The Potential Effects of Policy-driven Air Pollution Interventions on Childhood Lung Development.

Rationale: Although elevated air pollution exposure impairs lung-function development in childhood, it remains a challenge to use this information to estimate the potential public health benefits of air pollution interventions in exposed populations. Objectives: Apply G-computation to estimate hypothetical effects of several realistic scenarios for future air pollution reductions on lung growth. Methods: Mixed-effects linear regression was used to estimate FEV ₁ and FVC from age 11 to 15 years in 2,120 adolescents across 3 cohorts (1993-2001, 1997-2004, and 2007-2011). Models included regional pollutants (nitrogen dioxide [NO ₂ ] or particulate matter with an aerodynamic diameter ≤2.5 μm [PM _2.5 ]) and other important covariates. Using G-computation, a causal inference-based method, we then estimated changes in mean lung growth in our population for hypothetical interventions on either NO ₂ or PM _2.5 . Confidence intervals (CIs) were computed by bootstrapping ( N  = 1,000). Measurements and Main Results: Compared with the effects of exposure from observed NO ₂ concentrations during the study period, had communities remained at 1994 to 1997 NO ₂ levels, FEV ₁ and FVC growth were estimated to have been reduced by 2.7% (95% CI, -3.6 to -1.8) and 4.2% (95% CI, -5.2 to -3.4), respectively. If NO ₂ concentrations had been reduced by 30%, we estimated a 4.4% increase in FEV ₁ growth (95% CI, 2.8-5.9) and a 7.1% increase in FVC growth (95% CI, 5.7-8.6). Comparable results were observed for PM _2.5 interventions. Conclusions: We estimated that substantial increases in lung function would occur as a result of interventions that reduce NO ₂ or PM _2.5 concentrations. These findings provide a quantification of potential health benefits of air quality improvement.