AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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An Overview of Aerosol Sources and Chemistry from the Homechem Field Campaign
ERIN KATZ, Peter DeCarlo, Atila Novoselac, Jose-Luis Jimenez, Wyatt Brown, Rachel O'Brien, Delphine K. Farmer, Marina Vance, Drexel University
Abstract Number: 727 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract This presentation will focus on aerosol composition measurements made by an online high-resolution aerosol mass spectrometer (HR-AMS) from a recent indoor field measurement campaign called “HOMEChem” (House Observations of Microbial and Environmental Chemistry). This study brought together a myriad of state-of-the-art analytical techniques to measure outdoor air, indoor air, and interactions between the two and with building materials. Additionally, the effect of everyday activities on indoor chemistry was investigated by performing planned perturbations to indoor air quality such as cooking, cleaning, and occupancy experiments.
We present an overview of HR-AMS data from HOMEChem beginning with baseline unoccupied periods and moving to cooking events where aerosol concentrations exceeded outdoors by ~10 times or more. In the absence of cooking activity, we find that aerosol concentrations are lower indoors than outdoors. We describe transformations of aerosols from outdoors to indoors by normalizing to the indoor-to-outdoor ratio of sulfate and find that semi-volatile partitioning from surfaces contributes additional organic mass to aerosols. We link this additional organic mass to surface samples collected during the campaign. On-line analysis of cooking aerosol during stir frying indicates that the mass spectral signature of stir fry cooking aerosol is highly correlated with the mass spectra of cooking oil, suggesting oil comprises a dominant fraction of the stir fry aerosol. We also present evidence of a source-dependent ionization efficiency for organic aerosols emitted during cooking. Finally, we describe the complex chemical composition and dynamic behavior of inorganics and organics measured in the particle phase during preparation of Thanksgiving Dinner. Notably, increases in sulfate and nitrate were observed during this event. We anticipate that the results of this study will influence how we view and control our indoor spaces to reduce exposure to indoor air pollution.