Department of Global and Community Health, College of Health and Human Services, George Mason University, 4400 University Drive MS 5B7, Fairfax, VA, 22030, USA.
Department of Environmental Health, Emory University, Atlanta, USA.
J Expo Sci Environ Epidemiol. 2018 Jun;28(4):337-347. doi: 10.1038/s41370-017-0016-7. Epub 2018 Jan 3.
Concentrations of traffic-related air pollutants are frequently higher within commuting vehicles than in ambient air. Pollutants found within vehicles may include those generated by tailpipe exhaust, brake wear, and road dust sources, as well as pollutants from in-cabin sources. Source-specific pollution, compared to total pollution, may represent regulation targets that can better protect human health. We estimated source-specific pollution exposures and corresponding pulmonary response in a panel study of commuters. We used constrained positive matrix factorization to estimate source-specific pollution factors and, subsequently, mixed effects models to estimate associations between source-specific pollution and pulmonary response. We identified four pollution factors that we named: crustal, primary tailpipe traffic, non-tailpipe traffic, and secondary. Among asthmatic subjects (N = 48), interquartile range increases in crustal and secondary pollution were associated with changes in lung function of -1.33% (95% confidence interval (CI): -2.45, -0.22) and -2.19% (95% CI: -3.46, -0.92) relative to baseline, respectively. Among non-asthmatic subjects (N = 51), non-tailpipe pollution was associated with pulmonary response only at 2.5 h post-commute. We found no significant associations between pulmonary response and primary tailpipe pollution. Health effects associated with traffic-related pollution may vary by source, and therefore some traffic pollution sources may require targeted interventions to protect health.
交通相关空气污染物的浓度在通勤车辆内通常比环境空气中更高。车内污染物可能包括来自排气管尾气、刹车片磨损和道路扬尘源的污染物，以及车内源的污染物。与总污染相比，特定来源的污染可能代表更好地保护人类健康的监管目标。我们在通勤者的面板研究中估计了特定来源的污染暴露和相应的肺部反应。我们使用约束性正矩阵因子分解来估计特定来源的污染因子，随后使用混合效应模型来估计特定来源的污染与肺部反应之间的关联。我们确定了四个污染因子，分别命名为：地壳、主要排气管交通、非排气管交通和二次。在哮喘患者（N=48）中，地壳和二次污染的四分位间距增加与肺功能的变化分别为 -1.33%（95%置信区间 (CI): -2.45, -0.22）和 -2.19%（95% CI: -3.46, -0.92）。在非哮喘患者（N=51）中，仅在通勤后 2.5 小时，非排气管污染与肺部反应相关。我们没有发现肺部反应与主要排气管污染之间存在显著关联。与交通相关的污染相关的健康影响可能因来源而异，因此一些交通污染源可能需要针对性的干预措施来保护健康。
