Table 4

Adjusted odds ratios† (ORs) and 95% confidence intervals (CIs) for gaseous pollutants‡ in relation to asthma hospitalisation in girls aged 6 to 12 years, Toronto

Exposure averaging period
1 day2 days3 days4 days5 days6 days7 days
AnalysisOR95% CIOR95% CIOR95% CIOR95% CIOR95% CIOR95% CIOR95% CI
*p Value ≤0.05. †The odds ratios were calculated for an interquartile range increment of each gaseous pollutant, which was calculated based on daily levels. ‡CO=carbon monoxide; SO2=sulphur dioxide; NO2=nitrogen dioxide; O3=ozone. §A=odds ratios adjusted for daily weather conditions; B=odds ratios adjusted for particulate matter (PM10-2.5 and PM2.5) and daily weather conditions.
Daily average CO (0.5 ppm)
    A§1.000.93 to to to 1.090.980.89 to to to to 1.17
    B§1.000.93 to to 1.100.990.90 to 1.090.970.87 to 1.080.990.89 to to to 1.20
Daily average SO2 (7 ppb)
    A1.040.97 to to to to to 1.28*1.171.02 to 1.34*1.201.04 to 1.39
    B1.060.98 to to to to to 1.29*1.181.00 to 1.38*1.281.08 to 1.51
Daily average NO2 (11 ppb)
    A0.990.92 to to to to 1.21*1.141.02 to 1.28*1.161.02 to 1.31*1.161.02 to 1.32
    B0.990.92 to to to to to to 1.35*1.211.03 to 1.42
Daily maximum 1-hr O3 (20 ppb)
    A0.860.78 to 1.040.900.78 to 1.020.920.79 to 1.070.950.80 to to to 1.230.930.75 to 1.16
    B*0.860.78 to 0.960.880.77 to 1.010.890.76 to 1.040.920.77 to 1.100.970.80 to 1.180.950.78 to 1.170.890.72 to 1.12