Table 5

 Changes in birth weight (in grams) for a 1 unit change in exposure to air pollutants (PM10 and PM2.5 in μg/m3; CO in ppm; O3, NO2 in ppb) at each trimester, and last month of pregnancy; results of linear regression models adjusted for covariates

PollutantExposure period
One month before birthThird trimesterSecond trimesterFirst trimester
Multiple linear regression coefficient95% confidence limitsMultiple linear regression coefficient95% confidence limitsMultiple linear regression coefficient95% confidence limitsMultiple linear regression coefficient95% confidence limits
ppb, parts per billion (10−9); ppm, parts per million (10−6).
Units and averaging periods:
PM10 (μg/m3): 24 hour av
PM2.5 (μg/m3): 24 hour av
CO (ppm): 8 hour av
O3 (ppb): 1 hour max
NO2 (ppb): 1hour max
All births
PM10−1.21−2.31−0.11−0.95−2.300.40−2.05−3.36−0.74−0.14−1.371.09
PM2.5−2.48−4.58−0.38−0.98−3.741.78−4.10−6.79−1.410.36−2.293.01
CO−15.28−25.59−4.97−6.63−18.575.31−10.72−23.091.651.86−8.3112.03
NO2−0.76−1.720.20−1.48−2.70−0.26−0.95−2.070.17−1.07−2.07−0.07
O3−0.11−0.560.34−0.45−1.080.18−0.75−1.38−0.12−0.09−0.660.48
5 km births
PM10−2.98−4.25−1.71−3.84−5.35−2.33−4.28−5.79−2.77−2.57−4.04−1.10
PM2.5−2.70−6.801.40−2.83−9.003.341.54−4.597.671.89−1.995.77
CO−10.41−30.039.21−22.88−44.58−1.18−28.87−50.98−6.76−8.96−28.6010.68
NO2−19.68−27.83−11.53−32.17−41.81−22.53−33.85−43.38−24.32−26.22−35.41−17.03
O3−0.65−6.515.21−2.00−9.645.648.771.0516.498.99−0.5918.57