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Modification of a conventional photolytic converter for improving aircraft measurements of NO$_{2}$ via chemiluminescence

Nussbaumer, C. M.; Parchatka, U.; Tadic, I.; Bohn, B.; Marno, D.; Martinez, M.; Rohloff, R.; Harder, H.; Kluge, F.; Pfeilsticker, K.; Obersteiner, F.; Zöger, M.; Doerich, R.; Crowley, J. N.; Lelieveld, J.; Fischer, H.

Abstract:
Nitrogen oxides (NO$_{x}$≡NO+NO$_{2}$) are centrally involved in the photochemical processes taking place in the Earth's atmosphere. Measurements of NO$_{2}$, particularly in remote areas where concentrations are of the order of parts per trillion by volume (pptv), are still a challenge and subject to extensive research. In this study, we present NO$_{2}$ measurements via photolysis–chemiluminescence during the research aircraft campaign CAFE Africa (Chemistry of the Atmosphere – Field Experiment in Africa) 2018 around Cabo Verde and the results of laboratory experiments to characterize the photolytic converter used. We find the NO$_{2}$ reservoir species MPN (methyl peroxy nitrate) to produce the only relevant thermal interference in the converter under the operating conditions during CAFE Africa. We identify a memory effect within the conventional photolytic converter (type 1) associated with high NO concentrations and rapidly changing water vapor concentrations, accompanying changes in altitude during aircraft measurements, which is due to the porous structure of the converter material. As a result, NO$_{2}$ artifacts, which are amplified by low conversion efficiencies, and a varying instrumental background adversely affect the NO$_{2}$ measurements. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000139740
Veröffentlicht am 12.11.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Meteorologie und Klimaforschung - Atmosphärische Spurenstoffe und Fernerkundung (IMK-ASF)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1867-1381, 1867-8548
KITopen-ID: 1000139740
Erschienen in Atmospheric Measurement Techniques
Verlag Copernicus Publications
Band 14
Heft 10
Seiten 6759-6776
Nachgewiesen in Web of Science
Scopus
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