Reactions on Atmospheric Dust Particles: Surface Photochemistry and Size-Dependent Nanoscale Redox Chemistry

Mineral dust aerosol is indisputably an important component of the Earth's atmosphere and provides a reactive surface for heterogeneous chemistry to occur. These reactions can alter concentrations of key trace atmospheric gases as well as change the physicochemical properties of the dust particles. The focus of this Perspective article is on several new mechanisms and reaction pathways identified in laboratory studies on components of mineral dust and on nanodust, a potentially new source of metal-containing dust from engineered nanomaterials. These reactions include surface photochemical mechanisms for renoxification and sulfur dioxide oxidation and size-dependent redox chemistry of metal-containing dusts in low-pH environments including naturally occurring iron oxides and engineered metal nanoparticles. These newly identified reactions have the potential to play an important role in atmospheric chemistry.