, sites of heterogeneous gas-condensed-phase reactions, and exposure routes for human health impacts. The majority of studies investigating these films have been performed on impermeable surfaces, typically window glass. Painted surfaces, which tend to dominate by surface area, potentially differ from glass in several important ways, and are therefore an understudied aspect of indoor environments. The presence of unsaturated compounds within these films can result in secondary emissions from surfaces through ozonolysis reactions. To explore these areas of interest we characterized a method for quantitatively sampling the low-volatility, organic portion of a surface film using a surface wipe and developed a spectrophotometric method for quantifying nanomole quantities of alkenes. Samples were also derivatized, adding a readily ionizable group to non-conjugated double bonds, allowing for identification by positive-mode ESI-MS. Samples from neighboring glass and painted surfaces were collected from a variety of locations, including a classroom, graduate student offices, a bowling alley, a gym, and more. Filter and surface samples taken concurrently allowed the ambient aerosol to be compared with nearby surface films. To investigate the effect of cooking on nearby surface concentrations we pan-fried three different cooking oils at high temperatures and analyzed the double bond content of the raw oil, cooked oil, and nearby surfaces. Samples taken during the indoor air field studies HOMEChem and ATHLETIC were also analyzed. The results from this work should be useful to the modeling of indoor environments and help assess the importance of surfaces to indoor chemistry.