Collaborative Research: Atmospheric Nanoparticle Growth from Nitrate (NO3) Radical Initiated Oxidation of Monoterpenes

该项目将实验室研究结果与数值模拟相结合，以研究大气中微小纳米颗粒的生长。了解这些微小颗粒的生长是很重要的，因为它们会影响云滴的形成和性质。这项研究将导致一个机械模型的发展，以更好地预测气溶胶对气候和空气质量的影响。 将进行实验室实验以鉴定和量化NO3自由基与三种常见单萜反应的气相和颗粒相产物：#945;-蒎烯、#946;-蒎烯、3-<$烯和另外的化合物#945;-侧柏烯，其在结构上类似于#945;-蒎烯，并且同样应该形成对纳米颗粒生长贡献最小的气相产物。这些实验将在一系列NO3浓度、湿度和温度下进行。计算化学的研究将提供对NO3自由基氧化单萜可能的反应机理和纳米颗粒生长的深入了解。本项目的三个目标是：（1）实施计算化学方法来阐明反应途径和发展CIMS检测策略;（2）进行NO3自由基引发的单萜氧化的比较实验室研究;（3）获得气相前驱体与纳米粒子物理化学性质之间的化学封闭性。通过该项目开发的纳米颗粒生长的过程级模型将使用实验测量的生长速率进行测试。纳米粒子的生长直接关系到这些粒子影响云凝结核种群的能力，并影响云滴的形成和性质。 该合作项目包括一个“近同行”计划，该计划将加州大学欧文分校的研究生与里德学院的本科生配对，以促进科学交流，并为本科生的研究生学习做好准备。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

This project combines the results of laboratory studies with numerical modeling to investigate the growth of tiny nanoparticles in the atmosphere. It is important to understand the growth of these tiny particles because they can influence the formation and properties of cloud droplets. This research will lead to the development of a mechanistic model to better predict the influence of aerosol on climate and air quality. Laboratory experiments will be conducted to identify and quantify the gas- and particle-phase products of the reactions of NO3 radicals with three common monoterpenes: &amp;#945;-pinene, &amp;#946;-pinene, 3-carene, and an additional compound, &amp;#945;-thujene, which is structurally similar to &amp;#945;-pinene and should likewise form gas phase products that contribute minimally to nanoparticle growth. These experiments will be conducted for a range of NO3 concentrations, humidities, and temperatures. Computational chemistry studies will provide insight into possible reaction mechanisms and nanoparticle growth due to monoterpene oxidation by NO3 radicals.The three objectives of the project are: (1) Implement computational chemistry methods for elucidating reaction pathways and developing CIMS detection strategies; (2) Perform comparative laboratory studies of NO3 radical initiated oxidation of monoterpenes; and (3) Obtain chemical closure between gas phase precursors and nanoparticle physicochemical properties. The process-level model for nanoparticle growth, developed through this project, will be tested using experimentally measured growth rates. Nanoparticle growth is directly tied to the ability of these particles to influence cloud condensation nuclei populations and affect the formation and properties of cloud droplets. This collaborative project includes a "near-peer" program that pairs University of California at Irvine graduate students with Reed College undergraduates in order to facilitate scientific interactions and to prepare the undergraduates for graduate study.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.