Table 3.
Percentage increase in daily hospital admissions for asthma for age <=18 year old per interquartile range (IQR) increase of pollutants at different lags, Hong Kong 1997–2002
| Lag | PM10; IQR: 33.4 μg/m3 | PM2.5; IQR: 20.6 μg/m3 | SO2; IQR: 11.1 μg/m3 | NO2; IQR: 27.1 μg/m3 | O3; IQR: 23.0 μg/m3 |
|---|---|---|---|---|---|
| 0 | 4.97 (2.96–7.03) | 5.10 (2.95–7.30) | −1.57 (−2.87–−0.26) | 4.37 (2.51–6.27) | 2.34 (0.40–4.31) |
| 1 | 5.71 (3.78–7.68) | 5.00 (2.88–7.16) | −1.77 (−3.06–−0.46) | 5.88 (4.00–7.70) | 4.59 (2.71–6.51) |
| 2 | 6.40 (4.51–8.32) | 4.83 (2.75–6.95) | −1.15 (−2.42–0.14) | 7.19 (5.37–9.04) | 5.97 (4.10–7.89)* |
| 3 | 7.25 (5.38–9.16) | 4.83 (2.78–6.93) | 0.82 (−0.45–2.11) | 9.08 (7.26–10.93)* | 3.87 (2.02–5.75) |
| 4 | 7.45 (5.58–9.35)* | 6.59 (4.51–8.72)* | 1.40 (0.13–2.69) | 7.64 (5.84–9.48) | 2.41 (0.58–4.26) |
| 5 | 5.96 (4.11–7.85) | 5.24 (3.18–7.34) | 1.46 (0.19–2.74)* | 6.40 (4.60–8.22) | 0.86 (−0.94–2.7) |
Data presented as percentage increase (95% confidence interval). PM10: aerodynamic diameter <10 μm; PM2.5,aerodynamic diameter <2.5 μm; SO2, sulphur dioxide; NO2, nitrogen dioxide; O3, ozone.
*
Highest percentage change after control for the mean daily temperature, relative humidity, daily hospital admissions for influenza, total daily hospital admission and indicator variables for day of the week and holidays.