Highly oxygenated organic molecules (HOM) formation in the isoprene oxidation by NO3 radical
- 1Fudan University, Department of Atmospheric and Oceanic Science/Institute of Atmospheric Sciences, Shanghai, China (dfzhao@fudan.edu.cn)
- 2Institute of Energy and Climate Research, IEK-8: Troposphere, Forschungszentrum Jülich, 52425, Jülich, Germany
Highly oxygenated organic molecules (HOM) are found to play an important role in the formation and growth of secondary organic aerosol (SOA). SOA is an important type of aerosol with significant impact on air quality and climate. Compared to the oxidation of volatile organic compounds by O3 and OH, HOM formation in the oxidation by NO3 radical, an important oxidant at night-time and dawn, has received less attention. In this study, HOM formation in the reaction of isoprene with NO3 was investigated in the SAPHIR chamber (Simulation of Atmospheric PHotochemistry In a large Reaction chamber). A large number of HOM including monomers (C5), dimers (C10), and trimers (C15), both closed-shell compounds and open-shell peroxy radicals, were detected. HOM were classified into various series according to their formula, which included monomers containing one or more N atoms, dimers containing 1-4 N atoms, and trimers containing 3-5 N atoms. Tentative formation pathways of HOM were proposed reflecting known NO3 and RO2 chemistry in the literature under consideration of the autoxidation via peroxy pathways and peroxy-alkoxy pathways. Further mechanistic constraints were given by the time profiles of HOM after sequential isoprene addition which enabled to differentiate first- and second-generation products. Total HOM molar yield was estimated, which suggests that HOM may contribute a significant fraction to SOA yield in the reaction of isoprene with NO3.
How to cite: Zhao, D., Pullinen, I., Fuchs, H., Schrade, S., Wu, R., Acir, I.-H., Tillmann, R., Rohrer, F., Wildt, J., Guo, Y., Kiendler-Scharr, A., Wahner, A., Kang, S., Luc Vereecken, L., and Mentel, T.: Highly oxygenated organic molecules (HOM) formation in the isoprene oxidation by NO3 radical, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9652, https://doi.org/10.5194/egusphere-egu21-9652, 2021.