Face Mask Image
A dynamic respirator changes its pore size in response to changing conditions, making it easier for the wearer to breathe. (Credit: Adapted from ACS Nano 2021, DOI: 10.1021/acsnano.1c06204)

Researchers 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 levels of filtration are not required.

A dynamic air filter with micropores expands when the filter is stretched, allowing more air to pass through. A large increase in the breathability of the filter, which was made of electrospun nanofibers, was achieved with only about a 6 percent loss in filtration efficiency. 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 reacts to particulate matter in the air, as well as changes in the wearer’s respiratory patterns during exercise. Two of the filters were placed on each 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 they exercised in clean air.

Notably, the AI software allows the respirator to adapt to individuals’ unique respiratory characteristics, which could be used to develop a personalized face mask, the researchers say. To make the system smaller, lighter and less cumbersome, the stretcher could eventually be redesigned to have a pump-free mechanism, they add.