The total stratospheric organic chlorine and bromine burden was derived from balloon-borne measure- ments in the tropics (Teresina, Brazil, 5◦04? S, 42◦52? W) in 2005. Whole air samples were collected cryogenically at altitudes between 15 and 34 km. For the first time, we report measurements of a set of 28 chlorinated and bromi- nated substances in the tropical upper troposphere and strato- sphere including ten substances with an atmospheric lifetime of less than half a year. The substances were quantified using pre-concentration techniques followed by Gas Chro- matography with Mass Spectrometric detection. In the trop- ical tropopause layer at altitudes between 15 and 17km we found 1.1–1.4% of the chlorine and 6–8% of the bromine to be present in the form of very short-lived organic com- pounds. By combining the data with tropospheric reference data and age of air observations the abundances of inorganic chlorine and bromine (Cly and Bry) were derived. At an al- titude of 34km we calculated 3062 ppt of Cly and 17.5 ppt of Bry from the decomposition of both long- and short-lived organic source gases. Furthermore we present indications for the presence of additional organic brominated substances in the tropical upper troposphere and stratosphere.
Laube, J. C., Engel, A., Bönisch, H., Möbius, T., Worton, D. R., Sturges, W. T., … Schmidt, U. (2008). Contribution of very short-lived organic substances to stratospheric chlorine and bromine in the tropics ĝ€" a case study. Atmospheric Chemistry and Physics, 8(23), 7325–7334. https://doi.org/10.5194/acp-8-7325-2008