Science & Technology

The results show that masks and proper ventilation can be the key to enabling more capacity in schools, businesses and other indoor areas-ScienceDaily.

A new study from the University of Central Florida suggests that masks and good ventilation systems are more important than social distance to reduce the aerial spread of COVID-19 in the classroom.

Studies recently published in the journal Fluid physicsComes at an important time when schools and colleges are considering returning to more face-to-face classes in the fall.

“This study is important because it provides guidance on how we understand safety in indoor environments,” said Michael Kinzel, an assistant professor and co-author of the study at UCF’s Department of Mechanical and Aerospace Engineering. I am.

“This study found that when masks were mandated, aerosol propagation pathways did not indicate the need for a social distance of 6 feet,” he says. “These results emphasize that the use of masks does not reduce the chance of infection over longer physical distances, as the obligation of masks enhances competence in schools and elsewhere. It emphasizes that it can be the key to. “

In this study, researchers created a computer model of a classroom with students and teachers, then modeled airflow and disease transmission, and calculated the risk of transmission from aerial infections.

According to Kinsel, the classroom model is 709 square feet and has a ceiling height of 9 feet, similar to a small college classroom. The model had a masked student (everyone could be infected) and a masked teacher in front of the classroom.

Researchers examined classrooms using two scenarios, ventilated and unventilated classrooms, and two models, Wells-Riley and Computational Fluid Dynamics. Wells-Riley is commonly used to assess indoor propagation probabilities, and computational fluid dynamics is often used to understand the aerodynamics of automobiles, aircraft, and the underwater motion of submarines.

The mask has been shown to be beneficial by preventing direct exposure of the aerosol. The mask provides a weak puff of warm air, moving the aerosol vertically and preventing it from reaching adjacent students.

In addition, the ventilation system combined with a good air filter reduced the risk of infection by 40-50% compared to classrooms without ventilation. This is because the ventilation system creates a steady-state airflow that circulates much of the aerosol through the filter, removing some of the aerosol, compared to a non-ventilated scenario where the aerosol gathers over the people in the room.

These results support recent guidelines from the Centers for Disease Control and Prevention that recommend reducing primary school social distances from 6 feet to 3 feet when mask use is universal, Kinsel said. I will.

“Comparing the chances of getting infected when wearing a mask, a social distance of 3 feet does not show an increase in the chance of getting infected for 6 feet. This means that schools and other companies are safe for the rest of the pandemic. May provide evidence to operate in. “

“The results suggest exactly what the CDC is doing, the use of ventilation systems and masks is of paramount importance to prevent infection, and social distance will be the first to relax.” Researchers say.

Comparing the two models, researchers found that Wells-Riley and Computational Fluid Dynamics produced similar results in particularly unventilated scenarios, while Wells-Riley had an infection probability of approximately 29% in ventilated scenarios. I found that I was underestimating.

As a result, they recommend applying some of the additional complex effects captured in computational fluid dynamics to Wells-Riley to better understand the risk of infection in space. Aaron Foster, a PhD student in the UCF Faculty of Mechanical Engineering, says. Leading author of aerospace engineering and research.

“Detailed computational fluid dynamics results provided new insights into the relationship between risk variation and distance, but are more commonly used as they capture most of the benefits of ventilation with reasonable accuracy. We also tested the Wells-Riley model, “says Foster. “This is important because these are publicly available tools that anyone can use to mitigate risk.”

This study is part of a larger overall effort to control the transmission of airborne infections and better understand the factors associated with being a superspreader. Researchers are also testing the effect of masks on aerosol and droplet propagation distances. This work is partially funded by the National Science Foundation.

Kinzel received his PhD in aerospace engineering from Pennsylvania State University and joined the UCF in 2018. In addition to being a member of UCF’s Department of Mechanical and Aerospace Engineering, which is part of UCF’s University of Engineering and Computer Science, UCF’s Center for Advanced Turbomachinery and Energy Research.

The results show that masks and proper ventilation can be the key to enabling more capacity in schools, businesses and other indoor areas-ScienceDaily. The results show that masks and proper ventilation can be the key to enabling more capacity in schools, businesses and other indoor areas-ScienceDaily.

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