Better masks, proper ventilation can reduce the spread of COVID-19 virus indoors

With research increasingly showing that the COVID-19 virus is transmitted through small droplets suspended in the air, there is growing concern that current public health guidelines for wearing masks and social removal are insufficient to combat the spread of indoor environments, such as prisons, hospitals and meat packaging. plants, where people are usually nearby.

Most research has focused on coughing and sneezing. But studies on how simple breathing can contribute to the spread of the virus in the air are rare.

In AIP Advances, published in AIP Publishing, researchers at the Indian Institute of Technology Bhubaneswar show that distancing is just as important as wearing masks when people indoors are just breathing or engaging in normal conversation, even when there is no risk of coughing or sneezing. . They also found that leaking masks in the same scenario posed a significant challenge in preventing the spread of the virus.

Our findings demonstrate the need for good ventilation systems that take into account the 5 to 10% leakage of aerosolized particles that occur in each breathing cycle as a way to reduce the concentration of droplets indoors. An innovation in the design of the mask is also needed in order to reduce the leakage of side and lower drops, while providing adequate comfort to the face. “

Venugopal Arumuru, Study Author, Indian Institute of Technology Bhubaneswar

In the experimental environment, a mechanical breathing simulator is connected to a model standing at a height of 5 feet and 8 centimeters to simulate regular breathing and a slightly longer breath typical of healthy adults standing still or engaged in moderate activities such as walking, talking or participation in gathering work.

The researchers evaluated the effectiveness of different types of masks, the mask-shield combination and the use of face shields alone.

The mist generator was filled with a mixture of water and glycerin to mimic the consistency of saliva droplets 1–10 micrometers in diameter to reflect airborne portability. The droplet exposure was illuminated and recorded with a video camera.

Researchers have found that without covering the face, breathing droplets can travel up to 4 meters in five seconds.

The commercial five-layer mask has been found to provide the best protection, with complete face protection and minimal leakage under the chin. The commercial N-95 mask prevents the drops from leaking in front, but the leaks in the gaps between the mask and the nose were significant.

There was an obvious leak from the front of the surgical mask, although the addition of a face shield increased the limitation of the drops.

“However, droplets that are deposited under the shield are worrying, and the pairing of surgical masks with shields is not adequate in hospitals and other places where it is difficult to follow strict guidelines for social removal,” Arumuru said.


American Institute of Physics

Journal reference:

Hill, MD, and others. (2021) Perspective of ceramic materials for 5G wireless communication systems. Letters of applied physics.