9523186 Jayne This research is to develop an aerosol mass spectrometer for size and composition analysis of sub-micron size particles in the atmosphere. The technology for this device will build on a combination of proven technology for both aerosol sampling and mass spectrometry to develop a novel approach to particle composition analysis based on hot wire vaporization of size selected submicron particles. This spectrometer will have the ability to determine the simultaneous chemical composition of the full range of aerosol particles, without the use of expensive and delicate laser systems. The successful development of this spectrometer will be more cost effective than most competing systems now under development and will be useful in a wide variety of field applications. These applications include environmental aerosol monitoring, laboratory aerosol physics, and other studies of aerosol formation and growth mechanics.