The QuaLIDAD Project starts from the studies on Quantum Cascade Lasers (QCLs) performed within the Qombs Project and is aimed at the development of a compact LIDAR system for air multi-component chemical analysis, particulate (PM10) detection and range finding. QuaLIDAD wants to exploit two alternative approaches, namely either the detection of backscattered light from air particulate, or the detection of reflected/scattered light by retroreflectors/obstacles. The prototype will work in the 4-5 μm window, where water absorption is low and several important greenhouse/toxic gases (CO2, CO, N2O, …) can be detected. The LIDAR will be operated with the Pseudo Random Noise (PRN) technique, using fast modulation of a continuous-wave source with a specific digital pattern. This technique is better suited for QCLs and allows identifying the target distance.