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The Underappreciated Role of Indoor Deposition in Determining Person-to-Person Aerosol Transmission
TAMI BOND, Delphine K. Farmer, Paul Francisco, Shantanu Jathar, Jeffrey R. Pierce, Colorado State University
Abstract Number: 450
Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases
Abstract
The COVID-19 pandemic demonstrated that the public health community would benefit from better information on the mechanisms of particle transport between individuals. In outdoor settings, transport between two people is driven by wind and its fluctuations, and deposition has little effect on transport between people except for the very largest particles (100 μm). In indoor settings, both dispersion and removal of contaminated air are slower, so particle sizes that might carry infectious agents (1 or 10 μm) have longer transit times between people than they do outdoors. These longer person-to-person transit times mean that deposition to indoor surfaces plays an important role in the prediction of transport. For 10 μm particles, deposition loss rates are of the same order as ventilation loss rates. Yet particle deposition velocities are not well understood, with established models predicting much lower deposition rates than the sparse existing measurements. Building-management strategies, such as increasing ventilation or filtration, can decrease exposure to airborne infectious agents. We simulate mitigation strategies in residential and commercial situations using a multi-zone process model, and show how uncertainties in deposition velocity might cloud the ability to predict the benefit of these strategies.