Table 3

Regression of respiratory function (PEF, FEV1 and FVC) on pollutant level* (previous day)

 Estimate† (per unit change) (95% CI) p Value Estimate‡ (per IQR change) PEF (l/min) n=94 NO2 (ppb) 0.013 (0.002 to 0.024) 0.026 0.179 O3 (ppb) −0.015 (−0.039 to 0.009) 0.229 −0.211 SO2 (ppb) 0.031 (−0.010 to 0.072) 0.133 0.191 PM10 (μg/m3) 0.009 (−0.006 to 0.023) 0.253 0.164 Black smoke (μg/m3) 0.011 (−0.005 to 0.028) 0.180 0.103 FEV1 (ml) n=28 NO2 (ppb) 0.005 (−0.106 to 0.116) 0.929 0.071 O3 (ppb) −0.081 (−0.258 to 0.096) 0.369 −1.143 SO2 (ppb) −0.035 (−0.386 to 0.315) 0.843 −0.216 PM10 (μg/m3) 0.031 (−0.067 to 0.129) 0.536 0.588 Black smoke (μg/m3) 0.045 (−0.113 to 0.203) 0.576 0.405 FVC (ml) n=28 NO2 (ppb) 0.071 (−0.189 to 0.332) 0.591 1.000 O3 (ppb) 0.162 (−0.238 to 0.562) 0.426 2.288 SO2 (ppb) −0.335 (−1.192 to 0.522) 0.444 −2.043 PM10 (μg/m3) 0.187 (−0.017 to 0.392) 0.073 3.561 Black smoke (μg/m3) 0.166 (−0.218 to 0.551) 0.396 1.498
• * 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.

• Estimates represent the change in lung function for a 1 unit change in pollutant level (ppb for NO2, O3, SO2; μg/m3 for PM10, black smoke).

• Estimates represent the change in lung function for an IQR change in pollutant level.

• FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; PEF, peak expiratory flow; PM, particulate matter.