Collaborative research: Linking gas phase precursors with aerosol size, number and composition in new particle formation

这项研究将提高对大气中非常小的颗粒的形成和生长的理解。这项实验室研究将评估温度、相对湿度和气相物种浓度对小颗粒形成和生长速度的影响。研究生将参与该项目，并将接触到在大气化学中使用最先进的仪器。该研究将适用于改进预测大气中云凝结核形成的模型。该项目围绕三个主要主题组织：硫酸成核和生长，生物源新颗粒形成（NPF），特别是异戊二烯的作用，以及特定氧化剂在NPF中的作用。将解决以下科学问题：(1)温度和相对湿度如何影响硫酸成核速率，特别是在高温和/或相对湿度等不太可能观察到环境NPF的条件下？(2)胺和氨在颗粒形成和生长中的作用，特别是在颗粒酸度方面的作用？(3) 2- 10nm尺寸范围内的生长速率如何受到生长蒸汽类型的影响，特别是冷凝与分配有机物质？(4)异戊二烯在生物成核和生长中的作用是什么？它是否抑制了NPF进程？(5)光化学和氧化过程对生物源NPF的影响，特别是低NOx混合比和高NOx混合比的作用？

This research will improve the understanding of the formation and growth of very small particles in the atmosphere. This laboratory study will assess the effects of temperature, relative humidity, and the concentrations of gas phase species to the formation and growth rates of small particles. Graduate students will participate in the project and will be exposed to the use of state-of-the-art instrumentation in atmospheric chemistry. The research will be applicable to improving models that predict the formation of cloud condensation nuclei in the atmosphere.The project is organized around three major themes: sulfuric acid nucleation and growth, biogenic new particle formation (NPF) particularly the role of isoprene, and the role of specific oxidants in NPF. The following scientific questions will be addressed: (1) How do temperature and RH affect sulfuric acid nucleation rates, especially under conditions such as high temperature and/or RH where ambient NPF is unlikely to be observed? (2) What are the roles of amines and ammonia in particle formation and growth, particularly with regard to particle acidity? (3) How are growth rates in the 2-10 nm size range affected by the types of growth vapors present, especially condensing vs. partitioning organic species? (4) What is the role of isoprene in biogenic nucleation and growth ? does it suppress the NPF process? (5) What are the effects of photochemical and oxidation processes on biogenic NPF, especially the role of low vs. high NOx mixing ratios?