Chemical Composition of Gas-Phase Oxidation Products from Biogenic Sources in the Southeast US during SOAS
Abstract
Reduced species emitted to the atmosphere are chemically transformed by atmospheric oxidants. The measurement of the large number of resulting oxidized compounds is crucial to understand and quantify these transformation processes. We analyzed datasets from four high-resolution time-of-flight chemical ionization mass spectrometers (HRToF-CIMS) during the Southern Oxidant and Aerosol Study (SOAS) in June and July 2013 at the Alabama Supersite in the Southeast U.S. These datasets allow specification and quantification of the multiple gas-phase compounds produced by chemical oxidation. The mass spectrometers used different reagent ions, nitrate (NO3-), acetate (CH3COO-), and iodide (I-). In this study, we will present the chemical composition of isoprene and terpene oxidation products as measured by the different techniques. When comparing the concentration and composition at different conditions (e.g., time of day, NOx levels, aerosol loading, RH), differences in gas-phase composition provide indications of both the changes in chemical processing arising from the different conditions as well as different sensitivities of the reagent ions. We will discuss these differences in terms of bulk chemical parameters such as carbon oxidation state, carbon number and oxygen-to-carbon ratio.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A13A0159S
- Keywords:
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- 0315 ATMOSPHERIC COMPOSITION AND STRUCTURE Biosphere/atmosphere interactions;
- 0322 ATMOSPHERIC COMPOSITION AND STRUCTURE Constituent sources and sinks;
- 0365 ATMOSPHERIC COMPOSITION AND STRUCTURE Troposphere: composition and chemistry;
- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE Pollution: urban and regional