Model	Time	PM_2.5 μg/m³
Model	Time	Reg-R^2d	MSE-R^2e	MPE^f	RMSPE^g	Slope
NM	None	0.64	0.60	−0.299	3.19	0.80
	Month	0.60	0.53	−0.300	3.03	0.76
	1 Year	0.64	0.60	−0.309	2.28	0.82
	5 Year	0.67	0.63	−0.282	2.14	0.83
IDW	None	0.73	0.72	−0.212	2.64	0.99
	Month	0.68	0.68	−0.213	2.51	0.99
	1 Year	0.71	0.70	−0.232	1.97	1.02
	5 Year	0.73	0.72	−0.195	1.85	1.01
GAM	None	0.80	0.80	0.066	2.23	0.99
	Month	0.76	0.76	0.066	2.16	0.99
	1 Year	0.81	0.81	0.080	1.55	0.98
	5 Year	0.82	0.82	0.116	1.49	0.97
GAM (FRM^h)	None	0.78	0.78	0.041	2.24	0.97
	Month	0.72	0.72	0.041	2.15	0.95
	1 Year	0.76	0.76	0.039	1.49	0.96
	5 Year	0.79	0.79	0.041	1.40	0.96