My research is focused on the relationships among atmospheric aerosol chemical and optical properties and their impacts on the solar radiation budget. Aerosols, solid or liquid particles suspended in the atmosphere, remain one of the largest sources of uncertainty in future climate scenarios.  The uncertainty stems from the nature and magnitude of perturbations to the radiative balance of the Earth-atmosphere system caused by aerosol climate forcing.  It is estimated that climate forcing due to aerosols is causing an overall net cooling of the global climate, comparable in magnitude to the warming effect of anthropogenic greenhouse gases.

Aerosol particles are either emitted directly into the atmosphere or formed via heterogeneous chemical reactions from precursor gases of both anthropogenic and biogenic origins. The chemical composition of the aerosols dictates their optical properties and radiative impacts.  The major contributors to aerosol composition in the eastern U.S. are sulfates, nitrates, organic carbon, and elemental carbon. Many of the organic carbon species that make up a significant fraction of the aerosol mass are not well characterized. Organic carbon species scatter sunlight in the visible portion of the spectrum, but tend to absorb ultraviolet radiation. I am particularly interested in characterizing the species comprising the organic fraction of aerosols and quantifying the role they play in the absorption of ultraviolet radiation.