Sorbent tube sampling and an Automated Thermal Desorption system for halocarbon analysis

Development and deployment of the analytical system, ATD-GC-ECD has been established to monitor a suite of halogenated compounds found in the atmosphere at trace concentrations. The instrument has been used to monitor urban background emission flux levels in Bristol, UK as well as Yellowstone National Park, USA and an indoor rainforest (Wild Walk-Bristol, UK). The newly established sorbent tube sampling system is small and easily portable and has been used for large volume sample collection from remote areas. Automated Thermal Desorption (ATD) provides routine atmospheric measurements without cryogenic pre-concentration. The instrument provides good precision where the detection limit was < 3 pptv for the species of interest and the reproducibility was within 4% for all of the selected halocarbons. The results from two field experiments have also provided insight about natural missing sources of some ozone depleting halocarbons.