The University of Colorado Boulder study shows that cloth masks or reusable masks won’t reduce their ability to filter viral particles after washing them.
According to recent research done by the University of Colorado Boulder in Washington, even though the reusable or cloth masks seems weird on wearing, their viral filtering property won’t diminish on washing and drying.
It also ensures that wearing a cloth mask on top of a surgical mask is always better than a cloth mask alone. They published this new study in the “Aerosol and Air Quality Research” journal.
Marina Vance, Assistant Professor in Paul M Rady Department of Mechanical Engineering, says sustainability is good news.
Also, she added, the cloth mask that we use, which we have been washing, is still good to use and don’t need to be thrown away.
Since the emerging of the pandemic, medical industries as well as ordinary people produce around 7,200 tons of medical waste every day, including PPE’s, gloves, syringes, and mainly disposable masks.
Marina Vance said that the authorities were concerned about the increasing quantity of medical wastes like disposable masks littering the environment. Vance is also on the faculty in the environmental engineering program.
Scientists at the nearby National Renewable Energy Laboratory (NREL) approached Vance to research how washing and drying effect reusable cloth masks.
Procedure of Study
The process of study was not much complex. It includes creating double-layered squares of cotton, washing and drying them continuously up to 52 times and examining them between every seven cleaning cycles.
The researchers mounted the masks on one end of a steel funnel instead of testing them on people.
Through the steel funnel, researchers could regulate a steady flow of air and airborne particles.
The researchers tested the masks through realistic conditions like high humidity levels and temperatures to imitate the effect of breathing on the mask.
During the continued washing and drying, the cotton fibres began to fall apart, but the filtration efficiency of the cloth remained unchanged during this whole process.
In any case, there was a slight expansion in the inhalation resistance seen after this process; the person wearing this mask may feel a little uncomfortable breathing.
Filtration efficiency of different masks
It is not the first time a study mentioning that cloth masks offer less protection than surgical masks or a layered combination of surgical and cloth masks.
This study finds out that cloth masks filtered out up to 23 per cent of the small particle size on which the virus can pass through; when it comes to Bandanas, it filters only 9 per cent.
Instead, surgical masks filtered out around 42-88 per cent of the viral particles, and the combination of cotton masks and surgical masks had around 40 per cent filtration efficiency.
Among all these, KN95 and N95 masks have the best filtering efficiency, approximately 83-99 per cent.
Additional authors on this publication include Sumit Sankhyan, Sameer Patel and Hannah Teed of the University of Colorado Boulder; Karen N. Heinselman, Peter N. Ciesielski Teresa Barnes and Michael E. Himmel of the Renewable Resources and Enabling Sciences Center at the National Renewable Energy Laboratory.
