Table 3. Comparative Analysis of Chemiresistive Gas Sensors Using ML^a.

sensor system	target gas	LOD (ppb)	response time	recovery time (s)	ML algorithm	accuracy (%)	ref
(120 °C) ZIF-8/WO3	acetone	0.19	5 s	10	XGBoost + MV	97.22	this work
WO3 nanoplates	formaldehyde	200	60 s	90	MLP	96.9	(41)
commercial sensors	VOC mixtures		20 min		LDA	79	(42)
SnO2 hollow spheres	formaldehyde		190 s	35	RF	85.93	(43)

^aMV = majority vote; MLP = multilayer perceptron, LDA = linear discriminant analysis, RF = random forest.