校车使用清洁燃料和技术：污染及对儿童健康的影响
2015/06/18
摘要
背景：超过2500万美国儿童呼吸来自柴油校车的污染空气。存在减排政策，但对每个儿童健康的危害并未进行评估。
方法：研究采用自然试验，检测2005年-2009年间采用清洁技术和燃料前、中、后275位校车司机的污染空气暴露和健康情况。检测188辆校车的597次路程的空气污染。每月一次重复检测呼出气一氧化氮(FENO)、肺功能（第一秒用力呼气容积（FEV1），用力肺活量（FVC））和误工次数（1768次访视）。使用混合效应模型纵向联系柴油机氧化催化剂(DOC)的使用、闭式曲轴箱通风系统(CCV)、超低硫柴油(ULSD)，或生物柴油与污染空气暴露和健康。
结果：使用ULSD、DOCs、和/或 CCVs的校车的微小和超微粒子的含量下降10-50%。使用ULSD能够使与哮喘密切相关的FENO降低16% (95% 可信区间: 10, 21%)，FVC(95% 可信区间: 0.003, 0.05)和FEV1(95%可信区间: -0.006, 0.03)分别增加0.02和0.01L/年，与哮喘密切相关的误工下降8%(95% 可信区间: 16.0, 0.7%)。DOCs和较小范围的CCVs也能够改善FENO, FVC增加和误工，但是这些发现主要限定于持续性哮喘患者，对ULSD的控制敏感。生物燃料不能增加健康获益。由此推测到美国人群，改变燃料/技术可能降低＞1400万/年的旷工人数。
结论：国家和地方的柴油政策已经降低儿童的污染暴露并改善了健康状况。
（杨冬 审校）
Am J Respir Crit Care Med. 2015 Apr 13. [Epub ahead of print]
Adopting Clean Fuels and Technologies on School Buses: Pollution and Health Impacts in Children.
Adar SD1, D'Souza J, Sheppard L, Kaufman JD, Hallstrand TS, Davey ME, Sullivan JR, Jahnke J, Koenig J, Larson TV,Liu LJ.
Author information
Abstract
BACKGROUND:Over 25 million American children breathe polluted air on diesel school buses. Emission reduction policies exist but the health impacts to individual children have not been evaluated.
METHODS:Using a natural experiment, we characterized the exposures and health of 275 school bus riders before, during, and after the adoption of clean technologies and fuels between 2005 and 2009. Air pollution was measured during 597 trips on 188 school buses. Repeated measures of exhaled nitric oxide (FENO), lung function (forced expiratory volume in the first second (FEV1), forced vital capacity (FVC)) and absenteeism were also collected monthly (1,768 visits). Mixed-effects models longitudinally related the adoption of diesel oxidation catalysts (DOC), closed crankcase ventilation systems (CCV), ultralow sulfur diesel (ULSD), or biodiesel with exposures and health.
RESULTS:Fine and ultrafine particle concentrations were 10-50% lower on buses using ULSD, DOCs, and/or CCVs. ULSD adoption was also associated with -16% (95% CI: -10, -21%) reduced FENO, 0.02 (95% CI: 0.003, 0.05) and 0.01 (95% CI: -0.006, 0.03) L/year greater changes in FVC and FEV1, respectively, and -8% (95% CI: -16.0, -0.7%) lower absenteeism with stronger associations among asthmatics. DOCs and, to a lesser extent CCVs, also were associated with improved FENO, FVC growth, and absenteeism, but these findings were primarily restricted to persistent asthmatics and were often sensitive to control for ULSD. No health benefits were noted for biodiesel. Extrapolating to the US population, changed fuel/technologies likely reduced absenteeism by >14 million/year.
CONCLUSIONS:National and local diesel policies appear to have reduced children's exposures and improved health.
Am J Respir Crit Care Med. 2015 Apr 13. [Epub ahead of print]
