Large PEF decrements, COPD exacerbations and PEF exacerbations*
| Pollutant | OR† (unit change) (95% CI) | p Value | Estimate‡ (per IQR change) |
| Large PEF decrements | |||
| NO2 (ppb) | 1.000 (0.995 to 1.004) | 0.844 | 0.994 |
| O3 (ppb) | 0.996 (0.989 to 1.004) | 0.362 | 0.950 |
| SO2 (ppb) | 1.001 (0.988 to 1.014) | 0.890 | 1.006 |
| PM10 (μg/m3) | 0.999 (0.995 to 1.003) | 0.712 | 0.985 |
| Black smoke (μg/m3) | 1.001 (0.991 to 1.011) | 0.851 | 1.009 |
| COPD exacerbations | |||
| NO2 (ppb) | 1.002 (0.996 to 1.008) | 0.469 | 1.032 |
| O3 (ppb) | 1.005 (0.987 to 1.023) | 0.598 | 1.070 |
| SO2 (ppb) | 1.002 (0.982 to 1.022) | 0.878 | 1.010 |
| PM10 (μg/m3) | 1.004 (0.998 to 1.010) | 0.234 | 1.075 |
| Black smoke (μg/m3) | 1.003 (0.994 to 1.013) | 0.497 | 1.029 |
| Symptomatic fall in PEF | |||
| NO2 (ppb) | 1.004 (0.999 to 1.009) | 0.137 | 1.058 |
| O3 (ppb) | 1.002 (0.984 to 1.020) | 0.840 | 1.026 |
| SO2 (ppb) | 1.004 (0.987 to 1.022) | 0.622 | 1.026 |
| PM10 (μg/m3) | 1.006 (1.001 to 1.012) | 0.029 | 1.124 |
| Black smoke (μg/m3) | 1.007 (1.000 to 1.014) | 0.050 | 1.066 |
↵* In addition to individual pollutants (previous day), each model includes outdoor temperature (average of the minimum and maximum) and season (four categories) plus control for autocorrelation.
↵† ORs are for a 1 unit change in pollutant level (ppb for NO2, O3, SO2; μg/m3 for PM10, black smoke).
↵‡ ORs are for an IQR change in pollutant level.
COPD, chronic obstructive pulmonary disease; PEF, peak expiratory flow; PM, particulate matter.