Mechanistic Investigations of Secondary Organic Aerosol Growth

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。该项目的主要目标是通过实验室对二次有机气溶胶(SOA)生长和加工的反应室实验，改善对生物萜类和还原有机氮化合物衍生的有机气溶胶大气老化周期的基本了解。将确定作为SOA直接前体的关键半挥发性物种，并对各种已知的生物和人为大气排放的SOA产率进行量化。在线软电离(光电子共振捕获电离，PERCI)气溶胶质谱仪(AMS)与气相色谱分析的独特组合将被用来直接测量典型挥发性萜类化合物向气溶胶相的转变。类似的实验将研究有机气溶胶对还原氮的封存，并对这种封存如何影响SOA的老化和生长以及SOA在还原氮的传输和沉积中所起的作用有一个更基本的理解。最终，这项工作的结果将提供各种大气相关氧化剂混合物下的详细化学机制、产品分支率和SOA产量，以及各种化合物类别、浓度和相对湿度。这一知识将使广大化学受众对混合相化学反应机理感兴趣，并对大气社区在量化氧化气体到粒子的转变方面感兴趣，这是大气化学领域的一个高度不确定的领域。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The main objective of this project is to provide an improved fundamental understanding of the atmospheric aging cycle of organic aerosol derived from biogenic terpenoid and reduced organic nitrogen compounds through laboratory reaction chamber experiments on secondary organic aerosol (SOA) growth and processing. Key semi-volatile species that are direct precursors to SOA will be identified and SOA yields quantified for a wide variety of known biogenic and anthropogenic atmospheric emissions. A unique combination of online soft-ionization (photoelectron resonance capture ionization, PERCI) aerosol mass spectrometry (AMS) with gas chromatographic analysis will be used to directly measure the transformation of representative volatile terpenoid compounds to the aerosol phase. Similar experiments will investigate the sequestration of reduced nitrogen by organic aerosols and develop a more fundamental understanding of how this sequestration impacts SOA aging and growth as well as the role SOA has in the transport and deposition of reduced nitrogen.Ultimately, the results from this work will provide detailed chemical mechanisms, product branching ratios, and SOA yields under a variety of atmospherically relevant oxidant mixtures, for a variety of compound classes, concentrations and relative humidities. This knowledge will be of interest both to a broad chemical audience regarding mixed phase chemical reaction mechanisms and also to the atmospheric community in terms of quantifying oxidative gas to particle transitions, a highly uncertain area of the field of atmospheric chemistry.