Table 4.

Results from the analysis of the relation between annoyance, asthmatic symptoms, NO₂ and traffic flow¹

	Highly annoyed by vehicle exhausts2			Air as daily or almost daily irritating3			Asthmatic symptoms4
NO2 winter
	N	ORa	95% CIb	N	OR	95% CI	N	OR	95% CI
All participants5	2582	1.14	1.11–1.18	2526	1.09	1.05–1.13	2610	1.04	1.01–1.07
Non-asthmatics	2336	1.15	1.12–1.19	2289	1.07	1.05–1.10	2363	1.03	0.99–1.07
Asthmatics	246	1.06	0.97–1.15	237	1.09	1.03–1.15	247	1.05	0.97–1.14
For each city6
Umea	921	2.32	1.54–3.51	897	1.51	0.84–2.72	927	1.28	0.84–1.94
Gothenburg	762	2.39	1.90–3.01	742	1.82	1.36–2.44	775	1.32	0.99–1.76
Uppsala	899	1.99	1.55–2.55	887	1.43	1.03–2.00	908	1.10	0.84–1.44
Private vehicle outside the kitchen window
	N	OR	95% CI	N	OR	95% CI	N	OR	95% CI
Seldom/never	1317	1		1299	1		1329	1
Often	634	0.95	0.58–1.57	617	0.89	0.45–1.76	637	1.01	0.67–1.54
Constantly	601	6.28	4.44–8.89	580	4.44	2.79–7.08	610	1.38	0.93–2.04
Heavy vehicle outside the kitchen window
	N	OR	95% CI	N	OR	95% CI	N	OR	95% CI
Seldom/never	1950	1		1919	1		1964	1
Often	331	3.89	2.59–5.78	320	4.03	2.40–6.77	335	1.38	0.84–2.25
Constantly	278	10.5	7.38–15.02	265	6.01	3.69–9.79	282	2.38	1.52–3.73

^aOR = odds ratio; ^bCI = confidence interval

¹ Logistic regression was used to estimate OR's and CI's. All models were adjusted for city, sex, age, asthma and smoking, except the separate models for non-asthmatics and asthmatics which were not adjusted for asthma.

² Estimated their degree of annoyance to 9 or higher on a 1 to 11 graded scale

³ Reported the air outside home as daily or almost daily irritating

⁴ Reported asthmatic symptoms during the last 12 months

⁵ OR per change of 1 μg/m³ in exposure

⁶ OR for an Inter Quartile Range (IQR) increase in exposure