Darmstadt 2008 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 1: Atmosphäre und Klima

UP 1.1: Vortrag

Dienstag, 11. März 2008, 08:30–08:45, 3B

First atmospheric observations of C2F3Cl and C3F5Cl by means of GC/ECD/MS — •Johannes Laube, Anja Werner, and Andreas Engel — Institut für Atmosphäre und Umwelt, Universität Frankfurt, Frankfurt (Main), Deutschland

We report the first atmospheric observations of the Chlorofluorocarbons (CFCs) Trifluorochloroethene and 3-Chloropentafluoropropene in air samples taken at the Taunus Observatory near Frankfurt (Main). Both substances belong to a class of CFCs containing a double bond and are connected to the preparation and thermal degradation of Polychlortrifluoroethene (PCTFE), a widely used Fluoropolymer. Their atmospheric lifetimes are expected to be rather short. To analyse the air samples trace gases were pre-concentrated cryogenically, separated by Gas Chromatography and identified using an Electron Capture detector and a quadrupole Mass Spectrometer run in electron impact mode. A quantitative calibration is not available for these species, yet. The first identification was possible because of an air sample which showed high concentrations of these substances. We suggest that the very high abundances found on this occasion originated from a local source. However, we also observed the novel CFCs in air masses representing back ground conditions, though with much lower concentrations. These species are toxic and could also contribute to stratospheric chlorine which is relevant for ozone depletion. Therefore it is important to find out more about their sources and distribution in the atmosphere.