https://doi.org/10.5194/acp-2020-910 Preprint. Discussion started: 23 September 2020 c Author(s) 2020. CC BY 4.0 License. Chemical Composition of PM2.5 in October 2017 Northern California Wildfire Plumes Yutong Liang1, Coty N. Jen1,2, Robert J. Weber1, Pawel K. Misztal1,3, Allen H. Goldstein1,4 1Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, 94720, 5 USA 2Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA 3Department of Civil, Architectural and Environmental Engineering, University of Texas at Austin, Austin, TX 78712, USA 4Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, USA 10 Correspondence to: Yutong Liang (
[email protected]) Abstract. Wildfires have become more common and intense in the western US over recent decades due to a combination of historical land management and warming climate. Emissions from large scale fires now frequently affect populated regions such as the San Francisco Bay Area during the fall wildfire season, with documented impacts of the resulting particulate 15 matter on human health. Health impacts of exposure to wildfire emissions depend on the chemical composition of particulate matter, but the molecular composition of the real biomass burning organic aerosol (BBOA) that reaches large population centers remains insufficiently characterized. We took PM2.5 (particles having aerodynamic diameters less than or equal to 2.5 μm) samples at the University of California, Berkeley campus (~60 km downwind of the fires) during the October 2017 Northern California wildfires period, and analyzed molecular composition of OA using a two-dimensional gas- 20 chromatography coupled with high resolution time-of-flight mass spectrometer (GC×GC ToFMS).