Detecting and Identifying Industrial Gases by a Method Based on Olfactory Machine at Different Concentrations

Figure 2

The sensor response map of CO₂, CH₄, NH₃, and corresponds to (a), (b), (c), and (d), respectively, when the concentration was 300 ppm. The horizontal axis stands for the sampling time (0–120 s) and the vertical axis denotes the amplitude of sensor output impedance ratio.

(a)

(b)

(c)

(d)