Light scattering by aerosols in the atmosphere is responsible for sunrises and sunsets, the deterioration of visibility and the formation of rainbows, along with many other optical phenomena. Light scattering from aerosols is also apparent in polluted urban environments (eg. smog) when concentrations of particulates are high.
Aerosols are recognised as presenting one of the largest uncertainties in understanding past climate and in predicting future climate change. To quantify the impact of aerosols on the earth's climate, it is crucial to understand the change in particle size with humidity to determine the ability of particles to scatter and absorb sunlight. We must also understand how aerosol particles activate to form cloud droplets to predict cloud albedo and lifetime. Thus, key themes of our research are to understand how the equilibrium size of a particle changes with humidity, and the efficiency of scattering and absorbing light.