Assessing Inhalation Exposure to Aerosolized Contaminants from Drinking Water

1605355饮食这项拟议的项目填补了关于人类在空气-水-人体界面接触超声波加湿器排放的气雾剂污染物的关键知识空白。通常情况下，消费者购买超声波加湿器，向其注入饮用水，然后每天在卧室等狭小空间使用几个小时。从超声波加湿器得到的吸入暴露信息将使科学家能够合理地评估与饮用水中溶解的污染物有关的人体健康风险，并随后为消费者提供使用建议。超声加湿器气雾剂的基本特征，在现实生活条件下的命运和运输，以及婴儿、儿童和成人吸入暴露的倾向和由此产生的吸入剂量，将是第一次评估空气-水-人体界面的这一方面。描述气溶胶尺寸-污染物浓度与房间表面气溶胶沉积模式之间的关系将为气溶胶对健康的影响提供新的数据和前景。由于雾化饮用水吸入暴露的不确定性，该项目对人类健康具有影响。实验研究有四个目标，研究以四个假设为指导：1)使用粒度和级联冲击器仪器，结合电感耦合等离子体质谱，综合表征加湿器气溶胶的尺寸、分布和无机化学组成，以代表现实饮用水的不同水质。假设1：对于给定的水质，所有气溶胶颗粒的无机污染物浓度都是相同的。2)在真实的室内生活场景中，表面气溶胶沉积被确定为与加湿器的距离的函数。采样位置在加湿器烟柱内外。假设2：无机污染物浓度将以类似的空气浓度沉积在房间的所有位置。3)实验数据是对USEPA Risk室内空气质量模型首次应用于房间大小的超声加湿器进行校准和验证的输入。假设3：USEPA风险模型可以使用本研究的实验数据进行校准，以满足ASTM空气建模指南(1991)。4)获得的数据将使用美国环保局的风险模型来评估涉及婴儿、儿童和成人的许多实际暴露情景下人类吸入气雾化污染物的情况。假设4：室内空气模型证实，人体吸入超声加湿器气雾剂中的无机污染物超过了健康标准。模型结果将根据吸入暴露法规、现有剂量数据和地理变化的水质进行评估。PI和共同PI致力于发展学生在这个项目上的专业、道德、外展和研究准备。博士生和本科生将从代表性不足的群体中积极招聘，参与该项目的教职员工多年来一直在这样做。该项目将招收代表性不足的学生，并为他们提供教育、研究和专业经验，包括指导6-12年级的学生。学生研究人员将通过水界面网站(由弗吉尼亚理工大学研究生院为水研究教职员工和学生维护的https://blogs.lt.vt.edu/water/)，)上的博客在全球范围内交流他们的结果，并出版科学文章。

1605355DietrichThis proposed project fills a critical knowledge gap concerning human exposure, at the air-water-human interface, to contaminants from aerosols emitted by ultrasonic humidifiers. Typically, consumers purchase ultrasonic humidifiers, fill them with drinking water, and use them in confined spaces such as bedrooms for several hours per day. The resulting inhalation exposure information, from ultrasonic humidifiers, will allow scientists to reasonably assess the human health risks associated with dissolved contaminants in drinking water and subsequently offer recommendations for consumer use.The fundamental characterization of ultrasonic humidifier aerosol composition, fate and transport under realistic living conditions, and propensity for infant, child, and adult inhalation exposure and resulting inhaled dose, will be the first of its kind for assessing this aspect of the air-water-human interface. The description of the relationships between aerosol size - contaminant concentration and aerosol deposition patterns on room surfaces will provide new data and perspective for the health effects of aerosols. This project has implications for human health because of the uncertainty surrounding inhalation exposures from aerosolized drinking water. The experimental research has four objectives and the reseach is guided by four hypotheses: 1) To use particle size and cascade impactor instruments, in conjunction with inductively coupled plasma mass spectrometry, to comprehensively characterize humidifier aerosols in size, distribution, and inorganic chemical composition for varying water qualities representative of realistic drinking waters. Hypothesis 1: Inorganic contaminant concentrations are the same in all aerosol particle sizes for a given water quality. 2) To examine aerosol deposition on surfaces is determined as a function of distance from a humidifier which is situated in realistic indoor living scenario. Sampling locations are both within and outside the humidifier plume. Hypothesis 2: Inorganic contaminant concentrations will be deposited at similar aerial concentrations in all locations of the room. 3) The experimental data are inputs to calibrate and validate the USEPA RISK Indoor Air Quality model for its first application to room-sized ultrasonic humidifiers. Hypothesis 3: The USEPA RISK model can be calibrated to meet ASTM air modeling guidelines (1991) using the experimental data from this study. 4) The data obtained will use the USEPA RISK model to assess the human inhalation exposure to aerosolized contaminants for many realistic exposure scenarios involving infants, children, and adults. Hypothesis 4: The indoor air model confirms that human inhalation exposure to inorganic contaminants in ultrasonic humidifier aerosols exceed health guidelines. The model results will be evaluated with respect to inhalation exposure regulations, existing dose data, and geographically varying water quality. The PI and co-PIs are committed to developing the professional, ethical, outreach, and research preparation of students on this project. The PhD and undergraduate students will be actively recruited from underrepresented groups, as has been done for many years by the faculty involved in this project. This project will recruit underrepresented students and provide them educational, research, and professional experiences, including mentoring grade 6-12 students. The student researchers will communicate their results throughout the globe through blogs at the Water INTERface website (https://blogs.lt.vt.edu/water/), maintained by the Virginia Tech Graduate School for faculty and students in water research and though publication of scientific articles.