Atmospheric Aerosol Group

The Russell group develops models and analyzes observations to understand the microphysical and chemical evolution of aerosol particles in the atmosphere. Our aim is to characterize the role of atmospheric aerosols on the Earth's climate.
Aerosol particles play an important role in the radiative balance of the atmosphere, with their organic fraction representing one of the largest uncertainties in our ability to quantify climate cooling and feedback effects. The Earth's radiative forcing can be directly affected by anthropogenically-produced particles, and the man-made particles over North America typically include between 20% and 80% organic compounds by mass. The composition and properties of these organic particles have been the focus of significant field and laboratory efforts in the last 5 years. Yet two problems remain. The first is that we still have only a very limited understanding of the types of organic compounds present in most areas of the world, and for most areas we do not even know what functional groups are present. The second problem is that for the areas for which we know something about the organic composition, we have only a very limited idea of the phase partitioning of those organics between the gas and particle phases and, subsequently, of the hygroscopicity of the particle phase.
The Atmospheric Aerosol Group at the Scripps Institution of Oceanography investigates the behavior of aerosol particles in the Earth's atmosphere under both pristine marine and polluted urban conditions. Measuring the properties of atmospheric structure and its chemical constituents is an important part of these investigations, for which our group has developed instruments that we have used in the field for airborne and shipboard observations. We have developed significant expertise in using synchrotron radiation to measure organic composition in individual organic particles with soft x-rays. Field projects are an important part of our research effort, providing evidence of the role of aerosol particles in atmospheric chemistry, meteorology, and radiation. Interpreting the results of field projects involves both analysis with numerical models of aerosol evolution and laboratory investigations.