Studies suggest that ventilation systems may increase the risk of exposure to Covid in winter

Scientists, including scientists at the University of Cambridge, UK, have found that a widely used “mixed ventilation” system designed to keep conditions uniform across all parts of the room allows pollutants in the air to spread throughout the space. I found that it was evenly distributed.

According to a study published in the Journal of Fluid Mechanics, these pollutants may contain droplets and aerosols, and may contain viruses such as the new coronavirus SARS-CoV-2. there is.

Appropriate for reducing the risk of SARS-CoV-2 infection, as there is increasing evidence that the coronavirus spreads primarily through droplets and aerosols released during coughing, sneezing, conversation, and breathing. The need for good ventilation and wearing a mask became clear.

Based on studies conducted so far, researchers have stated that indoor permeation is much more common than outdoor permeation-perhaps an increase in exposure time and a decrease in the rate of dispersion of droplets and aerosols. It is the cause.

“As winter approaches in the Northern Hemisphere and people spend more time indoors, understanding the role of ventilation estimates the risk of getting a virus,” said Paul Linden, a research co-author at the University of Cambridge. It helps to slow the spread. ” ..

According to Linden, small breathing aerosols containing the virus are transported along with the carbon dioxide produced by breathing and carried around the room by a stream of ventilation.

“Insufficient ventilation can increase carbon dioxide levels and increase the risk of exposure to the virus,” he explained.

According to scientists, the flow of air in a building works in either of two main modes: mixed ventilation or replacement ventilation.

They are most common in the former mode, with vents arranged to keep the air in the space well mixed so that the temperature and concentration of contaminants are kept uniform throughout the space. I said there is.

In the second mode, replacement ventilation, vents are placed at the bottom and top of the room, the lower zone is cooler, the upper zone is warmer, and warm air is extracted from the top of the room, researchers say. Stated.

They explained that the exhalation was also warm, and most of it accumulated at the top.

If the interface between the zones is high enough, research shows that contaminated air can be extracted by the ventilation system rather than being inhaled by someone else.

Scientists suggest that, when properly designed, replacement ventilation reduces the risk of respiratory mixing and mutual contamination, thereby reducing the risk of exposure.

“These two concerns are related, but different, and there is a tension that emerged during the pandemic,” said Rajesh Bagat, another co-author at the University of Cambridge.

“Maximizing ventilation while keeping the temperature at a comfortable level without excessive energy consumption is difficult to balance,” Bagat said.

To model how coronavirus or similar virus spreads indoors, scientists have identified where breathing goes when people exhale, and how it changes with ventilation. I believe it is important to know.

“These data can be used to estimate the risk of catching a virus indoors,” Linden said.

In this study, scientists investigated different breathing modes (nasal breathing, conversation, laughter, with and without masks, respectively) by imaging the heat associated with breathing.

“When you sit still, humans generate heat and the heat rises, so when you exhale, your breath rises and accumulates near the ceiling,” said Bagat.

Researchers say that laughing in particular causes a great deal of confusion, suggesting that laughing indoors by an infected person without a mask greatly increases the risk of infection.

“One of the obvious things is that one of the ways the mask works is to stop breathing,” Linden said.

“Almost all masks have some leakage from the top and sides, but slowing the exhaled pollutant momentum reduces the chances of direct exchange of aerosols and droplets when breathing remains. It’s not that important. It’s in the body’s aerosol and is carried upwards towards the ceiling, “he said.

According to scientists, a three-layer mask reduces the amount of pollutants that recirculate the room through ventilation.

“Wearing a mask with the windows open seems to be the best advice. Obviously there are less problems during the summer, but you have to worry during the winter,” Linden said.

This story was published from a news agency feed without changing the text.