- 1Max Planck Institute for Chemistry, Mainz, Germany
- 2Institute for Atmospheric and Environmental Sciences, Goethe University Frankfurt, Frankfurt, Germany
- 3Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland
- 4Institute for Ion Physics and Applied Physics, University of Innsbruck, Innsbruck, Austria
- 5CERN, the European Organization for Nuclear Research, Geneva, Switzerland
- 6Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
Isoprene, the most abundantly volatile organic compound (VOC), plays a significant role in atmospheric chemistry, particularly in the upper troposphere. In the tropics, it is emitted in large quantities by rainforests. Driven by prevailing high solar radiation, temperature, and humidity, Isoprene rich air is transported from the boundary layer to the upper troposphere by deep convective systems. Without nighttime photo-oxidation, isoprene can accumulate in this region, where it reacts with hydroxyl radicals during the day, contributing to aerosol formation (Shen et al, 2024, Curtius et al., 2024). This study explores the oxidation processes of isoprene at low temperatures (-50°C), typical of the upper troposphere, with a focus on the effects of varying NOx concentrations (low and high NOx) on these mechanisms. Experiments were conducted in the CLOUD chamber at CERN, simulating these atmospheric processes under controlled conditions.
While previous research has largely focused on isoprene oxidation at relatively high near-surface temperatures, the chemistry at low temperatures, particularly radical recycling, has not been sufficiently studied. Our study's cold-temperature measurements are particularly relevant for understanding upper tropospheric processes. We aim to elucidate the oxidation mechanisms of isoprene by analyzing radical production, concentration, and recycling under various chemical conditions at low temperatures. The findings will enhance our understanding of atmospheric chemistry in the upper troposphere and improve the accuracy of climate and air quality models.
References:
Shen, J., et al. New particle formation from isoprene under upper-tropospheric conditions. Nature 636, 115–123 (2024).
Curtius, J., et al. Isoprene nitrates drive new particle formation in Amazon’s upper troposphere. Nature 636, 124–130 (2024).
How to cite: Kunkler, F., Holzbeck, P., Russell, D., Shen, J., Mentler, B., Hansel, A., Kirkby, J., He, X.-C., Curtius, J., Lelieveld, J., and Harder, H.: Investigating Isoprene Oxidation in the Upper Troposphere: Insights from Cold-Temperature Chamber Experiments, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17088, https://doi.org/10.5194/egusphere-egu25-17088, 2025.
