Characterization of Secondary Organic Aerosol Exposed to Acidic Sulfates: Chamber and Field Studies

该项目提出了一个假设，即酸性硫酸盐对大气中二次有机气溶胶（SOA）的形成有重大影响，这些气溶胶通过非均相反应形成非挥发性产物，包括有机硫酸盐（OS）。主要目标是：(1)开发新的分析技术来测量气溶胶酸度和本体相产物；(2)阐明多组分有机和无机混合物中SOA形成的机理；(3)评价酸性硫酸盐对环境空气中SOA形成的影响。在大气中发现的有机化合物将暴露于酸性硫酸盐溶液中，以模拟酸性气溶胶中的非均相化学。聚四氟乙烯室将用于将有机化合物暴露于亚微米酸性硫酸盐气溶胶中，并进行广泛的SOA实验。各种光谱方法将被用于分析气溶胶体相产品。将发展一种利用比色法和反射紫外-可见光谱法（C-RUV）动态测量气溶胶酸度的新技术。然后将从实验室研究中获得的结果应用于实地数据，以评估酸性硫酸盐对有机碳的影响。将开发一个新的预测模型来量化异构化学在SOA形成和发展中的作用。这项研究将有助于解释非均相反应如何改变大气中水滴（如云中的水滴）的化学性质，以及它们如何影响气溶胶的光学性质。它还对能见度和公共卫生产生影响。更广泛的影响还包括支持多样化的研究生和本科生群体。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。

This project addresses the hypothesis that acidic sulfates have a significant impact on secondary organic aerosol (SOA) formation in the atmosphere via heterogeneous reactions that form nonvolatile products including organic sulfates (OS). The major goals are (1) to develop new analytical techniques to measure aerosol acidity and bulk phase products; (2) to elucidate the mechanism of SOA formation in multicomponent organic and inorganic mixtures; and (3) to evaluate the impact of acidic sulfates on SOA formation in ambient air. Organic compounds found in the atmosphere will be exposed to acidic sulfate solutions to imitate heterogeneous chemistry in acidic aerosols. Teflon chambers will be used to expose organic compounds to submicron acidic sulfate aerosols and to perform a wide range of SOA experiments. Various spectroscopic methods will be used to analyze the aerosol bulk phase products. A new technique will be developed to dynamically measure aerosol acidity using colorimetry coupled with reflectance UV-Visible spectrometry (C-RUV). The results obtained from the laboratory studies will then be applied to field data to evaluate the impact of acidic sulfate on organic carbon. A new predictive model will be developed to quantify the role of heterogeneous chemistry in SOA formation and growth.This study will help to explain how heterogeneous reactions change the chemical properties of atmospheric aqueous droplets, such as those in clouds, and how they affect aerosol optical properties. It also has implications for visibility and public health. Broader impacts also include support for a diverse group of graduate and undergraduate students. This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).