Modification of a conventional photolytic converter for improving aircraft measurements of NO2 via chemiluminescence
<p><strong class="journal-contentHeaderColor">Abstract.</strong> Nitrogen oxides (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath=&q...
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| Main Authors: | , , , , , , , , , , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
20 October 2021
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| In: |
Atmospheric measurement techniques
Year: 2021, Volume: 14, Issue: 10, Pages: 6759-6776 |
| ISSN: | 1867-8548 |
| DOI: | 10.5194/amt-14-6759-2021 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.5194/amt-14-6759-2021 Verlag, lizenzpflichtig, Volltext: https://amt.copernicus.org/articles/14/6759/2021/ 
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| Author Notes: | Clara M. Nussbaumer, Uwe Parchatka, Ivan Tadic, Birger Bohn, Daniel Marno, Monica Martinez, Roland Rohloff, Hartwig Harder, Flora Kluge, Klaus Pfeilsticker, Florian Obersteiner, Martin Zöger, Raphael Doerich, John N. Crowley, Jos Lelieveld, and Horst Fischer |
| Summary: | <p><strong class="journal-contentHeaderColor">Abstract.</strong> Nitrogen oxides (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mrow class="chem"><msub><mi mathvariant="normal">NO</mi><mi>x</mi></msub></mrow><mo>≡</mo><mrow class="chem"><mi mathvariant="normal">NO</mi></mrow><mo>+</mo><mrow class="chem"><msub><mi mathvariant="normal">NO</mi><mn mathvariant="normal">2</mn></msub></mrow></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="85pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="2f82bf52594ce7ed0138de6f6b27db69"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="amt-14-6759-2021-ie00001.svg" width="85pt" height="13pt" src="amt-14-6759-2021-ie00001.png"/></svg:svg></span></span>) are centrally involved in the photochemical processes taking place in the Earth's atmosphere. Measurements of <span class="inline-formula">NO<sub>2</sub></span>, 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 <span class="inline-formula">NO<sub>2</sub></span> 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 <span class="inline-formula">NO<sub>2</sub></span> 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, <span class="inline-formula">NO<sub>2</sub></span> artifacts, which are amplified by low conversion efficiencies, and a varying instrumental background adversely affect the <span class="inline-formula">NO<sub>2</sub></span> measurements. We test and characterize an alternative photolytic converter (type 2) made from quartz glass, which improves the reliability of <span class="inline-formula">NO<sub>2</sub></span> measurements in laboratory and field studies.</p> |
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| Item Description: | Im Titel ist "2" nach "NO" tiefgestellt Gesehen am 04.02.2022 |
| Physical Description: | Online Resource |
| ISSN: | 1867-8548 |
| DOI: | 10.5194/amt-14-6759-2021 |