Table 2.

R², RMSE and %NRMSE value for the external validation and lockdown sets from the best model.

D_NO2	D_PM10	N_NO2	N_ Ox	N_O3	N_PM10	O_NO2	O_PM10	S_NO2	S_ Ox	S_O3	S_PM10	W_NO2	W_PM10
0.55	0.61	0.76	0.5	0.87	0.72	0.5	0.42	0.45	−0.07	0.84	0.71	0.81	0.66	R2 VS
15.32	26.29	17.52	12.46	24.6	28.81	22.35	38.78	20.04	21.46	33.37	25.08	13.47	29.1	%NRMSE VS
46.64	29.63	59.89	8.96	14.01	27.96	80.1	37.27	53.97	13.78	17.35	28.76	38.59	28.3	%NRMSE LD
58.28	35.98	81.29	7.1	13.9	30.15	103.82	36.96	68.26	8.18	13.9	33.33	49.27	30.88	%NRMSE HLD
7.43	9.04	5.3	7.19	6.76	7.09	7.63	13.44	7.26	11.92	6.43	8.52	4.74	8.11	RMSE VS
14.48	7.22	7.83	7.17	9.38	5.33	12.3	8.02	10.9	10.31	9.47	6.65	7.91	6.23	RMSE LD
16.76	8.6	9.25	6.11	10.38	6.51	14.18	8.4	12.67	6.56	8.56	8.16	9.32	7.11	RMSE HLD
38	27.58	20.06	68.73	48.67	20.71	23.12	26.34	26.26	65.6	39.33	26.46	25.9	23.11	True Mean
81.8	78.77	53.36	106.89	93.71	65.56	58.14	111.51	65.05	97.77	86.13	78.23	62.28	69.47	True Max
8.02	6.63	1.14	34.14	3.64	5.6	1.98	7.59	2.92	28.67	1.08	6.93	3.11	5.58	True Min