Heidelberg 2015 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 8: Accelerator Mass Spectrometry and Applications 1

MS 8.4: Talk

Wednesday, March 25, 2015, 15:30–15:45, PH/HS2

Offline and online radiocarbon measurements of carbonaceous aerosols — •Sönke Szidat, Konstantinos Agrios, and Gary A. Salazar — Universität Bern, Departement für Chemie und Biochemie & Oeschger-Zentrum für Klima- und Klimafolgenforschung, Bern, Schweiz

Atmospheric aerosols are of concern due to their impacts on human health and the global climate. Legislative measures of air quality improvement require a detailed knowledge of emission sources of the aerosols, which is still lacking. Radiocarbon analyses provide a large potential in this context, as they distinguish between fossil and non-fossil sources of carbonaceous aerosols. To fully exploit this potential, the aerosol fractions organic carbon (OC) and elemental carbon (EC) should be separated and measured with AMS individually, preferably from numerous aerosol filters. In order to fulfil this goal, we have investigated the separation of OC and EC with a commercial thermo-optical aerosol analyzer and offline radiocarbon determinations. Furthermore, we coupled this instrument to the gas ion source of the MICADAS in Bern with two different online approaches a) by trapping portions of the carbon dioxide that evolves from aerosol analyzer with a zeolite molecular sieve and b) by direct transfer of the gas into the ion source using a flow separator for real-time analysis. Here, we present the technical setups, strategies for semi-automated measurements and the validation of the methods with standards and ambient aerosol samples.