BaySpec Inc., in collaboration with Pacific Northwest National Laboratory, proposes to develop an innovative orthogonal sensor systemthat would be able to detect, identify and quantify the inorganic components of breathing mixes, (i.e., nitrogen, oxygen, carbon dioxide, argon, helium, and water vapor), as well as individual detectable VOCs within the exhaled breath in real-time. The Phase I research aims to demonstrate the feasibility of such a gas sensor and design a laboratory prototype for Phase II construction. The proposed research will result in a system that can be used to establish and monitor the frequency, magnitude, and chemical make-up of exhaled VOCs to detect the generation of specific VOC profiles associated with mal-adaptive physiological responses, alert the operator and supervisor(s) to injury prior to performance decrement, and correlate exposure parameters to injury onset for potential mitigation prior to warfighter compromise.