Table 2

Associations between air pollution and daily asthma admissions in London 1987–92. Percentage increase/decrease (95% confidence intervals). The most significant single day (lx) and cumulative day (l0x) lags are shown

Age group (years)Season8 h ozone
Single lag
8 h ozone Cumulative lag24 h NO2 Single lag24 h NO2 Cumulative lag24 h SO2 Single lag24 h SO2 Cumulative lag24 h BS
Single lag
24 h BS Cumulative lag
0–14Whole year0.17l0 0.49l02 1.252-150 l2 1.77** l03 1.642-150 l1 2.042-150 l03 0.58l2 0.88l03
−1.56,1.94−1.7,2.730.3,2.20.39,3.180.29,3.010.29,3.83−1.27,2.46−1.85,3.7
Warm season1.48l0 2.692-150 l02 1.42l2 3.012-150 l03 3.33** l1 3.402-150 l02 −1.33l2 −4.13l03
−0.51,3.500.21,5.22−0.3,3.173.8,5.721.09,5.630.41,6.48−5.35,2.87−10.18,2.32
Cool season−2.952-150 l0 −5.75** l02 1.182-150 l2 1.22l03 0.56l1 1.24l02 1.08l2 2.09l03
−5.80,−0.02−9.4,−1.950.02,2.35−0.48,2.96−1.16,2.32−0.95,3.49−0.98,3.19−0.99,5.25
15–64Whole year3.93*** l1 3.37** l02 0.95l0 0.99l01 −0.69l2 −0.71l02 0.61l0 0.47l01
1.77,6.150.7,6.12−0.26,2.17−0.36,3.36−2.28,0.94−2.69,1.30−1.73,3.01−2.17,3.18
Warm season4.25*** l1 3.18** l02 0.46l0 0.05l01 −1.39l2 −2.2l02 1.59l0 −0.78l01
1.83,6.740.21,6.25−1.70,2.67−2.45,2.61−3.97,1.27−5.46,11.8−3.81,7.30−7.01,5.86
Cool season2.98l1 3.74l02 1.21l0 1.43l01 −0.24l2 0.20l02 0.41l0 0.72l01
−0.61,6.70−0.88,8.57−0.22,2.5−0.18,3.06−2.28,1.84−2.28,2.74−2.16,3.04−1.28,3.71
65+Whole year2.67l2 −2.64l01 2.96** l2 3.14l03 2.82l2 3.06l03 5.602-150 l2 8.61** l03
−1.66,7.20−6.93,1.860.67,5.31−0.04,6.42−0.82,5.96−0.72,6.981.09,10.312.39,15.2
Warm season3.68l2 0.31l01 1.89l2 −1.76l03 −2.62l2 −4.27l03 7.46l2 2.99l03
−1.12,8.71)−4.63,5.31−2.41,6.38−7.27,4.07−7.31,2.31−9.89,1.71−3.42,19.57−11.11,19.08
Cool season0.14l2 −9.0l01 3.522-150 l2 5.57** l03 5.85** l2 7.28** l03 4.20l2 7.912-150 l03
−6.87,7.68−16.0,1.420.81,6.301.85,9.431.81,10.052.19,12.62−0.81,9.460.98,15.32
All agesWhole year6.90l1 0.42l02 1.25*** l2 2.05** l03 1.642-150 l1 2.75*** l03 1.22l2 2.352-150 l03
−0.07,1.02−1.31,2.170.49,2.020.96,3.150.54,2.751.22,4.30−0.31,2.780.16,4.58
Warm season2.21** l1 2.102-150 l02 1.15l2 1.54l03 2.022-150 l1 2.602-150 l03 −0.61l2 −1.10l03
0.62,3.820.13,4.10−0.25,2.57−0.54,3.670.22,3.850.02,5.25−3.94,2.84−6.26,4.34
Cool season−3.17** l1 −4.312-150 l02 1.30** l2 2.26*** l03 1.41l1 2.83** l03 1.66l2 3.072-150 l03
−5.44,−0.84−7.27,−1.260.38,2.230.94,3.590.0,2.830.89,4.81−0.04,3.370.65,5.56
  • BS = black smoke.

  • 2-150 p<0.05, **p<0.01, ***p<0.001.