Atmos. Chem. Phys. Discuss., 4, 6149-6183, 2004
www.atmos-chem-phys-discuss.net/4/6149/2004/
doi:10.5194/acpd-4-6149-2004
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Measurements of total odd nitrogen (NOy) aboard MOZAIC in-service aircraft: instrument design, operation and performance
A. Volz-Thomas, M. Berg, T. Heil, N. Houben, A. Lerner, W. Petrick, D. Raak, and H.-W. Pätz
Institut für Chemie und Dynamik der Geosphäre II: Troposphäre, Forschungszentrum Jülich, Jülich, Germany

Abstract. A small system for the unattended measurement of total odd nitrogen (NOy, i.e., the sum of NO and its atmospheric oxidation products) aboard civil in-service aircraft in the framework of MOZAIC is described. The instrument employs the detection of NO by its chemiluminescence with O3 in combination with catalytic conversion of the other NOy compounds to NO at 300°C on a gold surface in the presence of H2. The instrument has a sensitivity of 0.4–7 cps/ppt and is designed for unattended operation during 1–2 service cycles of the aircraft (400–800 flight hours). The total weight is 50 kg, including calibration system, compressed gases, mounting, and safety measures. The layout and inlet configuration are governed by requirements due to the certification for passenger aircraft. Laboratory tests are described regarding the conversion efficiency for NO2 and HNO3 (both >98%). Interference by HCN and NH3 is 100% and <1%, respectively. The time response (90% time) of the instrument is <1 s for NO2 and 150 s for HNO3, the latter being caused by memory effects in the 80 cm long inlet line.

Citation: Volz-Thomas, A., Berg, M., Heil, T., Houben, N., Lerner, A., Petrick, W., Raak, D., and Pätz, H.-W.: Measurements of total odd nitrogen (NOy) aboard MOZAIC in-service aircraft: instrument design, operation and performance, Atmos. Chem. Phys. Discuss., 4, 6149-6183, doi:10.5194/acpd-4-6149-2004, 2004.
 
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