A Machine Learning Approach to Predict Air Quality in California

Table 8

Error metrics from NO₂ forecasting models in the training and validation sets.

Error metrics	PCA SVR-RBF		SVR-RBF
	Training set	Validation set	Training set	Validation set
MAE	0.106	0.229	0.095	0.162
R^2	0.975	0.885	0.981	0.937
RMSE	0.150	0.316	0.132	0.238
nRMSE	0.029	0.051	0.025	0.038