Determining the Coagulation Sink Rate for Sub-10 nm Atmospheric Particles

这项建议中的研究小组将结合实验室实验和理论建模，以解决我们对云凝结核凝结沉降率及其对气溶胶、其大气生存以及气溶胶清除和凝结的影响的理解中的不确定性和过于简单化。由于凝血沉降率不能直接测量，目前它们是通过“硬球”模型近似计算的，该模型具有已知的不确定性和局限性。这项工作旨在填补这一知识空白。该项目的成功将对科学研究的多个领域产生积极影响，包括大气科学以外的领域。拟议的教育和推广计划是强有力的，因为K-12、本科生和研究生将在这个项目中获得宝贵的知识和经验。具体地说，这项拟议的工作将通过比较小于10纳米和50-100纳米云凝结核之间的凝固率来调查凝结下沉事件。这项拟议的工作有三个主要目标。首先，研究了范德沃尔斯增强的新形成颗粒的凝聚沉降率。其次，探讨了图像电位增强的凝血沉降率。最后，评价了化学成分对混凝沉降率的影响。该项目的研究任务包括：(1)首次实验验证包括10纳米以下和50-100纳米云凝结核的Van der wall势的凝聚速率模型；(2)创新地研究图像势对凝聚速率的影响；(3)更新我们对化学非均质颗粒凝聚的凝聚沉降率的理解；以及(4)改进的凝聚模型。这项拟议工作的结果将纳入课程，其中包括本科生和研究生的动手实验室经验。此外，还将为面向K-12学生的夏令营项目制定课程。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The research team in this proposal will combine laboratory experiments and theoretical modeling in order to address uncertainties and oversimplifications in our understanding of coagulation sink rates of cloud condensation nuclei and their impacts on aerosols, their atmospheric survival, and aerosol scavenging and coagulation. As coagulation sink rates cannot be directly measured, they are currently approximated via the “hard-sphere” model, which has known uncertainties and limitations. This work aims to fill this knowledge gap. Success in this project will positively impact multiple fields of scientific research, including fields outside of the atmospheric sciences. The proposed educational and outreach plans are strong as K-12, undergraduate, and graduate students will gain valuable knowledge and experience during this project.Specifically, this proposed work will investigate coagulation sink events by comparing coagulation rates between sub-10 and 50-100 nanometer cloud condensation nuclei. There are three primary objectives in this proposed work. First, an investigation of Van der Walls-enhanced coagulation sink rates of newly formed particles. Second, an exploration of image potential-enhanced coagulation sink rates. Finally, an evaluation of the impact of chemical composition on coagulation sink rates. Research tasks in this project include: (1) the first experimental validation of coagulation rate models that incorporate Van der Walls potentials for sub-10 nanometer and 50-100 nanometer cloud condensation nuclei; (2) an innovative investigation of image potential effects on coagulation rates; (3) an update to our understanding of coagulation sink rates for chemically heterogenous particle coagulation; and (4) an improved coagulation model. Results from this proposed work will be incorporated into curricula which includes hands-on laboratory experience for both undergraduate and graduate students. Additionally, a curriculum for summer camp programs reaching K-12 students will be developed.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.