During the coronavirus pandemic, many people have grown accustomed to wearing face masks to protect themselves and others, but that doesn’t mean the masks are always comfortable, especially during exercise. Now, researchers reporting in ACS Nano have developed a dynamic respirator that modulates its pore size in response to changing conditions, such as exercise or air pollution levels, allowing the wearer to breathe easier when the highest filtration levels are not not required.
Face masks protect against the spread of the virus that causes COVID-19, but they are also worn by people with respiratory problems to filter out harmful pollutants. However, in some circumstances high levels of filtration are not needed, such as when air pollution levels are low or when someone is exercising alone outdoors, which is generally considered as a low risk activity for the spread of COVID-19. But current masks cannot adapt to changing conditions. Over time, trapped and exhaled breaths can create sensations of heat, humidity, bad breath, and discomfort, especially as the breath is exhaled during exercise. Seung Hwan Ko and his colleagues wanted to make a respirator that could automatically adjust its filtration characteristics in response to changing conditions.
Researchers have developed a dynamic air filter with micropores that expand when the filter is stretched, allowing more air to pass through. A strong increase in the breathability of the filter, composed of electrospun nanofibers, was obtained with a loss of filtration efficiency of only about 6%. The team then placed a stretcher around the filter that was connected to a lightweight portable device containing a sensor, air pump, and microcontroller chip. The device communicates wirelessly with an external computer running artificial intelligence (AI) software that responds to particles in the air, as well as changes in the wearer’s breathing patterns during exercise. Two of the filters were placed on either side of a face mask and tested on human volunteers. The stretcher correctly generated a smaller increase in pore size when a volunteer exercised in a polluted atmosphere than when exercising in clean air. Notably, the AI ââsoftware allows the respirator to adapt to individuals’ unique respiratory characteristics, which could be used to develop a personalized face mask, the researchers said. To make the system smaller, lighter and less cumbersome, the stretcher could possibly be redesigned to have a pump-less mechanism, they add.
The authors acknowledge funding from the National Research Foundation of Korea.
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