Something in the Air

Abstract
The analysis of aerosol particles in Earth9s atmosphere is highly challenging, because the particle concentrations are low, the particles small, and their compositions highly complex. Yet knowledge of their properties is crucial for understanding how they influence climate and human health. In his Perspective, Murphy discusses recent advances in developing instruments that analyze these particles directly from the air. Such �on-line� techniques have shed light on the complex chemical composition of the particles and have contributed to the recognition that organic compounds play a globally important role in atmospheric aerosols.