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Copyright Copernicus GmbH 2014

Abstract

The chemistry of the troposphere and specifically the global tropospheric ozone budget is affected by reactive halogen species such as bromine monoxide (BrO) or chlorine monoxide (ClO). Especially BrO plays an important role in the processes of ozone destruction, disturbance of NOx and HOx chemistry, oxidation of dimethyl sulfide (DMS), and the deposition of elementary mercury. In the troposphere BrO has been detected in polar regions, at salt lakes, in volcanic plumes, and in the marine boundary layer. For a better understanding of these processes, field measurements as well as reaction chamber studies are performed. In both cases instruments with high spatial resolution and high sensitivity are necessary. A Cavity-Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) instrument with an open path measurement cell was designed and applied. For the first time, a CE-DOAS instrument is presented using an UV LED in the 325-365 nm wavelength range. In laboratory studies, BrO as well as HONO, HCHO, O3 , and O4 could be reliably determined at detection limits of 20 ppt for BrO, 9.1 ppb for HCHO, 970 ppt for HONO, and 91 ppb for O3 , for five minutes integration time. The best detection limits were achieved for BrO (11 ppt), HCHO (5.1 ppb), HONO (490 ppt), and O3 (59 ppb) for integration times of 81 minutes or less. Comparison with established White system (WS) DOAS and O3 monitor measurements demonstrate the reliability of the instrument.

Details

Title
An instrument for measurements of BrO with LED-based Cavity-Enhanced Differential Optical Absorption Spectroscopy
Author
Hoch, D. J.; Buxmann, J.; Sihler, H.; Pöhler, D.; Zetzsch, C.; Platt, U.
First page
199
Publication year
2014
Publication date
2014
Publisher
Copernicus GmbH
ISSN
18671381
e-ISSN
18678548
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1495921001
Copyright
Copyright Copernicus GmbH 2014