Aircraft Measurements from a U.S. Western Wildfire Demonstrating Day and Night Differences in the Chemical Composition and Optical Properties of Biomass Burning Aerosols and Their Atmospheric Evolution

作者：Felipe Rivera-Adorno, Lisa Azzarello, Michael Robinson, Zachary C. J. Decker, R. A. Washenfelder, Katherine Hayden, Alessandro Franchin, Christopher D. Holmes, Cora J. Young, Carley D. Fredrickson, Brett B. Palm, C. C. Schmidt, A. J. Soja, Emily Gargulinski, Steven S. Brown, A. M. Middlebrook, Alexander Laskin · 发表于：ACS Earth and Space Chemistry · 年份：2024 · DOI：10.1021/acsearthspacechem.4c00215 · 被引用次数：7 · 研究领域：Atmospheric chemistry and aerosols、Atmospheric aerosols and clouds、Air Quality and Health Impacts

The composition and transformations of biomass burning aerosols (BBA) have been measured onboard the NOAA Twin Otter research aircraft during the Fire Influence on Regional to Global Environments and Air Quality field study. We analyze real-time aerosol mass spectrometry measurements across three flights during the afternoon, late afternoon, and night of August 28, 2019, for one midsized wildfire. Analysis of several metrics showed that the aerosol composition and optical properties varied depending on the burning conditions at the fire zone and the time of day the BBA was emitted, with substantial variations in the available sunlight. The total aerosol mass loadings were dominated by organic components with a much smaller contribution from inorganic species. A gradual buildup of organic material was observed during the afternoon as the plume aged, indicating the condensation of photochemically formed low-volatility oxidized organic compounds. Highly hygroscopic ammonium nitrate was the main inorganic component, suggesting potential water content in BBA particles and the likelihood of their aqueous-phase reactivity. Depletions of particle-phase NO 3 – and Cl – relative to carbon monoxide were observed in the late afternoon and nighttime plumes, respectively, aligning with known gas-particle partitioning thermodynamics and the heterogeneous chemistry of dissolved nitrate and chloride. The wavelength-dependent light absorption by aerosol species was higher for the plume sampled...