While some are still wondering about wearing year-round masks into the pandemic, scientists have gotten ahead with working out what the best strategy is – and face masks are cotton just on the second get another agreement.
Various studies have tested different substance compounds and health authorities such as the World Health Organization and the CDC recommend clothing masks for the general public, based on their findings. But some of those studies oversaw an important feature in the world – those face masks get wet from our breath.
Now, a team of researchers has tested mask products under high humidity conditions similar to the air expelled from our mouths.
“This new study shows that cotton clothing actually performs better in masks than we thought,” said materials scientist Christopher Zangmeister of the U.S. National Institute of Standards and Technology (NIST) .
Zangmeister and colleagues tested nine different types of cotton and six types of synthetic yarns including polyester and rayon in 99 percent humidity (about the humidity of our breath) and 55 percent humidity.
As a result there was a marked difference in cotton performance.
Cotton masks are going to be better filters when they capture the moisture from your breath, making them even better at slowing down COVID-19 than we thought: https://t.co/qbGtnC4a42 pic.twitter.com/91hNVIvlTX
– National Institute of Standards and Technology (@NIST) March 9, 2021
Although synthetic clothing, which also performed poorly compared to dry cotton, did not change performance under humid conditions, cotton clothing increase the ability to capture material 33 percent.
The researchers used pieces of salt of various sizes as a test site for virus-carrying granules and aerosol, and these appeared to contain some of the moisture trapped by the attracting cotton fibers. water. The grains go up in volume, which makes it harder for them to pass through the fabric unhindered.
Synthetic fiber, however, reacts with water, so as not to create the humid environment inside the mask itself for this prevention to occur. There was also no change in medical masks – but they are designed to work at high levels in all conditions (equivalent levels of cotton).
Cotton flannel was the best type of cotton to play, according to the results.
Microscopic images of the materials show a significant difference in structure – an orderly knitting pattern in synthetic polyester as opposed to the chaotic network of crisscrossing needles that give a soft-to-flannel feel.
NIST researchers believe that it is this fibrous patch that increases the chance of airborne particles passing through the mask clogging and sticking to the fabric.
Cotton flannel (left), polyester (right). (EP Vicenzi / Smithsonian Museum / NIST)
However, all this does not mean that wet masks are better: If your mask gets wet, it should be replaced. The amount of liquid present in the grooves in these humid conditions is only a few seconds, which does not alter the breathability of the material – the team found that air pressure on both sides of the fabric was still relatively similar.
This is good news from an environmental perspective as well. By removing waste from a disposable surgical mask that removes microplastics, it is comforting to know that there is a safe, reusable option.
Research suggests that a handful of reusable machine-washable masks are the best choice for keeping you and your loved ones safe.
While the team says more research is needed to fully appreciate the interactions between masks, moisture, and aerosol granule transfer, their study has contributed to the first standards between for clothing masks meant to slow down the release of COVID-19, which was recently released by the standards – development agency ASTM International.
“To understand how these products perform in the real world we need to study them under real conditions,” Zangmeister concluded.
This research was published in ACS Activated Nano Materials.