The coronavirus pandemic has made many people get accustomed to wearing face masks to safeguard themselves and others. However, that does not mean it is always easy to wear them — particularly during exercise.
A dynamic respirator changes its pore size in response to changing conditions, making it easier for the wearer to breathe; clear tubing connects the mask to a portable device that communicates with a computer. Image Credit: Adapted from ACS Nano 2021, doi.org/10.1021/acsnano.1c06204.
Currently, researchers reporting in the journal ACS Nano have come up with a dynamic respirator capable of adjusting its pore size in response to varying conditions, like exercise or air pollution levels. This enables the wearer to breathe in an easy way when there is no need for the highest levels of filtration.
Face masks help protect against the spread of the virus that is responsible for causing COVID-19, but they are also worn by people with respiratory issues to remove harmful pollutants.
However, at times, high levels of filtration are not required, like when the levels of air pollution are low, or when someone is exercising alone outdoors, which is usually considered a low-risk activity for spreading COVID-19. Yet, masks that are worn by people at present do not have the ability to adjust to varying conditions.
As time passes, the trapped and exhaled breath can create sensations of humidity, heat, bad breath and discomfort, particularly as more breath gets exhaled during exercise. Seung Hwan Ko and collaborators wished to develop a respirator that could have the ability to automatically adjust its filtration characteristics in reaction to changing conditions.
A dynamic air filter with micropores was designed by the scientists that could expand on stretching the filter. This enables more air to pass through. A sharp increase in the filter’s breathability was made of electrospun nanofibers and was achieved with only around a 6% loss in filtration efficiency. Furthermore, the team placed a stretcher near the filter that was linked to a lightweight and portable device containing an air pump, sensor and microcontroller chip.
The device communicates without cables, with an external computer running artificial intelligence (AI) software that responds to particulate matter in the air, as well as variations in the respiratory patterns of the wearer during exercise. Two of the filters were positioned on each side of a face mask and were tested on human volunteers.
A slight increase in pore size was properly produced by the stretcher when a volunteer exercised in a polluted atmosphere compared to when they exercised in clean air. Remarkably, the AI software enables the respirator to adapt to the special respiratory characteristics of the individuals.
The researchers feel that this could be utilized to develop a personalized face mask. To make the system lighter, smaller and less heavy, the stretcher could finally be redesigned to have a pump-free mechanism.
The authors of the study acknowledge financial support from the National Research Foundation of Korea.
Journal Reference:
Shin, J., et al. (2021) Dynamic Pore Modulation of Stretchable Electrospun Nanofiber Filter for Adaptive Machine Learned Respiratory Protection. ACS Nano. doi.org/10.1021/acsnano.1c06204.