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A Mason scientist warns that ventilation systems could spread COVID-19

April 20, 2020   /   by John Hollis

Mason scientist Rainald Löhner warns that hospital ventilation systems could be helping spread COVID-19. Video provided.

A George Mason University professor is warning hospitals treating COVID-19 patients that their ventilation systems may be inadvertently spreading the virus and putting medical personnel at more risk.

Rainald Löhner, the director of Mason’s Center for Computational Fluid Dynamics and an expert in the dispersion of contaminants, suspects that the role of  ventilation systems in the spread of the virus is being overlooked as overwhelmed hospitals struggle with surging patient numbers. In an e-mail to colleagues, Löhner spoke of numerous simulations he has done that show smaller droplets from a sneeze or cough of an infected patient remain in the air considerably longer than larger ones that fall almost immediately. That means ventilation systems could drive the contagious particles further throughout the entire hospital and infect more people.

“Think of it like smoking,” he said. “If you were in a large room and somebody on the other side of the room were smoking, you would be affected by it. We should think in the same way about COVID-19.”

Löhner said it is imperative that air flow be managed, noting that at times a quarter of all those infected in Spain with the coronavirus were doctors and nurses. Löhner recommends hospitals examine their ventilation systems in rooms with infected patients to make sure no air particles from these rooms move into corridors or adjacent rooms.

Löhner said that an increased understanding of air flow could help minimize the risks to doctors and nurses by helping them to better position themselves within high-risk rooms. These simple, low-level engineering measures would have an immediate effect on their protection.

In a video he produced of a simulation inside a typical hospital room, Löhner showed how the larger droplets fell quickly, while smaller ones remained airborne for up to two hours and followed the airstream. This behavior has also been reproduced and measured experimentally, corroborating the simulations. Given that the virus can stay alive in air for up to an hour, if the airflow is not managed properly it could propagate and spread contagion to considerable distances.