Physicochemical Investigations of Aerosol Particles

点击翻译按钮获取中文摘要

Aerosols are small particles suspended in a gas and their presence in our atmosphere affects Earth's environment in many ways. For example, their direct effect on radiative forcing influences climate change, they serve as sites for many different chemical reactions, and they act as cloud condensation nuclei. Furthermore, aerosols impact human health on a daily basis as they are, of course, present in the air we breathe. Understanding the properties of aerosols is therefore of crucial importance for quantifying their impact on climate and health. Currently, there exist many gaps in both our chemical and physical knowledge of aerosols. The focus of the proposed research program is to address many of these knowledge gaps through the simultaneous development of experimental and theoretical tools for the study of atmospherically relevant aerosol particles. Optical trapping of individual particles will be the primary technique used to study aerosols. By taking measurements at the single particle level, it is possible for microphysical and chemical processes to be investigated with great accuracy and low uncertainties over a wide range of timescales. A comprehensive research program will be implemented based on four inter-related projects, each of which is designed around one of the following four optical traps: 1. Aerosol optical tweezers, 2. Optical Bessel beam trap, 3. Holographic optical tweezers, and 4. Low temperature optical tweezers. These optical traps will be used to study several fundamental aerosol processes that influence cloud condensation nuclei and the process of cloud formation. Parameters vital to aerosol science such as hygroscopicity, surface tension, viscosity, scattering and absorption of electromagnetic radiation, and heat and mass transfer will be determined with very high precision. Achieving a deeper, more detailed understanding of these phenomena is a major goal of the proposed research project, as it will greatly improve our knowledge of aerosols and their role in climate. The optical traps will be able to examine particles with sizes ranging from several micrometers down into the nanometer size regime and will be at the forefront of research in the field of aerosol science. In broad terms, the proposed program aims to develop state-of-the-art analytical tools for aerosol research and, simultaneously, validate or improve the models we currently use to understand the chemistry and physics of atmospheric aerosols.