The primary goal of this project is to conduct an intercomparison on the measurement of sulfur gases in the air between various research groups who are measuring the gases. These gases are of major atmospheric importance, but at this time we do not know if the different analytical instrumentation and methods are equivalent in their measurement capability. This is due to the variety of preconcentration methods and equipment which are used to measure the gases and to the high reactivity of these sulfur gases with a variety of chemical species in the air, water, soils, etc. This proposal is an omnibus proposal to provide for the logistical support to perform the intercomparison and to analyze the data generated from the intercomparison. The experimental design is such that both laboratory and field exercises will be performed and that the range of concentration for intercalibration of each gas will be from about five times the minimum detectable limit of each gas to two orders of magnitude higher. This range will cover the range of natural measurements (part per trillion by volume to part per billion by volume) and provide an experiment which can provide for good statistical validity in the intercomparison. A successful intercomparison, with the validation of several research groups to measure sulfur gases, will result in the ability to perform coordinated research projects to understand the vital role of sulfur in global climate change.//
