Exposure to Traffic and Regional Air Pollution Throughout the Life Course on Lung Function

Abstract

Introduction: Several studies have reported adverse effects of near-roadway air pollution and regional air pollution on lung function in children. However, there has been little investigation as to whether there is a critical time when these pollutants may cause the largest detrimental effect to the developing lung. Methods: As part of the Children’s Health Study, repeated measurements of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were assessed on 1,502 children between the ages of 11 and 15 in eight Southern Californian communities. Residential measures of exposure to near-roadway air pollutants from either freeways or large roads (freeway or non-freeway nitric oxides [NOx]) were estimated using the CALINE4 dispersion model, while regional pollutants (nitrogen dioxide [NO2], ozone [O3], and particulate matter with aerodynamic dynamiter of less than 2.5um and 10um [PM2.5 and PM10]) were estimated from inverse distance weighting of regional monitoring stations. All exposures were estimated from one year prior to birth until last year of follow-up. Mixed linear regression models were used to associate exposures during different periods of life and lung function. Results: Preliminary findings suggest that exposure to an increase of 18.9 ppb of freeway NOx one year before birth was associated with a 23.1 ml decrease in FVC (p-value = 0.02), while exposure to the same change in freeway NOx one year after birth was associated with a 16.0 ml decrease (p-value = 0.047). However, exposure to freeway NOx one year before lung function testing was associated with a non-significant decrease in FVC (13.2 ml deficit, p-value = 0.052). Conclusion: These results suggest that early life exposure to near-roadway air pollutants may be more impactful than during other periods in the trajectory of lung development through adolescence. There was less consistent findings with regional air pollution.