How ventilation, filtration, humidity prevent transmission

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New research helps explain the role of increased ventilation in preventing coronavirus transmission. Don Arnold/Getty Images
  • Researchers at the University of Oregon measured the amount of virus particles that 11 college students with COVID-19 released during certain activities.
  • The research team found that higher levels of ventilation, filtration and humidity reduced the amount of virus particles in the air.
  • The scientists believe their findings can help building operators create safer indoor environments.

Viruses, such as SARS-COV-2, which causes COVID-19, travel from host to host through the air.

A research team from the University of Oregon says ventilationfiltration and humidity indoor room levels can reduce how easily a virus spreads.

Additionally, they found that there was not much difference in the number of virus particles thrown into the air between people standing 4 feet (feet) or 11 feet apart.

The team believe their findings can help building operators create an indoor environment that helps improve the health and safety of people inside.

The results of this study appear in the journal Clinical infectious diseases.

Dr. Kevin Van Den Wymelenberg, professor of architecture and director of the Institute for Health in the Built Environment at the University of Oregon, was lead author on the new study.

According to Dr. Wymelenberg, the research team had three main goals for this study.

First, the team worked to verify the ability of scientific instrument company Thermo Fisher Scientific’s AerosolSense™ air sampler to detect virus particles in rooms with individuals diagnosed with COVID- 19 under different indoor air conditions. Thermo Fisher Scientific supported this research study as part of the development and commercialization of the device.

“Second, we sought to quantify the effectiveness of alternative ventilation, filtration, and humidification interventions in reducing aerosol viral load in indoor spaces,” Dr. Wymelenberg said. DTM.

“There are many mathematical models to estimate the effectiveness of indoor air disease transmission risk mitigation strategies, such as ventilation, filtration and humidification, but to increase confidence it is important to quantify these patterns in a physical setting.”

Finally, the research team’s third goal focused on quantifying the differences in near-field (4 feet) and far-field (11 feet) measurements of aerosol viral load.

For the study, the research team recruited 11 University of Oregon students with a diagnosis of COVID-19. Participants performed a variety of activities including talking, coughing, walking on a treadmill, and standing or sitting at a desk inside a self-contained, airtight modular building for 3 days. The room also included two AerosolSense air samplers.

During the activities, the researchers took air samples to measure the number of virus particles in the air. They also looked at the number of virus particles landing on surfaces in the room.

The team looked at how changes in ventilation, filtration and humidity levels in the room affected the number of virus particles in the air and landed on surfaces.

The team found that increasing levels of ventilation and filtration significantly reduced the amount of SARS-CoV-2 virus particles in the air and on surfaces.

As the humidity increased, virus particles in the air halved, causing more virus particles to land on surfaces.

Dr Van Den Wymelenberg also said the team’s findings suggest there are no statistically significant differences between the amount of virus particles in the air over near-field distances (4 feet) and far field (11 feet).

“After further interpretation of the results, I suspect that if there are differences between near-field and far-field aerosol viral load, that the differences are modest, and that we need to consider the importance of exposure in near-field and far-field, especially when we consider one-hour durations and room sizes similar to those used in this study,” he added.

Based on their findings, Dr. Van Den Wymelenberg and his team believe they will help building operators make changes to theirventilation, filtration and humidification systems to help stop the spread of viruses such as SARS-CoV-2.

“It is exciting to confirm that indoor air strategies, such as increased ventilation, filtration and mid-range humidification (40-60% relative humidity), can support safe air spaces. “, he explained.

“Intentional humidification is not often incorporated into indoor spaces due to cost or maintenance concerns, but should be considered as it may promote increased deposition of viral particles, as shown in this study, as well as support the natural defense mechanisms of our body by reducing the drying of our mucous membranes.

Dr Van Den Wymelenberg

Dr. Fady Youssef, board-certified pulmonologist, internist, and critical care specialist at MemorialCare Long Beach Medical Center, who was not involved in this research, said DTM he was thrilled to hear about this study and the innovation it offers.

“[A]s we enter the stage where we accept that we are going to live with COVID and it is going to be around us, but we have to go back to our normal life, it is going to be very important to focus on this aspect of it, “, explained Dr. Youssef. “I hope there will be more activity and interest in this kind of […] Implementation.”

“It’s not just about masking and social distancing – there are other things we can do for the spaces we live with so they are friendlier to us and less conducive to the virus.”

– Dr. Youssef

As for the next steps in this research, Dr Van Den Wymelenberg said they are continuing to study the differences between near-field and far-field exposures using new gas detection methods.

They also create design tools to help architects and building operators who want to design and operate safe airspaces and develop technology for near real-time virus surveillance information.

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