Table 4 Associations between incident wheezing symptoms for 3-day mean concentrations (lag 2–4) of air pollutants in infants (age 0–1 years) in period with available PM10 measurements (12 December 1998 to 19 December 2004)
One-pollutant modelTwo-pollutant modelTwo-pollutant modelTwo-pollutant model
OR* (95% CI)OR (95% CI)OR (95% CI)OR (95% CI)
n†189189189189
PM10 (μg/m3)1.21 (0.99 to 1.48)1.13 (0.88 to 1.45)1.16 (0.90 to 1.48)1.23 (0.96 to 1.57)
NO2 (ppb)1.46 (1.05 to 2.02)‡1.34 (0.90 to 1.99)
NOx (ppb)1.31 (1.01 to 1.68)‡1.21 (0.89 to 1.64)
CO (ppm)1.27 (0.86 to 1.89)1.03 (0.64 to 1.6)

  • CO, carbon monoxide; NOx, nitrogen oxide; NO2, nitrogen dioxide; PM10, particulate matter <10 μm in diameter.

  • *Odds ratios estimated per IQR of a pollutant and 3-day mean (lag 2–4 days) adjusted for age, gender, exposure to smoking, paternal asthma history, temperature and season.

  • †Number of COPSAC children in the model.

  • ‡p<0.05.