Table 2. Cross Validation Statistical Measures and Percent Change for Three Estimation Methods.

method	LUR only	(a) constant/hard	(b) LUR/hard	(c) LUR/hard and soft	% change from (a) to (b)	% change from (b) to (c)
MSEa	7.04	1.69	1.32	1.26	–21.89	–4.87
RMSEb	2.65	1.30	1.15	1.12	–11.62	–2.46
MAEb	1.97	0.79	0.63	0.63	–20.73	–0.45
MRb	1.86	1.87	1.12	1.07	–40.25	–4.08
Square Pearson’s Corr.c	0.50	0.68	0.87	0.88	28.94	0.78
Square Spearman’s Corr.c	0.55	0.67	0.89	0.89	32.13	0.32

^a[μg/m³]².

^bμg/m³.

^cUnitless.