The effect of environmental conditions at particle genesis stage of secondary organic aerosol formation

本项目由化学学部环境化学项目和大气与地球空间科学学部大气化学项目共同资助。佛蒙特大学的朱塞佩·佩特鲁奇教授研究了水（湿度）在大气中有机颗粒形成和老化中的作用。多叶的树木和植物在光合作用和呼吸作用中释放挥发性有机化合物。这些化合物与臭氧等污染物发生反应，产生大气中的大部分有机颗粒。彼得鲁奇教授和他的团队探索了湿度如何影响颗粒的化学成分、颗粒的相（液体或固体）以及它们散射和/或吸收光的能力。了解这些颗粒形成后所经历的化学变化对于了解它们对大气的影响至关重要。这项研究有助于更好地了解对流层（大气的最低部分）对人类健康、能见度和气候的影响。为研究生和本科生提供培训。研究小组还通过佛蒙特大学化学营向不同层次的K-12学生提供服务。确定大气中有机颗粒的组成具有挑战性，因为每个颗粒可能包含数百种不同的分子。此外，粒子在大气中的时间通常是5到7天，在此期间分子的类型可能会发生变化。彼得鲁奇教授和他的团队开发了一种新的环境室装置，用于研究粒子形成过程中的化学过程。该室允许使用质谱和光谱技术来研究颗粒的组成。这些技术还提供了由于反应条件（如湿度）的变化而导致的颗粒组成变化的信息。此外，研究人员使用另一种方法，将粒子撞击坚硬的表面，并计算有多少粒子被反弹，多少粒子被粘附。固体颗粒弹跳，而液体颗粒粘住。将颗粒的相与颗粒组成进行比较。最终，这项研究的目标是根据有机粒子的化学组成来预测它们的物理和光学性质。这些信息被用来开发描述气溶胶对地球辐射平衡的影响以及云的形成和性质的模型。与Petrucci教授一起工作的研究生、本科生和高中生获得了复杂实验方法的经验，以及化学反应机制、气溶胶科学和分析方法方面的技能。

This project is jointly funded by the Environmental Chemical Sciences Program in the Chemistry Division and the Atmospheric Chemistry Program of the Atmospheric and Geospace Sciences Division. Professor Giuseppe Petrucci of the University of Vermont investigates the role of water (humidity) in the formation and ageing of organic particles in the atmosphere. Leafy trees and plants release volatile organic compounds during photosynthesis and respiration. These compounds react with pollutants like ozone to produce the majority of organic particles in the atmosphere. Professor Petrucci and his group explore how humidity influences the chemical composition of particles, the phase (liquid or solid) of the particle, and their ability to scatter and/or absorb light. Understanding the chemical changes that these particles undergo once they are formed is crucial for understanding their impact on the atmosphere. This research is leading to a better understanding of the troposphere, the lowest part of the atmosphere, in terms of effects on human health, visibility, and climate. Training is provided to graduate and undergraduate students. The research team also carries out outreach to K-12 students at various levels through the University of Vermont Chemistry Camp. Determining the composition of organic particles in the atmosphere is challenging because each particle may contain hundreds of different molecules. In addition, the types of molecules may change during the particle's time in the atmosphere, which is typically five to seven days. Professor Petrucci and his group develop a novel environmental chamber setup for the study of chemical processes during particle formation. This chamber allows the use of mass spectrometric and spectroscopic techniques to study the particle's composition. These techniques also provide information on changes in particle composition due to changes in reaction conditions, like humidity. Further, using a separate approach, the researchers impinge particles at a hard surface and count how many bounce off compared to how many stick. Solid particles bounce, while liquid particles stick. The phase of the particles is compared with particle composition. Ultimately, the goal of this research is to predict the physical and optical properties of organic particles based on their chemical composition. This information is used to develop models that describe the effect of aerosols on the Earth's radiation balance and the formation and properties of clouds. The graduate, undergraduate and high school students working with Professor Petrucci gain experience in sophisticated experimental methods, and skills in chemical reaction mechanisms, aerosol science and analytical methodology.