Gaseous ammonia is continuously monitored in industrial refrigeration processes and biological degradation processes, including exhaled breath. Depending on the required sensitivity, different types of sensors are used (e.g., flame ionization detector, semiconductor, electrochemical, photonic membranes[22]). Detectors usually operate near the lower exposure limit of 25ppm;[23] however, ammonia detection for industrial safety requires continuous monitoring above the fatal exposure limit of 0.1%.[22]