Man's understanding of his global environment increases with each advance in his ability to measure its properties. In particular, knowledge of photochemical transformations in the earth's atmosphere and of the wide array of chemical processes occurring in both remote and urban areas has developed in conjunction with research quality instrumentation capable of probing the composition of the atmosphere with increasingly greater resolution. Several gases present at one part in a billion or trillion play important and often crucial roles in chemical or radiative processes in the atmosphere. In this project, a new and evolving experimental technique will be extended and applied to the measurement of important atmospheric gases. The technique involves the use of fixed frequency infrared gas lasers with frequency modulation methods. A major advance expected from this work is a laser absorption detection instrument with high sensitivity that uses a simple laser system, thus providing the versatility, affordability, sensitivity, and ruggedness necessary for extensive field measurements. Development of the instrument will be directed at the measurement of hydrogen peroxide and methane. The technique has potential for application to other atmospheric gases since several species are likely to have absorption in the infrared that can be probed by the gas laser system.
