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| Titel |
Comparison of N2O5 mixing ratios during NO3Comp 2007 in SAPHIR |
| VerfasserIn |
H. Fuchs, W. R. Simpson, R. L. Apodaca, T. Brauers, R. C. Cohen, J. N. Crowley, H.-P. Dorn, W. P. Dubé, J. L. Fry, R. Häseler, Y. Kajii, A. Kiendler-Scharr, I. Labazan, J. Matsumoto, T. F. Mentel, Y. Nakashima, F. Rohrer, A. W. Rollins, G. Schuster, R. Tillmann, A. Wahner, P. J. Wooldridge, S. S. Brown |
| 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 ; 5, no. 11 ; Nr. 5, no. 11 (2012-11-16), S.2763-2777 |
| Datensatznummer |
250003174
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| Publikation (Nr.) |
 copernicus.org/amt-5-2763-2012.pdf |
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| Zusammenfassung |
| N2O5 detection in the atmosphere has been accomplished using
techniques which have been developed during the last decade. Most techniques
use a heated inlet to thermally decompose N2O5 to NO3, which
can be detected by either cavity based absorption at 662 nm or by
laser-induced fluorescence. In summer 2007, a large set of instruments, which
were capable of measuring NO3 mixing ratios, were simultaneously
deployed in the atmosphere simulation chamber SAPHIR in Jülich, Germany.
Some of these instruments measured N2O5 mixing ratios either
simultaneously or alternatively. Experiments focused on the investigation of
potential interferences from, e.g., water vapour or aerosol and on the
investigation of the oxidation of biogenic volatile organic compounds by
NO3. The comparison of N2O5 mixing ratios shows an excellent
agreement between measurements of instruments applying different techniques
(3 cavity ring-down (CRDS) instruments, 2 laser-induced fluorescence (LIF)
instruments). Datasets are highly correlated as indicated by the square of
the linear correlation coefficients, R2, which values were larger than
0.96 for the entire datasets. N2O5 mixing ratios well agree within
the combined accuracy of measurements. Slopes of the linear regression range
between 0.87 and 1.26 and intercepts are negligible. The most critical aspect
of N2O5 measurements by cavity ring-down instruments is the
determination of the inlet and filter transmission efficiency. Measurements
here show that the N2O5 inlet transmission efficiency can decrease
in the presence of high aerosol loads, and that frequent filter/inlet
changing is necessary to quantitatively sample N2O5 in some
environments. The analysis of data also demonstrates that a general
correction for degrading filter transmission is not applicable for all
conditions encountered during this campaign. Besides the effect of a gradual
degradation of the inlet transmission efficiency aerosol exposure, no other
interference for N2O5 measurements is found. |
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