Dynamic Surface Properties of Atmospheric Aerosol and Resulting Climate Impacts

Lead Research Organisation: University of Bristol
Department Name: Chemistry

Abstract

Surface tension is a key parameter that determines the properties and dynamics of aerosol particles in the atmosphere, in spray drying processes and in the formulations of active pharmaceuticals in aerosol devices used in drug delivery to the lungs. For example, atmospheric aerosol particles represent a major uncertainty in our ability to accurately model climate, in part due to challenges in accurately predicting what fraction of atmospheric particles ultimately grow into cloud droplets. A supersaturation in relative humidity (i.e. RH > 100%) is required for a particle to grow into a cloud droplet, but this process has not yet been constrained by measurements and is highly dependent on the surface tension of atmospheric particles. The goal of this project is to develop a quantitative framework describing the dynamics of the aerosol particle surface by performing detailed experiments to identify how droplet surface tension changes as a function of droplet size, composition, and surface age using home-built instrumentation. This framework will permit the testing and refinement of models describing the particle surface, with an aim to ultimately evaluate the climate effects of droplet surface properties by incorporating the framework into a global climate model. Specific aims include: 1) Investigate how particle size affects the timescale of establishing equilibrium surface composition, 2) Quantify how equilibrium partitioning for specific surface-active molecules changes due to the high surface to volume ratio inherent in aerosol droplets, and 3) Collaborate with modelers to improve representations of surface tension and evaluate surface tension effects on climate. This project will also involve development of approaches to analyse optically trapped droplets by mass spectrometry to resolve their molecular composition, which will significantly improve the utility of the optical tweezers approach and enable study of more atmospherically relevant systems.


Please note - Student is in year 1. Will update when student starts project in year 2 (summer 2020).

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023593/1 01/04/2019 30/09/2027
2274588 Studentship EP/S023593/1 23/09/2019 22/09/2023 Joshua Harrison