Table 6.

RF: Random Forest, GBT: Gradient Boosted Tree; RR = Ridge Regression; SVM = Support Vector Machine; RMSE: Root Mean Squared Error; MAE: Mean Absolute Error; MAPE: Mean Absolute Percentage Error.

ID	Meth.	Variable Groups	TRAIN (80%)				TEST (20%)
			adj. R2	RMSE	MAE	MAPE	RMSE	MAE	MAPE
8	GBT	smoking + state + EQI	0.611	10.340	7.611	12.334	9.976	7.377	12.054
9	SVM	smoking + state + EQI + emissions	0.634	10.026	7.335	11.833	10.027	7.401	12.063
10	RF	smoking + state + EQI + emissions	0.639	9.960	7.268	11.926	10.068	7.314	11.977
11	GBT	smoking + state + EQI + emissions	0.625	10.151	7.445	12.132	10.239	7.535	12.252
12	RR	smoking + state + EQI + emissions	0.600	10.486	7.741	12.667	10.314	7.822	12.881
13	RR	smoking + state + EQI	0.598	10.507	7.758	12.688	10.322	7.793	12.784
14	RF	smoking + state + EQI	0.584	10.684	7.814	12.932	10.383	7.627	12.570