Makel Engineering, Inc. (MEI) proposes to develop a miniaturized Airborne Chemical Microsensor Instrument (ACMI) suitable for real-time, airborne measurements of trace carbon dioxide, sulfur dioxide, and methane for use on unmanned aerial vehicles (UAVs.) The potential of UAVs to carry instrument packages to support atmospheric science has been demonstrated over the past decade. The rapid expansion of available UAV types and increased mission capability (payload, flight duration, and system cost reductions) offers wide range of potential applications. The instrument package to be developed in the program will adapt low cost and low power chemical microsensor technology which has been demonstrated for fire detection and exhaust emission monitoring to airborne measurements. The fast time response and miniaturized system will provide a lightweight, low cost instrument for package for a wide range of deployments including aerostats (balloons and kites) to UAV such as Dragon Eye and SIERRA. Phase I of the program will fabricate and test a prototype system to demonstrate capability of the instrument.