Collaborative Research: Laboratory Investigations of Particle-Organic Vapor Interactions: Effects on Particle Formation, Growth, and Properties

该项目是四个机构之间的合作努力，以提高对大气气溶胶的基本生命周期的理解。这项工作的重点是在一系列条件下在大气中形成非常小的颗粒的过程。 拟议研究的目标是通过进行实验室测量，减少与模拟其形成，增长和大气重要属性相关的不确定性，以促进更准确地预测这些颗粒对气候的影响。项目团队拥有广泛的能力，包括产生主要气溶胶颗粒的能力，如煤烟和二次有机气溶胶（SOA），测量和控制颗粒尺寸和质量分布，通过羟基自由基和臭氧反应在从数小时到数天的等效大气寿命内控制这种颗粒的氧化老化，控制无机和有机颗粒涂层的生产，测量气相和凝相有机化合物的化学组成，测量所产生粒子的云凝结核（CCN）活性，并测量粒子的光学特性。拟议的三年实验室研究计划将提供有关SOA的相关物理化学特性的详细信息，作为氧化处理的函数，包括气相前体与凝结SOA的相互作用。SOA颗粒将在传统的环境室中产生，以及在最近开发的流动反应器中，该反应器可以在宽范围的模拟大气条件下产生具有高通量的SOA。流动反应器能够实现大气相关气相和冷凝相有机化合物的受控羟基自由基（OH）氧化。在反应器中的停留时间比在环境室中可达到的时间短约两个数量级（分钟而不是天），并且OH浓度高两到三个数量级。该项目将提供一个更可靠的数据库，用于建模和预测气溶胶在气候变化中的作用，并详细了解含碳气溶胶的化学，物理和光学特性是如何相互关联的，以及它们如何作为氧化老化的函数而变化。

This project is a collaborative effort among four institutions to improve understanding of the fundamental life cycle of atmospheric aerosol. The effort focuses on processes for the formation of very small particles in the atmosphere over a range of conditions. The goal of the proposed studies is to facilitate more accurate predictions of the influence of these particles on climate by conducting laboratory measurements that reduce uncertainties related to modeling their formation, growth and atmospherically important properties.Together the project team has extensive capabilities that include the ability to produce primary aerosol particles such as soot and secondary organic aerosol (SOA), measure and control the particle size and mass distributions, control oxidative aging of such particles via hydroxyl radical and ozone reactions over equivalent atmospheric lifetimes ranging from hours to multiple days, control production of both inorganic and organic particle coatings, measure the chemical composition of gas- and condensed-phase organic compounds, measure the cloud condensation nuclei (CCN) activity of generated particles, and measure particle optical properties.The proposed three-year laboratory research program will provide detailed information on relevant physiochemical properties of SOA as a function of oxidative processing, including interactions of gas-phase precursors with the condensed SOA. The SOA particles will be generated in conventional environmental chambers as well as in a more recently developed flow reactor that can produce SOA with high throughput over a wide range of simulated atmospheric conditions. The flow reactor enables controlled hydroxyl radical (OH) oxidation of atmospherically relevant gas phase and condensed-phase organic compounds. The residence time in the reactor is about two orders of magnitude shorter (minutes rather than days) and the OH concentration is two to three orders of magnitude higher than is attainable in environmental chambers. This project will provide a more reliable database for modeling and predicting the role of aerosols in climate change and lead to a detailed understanding of how the chemical, physical and optical properties of carbonaceous aerosols are interconnected and how they change as a function of oxidative aging.