Medical masks best, cotton good, bandanas worse: droplet study

14 masks tested

As students return to school and employees head back to the office all with new safety protocols likely including wearing a mask, a new study from Duke University explores which masks are more effective.

But are they all better than nothing?

Aside from simply believing manufacturers' claims, if you wanted to somehow test different masks against one another to compare how much protection they offer in the real world, how would you go about it?

He believed early on that masks would help stop the spread.

Now, many months into the pandemic we have a clearer picture of which masks work and which actually spread the virus.

Westman knew researchers had already discovered that coughing and sneezing would put respiratory droplets into the air.

The amount of droplets would then be counted by a computer algorithm.

Neck fleeces, also known as gaiters - which are often worn by runners - increased the number of respiratory droplets by turning large droplets into smaller droplets. A recent study has identified the most and least effective face coverings, with one face mask in particular claiming the No.1 spot for being the most effective at curbing the spread of COVID-19.

Researchers used a simple optical measurement method of a cellphone camera and laser pointer to illuminate particles emitted by someone wearing a variety of face coverings and masks.

'We were extremely surprised to find that the number of particles measured with the fleece actually exceeded the number of particles measured without wearing any mask, ' co-author Dr Martin Fischer, an associate research professor in the department of chemistry, told CNN.

The team conducted a proof-of-concept study, which was published in the journal Science Advances, wherein they revealed that the simple, low-priced technique provided visual proof that face masks are effective in reducing droplet emissions during normal wear. The test required the speakers to wear each mask while standing in a dark enclosure.

A surgical mask performed second best while a polypropylene mask came in third.

Ideally, masks are aimed at not only protecting the wearer from inhaling the virus from an infected patient, but also the patient from exhaling air-bone droplets the virus to a nearby person or into the air.

However, among the worst-performing were folded bandanas and knitted masks, which may look fashionable but barely prevented any particles from getting in.

The study found that many homemade masks perform well.

Multi-layered cotton masks, the researchers recommend, are good options as shown by their competitive performance, especially for price-conscious users who may be priced out of the expensive but efficient N95 and surgical masks.

Why you should wear a mask?


The study shows that "masks vary a lot in how much they protect other people", she said.

Fischer said the test was relatively simple and could be used by face masks companies.

The researchers stressed the need for further testing to investigate variations in masks, speakers, and how people wear them.

An N95 mask, which filters out almost all particles both large and small, reduced the odds of contracting COVID-19, the disease caused by the virus, the most.

"What we're really seeing is that most of the homemade solutions, if you fit them right so there aren't big gaps, they do a pretty decent job, working just about as well as the disposable medical masks", Warren said.



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