CAREER: Aerosol-Water Interactions in the Atmosphere

该项目的目标是在受控的实验室条件下研究气溶胶-水的相互作用，并调查吸水率与气溶胶粒子的物理化学性质的关系。将使用各种气溶胶产生和测量技术来创建真实的气溶胶，并分析它们与水的相互作用。这些设备将包括使用原子力显微镜(AFM)对干湿纳米气溶胶成像，用于测量云滴活化的云凝聚核计数器(CCNC)，用于测量调节后气溶胶种群变化的纳米串联微分迁移率分析仪(TDMA)，用于成像颗粒形态和有机颗粒水相互作用的环境扫描电子显微镜(ESEM)，用于成像无机物和确定剩余水存在的扫描电子显微镜(SEM)，以及用于在受控环境中产生和老化复杂气溶胶的烟雾室内。气溶胶的直径从3纳米到几微米不等，从实验室有机物到环境中的生物样品，其化学和物理性质差异很大。然后将对气溶胶进行实时分析或收集在基质上供以后研究。TDMA实验将允许在受控的温度、时间和相对湿度条件下调查气溶胶种群的变化。CCNC实验涉及过饱和条件。环境扫描电子显微镜、扫描电子显微镜和原子力显微镜允许在潮湿和干燥条件下对颗粒进行成像。这种仪器和技术的组合以前从未用于单一的综合研究，将有助于更好地了解气溶胶-水相互作用，并将结果应用于大气气溶胶分析和气溶胶模型。这一提议的更广泛影响包括在巴克内尔大学为本科生提供课程和实验室研究经验的研究机会，以及社区推广的服务学习部分。还将为化学工程师开发发现学习实验室和粒子技术新课程。

The goal of this project is to study aerosol-water interactions under controlled laboratory conditions and investigate the dependence of water uptake on the physicochemical properties of the aerosol particles. Various aerosol generation and measurement techniques will be used to create realistic aerosols and analyze their interactions with water. These will include imaging of wet and dry nano aerosols with Atomic Force Microscopy (AFM), a cloud condensation nucleus counter (CCNC) for measuring cloud droplet activation, a nano tandem differential mobility analyzer (TDMA) for measuring aerosol population changes after conditioning, an Environmental Scanning Electron Microscope (ESEM) for imaging particle morphology and water interactions of organic particles, SEM for imaging inorganics and for determining residual water presence (via a newly developed technique), and a smog chamber for generating and aging complex aerosols in a controlled environment. Aerosols will be generated with diameters ranging from 3 nm to several microns and widely varying chemical and physical properties, from laboratory organics to ambient biogenic samples. Aerosols will then be analyzed in real time or collected on substrates for later study. The TDMA experiments will permit investigation of aerosol population changes under controlled conditions of temperature, time, and relative humidity. The CCNC experiments involve supersaturation conditions. The ESEM, SEM, and AFM allow imaging of the particles under wet and dry conditions. This combination of instruments and techniques has never before been used in a single, comprehensive study and will allow an improved understanding of aerosol-water interactions and application of the results to the analysis of atmospheric aerosols and to aerosol models.The broader impacts of this proposal include research opportunities for undergraduates at Bucknell University, both within courses and in laboratory research experiences, and a service-learning component for community outreach. Discovery learning laboratories and a new course in particle technology for chemical engineers will also be developed.