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Preprints
https://doi.org/10.5194/egusphere-2023-1415
https://doi.org/10.5194/egusphere-2023-1415
26 Jul 2023
 | 26 Jul 2023

Towards a mechanistic description of autoxidation chemistry: from precursors to atmospheric implications

Lukas Pichelstorfer, Pontus Roldin, Matti Rissanen, Noora Hyttinen, Olga Garmash, Carlton Xavier, Putian Zhou, Petri Clusius, Benjamin Foreback, Thomas Golin Almeida, Chenjuan Deng, Metin Baykara, Theo Kurten, and Michael Boy

Abstract. In the last decades, atmospheric formation of secondary organic aerosol (SOA) gained increasing attention due to its impact on air quality and climate. However, methods to predict its abundance are mainly empirical and may fail at real atmospheric conditions. In this work, a close-to mechanistic approach allowing SOA quantification is presented, with focus on a chain-like chemical reaction called “autoxidation”. A novel framework is employed to a) describe the gas-phase chemistry, b) predict the products’ molecular structures and c) explore the contribution of autoxidation chemistry on SOA formation under various conditions. As a proof of concept, the method is applied to benzene, an important anthropogenic SOA precursor.

Our results suggest autoxidation to explain up to 100 % of the benzene-SOA formed under low-NOx laboratory conditions. While under atmospheric-like day-time conditions, the calculated aerosol mass continuously increases, as expected based on prior work. Additionally, a prompt increase, driven by the NO3 radical, is predicted at dawn. This increase has not yet been observed experimentally and questions the applicability of the widely accepted concept of OH-based SOA mass yield in the atmosphere.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Secondary organic aerosols (SOA) form effectively from gaseous precursors via a process called...
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