Solving the Mystery of Humidity's Effect on Viability of Airborne Microorganisms

1438103 Marr解决湿度对空气微生物生存能力的影响这个项目将通过加强对通过空气传播的传染病的了解而造福社会。研究结果可以用来改进对传染病传播的预测，并可能有助于解释某些疾病的季节性。结果的应用可能导致干预措施，如操纵液态化学，以降低从液体产生的气雾剂中病原体的生存能力。如果湿度被证明对空气传播的病原体活性起到控制作用，那么就可以制定关于室内湿度水平的建议。该项目将在大气科学和微生物学之间建立跨学科联系，这是在了解传染病传播方面取得进展所必需的。通过为从学前班到本科生的学生开发关于空气微生物的新教材，我们将提高科学素养，并有望有助于防止至少一例传染病。拟议研究的目标是发展关于环境湿度和气溶胶化学如何相互作用影响空气微生物生存的新的基础知识。该项目基于这样的假设，即蒸发引起的气溶胶化学成分的变化，如盐和蛋白质浓度的增加、pH的变化、溶质的结晶和相分离，影响了气溶胶中所含微生物的生存能力。通过应用环境工程工具来解决这个问题，我们准备在理解和潜在控制大气中微生物的动态方面取得潜在的变革性进展最近使用高通量测序的研究发现，在自然和建筑环境中存在着令人惊讶的多样化、复杂和动态的微生物群。微生物的气雾化有许多机会，例如废水处理厂、动物饲养作业、生物固体的土地应用、厕所、淋浴和加湿器。环境工程师在了解环境条件如何影响水中微生物方面取得了很大进展，但对空气中微生物的平行理解尚不存在。跨学科方法对于在这一领域取得进展至关重要。该项目将环境工程学、气溶胶科学和微生物学结合在一起，以发展对大气中微生物动态的新的跨学科理解。具体目标是：(1)从溶质浓度、pH、结晶和相分离方面描述蒸发引起的气溶胶成分的变化；(2)确定微生物活性与气溶胶中的溶质浓度、pH、结晶和相分离之间的关系；(3)描述微生物在气溶胶中的分配，并研究它们作为气溶胶化学的作用下的结构变化；以及(4)扩大学生和普通公众关于空气中微生物和传染病传播的科学素养。研究小组将产生不同初始化学成分(无机盐、有机物质、pH)和大小的液滴和气溶胶，将它们暴露在环境室内不同的相对湿度中，平衡后确定它们的最终化学成分，测量液滴和气溶胶中包含的微生物的灭活率，并使用电子显微镜观察微生物。

1438103MarrSolving the Mystery of Humidity's Effect on Viability of Airborne MicroorganismsThis project will benefit society by enhancing the understanding of transmission of infectious disease via the airborne route. Results could be used to improve prediction of the spread of infectious disease and may help explain the seasonality of some diseases. Application of the results could lead to interventions such as manipulating liquid-phase chemistry to reduce the viability of pathogens in aerosols generated from the liquid. If humidity is proven to play a controlling role in airborne pathogen viability, then recommendations about indoor humidity levels could be developed. The project will build interdisciplinary ties between atmospheric science and microbiology, which are needed for progress in understanding infectious disease transmission. By developing new educational material on airborne microorganisms for students ranging from the preschool to undergraduate level, we will improve scientific literacy and will hopefully help prevent at least one case of infectious disease.The goal of the proposed research is to develop new, fundamental knowledge about how ambient humidity and aerosol chemistry interact to affect the survival of airborne microorganisms. This project is based upon the hypothesis that evaporation-induced changes in the chemical composition of an aerosol, such as increases in salt and protein concentrations, shifts in pH, crystallization of solutes, and phase separation, affect the viability of microorganisms contained in the aerosol. By applying environmental engineering tools to this problem, we are poised to make potentially transformative advances in understanding and potentially controlling the dynamics of microorganisms in the atmosphere Recent studies employing high-throughput sequencing have found a surprisingly diverse, complex, and dynamic microbiome in the natural and built environments. There are many opportunities for aerosolization of microorganisms, such as from wastewater treatment plants, animal feeding operations, land application of biosolids, toilets, showers, and humidifiers. Environmental engineers have made large gains in understanding how environmental conditions affect microorganisms in water, but a parallel understanding for microorganisms in air does not yet exist. An interdisciplinary approach is critical to progress in this area. This project unites environmental engineering, aerosol science, and microbiology to develop a new interdisciplinary understanding of the dynamics of microorganisms in the atmosphere. Specific objectives are to (1) characterize evaporation-induced changes in aerosol composition in terms of solute concentrations, pH, crystallization, and phase separation; (2) determine the relationship between microorganism viability and solute concentrations, pH, crystallization, and phase separation in aerosols; (3) describe the partitioning of microorganisms in aerosols and examine structural changes in them as a function of aerosol chemistry; and (4) broaden the scientific literacy of students and the general public regarding airborne microorganisms and infectious disease transmission. The research team will produce droplets and aerosols of varying initial chemical composition (inorganic salts, organic material, pH) and size, expose the them to varying relative humidity in an environmental chamber, determine their final chemical composition after equilibration, measure the inactivation rate of microorganisms contained in the droplets and aerosols, and visualize the microorganisms using electron microscopy.