Relationship between area-level socioeconomic characteristics and outdoor NO2concentrations in rural and urban areas of northern Spain

Table 2 Distribution of census tract level modeled NO ₂ concentration (μg/m ³ ), socioeconomic index, and educational level

		n	Mean	S. D.	Min	P25	Median	P75	Max
NO ₂	Urban <50%	70	12.92	5.57	3.23	8.37	11.84	17.33	25.67
	Urban ≥50%	68	23.26	4.22	10.38	22.10	24.18	25.70	30.49
	All	138	18.02	7.16	3.23	11.32	19.42	24.19	30.49
SE index* ^a	Urban <50%	70	1.42	0.18	1.17	1.27	1.41	1.52	2.05
	Urban ≥50%	68	1.35	0.14	1.04	1.28	1.33	1.42	1.69
	All	138	1.38	0.16	1.04	1.27	1.34	1.48	2.05
Education* ^b	Urban <50%	70	3.38	0.32	2.72	3.10	3.39	3.58	4.10
	Urban ≥50%	68	3.49	0.32	2.93	3.32	3.44	3.62	4.26
	All	138	3.43	0.32	2.72	3.21	3.40	3.61	4.26

ISSN: 1471-2458