Abstract View
Chemical Imaging of Atmospheric Biomass Burning Particles from North American Wildfires
FELIPE RIVERA-ADORNO, Jay Tomlin, Kevin Jankowski, Rebecca Washenfelder, Ann M. Middlebrook, Swarup China, Daniel Knopf, Ryan Moffet, Lisa Azzarello, Alessandro Franchin, Alexander Laskin, Purdue University
Abstract Number: 295
Working Group: Carbonaceous Aerosol
Abstract
Smoke emissions impact atmospheric chemistry, visibility, human health, and climate. Specific effects of biomass burning aerosols (BBA), such as radiative forcing alterations and cloud formation propensity are highly influenced by variability in the chemical composition and internal structures of individual particles within smoke plumes. To improve our understanding of the chemical and physical properties of BBA and how these change during atmospheric aging, samples were collected onboard NOAA research aircraft during the 2019 FIREX-AQ field study. A time-resolved aerosol collector was used to collect BBA particles for later chemical imaging of ambient particles. We use synchrotron-based soft X-ray spectro-microscopy to visualize particles and their internal components. This provides advanced chemical speciation and mapping of carbon, allowing us to distinguish between organic carbon and elemental carbon (soot). Electron microscopy and elemental microanalysis, on the other hand, provides information on the size and morphology of particles by providing high resolution images and elemental composition on a particle-by-particle basis. Our results suggested notable differences in the internal and external mixing of particles collected during daytime and nighttime. While daytime-collected samples were dominated by organic carbon, nighttime samples were notably rich with inorganic material. Microscopy images showed that there are also differences between the morphology and consistency of daytime and nighttime-collected particles. Daytime particles were seen to be of spherical shape consistent with viscous or “glassy” composition. In contrast, nighttime particles appear to be of a more liquid consistency and had internal arrangements of inorganic cores with organic coatings. Ongoing work involves the correlation of our data with real-time records from co-deployed instruments that measured concentrations of trace gases, aerosol mass concentrations and optical properties.