Critical Role of Sea Spray Aerosol Production Pathways in Particulate Transfer Across the Sea-Air Interface

Sea spray aerosols (SSA) play a crucial role in transferring particulates from oceanic water to the atmosphere. The production pathways of SSA from bubble bursting include jet drops from bubble cavity collapse, surface film drops from bubble cap disintegration and collision film drops from underwater bubble collision. While the physical formation of these drops has been extensively studied, the mechanisms governing particle enrichment and transfer within these individual drop types remain poorly understood. This study systematically investigates particle enrichment and transfer across the three types of drops. While previous studies suggested only hydrophobic particles could be enriched by SSA, our findings reveal that both hydrophilic and hydrophobic particles can be enriched in all drop types, with surface film drops exhibiting significantly greater enrichment than previously reported. We propose for the first time that particle enrichment occurs during bubble film drainage because particles tend to remain within the thinning film rather than being uniformly drained out, leading to additional concentration within the film. These findings enhance our understanding of mass transfer at water-air interface.