Detailed Physical and Chemical Characterization of Respiratory Aerosol: Implications for Airborne Viral Viability

RYAN DAVIS, Paul Tumminello, Andres Sanchez, Samantha Kruse, Stephen House, Monica Manginell, Jesse Cahill, Nisha Duggal, Linsey Marr, George Bachand, Sandia National Laboratories

     Abstract Number: 113
     Working Group: Bioaerosols

Abstract
Respiratory aerosol particles are chemically complex and include various salts and biomolecules. This chemical composition can vary across individuals and origins in the respiratory tract. Respiratory particles can also promote disease transmission by carrying viable pathogens from host to host. The chemical composition of these particles can influence the viability of embedded pathogens. As respiratory particles are exposed to the ambient environment, the chemical species can undergo humidity-induced phased transformations, altering the physical properties of the local environment that a pathogen is exposed to in the aerosol particle. Understanding and characterizing the chemical and physical properties of respiratory particles is thus important for predicting and understanding the viability of pathogens. Here, we discuss efforts to characterize the humidity-dependent phase transformations and chemical composition of model and real respiratory particles. We have characterized phase transformations using a dual-balance electrodynamic trap, where different morphologies can be identified based on optical and rheological properties of particles, and cryogenic electron microscopy imaging. Chemical composition has been characterized using mass spectrometry, cryo-electron energy loss spectroscopy, and atomic force microscopy with embedded infrared spectroscopy. Implications for viral viability and disease transmission will be discussed.

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