Table 2.

Model performance indicators for the 2013 to 2016 model validation with 2019 data.

Station	Pollutant	Model Performance Indicator				Model Built Using Only MLR or CART and MLR
		R2	RMSE	MAE	BIAS	MLR	CART
Macao Roadside	PM10	0.88	8.6	5.8	1.8	✓
	PM2.5	0.86	5.4	3.7	1.5	✓
	NO2	0.89	8.0	5.9	0.4	✓
Macao Residential	PM10	0.89	8.8	5.9	−0.3	✓
	PM2.5	0.87	5.2	3.3	0.7	✓
	NO2	0.86	7.7	5.5	−0.4	✓
	O3 MAX	0.85	23.2	14.0	0.0	✓
Taipa Ambient	PM10	0.88	7.9	5.4	1.7	✓
	PM2.5	0.86	5.1	3.6	1.6	✓
	NO2	0.87	6.1	4.2	0.9	✓
	O3 MAX	0.86	24.4	14.8	−2.1	✓	✓
Taipa Residential	PM10	0.87	8.0	5.2	0.1	✓
	PM2.5	0.88	5.7	3.5	−0.1	✓
	NO2	0.87	5.6	4.2	0.8	✓
	O3 MAX	0.78	20.9	12.7	1.3	✓	✓
Coloane Ambient	PM10	0.88	8.7	6.2	2.4	✓
	PM25	0.86	5.4	3.7	1.3	✓
	NO2	0.81	7.8	5.5	−0.2	✓
	O3 MAX	0.79	24.7	15.9	−3.6	✓	✓