Aerosol particles larger than approximately one micrometer in size constitute a category of natural and manmade particulates known as the coarse-mode aerosol (CMA). Common types of CMA particles include mineral dust (MD) and biologic particles, like pollen. The ability to characterize CMA particles is important for agriculture, climate science, and manufacturing processes. For example, MD represents the largest component, by mass, of aerosols in continental regions and is an important mechanism for the transport of nutrients to land and marine ecosystems. Dust also reduces visibility, which impacts aviation. To best understand the impact of CMA particles in most applications, basic information such as particle size, shape, and number concentrations are needed. 

In this project, we demonstrated how flowing MD aerosol particles can be imaged in-air within a sensing volume of approximately one cubic centimeter in a time dependent manner. This is done with digital in-line holography (DIH) to render quasi-3D representations of individual particles in a 3D sensing volume in time steps of approximately 10 ms to create a video (below) of the flowing particles.