This MRI project supports part of the development and construction of an instrument which will provide information on both the composition of atmospheric semi-volatile aerosols particles and the associated gas phase species in the upper troposphere/lower stratosphere region. The development work will be accomplished through a collaboration between the California Institute of Technology, the National Center for Atmospheric Research (NCAR), Georgia Tech, and CDI Corporation. The instrument will be light-weight and autonomously operated on board of an ER-2 research aircraft. The technique of selected ion chemical ionization mass spectroscopy (SICIMS) will be combined with novel virtual impactor inlets to separate the gas phase from the aerosols. Central to this program is the design of a suitable calibration system that can be used during atmospheric observations. Also as part of this program, laboratory studies will be carried out at Caltech to develop and calibrate new ion techniques for detection of atmospherically important species such as peroxynitric acid and ammonia.
