A Machine Learning Approach to Predict Air Quality in California

Table 7

Error metrics from SO₂ forecasting models in the training and validation sets.

Error metrics	PCA SVR-RBF		SVR-RBF
	Training set	Validation set	Training set	Validation set
MAE	0.236	0.461	0.229	0.414
R^2	0.787	0.023	0.830	0.273
RMSE	0.364	0.752	0.352	0.703
nRMSE	0.036	0.053	0.035	0.049