Acute Impact of Hourly Ambient Air Pollution on Preterm Birth

http://dx.doi.org/10.1289/EHP200



Table 3. The risks of preterm birth at 75th and 95th percentiles of air pollution against the minimum preterm birth concentration of air pollution (threshold) in single-pollutant models.
Pollutant Threshold (ppb) 75th (ppb) 95th (ppb) OR (95% CI)
75th vs. threshold 95th vs. threshold
Abbreviations: CI, confidence interval; CO, carbon monoxide (mean of 0–24 hr preceding onset of labor); NO2, nitrogen dioxide (mean of 0–24 hr preceding onset of labor); OR, odds ratio; ppb, parts per billion; SO2, sulfur dioxide (mean of 24–48 hr preceding onset of labor).
NO2 7.6 8.3 11.3 1.01 (0.99, 1.03) 1.17 (1.08, 1.27)
SO2 3.8 2.2 4.8 1.04 (0.99, 1.08) 1.01 (0.99, 1.04)
CO 162.5 301.0 424.0 1.10 (1.01, 1.19) 1.18 (1.06, 1.32)