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| Titel |
Peroxy radical detection for airborne atmospheric measurements using absorption spectroscopy of NO2 |
| VerfasserIn |
M. Horstjann, M. D. Andres Hernández, V. Nenakhov, A. Chrobry, J. P. Burrows |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 5 ; Nr. 7, no. 5 (2014-05-13), S.1245-1257 |
| Datensatznummer |
250115755
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| Publikation (Nr.) |
 copernicus.org/amt-7-1245-2014.pdf |
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| Zusammenfassung |
| Development of an airborne instrument for the determination of peroxy
radicals (PeRCEAS – peroxy radical chemical enhancement and absorption
spectroscopy) is reported. Ambient peroxy radicals (HO2 and RO2, R
being an organic chain) are converted to NO2 in a reactor using a chain
reaction involving NO and CO. Provided that the amplification factor, called
effective chain length (eCL), is known, the concentration of NO2 can be
used as a proxy for the peroxy radical concentration in the sampled air. The
eCL depends on radical surface losses and must thus be determined
experimentally for each individual setup. NO2 is detected by
continuous-wave cavity ring-down spectroscopy (cw-CRDS) using an extended
cavity diode laser (ECDL) at 408.9 nm. Optical feedback from a V-shaped
resonator maximizes transmission and allows for a simple detector setup. CRDS
directly yields absorption coefficients, thus providing NO2
concentrations without additional calibration. The optimum 1σ
detection limit is 0.3 ppbv at an averaging time of 40 s and an inlet
pressure of 300 hPa. Effective chain lengths were determined for HO2
and CH3O2 at different inlet pressures. The 1σ detection
limit at an inlet pressure of 300 hPa for HO2 is 3 pptv for an
averaging time of 120 s. |
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