TABLE 3 Results of meta-analyses for the association between level and change of lung function and exposure to air pollution and traffic intensity indicators
Exposure (increment)Level of lung function (mL)#
FEV1FVC
Beta95% CII2 §
p-value (het)
Beta95% CII2 §
p-value (het)
NO2 (10 μg·m−3)−13.98−25.82 to −2.140.0%
p=0.625
−14.93−28.73 to −1.130.0%
p=0.977
NOx (20 μg·m−3)−12.91−23.79 to −2.040.0%
p=0.861
−13.25−25.85 to −0.650.0%
p=0.962
PM10 (10 μg·m−3)−44.56−85.36 to −3.760.0%
p=0.628
−58.96−112.27 to −5.650.0%
p=0.785
PM2.5 (5 μg·m−3)−21.14−56.37 to 14.080.0%
p=0.535
−36.39−83.29 to 10.500.0%
p=0.877
PM2.5 absorbance (1×10−5 m−1)−24.40−55.58 to 6.790.0%
p=0.709
−12.94−50.23 to 24.300.0%
p=0.619
Coarse PM (5 μg·m−3)−22.36−94.00 to 49.2712.6%
p=0.333
2.88−87.85 to 93.600.0%
p=0.760
Traffic intensity on nearest road (high/low)ƒ,##−27.61−59.62 to 4.3929.0%
p=0.228
−10.37−48.23 to 27.4927.3%
p=0.239
Traffic load on nearest major road in a 100-m buffer (high/low)##,¶¶−32.34−59.30 to −5.380.0%
p=0.784
−18.64−50.22 to 12.940.0%
p=0.967
Exposure (increment)Change in lung function (mL per year)
FEV1FVC
Beta§§95% CII2 § p-value (het)Beta§§95% CII2 § p-value (het)
NO2 (10 μg·m−3)0.30−0.39 to 0.980.0%
p=0.681
0.02−0.84 to 0.880.0%
p=0.532
NOx (20 μg·m−3)0.18−0.44 to 0.800.0%
p=0.708
−0.09−0.86 to 0.690.0%
p=0.804
PM10 (10 μg·m−3)−0.39−2.85 to 2.0653.1%
p=0.074%
−1.42−4.53 to 1.7028.4%
p=0.232
PM2.5 (5 μg·m−3)−0.14−2.26 to 1.9823.8%
p=0.263
−1.37−4.04 to 1.290.0%
p=0.964
PM2.5 absorbance (1×10−5 m−1)0.88−0.76 to 2.5254.5%
p=0.066
1.14−0.95 to 3.244.5%
p=0.381
Coarse PM (5 μg·m−3)0.26−3.92 to 4.4361.7%
p=0.034
−1.31−6.49 to 3.880.0%
p=0.506
Traffic intensity on nearest road (high/low)ƒ,##−0.74−2.58 to 1.100.0%
p=0.772
−0.15−2.49 to 2.1818.1%
p=0.299
Traffic load on nearest major road in a 100-m buffer (high/low)##,¶¶−0.32−1.81 to 1.180.0%
p=0.987
0.34−1.56 to 2.250.0%
p=0.672
  • FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; PM: particulate matter. #: level of lung function for cross-sectional analysis was derived from second spirometry. : the beta values for the association between level of lung function and exposure are adjusted for age, age squared, height, sex, body mass index (BMI), highest educational level, and smoking status at second spirometry; a negative sign indicates lower lung function with increasing exposure. §: I2 and Cochran's test for heterogeneity of effect estimates between cohorts. ƒ: low traffic intensity on nearest road: ≤5000 cars per day; high: >5000 cars per day. ##: associations with traffic intensity (high/low) and traffic load (high/low) were additionally adjusted for background NO2 concentrations. ¶¶: low traffic load on the nearest major road in a 100-m buffer: ≤500 car-km driven per day; high: >500 car-km driven per day. §§: the beta values of the association between change in lung function and exposure are adjusted for sex, age and height at first spirometry, highest educational level, smoking at first spirometry, smoking cessation and change in BMI to the second spirometry; a negative sign indicates steeper lung function decline with increasing exposure.