Table 4.
The association between outdoor SO2 and NO2 concentrations and prevalence of respiratory symptoms among schoolchildren in the questionnaire survey using a logistic model, adjusted for confounding variables (n = 1109)
| OR for absolute increase of per 1 ppb in air pollutants | ||
|---|---|---|
| Respiratory symptoms | SO2 | NO2 |
| Persistent cough | 1.12 (1.04–1.22) | 1.14 (0.97–1.34) |
| Persistent phlegm | 1.03 (0.94–1.12) | 1.07 (0.91–1.27) |
| Current wheezing | 1.06 (0.91–1.24) | 1.33 (1.01–1.75) |
Data are presented as OR—odds ratio (95% CI confidence interval)
Confounding variables: gender, age, history residence year, history of asthma and allergies, history of respiratory diseases before 2 years old, history of pneumonia, feeding method in infancy, parental smoking habits, heating type, distance from the major road
Mean concentrations for outdoor SO2 of each district 5.2 ppb, 4.4 ppb, 10.1 ppb, and 7.1 ppb, for NO2—30.0 ppb, 27.7 ppb, 30.0 ppb, and 18.2 ppb, respectively. And traffic volume was calculated as a value per thousand vehicles a day of each district: 16.84, 16.99, 19.47, and 7.19, respectively
Values in bold indicate statistical significant: p < 0.05