Offline Characterization of Smoke Aerosols Sampled in Western USA Using Size Exclusion Chromatography with Ultraviolet-Visible Detection and Ion Chromatography
Abstract
During the Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign in the of summer 2019, we sampled daytime and nighttime smoke plumes from wildfires in the western U.S using an instrumented Twin Otter aircraft. In existing literature, there remains uncertainty in the characterization of biomass-burning derived organics such as brown carbon. Brown carbon absorbs light in the ultraviolet to visible spectra region and is partially soluble in water; however, the composition and properties of the absorbing chromophores are not well known. We used an online Brown Carbon Particle into Liquid Sampler (BrC-PILS) to measure absorption at 315 - 500 nm and water-soluble organic carbon (WSOC), as well as to collect samples for offline analysis. Additionally, we used a Continuous Light Absorption Photometer (CLAP) to measure the light absorption of particles and collect filter samples for offline analysis. We analyzed the water samples and filter extracts using Size Exclusion Chromatography coupled to a diode array detector (SEC-UV). The SEC-UV analysis provides information regarding the optical properties of brown carbon by separating the absorbing species as a function of molecular weight. We also analyzed samples using Ion Chromatography with suppressed conductivity detection (IC-CD). This analysis allows for the quantification of major ions (e.g. NH4+, Cl-, PO43-) and alkylamines, which may be important to the formation and/or aging of brown carbon. We report measurements and trends that provide insight on daytime and nighttime plume aging in downwind transects.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMA223.0013A
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0325 Evolution of the atmosphere;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 0368 Troposphere: constituent transport and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTURE