Table 2.

Comparison of multiple models.

Model	Use of Predictive Variables and Residual Kriging	R2	CV a R2	CV RMSE b ($\mathsf{\mu }$g/m3)
Model 1	GAM with no use of PM10 data and residual kriging	0.53	0.53	34.69
Model 2	GAM with PM10 data but without residual kriging	0.81	0.81	21.87
Model 3	Bagging without PM10 data and residual kriging		0.53	34.79
Model 4	Bagging without PM10 data but with residual kriging		0.86	18.85
Model 5	Bagging with PM10 data but without residual kriging		0.82	21.82
Model 6	Bagging with PM10 data and residual kriging		0.89	17.06

^a CV: Cross Validation; ^b RMSE: Root Mean Squared Error.