AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Observations of Semi-volatile Siloxane Partitioning to Airborne Particles during Oven Use at Homechem
ERIN KATZ, David Lunderberg, William Nazaroff, Allen Goldstein, Peter DeCarlo, Drexel University
Abstract Number: 713 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract Aerosol composition measurements during a recent field campaign entitled “HOMEChem” (House Observations of Microbial and Environmental Chemistry) investigated the impact of human activities on indoor chemistry. Throughout the campaign, events simulated everyday activities such as stir frying, oven use, and bleach mopping. Numerous in-situ gas and aerosol phase instruments were deployed to analyze indoor and outdoor air during this campaign. Here, we present results from a high-resolution aerosol mass spectrometer (HR-AMS) and a thermal desorption aerosol gas chromatograph (SV-TAG). We focus on observations of high levels of siloxane mass in the particle phase during oven use at HOMEChem. Polysiloxanes, also termed silicone, consist of a linear or cyclic variable-length polymer with an [R2-SiO] monomer unit and R typically as a methyl or ethyl group. These polymers are widely used in consumer products and are also often found in building materials such as sealants and coatings. During HOMEChem oven use events, siloxane mass measured by the HR-AMS trended linearly with total aerosol mass concentration, comprising a surprisingly high 5-20% of the total. We also found that this fraction was related to the oven surface temperature. During periods when siloxane concentration was elevated, HR-AMS size distributions indicated that siloxane species matched the bulk organics size distribution characteristics. SV-TAG chromatograms acquired during oven use events provide additional insight into the types of molecules emitted and partitioned to particles; multiple lower volatility polysiloxane species were identified corresponding with oven usage. We infer that during oven use, heating of silicone/polysiloxane containing materials in and near the oven led to volatilization of these siloxane species with subsequent partitioning to indoor airborne particles.