ROOOH: the missing piece of the puzzle for OH measurements in low NO environments

Show simple item record Fittschen, Christa Al Ajami, Mohamad Batut, Sebastien Ferracci, Valerio Archer-Nicholls, Scott Archibald, Alexander T. Schoemaecker, Coralie 2019-01-10T20:38:56Z 2019-01-10T20:38:56Z 2019-01-10
dc.identifier.citation Christa Fittschen, Mohamad Al Ajami, Sebastien Batut, et al., ROOOH: the missing piece of the puzzle for OH measurements in low NO environments. Atmospheric Chemistry and Physics, 2019 Volume 19, Issue 1, pp. 349-362 en_UK
dc.identifier.issn 1680-7316
dc.description.abstract Field campaigns have been carried out with the FAGE (fluorescence assay by gas expansion) technique in remote biogenic environments in the last decade to quantify the in situ concentrations of OH, the main oxidant in the atmosphere. These data have revealed concentrations of OH radicals up to a factor of 10 higher than predicted by models, whereby the disagreement increases with decreasing NO concentration. This was interpreted as a major lack in our understanding of the chemistry of biogenic VOCs (volatile organic compounds), particularly isoprene, which are dominant in remote pristine conditions. But interferences in these measurements of unknown origin have also been discovered for some FAGE instruments: using a pre-injector, all ambient OH is removed by fast reaction before entering the FAGE cell, and any remaining OH signal can be attributed to an interference. This technique is now systematically used for FAGE measurements, allowing the reliable quantification of ambient OH concentrations along with the signal due to interference OH. However, the disagreement between modelled and measured high OH concentrations of earlier field campaigns as well as the origin of the now-quantifiable background OH is still not understood. We present in this paper the compelling idea that this interference, and thus the disagreement between model and measurement in earlier field campaigns, might be at least partially due to the unexpected decomposition of a new class of molecule, ROOOH, within the FAGE instruments. This idea is based on experiments, obtained with the FAGE set-up of the University of Lille, and supported by a modelling study. Even though the occurrence of this interference will be highly dependent on the design and measurement conditions of different FAGE instruments, including ROOOH in atmospheric chemistry models might reflect a missing piece of the puzzle in our understanding of OH in clean atmospheres. en_UK
dc.language.iso en en_UK
dc.publisher European Geosciences Union (EGU) / Copernicus Publications en_UK
dc.rights Attribution 4.0 International *
dc.rights.uri *
dc.title ROOOH: the missing piece of the puzzle for OH measurements in low NO environments en_UK
dc.type Article en_UK

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