This Small Grant for Exploratory Research (SGER) project is an effort to develop a new capability for the analysis of stable carbon isotope ratios and carbon dioxide concentration in air. The method to be developed is laser-assisted isotope ratio anaysis (LARA). The technique utilizes fixed wavelength isotopic lasers for specificity and the optogalvanic effect for sensitivity. The research to be carried out in this study involves optimizing electronics, laser systems, and radio frequency discharge conditions to maximize signal to noise ratios and long-term stability. The system will be tested under a variety of temperature, flow and humidity conditions using standard air in order to study the effect of these parameters on system precision and accuracy. Experiments will be carried out with ambient air and intercomparisons with standard isotope ratio mass spectrometry will be done using flask air samples provide by existing air sampling networks. The LARA technique has the potential to be a low-cost, field deployable research instrument for use on fixed and mobile platforms.