Collaborative Research: Theoretical and Experimental Characterization of the Dynamics of Secondary Organic Aerosol (SOA) Materials

本项目由美国国家科学基金会化学部环境化学项目资助，研究大气中由气相有机化学物质（由植被、工业和交通来源排放）与臭氧和羟基自由基反应产生的二次有机气溶胶（SOA）颗粒的化学和物理性质。SOA是数千种低挥发性有机物质的复杂混合物，它们凝结在先前存在的大气颗粒上，形成很大一部分影响人类健康和改变能见度的大气颗粒。该项目训练学生在一个跨学科的团队中工作，包括基础物理化学家、应用气溶胶物理学家和大气化学家。这个合作项目汇集了波士顿学院（BC）和Aerodyne研究公司（ARI）的研究小组，他们在SOA生产和亚微米SOA颗粒特性的测量方面具有专业知识，以及加州大学伯克利分校（UCB）的研究小组，他们具有模拟液体、玻璃和晶体有机材料的热力学和分子动力学特性的能力。该项目支持由BC大学的Paul Davidovits教授和ARI的Charles Kolb博士指导的一系列实验室实验，这些实验表征了类似SOA的替代化学物质混合物以及实验室生成的SOA颗粒的动态特性。由David Chandler教授领导的UCB理论团队正在制定模型，以重现在薄膜沉积和细颗粒反应吸收实验中测量到的SOA动态特性，其目标是预测相对湿度和温度对大气中SOA/水系统的热力学和动力学特性的影响。玻璃状有机材料的基础、理论和实验动力学的耦合有助于阐明SOA在云形成、云和气溶胶辐射特性以及云降水中的作用。由此产生的理论工具被大气科学界用于更好地预测和参数化SOA颗粒气候影响和SOA颗粒吸入暴露。

This project, funded by the Environmental Chemistry program of the Chemistry Division at the national Science Foundation, investigates the chemical and physical properties of secondary organic aerosol (SOA) particles produced in the atmosphere by reactions of gas-phase organic chemicals (emitted by vegetation, industrial and transportation sources) with ozone and hydroxyl radicals. SOA is a complex mixture of thousands of low-volatility organic species that condense on preexisting atmospheric particles and form a large fraction of atmospheric particulates that impact human health and alter visibility. The project trains students to work in an interdisciplinary team that includes fundamental physical chemists, applied aerosol physicists and atmospheric chemists. This collaborative project brings together research groups from Boston College (BC) and Aerodyne Research, Inc. (ARI) with expertise in SOA production and measurement of submicron SOA particle properties and a group at the University of California, Berkeley (UCB) with capabilities in modeling the thermodynamic and molecular dynamic properties of liquid, glassy and crystalline organic materials. The project supports a series of laboratory experiments, directed by Professor Paul Davidovits at BC and Dr. Charles Kolb at ARI, that characterize the dynamic properties of mixtures of SOA-like surrogate chemicals as well as laboratory generated SOA particles. The UCB theoretical team, led by Professor David Chandler, is formulating models to reproduce the dynamic properties of SOA measured in thin film deposition and fine particle reactive uptake experiments, with the goal of predicting the impact of relative humidity and temperature on thermodynamic and kinetic properties of SOA/water systems found in the atmosphere. The coupling of fundamental, theoretical, and experimental dynamics of glassy organic material help clarify and codify the roles of SOA in cloud formation, cloud and aerosol radiative properties and cloud precipitation. The resulting theoretical tools is used by the atmospheric science community to better predict and parameterize SOA particle climate impacts and SOA particle inhalation exposures.