Table 4.
Associations of emergency department visits for asthma or wheeze with three-day moving average population-weighted average ambient air pollutant concentrations and with pollutant concentrations one day in the future: sensitivity to varying control in the regression time spline.3
| 6 df per year | 8 df per year | 12 df per year | ||||
|---|---|---|---|---|---|---|
| Lag 0-1-2 concentration RR per IQR (95% CI) | Future concentration RR per IQR (95% CI) | Lag 0-1-2 concentration RR per IQR (95% CI)b | Future concentration RR per IQR (95% CI) | Lag 0-1-2 concentration RR per IQR (95% CI) | Future concentration RR per IQR (95% CI) | |
| CO | 1.026 (1.014–1.039) | 1.006 (0.999–1.039) | 1.026 (1.013–1.038) | 1.007 (1.000–1.015) | 1.007 (0.995–1.020) | 1.004 (0.996–1.012) |
| NO2 | 1.038 (1.022–1.055) | 1.008 (0.999–1.017) | 1.041 (1.025–1.058) | 1.010 (1.001–1.019) | 1.014 (0.998–1.031) | 1.005 (0.995–1.014) |
| O3 | 1.074 (1.044–1.105) | 0.999 (0.984–1.014) | 1.082 (1.051–1.114) | 1.003 (0.988–1.018) | 1.053 (1.021–1.085) | 1.001 (0.986–1.016) |
| PM10 | 1.032 (1.018–1.047) | 1.017 (1.007–1.027) | 1.029 (1.014–1.044) | 1.017 (1.007–1.027) | 1.001 (0.986–1.017) | 1.016 (1.006–1.026) |
| PM2.5 | 1.031 (1.019–1.043) | 1.011 (1.003–1.020) | 1.032 (1.019–1.044) | 1.013 (1.004–1.022) | 1.010 (0.997–1.022) | 1.010 (1.001–1.019) |
| SO42+ | 1.032 (1.021–1.044) | 1.010 (1.002–1.019) | 1.029 (1.017–1.041) | 1.010 (1.001–1.018) | 1.015 (1.003–1.027) | 1.007 (0.998–1.016) |
| NO3− | 1.009 (0.998–1.020) | 0.995 (0.987–1.003) | 1.008 (0.997–1.020) | 0.997 (0.989–1.005) | 1.002 (0.990–1.013) | 0.997 (0.989–1.005) |
| NH4+ | 1.026 (1.016–1.036) | 1.009 (1.001–1.017) | 1.022 (1.012–1.032) | 1.008 (1.000–1.016) | 1.011 (1.001–1.021) | 1.007 (0.999–1.015) |
| EC | 1.025 (1.013–1.036) | 1.010 (1.002–1.017) | 1.020 (1.008–1.032) | 1.009 (1.001–1.017) | 1.000 (0.988–1.012) | 1.007 (0.999–1.014) |
| OC | 1.026 (1.014–1.037) | 1.011 (1.003–1.018) | 1.026 (1.014–1.038) | 1.011 (1.004–1.019) | 1.004 (0.992–1.016) | 1.008 (1.000–1.015) |
df, degrees of freedom;
a
Rate ratios scaled to interquartile range increases in three-day moving average population-weighted average ambient air pollutant concentrations: 0.23 ppm for CO, 8.50 ppb for NO2, 24.03 ppb for ozone, 10.40 μg/m3 for PM10, 6.60 μg/m3 for PM2.5, 2.44 μg/m3 for SO42−, 0.51 μg/m3 for NO3−, 0.71 μg/m3 for NH4+, 0.45 μg/m3 for EC, and 1.29 μg/m3 for OC.
b
Results from primary analysis.