Identifying Criegee intermediates as potential oxidants in the troposphere
Authors
Novelli, AnnaHens, Korbinian
Tatum-Ernest, Cheryl
Martinez, Monica
Noelscher, Anke C.
Sinha, Vinayak
Paasonen, Pauli
Petaja, Tuukka
Sipila, Mikko
Elste, Thomas
Plass-Dulmer, Christian
Phillips, Gavin J.
Kubistin, Dagmar
Williams, Jonathan
Vereecken, Luc
Lelieveld, Jos
Harder, Hartwig
Affiliation
Max Planck Institute for Chemistry, IEK-8 Forschungzentrum Juelich, University of Helsinki, University of Chester, Deutscher WetterdienstPublication Date
2015-10
Metadata
Show full item recordAbstract
Criegee intermediates (CI) are formed during the ozonolysis of unsaturated compounds and have been intensively studied in the last few years due to their possible role as oxidants in the troposphere. Stabilised CI (SCI) are now known to react very rapidly, k(298 K) = 10-12 to 10-10 cm3 molecule-1 s-1, with a large number of trace gases (SO2, NO2, organic acids, water dimers). Still, it remains challenging to assess their effective oxidative capacity, as CI chemistry is complex, spans a large range of rate coefficients for different SCI conformers reacting with water dimers and trace gases, and in addition no reliable measurement technique able to detect ambient SCI concentrations is currently available. In this study, we examine the extensive dataset from the HUMPPA-COPEC 2010 and the HOPE 2012 field campaigns, aided by literature data, to estimate the abundance of SCI in the lower troposphere. The budget of SCI is analyzed using four different approaches: 1) based on an observed yet unexplained H2SO4 production; 2) from the measured concentrations of unsaturated volatile organic compounds (VOC); 3) from OH reactivity measurements; 4) from the unexplained production rate of OH. A SCI concentration range between 5 x 103 and 2 x 106 molecule cm-3 is calculated for the two environments. The central weighted estimate of the SCI concentration over the boreal forest of ~ 5 x 104 molecules cm-3 implies a significant impact on the conversion of SO2 into H2SO4. In addition, we present measurements obtained using our inlet pre-injector laser-induced fluorescence assay by gas expansion technique (IPI-LIF-FAGE) for the above-mentioned campaigns. A recent laboratory study performed with the same instrumental setup showed that the IPI-LIF-FAGE system is sensitive to the detection of the OH formed from unimolecular decomposition of SCI. Building on these measurements, the background OH (OHbg) measured during the two field campaigns is investigated in comparison with many other trace gases to assess if the observations in controlled conditions are transferable to ambient conditions.Citation
Novelli, A., et al. (2015, December). Identifying Criegee intermediates as potential oxidants in the troposphere, Abstract A21B-0119. Poster session presented at 2015 Fall Meeting, AGU, San Francisco, CA.Publisher
American Geophysical UnionAdditional Links
https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/80255Type
PresentationLanguage
enDescription
Abstract and poster presented at the AGU Fall meeting, San Francisco 2015.ISSN
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