Durham Reporter

Faculty at Duke University conducted an informal test to attempt to determine whether some masks prevent more visible droplets from being emitted than others.

Dr. Eric Westman, an internal medicine physician at Duke University Health System, has been an advocate of mask wear since the beginning of the COVID-19 pandemic, according to ABC 11 report on Aug. 11.

"Like the common sense of just putting your hand in front of your face, we really thought that any mask would be better than nothing," Westman told ABC 11.

As someone who does not work with coronavirus patients or study the virus, Westman felt that he could help by asking Duke University physics professor Martin Fischer to help him perform a test of which masks permit the most visible droplets from being emitted.

Using a cell phone camera to record his results, Fischer had volunteers wearing different types of masks and speak into a cardboard box he assembled with a green laser to help make the visible droplets stand out, ABC 11 reported. Fischer found that some face coverings, such as neck gators and masks, did nothing to prevent the emission of visible droplets while speaking.

They also noted that some cloth masks appear to break up larger particles into smaller particles, as they based their measurements purely on the total number of visible droplets they counted, ABC 11 reported. However, Fischer also noted that smaller droplets could be more easily carried in the air than larger droplets.

Westman and Fischer said that their test was only meant to encourage more research into the effectiveness of different mask materials, and did not call it a study.

"This is really a preliminary investigation into something that needs much more science wrapped around it with other types of ways of measuring particulate matter,” Westman told ABC 11.