Traffic-related air pollution and alveolar nitric oxide in southern California children

摘要

Mechanisms for the adverse respiratory effects of traffic-related air pollution (TRAP) have yet to be established. We evaluated the acute effects of TRAP exposure on proximal and distal airway inflammation by relating indoor nitric oxide (NO), a marker of TRAP exposure in the indoor microenvironment, to airway and alveolar sources of exhaled nitric oxide (FeNO).FeNO was collected online at four flow rates in 1,635 southern California schoolchildren (ages 12–15) breathing NO-free air. Indoor NO was sampled hourly and linearly interpolated to the time of the FeNO test. Estimated parameters quantifying airway wall (diffusivity: DawNO and flux: J′awNO) and alveolar (concentration: CANO) sources of FeNO were related to exposure using linear regression to adjust for potential confounders.We found that TRAP exposure indoors was associated with elevated alveolar NO. A 10 ppb higher indoor NO concentration at the time of the FeNO test was associated with: 0.10 ppb higher average CANO (95% Confidence Interval (CI): 0.04, 0.16) [equivalent to a 7.1% increase from the mean], 4.0% higher J′awNO (95% CI: −2.8, 11.3), and 0.2% lower DawNO (95% CI: −4.8, 4.6).These findings are consistent with an airway response to TRAP exposure that was most marked in the distal airways.