Table 2.
Estimates of the Effect of Hypothetical Air Pollutant Interventions on FEV1 Growth between Ages 11 and 15 Years
| Mean (95% CI) FEV1 Growth from Ages 11 to 15 yr (ml) | Absolute Change (95% CI) | Percent Change (95% CI) | |
|---|---|---|---|
| NO2 | |||
| Observed exposure* | 1,183.8 (1,164.5 to 1,199.2) | Reference | Reference |
| Remain at cohort C levels† | 1,152.1 (1,129.7 to 1,169.2) | −31.7 (−42.6 to −20.9) | −2.7 (−3.6 to −1.8) |
| Percent reduction | |||
| 10% | 1,201.0 (1,181.0 to 1,218.0) | 17.2 (11.2 to 23.4) | 1.5 (0.9 to 2.0) |
| 20% | 1,218.2 (1,194.6 to 1,238.8) | 34.4 (22.4 to 46.8) | 2.9 (1.9 to 4.0) |
| 30% | 1,235.4 (1,208.3 to 1,261.0) | 51.6 (33.4 to 70.2) | 4.4 (2.8 to 5.9) |
| Hypothetical thresholds‡ | |||
| 30 ppb | 1,195.8 (1,176.2 to 1,212.3) | 12.0 (7.7 to 16.8) | 1.0 (0.6 to 1.4) |
| 20 ppb | 1,229.7 (1,203.6 to 1,253.6) | 45.9 (29.7 to 63.3) | 3.9 (2.5 to 5.4) |
| PM2.5 | |||
| Observed exposure* | 1,182.8 (1,163.8 to 1,198.4) | Reference | Reference |
| Remain at cohort C levels† | 1,152.2 (1,127.9 to 1,170.9) | −30.6 (−46.0 to −17.1) | −2.6 (−3.9 to −1.5) |
| Percent reduction | |||
| 10% | 1,192.8 (1,146.1 to 1,183.0) | 10.0 (5.5 to 15.4) | 0.8 (0.5 to 1.3) |
| 20% | 1,202.9 (1,160.5 to 1,196.0) | 20.1 (10.8 to 30.7) | 1.7 (0.9 to 2.6) |
| 30% | 1,212.9 (1,174.1 to 1,209.9) | 30.1 (16.2 to 46.1) | 2.5 (1.4 to 3.9) |
| Hypothetical thresholds‡ | |||
| 15 μg/m3 | 1,213.6 (1,190.0 to 1,236.6) | 30.8 (16.4 to 47.7) | 2.6 (1.4 to 4.0) |
| 12 μg/m3 | 1,225.5 (1,199.6 to 1,253.2) | 42.7 (23.0 to 65.8) | 3.6 (2.0 to 5.6) |
Definition of abbreviations: CI = confidence interval; NO2 = nitrogen dioxide; PM2.5 = particulate matter with an aerodynamic diameter ≤2.5 μm.
*
Predicted outcome based on observed exposure.
†
Predicted outcome if all participants in cohorts D and E had experienced exposures equal to that of participants in cohort C.
‡
Predicted outcome if all participants in communities that exceeded each threshold had been assigned exposures equal to that threshold.