Collaborative Research: Impact of Changing Volatile Organic Compounds (VOC) to NOx Ratios on Secondary Organic Aerosol Formation

一个为在加州大学滨江分校进行低氮氧化物实验而设计的最先进的90平方米的大型双环境室将用于模拟四种芳香族物质在大气中光化学产生二次有机气溶胶的情况-这些芳香族物质存在于卡特环境活性有机气体替代混合物中，并用于最先进的计算模块中;加州理工学院大气化学模块和预测有机物多相分配的模型（CACM/MPMPO）;模拟SOA的形成。一系列的实验，其中包括单一和二元混合物的芳烃，将探索导致SOA形成的化学机制，并被用来提高CACM/MPMPO modules.The SOA形成芳烃似乎是低估严重在目前的空气质量模型，由于，至少部分地依赖于实验数据室利用过高的NOx浓度。这项工作开发了必要的化学机制，以提高局部，区域和全球SOA形成的估计。预测模型将提供给更大的科学界，以评估气体到粒子的转化过程。在这个项目中评估的方案提供了关键的洞察芳香族物质在大气中的作用和通过稀释和/或调节改变ROG与NOx的比例的影响。将通过网站和同行评审的文献向整个社区提供改进的商会数据。该项目将涉及加州大学滨江分校的本科生和研究生研究人员以及莱斯大学的研究生研究人员。一个临时的研究生交流是将交叉培训建模为导向的学生从赖斯与实验室为导向的学生从加州大学河滨分校。

A large, state-of-the-art, dual 90-m3 environmental chamber, designed for low-NOx experiments at the University of California, Riverside (UCR) will be used to simulate atmospheric photochemical production of secondary organic aerosol (SOA) from four aromatic species--those present in the Carter ambient reactive organic gas (ROG) surrogate mixture and those used in state-of-the-art computational modules; the Cal Tech Atmospheric Chemistry Module and the Model to Predict the Multi-phase Partitioning of Organics (CACM/MPMPO); to simulate SOA formation. The series of experiments, which includes single and binary mixtures of the aromatic hydrocarbons, will explore the chemical mechanisms leading to SOA formation and be used to improve the CACM/MPMPO modules.The SOA formation from aromatic hydrocarbons appears to be underpredicted grossly in current air quality models due, at least in part, to the dependence on experimental data from chambers utilizing excessively high NOx concentrations. This work develops the necessary chemical mechanisms to improve estimation of SOA formation locally, regionally, and globally. The predictive models will then be available to the larger scientific community in assessing gas-to-particle conversion processes. The scenarios evaluated in this project provide critical insight into the role of aromatic species in the atmosphere and the impacts of changing ROG to NOx ratio through dilution and/or regulation. Improved chamber data will be available to the entire community through websites and peer-reviewed literature. The project will involve undergraduate and graduate researchers at UC Riverside and a graduate researcher at Rice. A temporary graduate student exchange is will cross-train modeling oriented students from Rice with laboratory oriented students from UCR.