AGE AND BODY SIZE FACTORS IN INHALED PARTICLE DEPOSITION

尽管新生儿、婴儿和年龄较大的儿童 每单位体重的通风量更大， 这些努力表明，他们通常从 吸入颗粒物比成年人多，没有经过验证的气溶胶 未成年人吸入剂量模型。 拟议的研究是 旨在弥补这一缺陷。 将进行研究 在两个领域;在成人中进行气溶胶沉积实验- 和儿童尺寸的中空气道模型，以及 计算机模型给孩子们。 这两种努力是相互的。 支持，因为中空模型数据可用于验证 和/或修改计算模型，并且计算模型 模型可用于识别 强烈决定颗粒沉积。 范围包括大多数颗粒的空气动力学直径 对毒理学感兴趣（0.1至20微米），年龄0岁至 成年人，几种活动状态（休息到剧烈运动），以及 研究继续进行，非典型的解剖学或生理学特征， 非理想颗粒和污染物的混合物。 实验室研究将使用专门设计的空心模型 从成长中的人的解剖学数据中， 考虑到已知的关键结构特征， 影响主要的气溶胶沉积机制（撞击， 扩散和沉降）。 这些模型将受到 实验室产生的已知大小的气溶胶在受控 将测量气流和颗粒沉积。 计算模型将基于已知的模型， 对成人有效，他们将包括在每个顺序沉积 解剖学区域。 空气中微粒的吸入性 各种尺寸的模型将被包括在计算模型中。 现有的计算模型将得到改进， 项目 结果将包括中空的气溶胶沉积效率 代表呼吸系统区域的各种尺寸的模型 道（鼻、口、咽、喉和气管支气管）。 结果还将包括这些的剂量计算 区域（和肺泡区域）的各种年龄和状态的 活动

Despite the facts that newborns, infants and older children have greater ventilation per unit of body weight and that modeling efforts indicate that they generally receive greater doses from inhaled particles than do adults, there are no validated aerosol inhalation dose models for pre-adults. The proposed research is intended to remedy this deficiency. Research will be conducted in two areas; performing aerosol deposition experiments in adult- and child-sized hollow airway models, and application of computational models to children. These two efforts are mutually supportive because the hollow model data can be used to validate and/or modify the computational models, and the computational models can be used to identify the hollow model features that strongly determine particle deposition. The scope includes the particle aerodynamic diameters of most interest in toxicology (0.1 to 20 micrometers), ages 0 years to adult, several states of activity (resting to heavy exertion), and as the study proceeds, atypical anatomical or physiological features, non-ideal particles, and mixtures of pollutants. Laboratory studies will use hollow models which are designed from anatomical data on growing people, and which take into account the critical structural features that are known to influence the major aerosol deposition mechanisms (impaction, diffusion and sedimentation). The models will be subjected to laboratory-generated aerosols of known sizes at controlled airflows and particle deposition will be measured. The computational models will be based on models known to be valid for adults and they will include sequential deposition in each of the anatomical regions. The inspirability of airborne particles of various sizes will be included in the computational model. Existing computational models will be improved as part of the project. The results will include aerosol deposition efficiencies in hollow models of various sizes that represent regions of the respiratory tract (nasal, oral, pharyngeal, laryngeal, and tracheobronchial). Results will also include dosimetric computations for these regions (and the alveolar region) for various ages and states of activity.