Project Summary/Abstract Viral transmission from an infected person or an animal to a new host can occur by direct or indirect routes. During indirect transmission, contaminated surfaces can play an important role. Although there are a number of methods for disease transmission in healthcare facilities, aerial transmission is often considered an important route for many organisms. The aerial path followed by pathogens from the source to recipients or surfaces and their viability upon impaction is affected by many factors, including room air exchange rates and air properties that may further challenge aerosolized bioparticles, including viruses. As ventilation systems are practically ubiquitous in the build environment, the effect of air properties on the infectivity and transport of aerosolized viruses is an important topic for study to reduce the spread of infectious viral particles. The proposed project is the first known comprehensive study on the impact of environmental conditions including temperature, humidity, and air velocity on the droplet size, spread, and deposition/resuspension of airborne viruses. The optimization of environmental conditions that lead to improved ventilation designs or mitigation strategies could significantly reduce the entrainment and spread of viable infectious viruses in the built environment. The PIs' have previously shown that a combined modeling and sampling approach is successful to mitigate transport of airborne infectious microorganisms in a ventilated facility The goal of this proposal is to understand the effect of environmental conditions on the transmission, deposition and resuspension of aerosolized virus particles and provide realistic measures to reduce their spread in the ventilation airflow in nosocomial and healthcare settings. The proposed goal will be achieved by combining betacoronavirus aerosol collection with biolayer interferometry, molecular dynamics and computational airflow modeling in model experiments and field testing. The research plan is based on three fundamental questions about 1) the effect of environmental conditions and surface characteristics on the size distribution, deposition, and resuspension of virus aerosols using biolayer interferometry, molecular dynamics modeling and computational flow simulation to visualize the airflow patterns in a 3 scale model hospital room. Elucidating the relationship between viable virus deposition and resuspension is the key for developing means to reduce transmission of viruses through airborne exposure; 2) using bioaerosol collectors to determine the rate and distance aerosolized viruses can spread in different environmental conditions analyzed by cell culture and quantitative polymerase chain reaction (qPCR); and 3) how mitigation efforts based on optimized ventilation can be applied to hospital settings. This innovative project will help develop and implement interdisciplinary ventilation design guidelines to educate scientists and engineers about bioaerosol transport and environmental effects on the spread of viruses in an effort to improve understanding of infectious disease considerations in design, management, and monitoring of healthcare facilities and other built environment.

Project Narrative Despite the increasingly recognized role of the environment in the spread of virus aerosol particles and controlling many of the pathways that lead to the deposition and resuspension of viruses, the mechanism underlying the effect of the environment is poorly understood. We propose to address this need by using molecular dynamics and computational modeling with the spatial, and temporal collection of aerosolized virus particles to track their deposition and resuspension within a model hospital room at different ventilation configurations. The knowledge gained in the process helps develop better ventilation strategy guidelines to reduce the spread of virus particles in hospitals and mitigate disease transfer in these or other facilities.