RUI: Laboratory Studies of Particle Nucleation--Homogeneous Nucleation Involving Sulfuric Acid (H2SO4), Water (H2O), and Ammonia (NH3) Vapors

RUI：粒子成核的实验室研究——涉及硫酸 (H2SO4)、水 (H2O) 和氨 (NH3) 蒸气的均质成核

• 批准号: 0943721
• 负责人: David Hanson
• 金额: $ 24.53万
• 依托单位: Augsburg University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-01-15 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943721&HistoricalAwards=false
• 关键词: RUI; Laboratory; Studies; Particle; Nucleation

The investigator will measure the rate of nucleation of new particles in flow reactor experiments. The formation rate of new particles will be measured as a function of sulfuric acid concentration, temperature, relative humidity and ammonia concentration. The researchers plan to deploy as sources of sulfuric acid both the vapor over the bulk liquid and in situ oxidation of sulfur dioxide via hydroxyl radical generated photolytically. Measurements in the binary system to higher relative humidities and to lower temperatures are needed as a baseline for understanding nucleation within the flow reactor and for evaluating theoretical models. The photolytic system will allow for an extended source of sulfuric acid that balances its loss to the wall, facilitating the analysis and interpretation of nucleation results. For example, it will allow for a controllable exposure to a particle growth agent so that particles can be efficiently detected by the particle detector. The extended source will also allow for exploration of nucleation at low sulfuric acid concentrations. Finally, verification is needed of recent work using a photolytic source that showed enhancements in the nucleation rate of factors of 105 or more over bulk source nucleation rates. This work will contribute to understanding nucleation in the atmosphere and how it influences the concentration of cloud condensation nuclei whose role in climate processes is believed to be large but is still quite uncertain. Understanding the formation of atmospheric particles is also important as inhaled particulate matter is a health hazard. Flow reactor experimental methods for measuring particle formation and growth will be further developed. Results for nucleation rates in the sulfuric acid, water, and ammonia systems will be synthesized and a comprehensive picture of laboratory work will be developed. This will aid interpretation of field data and evaluating mechanisms of nucleation.The project will enhance the research and the educational culture at Augsburg College by offering a research opportunity for undergraduates interested in the environmental sciences. The work is timely and important, which will foster a dedication to the work and fuel the student's imagination. The project will enhance undergraduate training by providing: (a) a high quality work experience where basic laboratory skills will be developed, (b) enhance motivation by obtaining research results that can affect our understanding of global warming processes, and (c) provide opportunities for presenting results at local and national meetings. This project will foster the continuation of the partnership between a private liberal arts college and a public research university, thereby expanding learning and training opportunities for Augsburg College's student population. It is expected that women and persons from underrepresented groups will continue to be the majority of the undergraduate students in the PI's lab. Dissemination of results will include presentations at local and national scientific meetings and manuscript publications.

研究者将测量流动反应器实验中新颗粒的成核速率。 新颗粒的形成速率将作为硫酸浓度，温度，相对湿度和氨浓度的函数测量。 研究人员计划将硫酸的来源部署在大块液体上的蒸气以及通过羟基自由基产生的光解产生的二氧化硫的原位氧化。 需要在二进制系统中对较高的相对湿度和较低温度的测量作为理解流动反应器内成核和评估理论模型的基线。 光解体系统将允许扩展的硫酸来源，以平衡其损失到壁上，从而促进成核结果的分析和解释。 例如，它将允许对颗粒生长剂的可控暴露，以便可以由粒子检测器有效地检测到颗粒。 扩展的源还将允许在低硫酸浓度下探索成核。 最后，需要使用光解源对最近的工作进行验证，该工作源显示出105或更多的因子成核率的增强率，而不是大量源成核速率。 这项工作将有助于理解大气中的成核及其如何影响云凝结核的浓度，云凝结核的浓度在气候过程中的作用被认为很大，但仍然不确定。 了解大气颗粒的形成也很重要，因为吸入颗粒物是一种健康危害。 流动反应器实验方法用于测量颗粒形成和生长。 将合成硫酸，水和氨系统中成核速率的结果，并将开发实验室工作的全面图景。 这将有助于解释现场数据并评估成核的机制。该项目将通过为对环境科学感兴趣的大学生提供研究机会来增强奥格斯堡学院的研究和教育文化。 这项工作是及时和重要的，这将促进对工作的奉献精神，并助长学生的想象力。 该项目将通过提供：（a）提供基本实验室技能的高质量工作经验来增强本科培训，（b）通过获得可能影响我们对全球变暖过程的理解的研究结果来增强动力，并且（c）在当地和国家会议上提供结果的机会。 该项目将促进私立文科学院与公立研究大学之间的伙伴关系，从而扩大了奥格斯堡学院的学生人数的学习和培训机会。预计妇女和人数不足的团体的人将继续是PI实验室中的大多数本科生。结果的传播将包括在当地和国家科学会议和手稿出版物上的演讲。