Development and application of new analytical approaches to understand the chemistry of the atmospheric condensed phase

需要紧急关注的环境化学领域的进展受到现有分析方法的限制。我的研究小组开发新技术，并使用它们来检查污染物的来源，影响和命运。在今后五年中，我们将利用这一方法来解决两个关键的不确定性领域：持久性污染物迁移和气候变化。这两个问题都处于国际监管的关键时刻。持久性污染物可进行远距离迁移，影响远离其排放的地区。短链全氟羧酸（scPFCAs）具有持久性和潜在毒性。我们最近表明，scPFCA在北极的积累是由臭氧消耗氯氟烃的替代品的监管替代造成的。2016年的一项政策修正案将极大地改变scPFCA的来源，影响运输和命运。我们将开发两种技术，这将代表第一个实时方法的气体和气溶胶相scPFCAs。这些将使我们能够在流管研究中探测气体-表面相互作用和物理特性，并首次实时测量气相和气溶胶相scPFCA。使用一种新的scPFCAs离线方法，我们还将收集和分析大气沉积样品。拟议的实验室和实地测量对于为化学品归趋模型提供信息和评估不断变化的监管对环境的影响至关重要。这项工作将涉及11名HQP（3名博士，3名硕士，5名本科生）。燃烧植被释放的有机气溶胶具有气候变暖的特性，但人们还没有很好地理解，这阻碍了它们在气候模型中的准确纳入。这种不确定性大部分来自于特性不佳的水溶性有机化合物，称为棕色碳（BrC）。我们的离线分析新方法表明，BrC是由比以前认为的大得多的分子组成的，并且使用电喷雾电离质谱法（MS）无法检测到。在此基础上，我们将探索MS电离技术，以确定一个更合适的方法BrC表征。这项新技术将用于研究大气处理对溴化碳的影响，方法是表征在流管中化学老化的样品和从受控燃烧研究中收集的样品。我们将把我们的方法与采样系统相结合，以创建第一个与化学分离相结合的BrC在线系统，该系统将应用于受火灾影响的地区。通过我们的测量提供的对BrC化学结构和命运的更好理解对于改进支持国际监管的气候模型至关重要。这项工作将涉及4名HQP（2名博士，2名本科生）。*通过开发和应用创新的新分析方法进行实验室和现场测量，我的团队将提供对有效环境监管至关重要的基本化学知识。

Progress in areas of environmental chemistry requiring urgent attention is limited by available analytical methods. My research group develops new techniques and uses them to examine sources, impacts, and fate of pollutants. Over the next five years, we will use this approach to target two critical areas of uncertainty: persistent pollutant transport and climate change. Both issues are at crucial junctures for international regulation.******Persistent pollutants can undergo long-range transport and impact areas far from their release. Short-chain perfluorocarboxylic acids (scPFCAs) are persistent and potentially toxic. We recently showed scPFCA accumulation in the Arctic was caused by the regulated replacement of ozone-depleting chlorofluorocarbons with alternatives. A 2016 policy amendment will dramatically change the sources of scPFCAs, impacting transport and fate. We will develop two techniques that will represent the first real-time methods for gas- and aerosol-phase scPFCAs. These will enable us to probe gas-surface interactions and physical properties in flowtube studies and make the first real-time measurements of gas- and aerosol-phase scPFCAs. Using a new offline method for scPFCAs, we will also collect and analyze atmospheric deposition samples. Proposed laboratory and field measurements are critical to inform chemical fate models and assess the environmental impacts of changing regulation. This work will involve 11 HQP (3 PhD, 3 MSc, 5 undergraduate).******Organic aerosols released from burning vegetation have climate-warming properties that are not well understood, impeding their accurate inclusion in climate models. Much of this uncertainty is derived from poorly-characterized water-soluble organic compounds, known as brown carbon (BrC). Our new method for offline analysis showed that BrC was composed of molecules much larger than previously believed and that it could not be detected using mass spectrometry (MS) with electrospray ionization. Building on this, we will explore MS ionization techniques to identify a more suitable method for BrC characterization. The new technique will be used to study impacts of atmospheric processing on BrC by characterizing samples chemically aged in a flowtube and samples collected from controlled burn studies. We will interface our method to a sampling system to create the first BrC online system coupled to chemical separation, which will be applied in fire-impacted areas. The improved understanding of chemical structure and fate of BrC provided by our measurements will be critical for improving climate models that underpin international regulation. This work will involve 4 HQP (2 PhD, 2 undergraduate).******Through development and application of innovative new analytical methods to laboratory and field measurements, my group will provide fundamental chemical understanding that is essential to effective environmental regulation.