Future activities of man, such as the expanded use of high- speed civil aircraft, can be expected to perturb the chemical and physical conditions of the lower stratosphere. The magnitudes of the effects of localized emissions of nitrogen and sulfur oxides, water vapor, particulate matter, and other substances on the natural trace gas life cycles and ozone depletion, especially in the face of altered aerosol and cloud characteristics, are highly uncertain at present. The work proposed here will provide important new data on the origins and behavior of various aqueous aerosol particles and their roles in the heterogeneous chemistry of the region. Laboratory experimentation will be performed with individual and swarms of aqueous particles levitated electrodynamically in an environment specifically controlled to simulate conditions in the lower stratosphere or upper troposphere. The levitated particles, as well as their growth and chemical reactions, will be interrogated by a variety of methods. Raman scattering will help determine the size, phase, and composition of the particles. Mass spectroscopy, and possibly resonance fluorescence and absorption techniques, will be used to measure the changes in the concentrations of the trace reactant and product gases. Other particle characteristics such as weight, fallspeed, and shape will be measured by techniques already used in our laboratories.
