Can you say a few words about yourself?

I am neither a true physicist nor a true chemist, but flying somewhere in the interdisciplinary field of the physical chemistry of the atmosphere, especially in terms of the multitude of chemical transformations in aerosol particles and their feedbacks to gas phase composition. I have been the leader of the Multiphase Chemistry Group at PSI since 27 years. While first focusing mostly on kinetics aspects of multiphase chemical processes in the atmosphere, I later started to develop in situ spectroscopy tools to track down chemical transformations inside individual particles and on the surface of atmospheric solids and liquids. I have remained intrigued by the molecular level details of the beautiful world within atmospheric particles.

What is your role in ReCLEAN?

I am the leading PI for the diverse contributions from PSI. In the research of my group, our contribution to ReCLEAN is related to the so called ReNOxification, which refers to the photochemical reduction of nitrate bringing back NOx into the active photooxidation cycles. This ranges from mixing extracts from biomass burning exhaust with nitrate to observe its photochemical reduction to spectroscopically interrogating the molecular environment of nitrate at the surface of aqueous solutions with synchrotron based X-ray photoelectron spectroscopy.

Why were you interested in ReCLEAN?

After my PhD in aerosol chemistry I delved into a project related to atmosphere – biosphere exchange by studying the uptake of traffic derived nitrogen oxides into spruce trees. This has triggered my early interest in nitrogen deposition and the accompanying effects and problems worldwide. The multiphase physical chemistry of nitrogen oxides has accompanied my career since then. At the moment the call for Joint Initiatives was launched by the ETH Domain, I immediately knew that this was the chance to bring back the topic of the nitrogen cycle back on stage in the Swiss research landscape. This then rapidly led to the present consortium of ReCLEAN.

What do you enjoy to do, outside of science and research?

I enjoy the mountains and spend a lot of my free time in all sorts of activities up there to enjoy nature, get distracted and refuel creativity for science.