EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Nighttime to daytime transition of the oxidation products of isoprene by NO3 radicals

Epameinondas Tsiligiannis1, Rongrong Wu2,3, Sungah Kang2, Luisa Hantschke2, Joel Thornton4, Hendrik Fuchs2, Thomas Mentel2, and Mattias Hallquist1
Epameinondas Tsiligiannis et al.
  • 1Department of Chemistry & Molecular Biology, University of Gothenburg, Göteborg, Sweden
  • 2Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich GmbH, Jülich, Germany
  • 3College of Environmental Sciences and Engineering, Peking University, Beijing, China
  • 4Department of Atmospheric Sciences, University of Washington, Seattle, WA, USA

Biogenic volatile organic compounds (BVOC) dominate the overall VOC emissions. Isoprene is the most common BVOC emitted from vegetation, accounting up to 50% of the total BVOC emissions. Despite being emitted in daytime it can accumulate in the stratified nocturnal layer. Thus, the oxidation of isoprene by nitrate radicals (NO3) may be of high importance. A series of experiments were conducted in the atmospheric simulation chamber SAPHIR in Jülich, Germany, in order to investigate the gas and particle phase products of the oxidation of isoprene by NO3, under a variety of conditions (e.g. high RO2, high HO2, nighttime to daytime transition, with and without seed aerosol) using a wide range of instrumentation. However, herein the focus is on the results of gas-phase product characterisation using high resolution time of flight chemical ionization mass spectrometers (HR-ToF-CIMS) using iodide or bromide as the primary reagent ion. The use of two HR-ToF-CIMS with different primary reagents provides possibilities to scrutinise the time profiles of isomers of selected products.

We will discuss qualitatively and quantitatively how the distribution of oxidation products change under different conditions, with a focus on the nighttime daytime transition of the major products and the role of subsequent OH oxidation on the products initially formed by NO3 oxidation. Generally, the dominant gas phase products include compounds like nitrooxy hydroperoxide (INP) & dihydroxy nitrate (IDHN) (C5H9NO5), carbonyl nitrate (ICN) (C5H7NO5), hydroxy nitrate (IHN) (C5H9NO4), hydroxy hydroperoxy nitrate (IHPN) (C5H9NO6), as well as a C4 compound (C4H7NO5) among others.

How to cite: Tsiligiannis, E., Wu, R., Kang, S., Hantschke, L., Thornton, J., Fuchs, H., Mentel, T., and Hallquist, M.: Nighttime to daytime transition of the oxidation products of isoprene by NO3 radicals, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-961,, 2019


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