The interaction of light with atmospheric aerosol remains one of the largest uncertainties in climate models. In particular, this aerosol-light interaction is understood poorly for a class of light absorbing aerosol referred to as brown carbon aerosol (BrC).

My research uses a suite of state-of-the-art aerosol optical spectrometers to measure the wavelength-dependent light scattering and absorption of organic aerosol during the formation and ageing of BrC. This talk focusses on the intrinsic optical properties of BrC formed from aqueous phase or heterogeneous reaction of a-dicarbonyl species with ammonium sulfate.