edu.ucar.opensky::articles:22702 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:31:28.772049 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7cz39zm Emission and evolution of submicron organic aerosol in smoke from wildfires in the western United States 2019-07-01T00:00:00Z publication https://n2t.org/ark:/85065/d7cz39zm https://doi.org/10.1021/acsearthspacechem.9b00125 Garofalo, L. A. author Pothier, M. A. author Levin, E. J. T. author Campos, Teresa author Kreidenweis, S. M. author Farmer, D. K. author UCAR/NCAR - Library publisher Despite increasing incidence of wildfires in the United States, wildfire smoke is poorly characterized, with little known about particle composition and emission rates. Chemistry in transported plumes confounds interpretation of ground and aircraft data, but near-field observations can potentially disentangle the effects of oxidation and dilution on aerosol mass and chemical composition. We report the organic aerosol (OA) emission ratios from aircraft observations near the fire source for the 20 wildfires sampled during the Western Wildfire Experiment: Cloud Chemistry, Aerosol Absorption, and Nitrogen (WE-CAN) study of summer 2018. We observe no changes in submicron nonrefractory OA mass concentration, relative to CO which accounts for simple dilution, between 0.5 and up to 8 h of aging. However, static OA excess mixing ratios hide shifts in the aerosol chemical composition that suggest near-balanced, simultaneous oxidation-driven condensation and dilution-driven evaporation. Specifically, we observe significant increases in the extent of oxidation, evident by an increase in oxidation marker f44 and loss of the biomass burning marker f60, as the smoke ages through chemistry and dilution. We discuss the competing effects of oxidative chemistry and dilution-driven evaporation on the evolution of the chemical composition of aerosols in wildfire smoke over time. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2019 American Chemical Society. None eng geoscientificInformation