Meeting at the Interface

Reactions on or within particles are an important aspect of atmospheric chemistry, but relatively little is known about such processes in the lower parts of the atmosphere. In this Perspective, Seinfeld discusses results by Knipping et al. that shed light on one of the key heterogeneous reactions in the troposphere, that of chlorine release from sea salt particles. It turns out that the surfaces of these particles may play a larger role in their reaction chemistry than previously believed.