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化学系的环境化学科学计划的支持下，加州大学河畔大学（UCR）的詹姆斯·戴维斯（James Davies）和三一大学的瑞安·戴维斯（Ryan Davis）将研究环境条件下混合有机无机气溶胶颗粒的相状态。气溶胶构成云的基础，并参与阳光的散射和吸收。气溶胶还会对空气质量产生负面影响，并为空气传播疾病的传播提供车辆。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状状态。对有机无机气溶胶的相位状态（例如在环境中发现的）的相位状态不足，这代表了气候和空气质量模型中不确定性的来源。混合有机无机颗粒可以根据环境条件形成一系列相状；这些包括液相和固相，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相状态的形成，并表征确定其在环境中影响的特性。 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三位一体大学科学大学 - 瑞安·戴维斯研究小组 - 将研究温度和相对湿度在内部混合有机无机气溶胶颗粒的相状状态和相关特性上的作用。含有有机物和无机化合物混合物的气溶胶颗粒响应于相对湿度（RH）和温度变化而表现出复杂的相行为，这是由于吸湿性相互作用而引起的。气溶胶颗粒的相形形态会影响它们与光的相互作用，由于粘度的变化而对化学处理的反应以及它们的冰和云成核能。该建议将研究暴露于受控RH和温度条件的内部混合有机无机气溶胶颗粒的相形形态和相关的流变特性。主要目标是：（1）系统地表征包含大气与大气相关的盐和氧化有机物的颗粒的粘度和粘度； （2）确定相位分离开始的温度和湿度条件，并与分子组成相关； （3）探讨粘度和相位分离对分子扩散速率的后果。为了实现这些目标，将使用电动力平衡来悬浮水性有机化合物的单个颗粒以及与大气相关的单盐和二价盐。光谱，显微镜和光散射方法将用于识别相位分离，而新的和已建立的表征方法将用于测量吸潮生长，粘度和扩散运输。 这项研究将通过将本科和研究生研究人员揭露在一个严格的研究和表征气溶胶的项目中，有助于激励下一代科学家，这在一个项目中更加普遍地与气候科学研究有关，该领域是一个极大的社会兴趣和重要性的领域，该领域是今天的法定任务，并通过评估了基金会的范围，反映了NSF的法定任务，并通过评估了基金会的范围。

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.