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face masks
August 31, 2020

Healthy advice: A research-based guide to choosing the right mask for you

Written By: Renee Meiller


For many Americans, face coverings have become a way of life.

In fact, by early-August 2020, 34 U.S. states, plus the District of Columbia, had implemented mandates for mask-wearing in public spaces.

At the same time, home-crafters and retail giants alike ramped up their production, making masks in every shape, size, material and fit.

And whether citizens are wearing a mask to comply with an order, trying to stay healthy, working to keep the community healthy—or all of the above—there’s a mask option that works with people’s preferences, lifestyle and goals, says Scott Sanders, a professor of mechanical engineering at the University of Wisconsin-Madison.

“For containing the droplets and particles we all spread as we talk, cough, sneeze and more, wearing any face covering helps,” he says. “While the best face covering is one that fits snugly and filters those droplets and particles, it’s also important to wear a mask that’s comfortable for your routine.”

A researcher who uses optical techniques to study and measure particulates in internal-combustion engine processes, Sanders more recently has applied his expertise to studying the efficacy of non-medical-grade mask alternatives.

In his latest tests, Sanders used a mannequin not wearing a mask to show how particles from a human breath and droplets from a sneeze spray forward. Then, he studied how adding various face coverings—including a face shield, a homemade four-layer tightly knit mask, and a disposable non-medical-grade filtering mask—to the mannequin trapped or released those particles and droplets.

His results, outlined in a new video, show progressively increasing effectiveness at containing both the tiny particles in a breath and the larger droplets of a sneeze. A face shield alone directed particles and droplets downward. The four-layer tightly knit mask trapped more particles and droplets, as did the disposable filtering mask, particularly when its nose piece was properly fitted. Sanders notes that adding a mask fitter, such as a rubber band chain, can improve any cloth or disposable mask’s effectiveness by enabling the mask to fit more tightly around the wearer’s nose, mouth and face.

And while the main focus of mask-wearing currently is on stopping the spread of COVID-19 (or avoiding getting sick in the first place), Sanders says his findings are broadly applicable beyond the pandemic. “Cold and flu season is right around the corner,” he says.

Other contributors to this research include mechanical engineering graduate students Logan Kossel and James Rice, College of Engineering makerspace director Lennon Rodgers; and Mechanical Engineering Assistant Professor Alejandro Roldan-Alzate, Professor David Rothamer and Professor Doug Reindl.