Probing the Molecular Basis of the "Burying" Mechanism: An Additional Route to Secondary Organic Aerosol (SOA) Particle Growth

探究“掩埋”机制的分子基础：二次有机气溶胶 (SOA) 颗粒生长的另一条途径

• 批准号: 2030175
• 负责人: Barbara Finlayson-Pitts
• 金额: $ 86.95万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-11-01 至 2024-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2030175&HistoricalAwards=false
• 关键词: Probing; Molecular; Basis; Burying; Mechanism

This project is focused on the investigation of a novel mechanism for the growth of new particles in the atmosphere. Uncertainties in the growth mechanisms of solid and semi-solid secondary organic aerosol (SOA) particles limit the ability to predict their impacts on visibility, health and climate, and hence the development of optimal control strategies. The research will provide the basic kinetic and thermodynamic data that will aid in developing and improving this predictive capability.Understanding the surface composition of organic particles is central to understanding the interaction of incoming gases with the surface and how this affects their uptake and contribution to particle growth. On a molecular level, it is expected that the residence time of gases on the surface of highly viscous particles will play a major role in their net uptake, yet there are few data on the fundamental parameters that determine this residence time. The ultimate goal of this research is to elucidate a hypothesized "burying" mechanism that incorporates gas phase species into highly viscous particles. A central aspect of this “burying” mechanism is the nature of the gas-surface interaction.The specific objectives of the experiments are to: (1) measure uptake coefficients as a function of temperature for a series of gases of selected structures and functional groups on self-assembled monolayers (SAMs) having well-defined terminal groups that are also common components of SOA particles as well as on SOA itself; (2) carry out temperature-programmed thermal desorption studies of the selected gases initially adsorbed on the SAMs to obtain kinetics data that will allow rate constants for desorption at different temperatures to be determined; and (3) carry out studies of the impact of lower volatility species with unique signatures on the uptake of organic nitrates into SOA particles formed from the ozonolysis of selected biogenics, with a focus on α-pinene.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.

该项目的重点是研究大气中新颗粒生长的新机制。固体和半固体二次有机气溶胶 (SOA) 颗粒生长机制的不确定性限制了预测其对能见度和健康影响的能力。该研究将提供基本的动力学和热力学数据，这将有助于开发和提高这种预测能力。了解有机颗粒的表面成分对于了解进入的气体与空气之间的相互作用至关重要。表面及其影响在分子水平上，预计气体在高粘性颗粒表面的停留时间将对其净吸收发挥主要作用，但关于决定的基本参数的数据很少。这项研究的最终目标是阐明一种将气相物质纳入高粘性颗粒中的“埋藏”机制。这种“埋藏”机制的一个核心方面是气体与表面相互作用的性质。具体目标实验的目的是：(1) 测量自组装单分子层 (SAM) 上具有选定结构和官能团的一系列气体的吸收系数随温度的变化，该自组装单分子层具有明确的末端基团，这些末端基团也是 SOA 颗粒的常见组成部分：以及 SOA 本身；(2) 对最初吸附在 SAM 上的选定气体进行程序升温热解吸研究，以获得动力学数据，从而确定不同温度下的解吸速率常数； (3) 研究具有独特特征的低挥发性物种对选定生物制剂臭氧分解形成的 SOA 颗粒吸收有机硝酸盐的影响，重点关注 α-蒎烯。该奖项反映了 NSF 的法定使命，并已被通过使用基金会的智力优点和更广泛的影响审查标准进行评估，认为值得支持。