Atmospheric Particle Formation in Two Systems: Sulfuric Acid (H2SO4)/Water (H2O) plus Ammonia (NH3) and/or Amines, and Oxidation Products from Organic Compounds

该项目涉及进行新的实验室实验，以研究大气中新粒子形成的基本过程，特别关注纳米粒子的形成和生长。与新粒子形成有关的不确定性和知识空白仍然存在，这项工作将提供对新粒子形成的见解，并增强我们对云的形成以及对气候变化和人类健康的影响的理解。实验将在之前nsf资助的工作中开发的两个反应堆中进行。本科生，包括那些来自代表性不足的群体，将在这个项目的过程中接受培训和教授实验室技术。两个流动反应器，在以前的nsf资助的工作中开发，将在这个项目中使用：光解流动反应器（PhoFR）和生长流动反应器（GroFR）。该实验将提供有关吉布斯能量、范德华效应和H2SO4/NH3体系颗粒相组成影响的基础知识，并重点研究生物源性挥发性有机化合物氧化形成的有机颗粒。PhoFR实验包括：(1)研究不同温度下H2SO4/H2O和三元体系（含NH3）的成核速率和团簇吉布斯能；(2)研究H2SO4吸收量对种子颗粒大小和组成的影响，并确定范德华力和纳米颗粒吸湿性的影响。用GroFR进行的实验包括：(1)研究单萜烯光氧化过程中种子粒径和生长的影响；(2)研究第一代单萜烯氧化产物及相关化合物的合成；(3)部署质谱仪。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project involves the conduct of new laboratory experiments to study fundamental processes underlying new particle formation in the atmosphere with a particular focus on the formation and growth of nanoparticles. There still exist uncertainties and knowledge gaps related to new particle formation, and this work will provide insights into new particle formation and enhance our understanding of the formation of clouds, as well as the impacts on a changing climate and human health. The experiments will be performed in two reactors developed in previous NSF-funded work. Undergraduate students, including those from underrepresented groups, will be trained and taught laboratory techniques over the course of this project.Two flow reactors, developed in previous NSF-funded work, will be used in this project: a Photolytic Flow Reactor (PhoFR) and a Growth Flow Reactor (GroFR). The experiments will provide fundamental knowledge pertaining to Gibbs energy, van der Waals effects, and the impact of particle phase composition of a H2SO4/NH3 system, as well as focus on organic particle formation from biogenic volatile organic compound oxidation. The experiments with the PhoFR include: (1) study the nucleation rates and cluster Gibbs energies in H2SO4/H2O and ternary (with NH3) systems under various temperatures; and (2) study the growth of seed particles by H2SO4 uptake as a function of seed particle size and composition, as well as determine the effects of van der Walls forces and the hygroscopicity of nanoparticles. The experiments with the GroFR include: (1) study the effect of seed particle size and growth during the photooxidation of monoterpenes; (2) study the synthesis of first-generation oxidation products of monoterpenes and related compounds; and (3) the deployment of a mass spectrometer.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.