This Small Business Innovative Research Phase I proposal seeks to develop an ultrasensitive, mid-infrared laser-based formaldehyde gas sensor system for airborne and ground-based atmospheric monitoring. The proposed instrument will be capable of accurately determining sub-parts-per-billion formaldehyde concentrations in seconds. This compact, lightweight instrument will be capable of long-term autonomous operation, and require minimal power. The Phase I research will demonstrate the feasibility of the technology by performing measurements on formaldehyde samples using Aeris' prototype compact spectrometer platform. The results of these tests will be used to quantify detection limits and hardware requirements for a Phase II instrument. Commercial systems based on the Phase II prototype will be developed and marketed during Phase III.