Table 9. Associations between measured environmental factors and remission of weekly symptoms during the two-year follow-up from 2010 to 2012 (N = 1283).

Type of exposures	Any skin symptoms (OR 95% CI)	Any mucosal symptoms (OR 95% CI)	Any general symptoms (OR 95% CI)	Any symptoms improved if away from school (OR 95% CI)	Any school related mucosal symptoms (OR 95% CI)	Any school related general symptoms (OR 95% CI)
Indoor climate and air pollutants in classrooms
SO2	1.02(0.99–1.04)	0.80(0.27–2.35)	1.34(0.39–4.58)	1.14(0.27–4.74)	0.96(0.77–1.20)	0.98(0.78–1.25)
NO2	1.02(0.93–1.12)	0.97(0.66–1.42)	0.95(0.62–1.45)	0.84(0.49–1.46)	0.91(0.39–2.12)	0.69(0.29–1.63)
O3	0.97(0.92–1.03)	0.97(0.74–1.29)	0.96(0.71–1.29)	1.24(0.88–1.74)	1.22(1.71–2.10)	0.86(0.53–1.41)
PM10	1.43(0.59–3.49)	0.71(0.54–0.93)*	0.82(0.63–1.08)	0.59(0.44–0.81)**	0.52(0.31–0.88)*	0.62(0.40–0.97)*
Temperature	0.69(0.42–1.14)	0.79(0.14–4.35)	1.00(0.82–1.22)	0.96(0.77–1.20)	0.75(0.52–1.08)	1.16(0.78–1.72)
CO2	0.51(0.13–2.05)	0.72(0.46–1.14)	1.02(0.62–1.66)	0.60(0.37–0.99)*	1.07(0.43–2.69)	1.26(0.49–3.22)
RH	0.92(0.35–2.40)	0.81(0.58–1.13)	1.02(0.72–1.45)	0.60(0.42–0.85)**	0.93(0.48–1.79)	0.99(0.53–1.86)
Air pollutants outside the school
SO2	1.01(0.99–1.04)	0.38(0.20–0.74)**	0.82(0.39–1.69)	0.80(0.34–1.91)	0.89(0.78–1.05)	0.93(0.81–1.07)
NO2	1.05(0.87–1.29)	0.50(0.24–1.04)	0.79(0.36–1.74)	0.37(0.15–0.89)*	0.91(0.79–1.04)	0.89(0.78–1.02)
O3	0.88(0.76–1.03)	0.80(0.41–1.54)	0.72(0.34–1.54)	0.90(0.37–2.18)	0.65(0.16–2.62)	1.03(0.88–1.20)
PM10	0.81(0.34–1.95)	0.83(0.68–1.01)	0.93(0.79–1.09)	0.72(0.60–0.85)***	0.78(0.58–1.04)	0.86(0.67–1.11)

Odds ratio (OR) with 95% confidence interval (CI) calculated by multiple logistic regression. Adjustment for age, gender and parental asthma or allergy, analysing each indoor climate variable separately.

*P<0.05.

**P<0.01.

***P<0.001.