Trace H2S Promotes Organic Aerosol Production and Organosulfur Compound Formation in Archean Analog Haze Photochemistry Experiments

Organic haze and sulfur gases are ubiquitous in planetary atmospheres and were likely present in Earth's Archean atmosphere. Currently, there are few experiments investigating how H2S influences organic haze chemistry on Archean Earth. Here, we present results from laboratory haze-analog experiments probing the role of H2S in the composition and total mass of aerosol produced from precursor mixtures of Archean-like gas fluxes (e.g., pCO(2) similar to 3-50xPAL). We show that trace H2S enhances organic aerosol production at all carbon dioxide mixing ratios studied, and we observe both organic and inorganic sulfur aerosol products. Our finding challenges predictions that H2SO4 and S-8 were the primary sulfur reservoirs in Earth's Archean atmosphere, and these results suggest that inorganic sulfur and organic haze chemistry are tightly coupled during the formation of organic hazes in the atmospheres of the Archean Earth and likely Archean-like exoplanets.

Automated summary

Research shows that H2S enhances the production of organic haze on Archean Earth, affecting both organic and inorganic sulfur aerosol products. This discovery challenges previous understanding of sulfur reservoirs in Earth's Archean atmosphere and suggests a close coupling between inorganic sulfur and organic haze chemistry during the formation of organic haze.