Caution with spectroscopic NO<sub>2</sub> reference cells (cuvettes)
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Published:2019-11-29
Issue:12
Volume:12
Page:6259-6272
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ISSN:1867-8548
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Container-title:Atmospheric Measurement Techniques
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language:en
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Short-container-title:Atmos. Meas. Tech.
Author:
Platt Ulrich,Kuhn Jonas
Abstract
Abstract. Spectroscopic measurements of atmospheric trace gases, for example, by
differential optical absorption spectroscopy (DOAS), are frequently supported
by recording the trace-gas column density (CD) in absorption cells
(cuvettes), which are temporarily inserted into the light path. The idea is
to verify the proper functioning of the instruments, to check the spectral
registration (wavelength calibration and spectral resolution), and to
perform some kind of calibration (absolute determination of trace-gas CDs).
In addition, trace-gas absorption cells are a central component in gas
correlation spectroscopy instruments. In principle DOAS applications do not
require absorption-cell calibration; however, in practice, measurements with
absorption cells in the spectrometer's light path are frequently performed. Since NO2 is a particularly popular molecule to be studied by DOAS, and
at the same time it can be unstable in cells, we chose it as an example to
demonstrate that the effective CD seen by the instrument can deviate greatly
(by orders of magnitude) from expected values. Analytical calculations and
kinetic model studies show the dominating influence of photolysis and
dimerization of NO2. In particular, this means that the partial
pressure of NO2 in the cell matters. However, problems can be
particularly severe at high NO2 pressures (around 105 Pa) as well as
low NO2 partial pressures (of the order of a few 100 Pa). Also, it can
be of importance whether the cell contains pure NO2 or is topped up
with air or oxygen (O2). Some suggestions to improve the situation are
discussed.
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference22 articles.
1. Alicke, B., Platt, U., and Stutz, J.: Impact of nitrous acid photolysis on
the total hydroxyl radical budget during the Limitation of Oxidant
Production/Pianura Padana Produzione di Ozono study in Milan, J. Geophys.
Res., 107, 8196, https://doi.org/10.1029/2000JD000075, 2002. 2. Atkinson, R., Baulch, D. L., Cox, R. A., Crowley, J. N., Hampson, R. F., Hynes, R. G., Jenkin, M. E., Rossi, M. J., and Troe, J.: Evaluated kinetic and photochemical data for atmospheric chemistry: Volume I – gas phase reactions of Ox, HOx, NOx and SOx species, Atmos. Chem. Phys., 4, 1461–1738, https://doi.org/10.5194/acp-4-1461-2004, 2004. 3. Bahe, F. and Schurath, U.: Measurement of O(1D) Formation by Ozone
Photolysis in the Troposphere, Pure Appl. Geophys., 116, 537–544, 1978. 4. Bahe, F. C., Marx, W. N., Schurath, U., and Röth, E. P.: Determination of the
absolute photolysis rate of ozone by sunlight O3+hν→O(1D)+O2(1Δg) at ground level, Atmos.
Environ., 13, 1515–1522, 1979. 5. Bronstein, I. N., Mühlig, H., Musiol, G., and Semendjajew, K. A.: Taschenbuch
der Mathematik (Bronstein), Verlag Europa-Lehrmittel, Nourney,
Vollmer GmbH & Co. KG, Haan-Gruiten, Germany, 2013.
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