Two articles published in JACS report the photochemical properties of these key sulfur intermediate species, which are building blocks in the formation atmospheric sulfuric acid.

Recent geoengineering plans propose to inject sulfuric acid (or its precursors) into de stratosphere to form reflective particles that might reflect enough sunlight to slow the Earth´s warming. In these reports, the photochemical properties of HOSO, HOSO2 and SO3 radicals, which are key intermediate species in the production of sulfuric acid, are investigated. The results show that both HOSO and HOSO2 undergo photolysis (mainly to OH + SO, and to OH + SO2, respectively) in short timeframes in the stratosphere, while SO3 might instead linger. These new fundamental results highlight the importance for Geoengineers to have a full understanding of sulfur chemistry before building a sulfuric atmosphere-wide sunshade. Javier Carmona-García, Antonio Francés-Monerris, Carlos A. Cuevas, Tarek Trabelsi, Alfonso Saiz-Lopez*, Joseph S. Francisco*, and Daniel Roca-Sanjuán*. Photochemistry and non-adiabatic photodynamics of the HOSO radical. JACS. https://pubs.acs.org/doi/10.1021/jacs.1c05149 Javier Carmona-García, Tarek Trabelsi, Antonio Francés-Monerris, Carlos A. Cuevas, Alfonso Saiz-Lopez*, Daniel Roca-Sanjuán*, and Joseph S. Francisco*. Photochemistry of HOSO2 and SO3 and implications for the production of sulphuric acid. JACS. https://pubs.acs.org/doi/abs/10.1021/jacs.1c10153