An Atmospheric Perspective on Emerging Water Microdroplet Chemistry

Microdroplets, as tiny liquid particles, are ubiquitous in Earth's atmosphere. They serve as dynamic microreactors that drive atmospheric processes, with profound implications for air quality, climate regulation, and atmospheric chemical cycles. Despite its importance, microdroplet-driven chemistry remains inadequately represented in global climate and air quality models. This perspective synthesizes emerging evidence on how microdroplet interface-enhanced multiphase chemistry modifies atmospheric processes including amplifying atmospheric oxidation capacity and accelerating the transformation of key reactive species. Advances in aerosol and microdroplet chemistry highlight the central role of the microdroplet interface in initiating accelerated kinetics and in enabling unprecedented chemical pathways distinct from those in macroscopic bulk solutions. We outline the current knowledge gaps and future directions for advancing the research in microdroplet chemistry from an atmospheric perspective. The concerted coordination among microdroplet chemistry and atmospheric communities across field, laboratory, and modeling has significant implications for understanding the critical role of microdroplet interface-driven chemistry in the atmosphere and climate change.