Effect of polyoxymethylene (POM-H Delrin) off-gassing within the Pandora head sensor on direct-sun and multi-axis formaldehyde column measurements in 2016–2019

• Published in: Atmospheric measurement techniques Vol. 14; no. 1; pp. 647 - 663
• Main Authors: Spinei, Elena, Tiefengraber, Martin, Müller, Moritz, Gebetsberger, Manuel, Cede, Alexander, Valin, Luke, Szykman, James, Whitehill, Andrew, Kotsakis, Alexander, Santos, Fernando, Abbuhasan, Nader, Zhao, Xiaoyi, Fioletov, Vitali, Lee, Sum Chi, Swap, Robert
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 28.01.2021; Copernicus Publications
• Subjects: Absorption; Air pollution; Analysis; Attenuation; Cooling rate; Damping; Delrin (trademark); Emissions; Exponential functions; Field study; Formaldehyde; Head; Heating and cooling; Laboratories; Sensors; Software; Telescopes; Temperature; Temperature dependence; Zenith; United States > US
• ISSN: 1867-8548; 1867-1381; 1867-8548
• DOI: 10.5194/amt-14-647-2021

Analysis of formaldehyde measurements by the Pandora spectrometer systems between 2016 and 2019 suggested that there was a temperature-dependent process inside the Pandora head sensor that emitted formaldehyde. Some parts in the head sensor were manufactured from the thermal plastic polyoxymethylene homopolymer (E.I. Du Pont de Nemour & Co., USA; POM-H Delrin.sup.®) and were responsible for formaldehyde production. Laboratory analysis of the four Pandora head sensors showed that internal formaldehyde production had exponential temperature dependence with a damping coefficient of 0.0911±0.0024 .sup." C.sup.-1 and the exponential function amplitude ranging from 0.0041 to 0.049 DU. No apparent dependency on the head sensor age and heating and cooling rates was detected.