Detecting breathborne biomarkers in exhaled aerosols presents an emerging non-invasive way to measure levels of human health, drug delivery response, and toxicity, such as drug abuse. Despite notable applications have introduced to examine the gas phase of the breath (e.g., capnography, alcohol breathalyzer, hydrogen breath test, maximum liver function capacity, etc), notable challenges have been encountered in (i) sampling breath, the gas phase of breath and (ii) collecting breath aerosols, the discrete phase of the breath. Future development and implementation of breath tests based on aerosol analysis require a clear understanding of how human factors interact with device design to influence particle transport and deposition. The computational fluid and particle dynamics (CFPD) algorithm calculates how particles are carried in a gas or liquid flow and deposited on surfaces. This numerical methodology can be used to investigate the phenomena of fluid particulate dynamics of polydisperse aerosols moving in any complex breath device and that are typically in the submicrometer diameter size. In this talk, it will be discussed the development of a 3D multiscale CFPD model to measure transport, particle capture, deposition mechanism, and distribution of polydisperse aerosols in a single impaction filter of a commercial aerosol collection device. CFPD findings are used as approximate solutions to (i) interpret the complex breath-aerosol cloud interaction phenomena and (2) bridge theory and experiment by means of a 3D computational visualization describing particle trajectories and capture of breath aerosols by decoupling human factors and variability. Thereby, facilitating the reproducibility and laboratory analysis of breath sampling and aerosol particle collection via breath devices that will be used for public health and safety.