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。我的研究小组开发了新技术，并用它们来检查污染物的来源、影响和命运。在接下来的五年里，我们将使用这种方法来针对两个关键的不确定领域：持久性污染物运输和气候变化。这两个问题都处于国际监管的关键时刻。持久性污染物可以进行长距离迁移，并影响远离其释放的地区。短链全氟甲酸(ScPFCA)具有持久性和潜在毒性。我们最近表明，北极地区单链全氟氯烃的积累是由消耗臭氧的氯氟烃被替代物规律性地替代造成的。2016年的一项政策修正案将极大地改变单链PFCA的来源，影响运输和命运。我们将开发两种技术，它们将代表气相和气相单链PFCA的第一个实时方法。这将使我们能够在流管研究中探索气体-表面相互作用和物理性质，并首次实时测量气相和气溶胶相单链聚全氟乙烷。我们还将使用一种新的离线方法收集和分析大气沉积样品。拟议的实验室和现场测量对于提供化学命运模型和评估法规变化的环境影响至关重要。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尚不清楚的气候变暖特性，阻碍了它们准确地纳入气候模型。这种不确定性很大程度上来自于特性不佳的水溶性有机化合物，即所谓的棕色碳(BRC)。我们新的离线分析方法表明，BRC的分子组成比以前认为的要大得多，并且无法用电喷雾电离的质谱仪(MS)进行检测。在此基础上，我们将探索MS电离技术，以确定更适合于BRC表征的方法。这项新技术将用于研究大气处理对BRC的影响，方法是对在流动管中化学老化的样品和从受控燃烧研究中收集的样品进行表征。我们将把我们的方法与采样系统相连接，以创建第一个与化学分离相耦合的BRC在线系统，该系统将应用于受火灾影响的地区。我们的测量提供了对BRC化学结构和命运的更好理解，这对于改进支撑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到实验室和现场测量，我的团队将提供对有效环境法规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.