Table 2

Associations between NO₂ and benzene (μg/m³), and social factors

	NO₂*				Benzene†
	β	SD	CI 95%		β	SD	CI 95%
Residential zone	Partial Corr²: 0.2364				Partial Corr²: 0.0436
Town centre	Ref				Ref
Residential zone	−5.50	1.06	−7.57	−3.43	−0.47	0.25	−0.96	0.02
Countryside	−9.57	0.98	−11.50	−7.64	−0.88	0.23	−1.33	−0.42
Residential building age	Partial Corr²: 0.0391				Partial Corr²: 0.0207
<5	Ref				Ref
5–14	0.63	0.88	−1.10	2.36	−0.19	0.21	−0.60	0.21
15–29	2.40	0.91	0.62	4.18	−0.39	0.21	−0.80	0.03
>29	2.75	0.74	1.30	4.21	−0.46	0.17	−0.80	−0.12
Participant's age					Partial Corr²: 0.0143
<25					Ref
25–29					0.27	0.32	−0.36	0.91
30–34					0.37	0.32	−0.26	1.01
35+					0.66	0.34	0.00	1.32
Education	Partial Corr²: 0.0063				Partial Corr²: 0.0015
Primary	Ref				Ref
Secondary	0.74	0.78	−0.79	2.27	0.05	0.18	−0.31	0.41
University	1.53	0.92	−0.28	3.35	0.21	0.22	−0.23	0.64
Social class (SC, mother)	Partial Corr²: 0.0028				Partial Corr²: 0.0074
SCI+II	Ref				Ref
SCIII	0.34	0.88	−1.40	2.07	−0.16	0.21	−0.57	0.24
SCIV+V	1.13	0.88	−0.60	2.85	0.34	0.21	−0.07	0.74
Working status (third term)	Partial Corr²: 0.0056				Partial Corr²: 0.0026
Yes	Ref				Ref
No	−0.98	0.70	−2.35	0.39	−0.16	0.16	−0.48	0.16
Parity					Partial Corr²: 0.0053
Primiparous					Ref
Multiparous					−0.15	0.14	−0.43	0.13
Smoking	Partial Corr²: <0.0001				Partial Corr²: 0.0003
Never smoking	Ref				Ref
No smoking during pregnancy	1.64	0.62	0.41	2.86	0.19	0.15	−0.09	0.48
Smoking but not after 12th week	1.32	3.88	−6.30	8.94	1.69	0.9	−0.09	3.47
Smoking after 12th week	−0.39	0.80	−1.95	1.18	−0.12	0.19	−0.49	0.24
Season of last menstruation	Partial Corr²: 0.0053				Partial Corr²: 0.0003
Winter	Ref				Ref
Spring	1.78	0.79	0.23	3.32	0.33	0.18	−0.03	0.69
Summer	2.29	0.80	0.73	3.86	−0.05	0.19	−0.42	0.32
Autumn	1.03	0.74	−0.43	2.49	0.18	0.17	−0.16	0.52

*Adjusted R²=0.2734.
†Adjusted R²=0.0908.