Grant: Discovery Grants Program - Individual

Although only microscopic in size, atmospheric particles can play an important role in Earth's climate by scattering and absorbing solar radiation and by acting as seeds for clouds. These particles can also provide a medium for chemistry. Examples of atmospheric particles include soot, mineral dust, and organic particles. Our research will focus on the reactivity and physical properties of atmospheric aerosol particles. A better understanding of the reactivity of particles and their physical properties should lead to better predictions of climate and atmospheric chemistry, including O3 chemistry. First, we will study the conditions at which atmospheric particles undergo conversion from solid to liquid, and vice versa. In other words, we will study phase transitions of atmospheric particles. Information on phase transitions of atmospheric particles is needed for predicting their light scattering properties and their reactivity. Second, we will determine the rates of reactions between N2O5 and aqueous inorganic solutions coated with organic films. A goal is to determine whether organic films slow down the reactions between N2O5 and aqueous inorganic particles. This information should be useful when estimating N2O5 chemistry in the atmosphere, which is tightly connected to atmospheric O3 concentrations. Third, we will study the rates at which species mix within organic particles of atmospheric relevance. Put another way, we will determine the rates of diffusion of species within organic particles. This information is needed to predict the rate of growth and evaporation of organic particles in the atmosphere and rates of reactions between organic particles and gas-phase oxidants.