A Machine Learning Approach to Predict Air Quality in California

Table 10

Forecasting models’ error metrics for particulate matter 2.5 measurements in the training and validation sets.

Error metrics	PCA SVR-RBF		SVR-RBF
	Training set	Validation set	Training set	Validation set
MAE	0.200	0.382	0.144	0.331
R^2	0.882	0.563	0.937	0.647
RMSE	0.273	0.576	0.205	0.512
nRMSE	0.041	0.074	0.031	0.066