Table 6

Further investigation of associations with PEF exacerbations and dyspnoea: single and multiple pollutant models*

Model*Single pollutant modelsMultiple pollutant models
OR (unit change)SEp ValueOR (unit change)SEp ValueOR (IQR change)
Symptomatic fall in PEF (N=78)
 Model 1
 Model 2
  Black smoke1.0070.0040.0501.0050.0050.3061.049
 Model 3
  Black smoke1.0070.0040.0501.0000.0050.9530.998
 Model 4
  Black smoke1.0070.0040.0501.0010.0060.9071.006
Dyspnoea n=77
 Model 1
 Model 2
  Black smoke1.0030.0050.5261.0030.0060.5981.159
 Model 3
  Black smoke1.0030.0050.5260.9960.0060.4550.961
 Model 4
  Black smoke1.0030.0050.5260.9980.0070.7330.979
  • * In addition to individual pollutants (previous day), each model includes outdoor temperature (average of the min and maximum) and season (four categories) plus control for autocorrelation. Models 1–3 each contain two pollutants analysed together. Model 4 includes all three pollutants.

  • ORs are for a 1 unit change in pollution level (ppb for NO2, O3, SO2; μg/m3 for PM10, black smoke).

  • ORs are for an IQR change in pollutant level.

  • PEF, peak expiratory flow; PM, particulate matter.