PNNL

Abstract

Ambient particles and droplets have a significant effect on climate, visibility, and human health. Once formed, they undergo continuous transformations through condensation and evaporation of water, uptake of low-volatility organic molecules, and photochemical reactions involving various gaseous and condensed-phase species in the atmosphere. These transformations determine the physical and chemical properties of airborne particles, such as their ability to absorb and scatter solar radiation and nucleate cloud droplets. The complexity, heterogeneity, and size of ambient particles make it challenging to understand the kinetics and mechanisms of their formation and chemical transformations. Mass spectrometry (MS) is a powerful analytical technique that enables detailed chemical characterization of both small and large molecules in complex matrices. We present an overview of new and emerging experimental MS-based approaches for understanding physical chemistry of environmental particles, droplets, and surfaces. In addition, we emphasize the role of fundamental physical chemistry studies in the development of new methods for chemical analysis of ambient particles and droplets.