Children's exposures/health effects/diesel exhaust

描述（由申请人提供）：柴油机尾气（DE）对健康，尤其是儿童健康的贡献具有巨大的公共卫生利益。DE与哮喘和过敏恶化以及其他重要的健康影响有关。减少DE暴露已成为一项主要的监管举措，联邦、州和地方司法管辖区正在投资数亿美元用于改造校车的柴油发动机和其他变革，以实现这一目标。然而，一个严重的问题仍然没有答案：这一重大的政府环境政策将对公众健康，特别是对乘坐柴油公交车的哮喘儿童的健康产生多大程度的影响？这项拟议的研究填补了知识空白，并通过检查乘坐校车的儿童中DE暴露对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范围内变化的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在校车车队从“脏”引擎和燃料改为“清洁”引擎和燃料之前和之后，DE对儿童健康的影响。该项目旨在：1）确定哮喘儿童更换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）量化和描述哮喘儿童中DE颗粒和有毒气体暴露的变化。本研究包括对华盛顿州普吉特海湾地区500名哮喘学童的3年暴露和健康监测。在学年期间，将对所有儿童进行每月肺功能测定，通过呼出的一氧化氮评估肺部炎症，哮喘症状，药物治疗和临床治疗。将从几个学区招募500名儿童，以代表3种暴露情景：1）125名儿童在研究的所有年份中乘坐改装的柴油公交车或开车上下班; 2）250名儿童乘坐旧柴油公交车，这些公交车将在研究的第一年和第二年后进行改装; 3）125名儿童在整个研究期间乘坐旧柴油公交车。将估计所有受试者的暴露量，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体暴露评估，以涵盖巴士类型和路线。这些个人暴露测量将用于表征和区分儿童暴露于DE与其他来源，并为那些没有亲自监测的人开发暴露模型。这项研究将提供减少柴油排放与减少接触和健康影响直接相关的关键缺失信息。

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.