Table 4.

Brief description of the parameters extracted from the sensor response.

Method	Description
Peak value	Max value of sensor response ${\text{ψ}}_i^{\max }$
Rising slope	$S_R=\frac{{\text{ψ}}_i^{\max }-Baseline}{T_1}$, T1 is the time from the beginning of the adsorption stage to peak value.
Descending slope	$S_F=\frac{{\text{ψ}}_i^{\max }-Baseline}{T_2}$, T2 is the time from peak value to the end of the desorption stage.
FFT	Coefficients of the DC component and first order harmonic component
DWT	Approximation coefficientsWavelet function is db5 wavelets and decomposition level 13.
WFC	The area value of sensor response curve and window curve surrounded
MWFC	The three area values of sensor response curve and window curve surrounded during the window moving process