Professor Gilbert Nathanson, University of Wisconsin. "Big Impacts of Little Droplets: Unraveling the Surface Chemistry of Sea Spray." Woodward CCB Departmental Colloquium.
Abstract: Sea spray is composed of tiny droplets generated by bursting bubbles at the surface of the ocean. These droplets contain water, salt, organic molecules, and even bacteria as they are lofted into the atmosphere. Although tiny, they have a substantial impact on our climate and air quality. In particular, aerosol droplets scatter sunlight back into space and they act as miniature chemical reactors, indirectly altering the concentrations of gases such as ozone and methane. The nighttime uptake of the nitrogen oxide, N2O5, into these droplets is among the most influential of these gas-particle reactions. N2O5 reactivity varies enormously, in part because of organic coatings on the droplet surface. I will describe gas-liquid scattering experiments and molecular dynamics simulations that are enabling us to develop a “blow-by-blow” description of this reaction and others. Our results show how organic monolayers can catalyze reactions of N2O5 rather than suppress them.