Children's exposures/health effects/diesel exhaust

描述(申请人提供)：柴油废气(DE)对健康的贡献，特别是对儿童的健康，具有巨大的公众健康利益。在其他重要的健康影响中，De与恶化的哮喘和过敏有关。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为校车改装柴油发动机和其他改变，以实现这一目标。然而，一个严肃的问题仍然没有得到回答：这项政府的重大环境政策将对公众健康，特别是乘坐柴油公交车通勤的哮喘儿童的健康产生多大影响？这项拟议的研究填补了这一知识空白，并通过检查乘坐校车的儿童暴露于DE对哮喘发病率的重要性，同时根据环境空气污染和其他随时间变化的因素的影响进行调整，提供了关于此类法规和全国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的发动机和燃料从“脏”改为“干净”前后DE对儿童健康的影响。该项目旨在：1)确定哮喘儿童改用更清洁的燃料和发动机的公交车是否降低了亚临床和临床哮喘的严重程度；2)确定DE暴露水平的增加是否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的颗粒物和有毒气体的变化。这项研究包括对华盛顿州普吉特湾地区500名通勤上学的哮喘学童进行为期3年的暴露和健康监测。将在学年内对所有儿童进行每月肺功能测量、通过呼出的一氧化氮评估肺部炎症、哮喘症状、药物治疗和临床接触。这500名儿童将从几个学区招募，代表3种暴露情景：1)125名儿童在所有研究年度乘坐改装柴油巴士或乘车通勤；2)250名儿童乘坐旧柴油巴士，将在研究第一年和第二年后进行改装；以及3)125名儿童在整个研究过程中乘坐旧柴油巴士。当局会评估所有受试者的辐射水平，并会在每个监测年度内，对144名受试者和48辆校巴进行深入的个别辐射评估，以涵盖各类巴士类型和路线。这些个人暴露测量将被用来表征和区分儿童暴露于DE与其他来源的特征，并为那些没有受到个人监测的人开发暴露模型。这项研究将提供关键的缺失信息，将柴油排放的减少与暴露和健康影响的减少直接相关。

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.