Collaborative Research: Humidity and Temperature Effects on Phase Separation and Particle Morphology in Internally Mixed Organic-Inorganic Aerosol

合作研究：湿度和温度对内部混合有机-无机气溶胶中相分离和颗粒形态的影响

• 批准号: 2107690
• 负责人: Ryan Davis
• 金额: $ 13.72万
• 依托单位: Trinity University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2107690&HistoricalAwards=false
• 关键词: Collaborative; Research; Humidity; Temperature; Effects

With support from the Environmental Chemical Sciences Program in the Division of Chemistry at NSF, James Davies of the University of California-Riverside (UCR) and Ryan Davis of Trinity University will study the phase state of mixed organic-inorganic aerosol particles under environmental conditions. Aerosols influence climate as they form the basis of clouds and are engaged in both the scattering and the absorption of sunlight. Aerosols can also negatively affect air quality and provide a vehicle for the spread of airborne disease. The specific environmental impact associated with aerosols depends upon the chemical composition and phase state of the aerosol particles. Inadequate knowledge of the phase state of organic-inorganic aerosols, such as those found in the environment, represents a source of uncertainty in climate and air quality models. Mixed organic-inorganic particles can form a range of phase states depending on environmental conditions; these include liquid and solid phases, and amorphous phases, such as viscous liquids, glasses, and gels. This project will explore the formation of amorphous phase states in aerosol particles and characterizes the properties that determine their impacts in the environment. This collaboration between UC Riverside and Trinity University will facilitate undergraduate and graduate research across both institutions and seeks to provide for an improved understanding of aerosol chemistry across a range of scientific disciplines.To enhance knowledge of aerosol particles in the environment, this project is a collaborative study between teams at an R1 public university, UC-Riverside--the James Davies research group--and at a predominantly undergraduate liberal arts and sciences university, Trinity University--the Ryan Davis research group--will examine the role of temperature and relative humidity on the phase state and associated properties of internally mixed organic-inorganic aerosol particles. Aerosol particles containing mixtures of organic and inorganic compounds exhibit complex phase behavior in response to changes in relative humidity (RH) and temperature due to hygroscopic interactions. The phase morphology of aerosol particles influences their interactions with light, their response to chemical processing due to changes in viscosity, and their ice and cloud nucleating potential. This proposal will investigate the phase morphology and associated rheological properties of internally mixed organic-inorganic aerosol particles exposed to controlled RH and temperature conditions. The main objectives are: (1) systematically characterize the hygroscopicity and viscosity of particles containing atmospherically-relevant salts and oxygenated organics; (2) determine the temperature and humidity conditions for the onset of phase separation and correlate with molecular composition; and (3) explore the consequences of viscosity and phase separation on the rate of molecular diffusion. To achieve these goals, single particles of aqueous oxygenated organic compounds and atmospherically-relevant mono- and divalent salts will be levitated using an electrodynamic balance. Optical spectroscopy, microscopy and light scattering methods will be used to identify phase separation while new and established characterization methods will be applied to measure hygroscopic growth, viscosity, and diffusive transport. The research will help to motivate the next generation of scientists by exposing undergraduate and graduate researchers to the physically rigorous study and characterization of aerosols in a project that relates more generally to climate science research, an area of great societal interest and importance today.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在NSF化学部环境化学科学计划的支持下，加利福尼亚大学河滨分校（UCR）的James Davies和Trinity大学的Ryan Davis将研究环境条件下混合有机-无机气溶胶颗粒的相态。气溶胶影响气候，因为它们形成云的基础，并参与散射和吸收阳光。气溶胶也会对空气质量产生负面影响，并为空气传播疾病提供媒介。与气溶胶相关的特定环境影响取决于气溶胶颗粒的化学成分和相态。对有机-无机气溶胶的相态，如环境中发现的气溶胶的相态了解不足，是气候和空气质量模型不确定性的一个来源。混合的有机-无机颗粒可以根据环境条件形成一系列相态;这些相态包括液相和固相，以及无定形相，例如粘性液体、玻璃和凝胶。该项目将探索气溶胶颗粒中无定形相态的形成，并描述决定其对环境影响的特性。加州大学滨江分校和Trinity大学之间的合作将促进两所大学的本科生和研究生研究，并寻求在一系列科学学科中提供对气溶胶化学的更好理解。为了提高对环境中气溶胶颗粒的认识，该项目是R1公立大学团队之间的合作研究，加州大学河滨分校--詹姆斯·戴维斯研究小组--在一所以本科为主的文科和理科大学，Trinity大学的Ryan Davis研究小组将研究温度和相对湿度对内部混合有机物相态和相关性质的作用，无机气溶胶粒子。含有有机和无机化合物的混合物的气溶胶颗粒由于吸湿相互作用而响应于相对湿度（RH）和温度的变化而表现出复杂的相行为。气溶胶粒子的相形态影响它们与光的相互作用，它们对粘度变化引起的化学过程的响应，以及它们的冰和云成核潜力。本提案将研究暴露于受控RH和温度条件下的内部混合有机-无机气溶胶颗粒的相形态和相关流变特性。主要目标是：（1）系统地表征含有与大气相关的盐和含氧有机物的颗粒的吸湿性和粘度;（2）确定相分离开始的温度和湿度条件并与分子组成相关联;以及（3）探索粘度和相分离对分子扩散速率的影响。为了实现这些目标，含水含氧有机化合物和大气相关的一价和二价盐的单颗粒将使用电动平衡悬浮。将使用光学光谱、显微镜和光散射方法来识别相分离，而新的和已建立的表征方法将用于测量吸湿增长、粘度和扩散传输。 这项研究将有助于激励下一代科学家，让本科生和研究生研究人员在一个更广泛地涉及气候科学研究的项目中对气溶胶进行严格的物理研究和表征，这个奖项反映了NSF的法定使命，并被认为是值得通过评估使用基金会的智力价值和更广泛的支持。影响审查标准。

项目成果

Exploring the hygroscopicity, water diffusivity, and viscosity of organic–inorganic aerosols – a case study on internally-mixed citric acid and ammonium sulfate particles

探索有机-无机气溶胶的吸湿性、水扩散性和粘度——内部混合柠檬酸和硫酸铵颗粒的案例研究

• DOI: 10.1039/d2ea00116k
• 发表时间: 2023
• 期刊: Environmental Science: Atmospheres
• 作者: Sheldon, Craig S.;Choczynski, Jack M.;Morton, Katie;Palacios Diaz, Teresa;Davis, Ryan D.;Davies, James F.
• 通讯作者: Davies, James F.

Tutorial: Electrodynamic balance methods for single particle levitation and the physicochemical analysis of aerosol

• DOI: 10.1016/j.jaerosci.2023.106255
• 发表时间: 2023-09-12
• 期刊: JOURNAL OF AEROSOL SCIENCE
• 影响因子: 4.5
• 作者: Kohli，Ravleen Kaur;Davis，Ryan D.;Davies，James F.
• 通讯作者: Davies，James F.