A scientific study supports the use of cloth clips after one year

The chinstraps or reusable cloth masks Which people have been using since the epidemic year and a half They got a boost to continue being champions In closed areas to avoid infection COVID-19.

A recent scientific study from the University of Colorado at Boulder found that washing and drying them does not reduce their ability to filter out viral particles. “Good news for sustainabilityThe main author said Marina VanceAssistant Professor in the Department of Mechanical Engineering Paul M. Satisfied. “That cotton mask you’ve been washing, drying, and reusing may still work fine.Don’t receive it.”

studying, published in the magazine Aerosol and Air Quality ResearchIt also confirms previous research that suggests that placing a cotton mask over a surgical mask – which fits properly on the face – provides more protection than cloth alone.

Science for Sustainability

Since the beginning of the epidemic, nearly 7,200 tons of medical waste have been generated every dayMany are single-use masks that end up in the trash at the end of the day or on a specific outing. “We were really upset from the start of the pandemic, when we would go out and see all these disposable masks scattered in the environment, so I was keen to join the scientists from the nearby National Renewable Energy Laboratory (NREL) who came to the facility,” said Vance, who is also a member of Faculty in the Environmental Engineering Program, “Examine How Washing and Drying Affects Reusable Cloth Masks.”

Their process was very simple: create double-layered cotton squares, wash and dry them frequently (up to 52 times, the equivalent of a year’s weekly wash), and test them between about every 7 cleaning cycles. While the masks were not tested on real people, but were instead mounted on one end of a steel funnel through which researchers could control the constant flow of air and airborne particles, the researchers tested the masks using real-world conditions. With high levels of humidity and temperatures to mimic the effect on our breathing mask.

Yes good Cotton fibers began to break down over time after repeated washing and drying, and the researchers found that this did not significantly affect the fabric’s filtration efficiency.. The only noticeable change was that the inhalation resistance increased a bit, which means that the mask may feel more difficult to breathe after a bit of wear.

Electron microscopy revealed that washing and drying led to a gradual dissolution of Cotton fibers on a scale of several micrometers to hundreds of nanometers in the form of fiber wall disassembly and fibrillation of nanofiber components. The authors conclude that the results suggest that cloth masks can be placed over surgical masks for additional benefits, and that cotton cloth masks can be washed and reused multiple times without significant loss in filtration efficiency.”

The fit of the mask is critical

Each person’s face shape varies greatly. Therefore, depending on the shape of the mask and how well a person fits it, it may or may not be suitable for him. Previous research has shown that an ill-fitting mask can allow up to 50% of the airborne particles we breathe and exhale, as well as the virus. This study is not the first to find that cloth masks provide less protection than surgical masks or a multi-layered combination of surgical and cloth masks.

measure quality The mask filtered the air that was inhaled (protecting the person wearing the mask, without reducing transmission at the source), and this study found that cotton cloth masks filtered up to 23% of the smallest particle size (0.3 microns) through which the virus can travel. Tissue leaked less, at just 9%. In contrast, surgical masks filtered between 42 and 88% of fine particles, and cotton masks over surgical masks achieved a filtration efficiency close to 40%. As expected, the KN95 and N95 masks performed the best, filtering 83-99% of these particles.

But while this study found that cloth masks alone provide less protection against the virus than a multi-layered approach or disposable masks, such as surgical masks, the KN95 and N95, they are still important information for those who rely on cloth for their comfort, affordability and and the possibility of re-use. , note the authors.

“I think the best mask might be the one you’re actually going to wear. This will fit perfectly on your face without feeling uncomfortable,” Vance said.

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