Spectroscopy of Atmospheric Aerosol Particles

大气气溶胶颗粒的光谱学

• 批准号: RGPIN-2021-03408
• 负责人: Preston, Thomas
• 金额: $ 2.62万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=742529
• 关键词: Spectroscopy; Atmospheric; Aerosol; Particles

Aerosols are liquid or solid particles suspended in a gas and are a key component in many atmospheric processes on Earth. Whether aerosols originate from natural or anthropogenic sources, they play an important role in the global climate as they greatly impact the Earth's radiation balance, act as cloud condensation nuclei, and serve as sites for chemical reactions. In many of these processes, however, the exact influence of aerosols is poorly understood. Optical tweezers are an analytical instrument at the frontier of high-precision single aerosol particle measurements as they allow for surface-free control of pico- and femtogram liquids and solids across phase states and timescales which are inaccessible via bulk measurements. With this tool, our group has been able to interrogate many important microphysical properties such as hygroscopic growth, surface tension, viscosity, liquid-liquid equilibrium, and atmospheric multiphase chemistry. The dual objectives of our research program are (i) the development of experimental platforms for spectroscopic measurements (e.g. cavity-enhanced Raman scattering) of single micron- and nanosized particles that can find application across a broad spectrum of disciplines and (ii) utilizing these platforms to address outstanding scientific questions within atmospheric aerosol science. In the coming grant period, we will build on our progress since 2014 and develop the next generation of optical trapping platforms and spectroscopic techniques to investigate the role that condensed-phase chemistry plays in Earth's atmosphere. Examples of phenomena that will be studied using our optical traps include multistep phase changes in supersaturated droplets, phase states of high viscosity organic aerosols (e.g. semisolid, glassy, and gel formation) and their effect on multicomponent mass transport, the role of surface tension in aerosol activation into cloud droplets, and measuring the optical properties of strongly absorbing particles (e.g. brown carbon). In addition to the new traps that will be designed and constructed to study these systems, we will simultaneously continue our development of the theoretical framework that is required to model light scattering, radiation pressure, multicomponent mass transport, and aerosol thermodynamics in our single particle experiments. These tools are important not only for the accurate retrieval of aerosol physical properties from spectroscopic measurements, but they also serve our overall goal of a detailed understanding of airborne particles. In summary, our program will continue to develop both state-of-the-art analytical instrumentation and models while studying systems of relevance to Earth's atmosphere. This is all in pursuit of improving our fundamental knowledge of the physical chemistry of atmospheric aerosol particles.

气溶胶是悬浮在气体中的液体或固体颗粒，是地球上许多大气过程的关键组成部分。无论气溶胶来自自然还是人为来源，它们在全球气候中发挥着重要作用，因为它们极大地影响了地球的辐射平衡，充当云凝结核，并作为化学反应的场所。然而，在许多这些过程中，对气溶胶的确切影响知之甚少。 光镊是一种处于高精度单个气溶胶颗粒测量前沿的分析仪器，因为它们允许在相态和时间尺度上对皮科和毫微微克液体和固体进行无表面控制，这是通过批量测量无法实现的。有了这个工具，我们的团队已经能够询问许多重要的微物理特性，如吸湿增长，表面张力，粘度，液-液平衡，和大气多相化学。我们的研究计划的双重目标是（一）光谱测量实验平台的发展（例如腔增强拉曼散射）的单个微米和纳米尺寸的颗粒，可以找到应用在广泛的学科和（ii）利用这些平台来解决大气气溶胶科学中的突出科学问题。在即将到来的资助期内，我们将在2014年以来取得的进展的基础上，开发下一代光学捕获平台和光谱技术，以研究凝聚相化学在地球大气中的作用。将使用我们的光学陷阱研究的现象的例子包括多步相变过饱和液滴，高粘度有机气溶胶（如半固体，玻璃状和凝胶形成）的相态和它们对多组分质量传输的影响，表面张力的作用气溶胶激活成云滴，并测量强吸收粒子（如棕色碳）的光学特性。除了将设计和建造新的陷阱来研究这些系统，我们将同时继续我们的理论框架，这是需要在我们的单粒子实验模型光散射，辐射压力，多组分质量输运和气溶胶热力学的发展。这些工具不仅对于从光谱测量中准确检索气溶胶物理特性非常重要，而且还有助于我们详细了解空气中颗粒物的总体目标。总之，我们的计划将继续发展最先进的分析仪器和模型，同时研究与地球大气相关的系统。这一切都是为了提高我们对大气气溶胶粒子物理化学的基础知识。