Children's exposures/health effects/diesel exhaust

描述（由申请人提供）：柴油废气（DE）对健康的贡献，特别是儿童的健康，是巨大的公共卫生利益。除其他重要的健康影响外，DE与哮喘和过敏的恶化有关。减少DE暴露已成为一项主要的监管举措，联邦、州和地方司法机构正在投资数亿美元改造校车的柴油发动机，并进行其他改革以实现这一目标。然而，一个严重的问题仍未得到解答：这项重大的政府环境政策将对公众健康产生多大的影响，尤其是对那些乘坐柴油公交车上下班的哮喘儿童的健康？这项拟议的研究填补了知识空白，并通过检查DE暴露对乘坐校车的儿童哮喘发病率的重要性，同时调整环境空气污染和其他随时间变化的因素的影响，提供了有关此类法规和全国变化影响的大量公共卫生信息。这项为期5年的研究将首次评估校车从“脏”发动机和燃料改为“清洁”发动机和燃料前后的儿童健康影响。该项目旨在：1)确定哮喘儿童乘坐使用清洁燃料和发动机的公共汽车是否会降低亚临床和临床哮喘严重程度；2)确定DE暴露水平的增加是否会导致哮喘临床特征的增加；3)量化和表征哮喘儿童暴露于DE的颗粒和有毒气体的变化。这项研究包括对华盛顿州普吉特海湾地区500名通勤上学的哮喘学童进行为期3年的接触和健康监测。使用肺活量测定法每月测量肺功能，通过呼出一氧化氮评估肺部炎症，哮喘症状，药物治疗和临床就诊，将在学年期间对所有儿童进行测量。这500名儿童将从几个学区招募，代表三种暴露情景：1)125名儿童在所有学习期间乘坐改装的柴油巴士或开车上下班；2) 250名儿童乘坐旧柴油巴士，这些巴士将在研究的第一和第二年后进行翻新；在整个研究过程中，125名儿童乘坐老式柴油公交车。将估计所有受试者的暴露情况，并在每个监测年度对144名受试者和48辆校车的子集进行深入的个人暴露评估，以涵盖校车类型和路线的范围。这些个人暴露测量将用于描述和区分儿童与其他来源的暴露，并为那些没有个人监测的儿童建立暴露模型。这项研究将提供有关减少柴油排放直接减少暴露和健康影响的关键缺失信息。

DESCRIPTION (provided by applicant): The contribution of diesel exhaust (DE) to health, especially children's health, is of tremendous public health interest. DE has been associated with worsening asthma and allergies, among other important health effects. Reducing DE exposures has become a major regulatory initiative, and federal, state, and local jurisdictions are investing hundreds of millions of dollars in retrofitting diesel engines in school buses and other changes to reach this goal. However, a serious question remains unanswered: what magnitude of impact will this major governmental environmental policy have on public health, especially the health of asthmatic children who commute by diesel bus? This proposed study fills in the knowledge gap and provides substantial public health information on the impact of such regulations and nationwide changes by examining the importance of DE exposures to asthma morbidity among children who ride school buses, while adjusting for the influence of ambient air pollution and other factors that change over time. This 5-year study will be the first to assess children's health effects from DE before and after the change from "dirty" to "clean" engines and fuels in school bus fleets. This project aims to: 1) determine whether asthmatic children changing to buses with cleaner fuels and engines have a reduction in sub-clinical and clinical asthma severity; 2) determine if increased levels of DE exposure lead to an increase in clinical features of asthma; and 3) quantify and characterize the changes in particle and toxic gas exposures to DE in asthmatic children. This study includes 3 years of exposure and health monitoring on 500 asthmatic school children who commute to school in the Puget Sound area of Washington State. Monthly measures of pulmonary function using spirometry, pulmonary inflammation assessed by exhaled nitric oxide, asthma symptoms, medications, and clinical encounters, will be obtained on all children during the school year. The 500 children will be recruited from several school districts to represent 3 exposure scenarios: 1) 125 children riding retrofitted diesel bus or commuting by car over all years of study; 2) 250 children riding old diesel buses, which will be retrofitted after the first and second year of the study; and 3) 125 children riding old diesel buses throughout the study. Exposures will be estimated for all subjects, and an in-depth individual exposure assessment will be performed on a subset of 144 subjects and 48 school buses in each monitoring year to cover the spectrum of bus type and routes. These personal exposure measurements will be used to characterize and distinguish children's exposure to DE from other sources, and develop an exposure model for those who are not personally monitored. This study will provide critical missing information relating reductions in diesel emissions directly to reductions in exposures and health effects.