Heterogeneous reactions have been found to be of crucial importance to various processes and phenomena in the atmosphere, such as the Antarctic ozone hole. Currently, there is increasing interest in the role of heterogeneous reactions in tropospheric chemistry. A unique experimental apparatus will be developed to study the interaction of particles with gases under conditions simulating atmospheric conditions. The apparatus will consist of: (1) a system capable of generating particles of known size distribution, number density, and composition; (2) a reaction chamber, which can be run in either a static or a dynamic mode, with temperature and pressure control; (3) an atmospheric pressure ionization mass spectrometer for measurement of a variety of gases at levels down to about 1 ppb; and (4) a long pathlength Fourier-transform Infrared Spectrometer to follow some aspects of particle composition in real time. Furthermore, incorporated into this new state-of-the-art system will be the capability of collecting particles for post-reaction analysis using a wide variety of analytical techniques available in the laboratory. Initial studies will focus on the interactions of sea salt particles with oxides of nitrogen, the subject of ongoing research and increasing international interest. Also, other reactions of atmospheric interest will be studied, including those of alumina particles emitted by solid fuel rockets. The mass spectrometer component will provide an important and unique analytical tool for probing experimental protocols or the sampling and analysis of a variety of species in ongoing tropospheric and stratospheric field campaigns. This system will play a role in expanding graduate programs in atmospheric chemistry at the University of California, Irvine.***
