Cavity ring-down spectroscopy is used to measure optical properties and observe composition change in single aerosol particles.More
Much of the chemistry occurring in the Earth’s atmosphere is driven by absorption of sunlight. We use cavity ring-down spectroscopy (CRDS) techniques to make measurements of quantum yields for photochemical processes of importance to the lower atmosphere (the troposphere) and to measure the rates of reactions of photochemical intermediates that participate in oxidation pathways for organic pollutants. We also develop infra-red laser based sensors to monitor trace levels of greenhouse gases (and their isotopologues) in ambient air using ultra-sensitive cavity enhanced absorption spectroscopy (CEAS) techniques. Our expertise in CRDS has recently been extended to the study of optical properties of single aerosol particles, for which we can follow processes such as evaporation of volatile organic constituents or uptake of water.