Indoor ventilation important to prevent COVID-19 spread: IIT Bombay

Researchers study ventilation of a shared toilet, where water usage can be a major source of aerosol (droplets emitted by a virus carrier). They discover chances of infection are higher in a dead zone that can be near a door or window, or right next to where your air conditioner is blowing in air. 

Ventilation of indoor spaces can stop the air-borne diseases such as COVID-19 from spreading. The virus lives inside tiny microscopic droplets or aerosol ejected from our mouths when we speak, cough, or sneeze. It then stays within the air, where it can be transmitted to other people.  

This motivated researchers at the Indian Institute of Technology (IIT) Bombay to explore how we can better understand and engineer airflow to mitigate the transmission of COVID-19. To do this, they used their knowledge of airflow around aircraft and engines to tailor the airflow within indoor spaces. 

Shared washroom potential source of infection transmission  

They studied the ventilation of a shared washroom, where the use of water can be a major source of aerosol. Shared washrooms are present within offices, restaurants, schools, airplanes, trains, and other public spaces. They have been identified as a potential source of infection transmission within crowded areas in India.  

Their study was featured in the ‘Physics of Fluids’ journal, published by the American Institute of Physics, where they reported computer simulations of airflow within a public washroom showing infectious aerosols in dead zones that can linger up to 10 times longer than the rest of the room. These dead zones of trapped air are frequently found in corners of a room or around furniture.  

“We explored a small, single-person facility used by many, one after another,” said Krishnendu Sinha, a professor of aerospace engineering at IIT Bombay. “I have a similar washroom in my house, which made it easier to study it. Mobility was restricted, and laboratories were closed, but this allowed us to continue our study during the lockdown,” he said.  

The researchers discovered that chances of infection are significantly higher in a dead zone. “Surprisingly, they can be near a door or window, or right next to where an air conditioner is blowing in air,” he said. “You might expect these to be safe zones, but they are not”. “Computer simulations show that air flows in circuitous routes, like a vortex,” said Vivek Kumar, a co-author. “Ideally, air should be continuously removed from every part of the room and replaced by fresh air. This isn’t easy to do when air is trapped in a dead zone.” The biggest question centers around how to ventilate indoor spaces to minimize infection spread. Where should fans and ventilation ducts be placed? How many of them? How much air should flow through them? 

Delhi pollution level poses health risks 

Also, the increasing Delhi pollution level is leading to various health issues. Those who are suffering from respiratory diseases or those whose lungs are compromised like in the COVID-19 patients are at an increased risk of health complications. So, there is an urgent need to monitor indoor air pollutants and ventilate indoor areas.

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