Effect of Heterogeneous Interactions on Optical, Hygroscopic, and Cloud Condensation Nuclei (CCN) Properties of Organic Atmospheric Aerosols

将开展一项实验室计划，系统地研究已知形态、大小和组成的有机气溶胶的云凝结成核(CCN)和光学性质如何受到氧化反应(以臭氧、硝酸根和羟基为氧化剂)的受控转变以及通过沉积形成的与大气相关的涂层的影响。实验将在尽可能接近大气中的条件下进行。这些实验将利用实验室仪器，该仪器结合了可控的粒子源、流动反应器和气溶胶质谱仪(AMS)来测量气溶胶粒子的组成及其形态(大小、密度、形状和分维)。该仪器还测量气溶胶的光学散射及其吸湿特性。将增加一台仪器来测量气溶胶的CCN活性。这将产生关于大气氧化反应动力学作为颗粒组成、结构、尺寸、表面性质和相对湿度的函数的数据，以及关于转变对模型颗粒的吸湿性、CCN活性和光学性质的影响的信息。这项工作将有助于更好地了解气溶胶在空气质量和气候中的作用。这笔助学金将支持一名研究生的参与。

A laboratory program will be carried out to systematically study how cloud condensation nucleating (CCN) and optical properties of organic aerosols of known morphology, size, and composition are affected by controlled transformations via oxidative reactions (using O3, NO3, and OH as oxidants), and by atmospherically relevant coatings formed by deposition. Experiments will be performed under conditions as close as possible to those found in the atmosphere. The experiments will utilize a laboratory apparatus that combines a controlled source of sized particles, a flow reactor, and an aerosol mass spectrometer (AMS) to measure the composition of aerosol particles and their morphology (size, density, shape, and fractal dimension). The instrument also measures optical scattering by aerosols and their hygroscopic properties. An instrument will be added to measure the CCN activity of aerosols. This will result in data on atmospheric oxidation reaction kinetics as a function of particle composition, structure, size, surface properties, and relative humidity, and on information on the effect of transformations on hygroscopicity, CCN activity and optical properties of model particles. This work will contribute to a better understanding of the role of aerosols in air quality and climate. The grant will support the participation of a graduate student.