A Journey into the Interfacial Chemistry of Wet Aerosols

Abstract

Aerosols and clouds are key players in tropospheric chemistry. These tiny particles suspended in the air, with a radius ranging from a few nanometres to tens of micrometres, impact atmospheric composition, represent one of the largest uncertainties in climatic projections and cause millions of deaths worldwide every year. Hence, they have enormous societal and economic consequences. Nonetheless, there is still a knowledge gap preventing us from describing the chemical evolution of aerosols and clouds during their atmospheric lifetime.

Water molecules in bulk liquid are stable and inert under ambient conditions. In sharp contrast, it has been very recently shown that the local orientation of water molecules at an air/water interface induces an electric field that generates spontaneous radicals in micron-sized droplets. This production does not involve any catalysts, such as light or heat. It is an intrinsic property of the air/water interface and is therefore potentially ubiquitous at air/water interfaces.

This spontaneous interfacial oxidant formation has never been explored for its atmospheric significance. Therefore, this presentation aims to unravel the atmospheric importance of this interfacial (dark) chemistry. If oxidants (including OH radicals) are in fact spontaneously produced at the air-water interface under atmospherically relevant concentrations, this would profoundly challenge our understanding and description of atmospheric multiphase chemistry.
 

About the Speaker

Prof. Christian GEORGE obtained his PhD in Physical Chemistry from the University Louis Pasteur in Strasbourg, France, in 1993. Throughout his career, he has held numerous prestigious positions, including Vice President of the University of Lyon 1 - Claude Bernard and Interdisciplinary Group Leader and Senior Research Scientist at the Centre National de la Recherche Scientifique (CNRS). He has also served on the board of trustees on behalf of the CNRS of the company PULSALYS, the University’s Technology Transfer Acceleration Company (SATT).

Prof. George's current research focuses on the intersection of atmospheric chemistry, environmental chemistry, physical chemistry, chemical kinetics, and photochemistry, aiming to enhance the understanding of processes occurring in the troposphere. In recognition of his contributions to science, Prof. George was elected as a member of Academia Europaea in 2022 and as a Fellow of the Royal Society of Chemistry in 2023.

Prof. George has contributed to various scientific committees, including the Scientific Steering Committee of the International Global Atmospheric Chemistry (IGAC) and the Steering Committee and Vice President of the International Commission on Atmospheric Chemistry and Global Pollution (iCACGP). He has chaired the program on Atmospheric Chemistry INTROP (Interdisciplinary Tropospheric Research: from the Laboratory to Global Change) at the European Science Foundation, and served on Review Panel for the Academy of Finland. Additionally, he is an editor for several notable journals, including the Journal of Geophysical Research: Atmospheres, Scientific Reports, and Atmospheric Chemistry and Physics.

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