Researchers have tested the effectiveness of 14 masks: some are better if they are not even used, they can do more damage

As cnn.com writes, the team’s analysis of the effectiveness of the masks began when a professor at the Djuko School of Medicine helped a local group purchase masks in bulk to distribute to community members. The professor wanted to make sure that the masks people bought were effective.

In a study published last Friday, researchers demonstrated a simple way to use a laser and a telephone to determine the effectiveness of a mask in stiffening the permeability of airway droplets during speech.

“We use a black box, a laser and a camera. The laser beam is vertically expanded to form a thin section of light that illuminates through the slots on the left and right sides of the box, ”said Martin Fisher, one of the study’s authors.

There is a hole in the front of the box through which a person must speak. The phone’s camera is built into the back of the case to record the light scattered in all directions by the droplets in the airways. When a person speaks, the laser beam crosses.

Then a simple computer algorithm calculates how many drops are released.

Encourage the use of effective masks

Health professionals have spent months and months emphasizing that masks are one of the most effective tools for managing a pandemic.

However, when analyzing the effectiveness of the masks, the researchers found that some of the masks are actually useless.

The researchers tested 14 commonly used masks, including the highest-rated N95 masks, the ones most used by healthcare professionals. The test was performed for the first time without wearing a mask. The researchers then conducted experiments with the masks. Each mask was tested by scientists 10 times.

The most effective mask was the N95. The three-layer cotton and surgical masks, which many people make at home, also worked well.

Neck couplings, commonly used by runners, have proven to be the least effective. These masks have even been shown to increase the number of droplets released, as the substance breaks down larger droplets into smaller ones and they are easily dispersed in the air.

Folded scarves and knitted masks also performed poorly and did not provide adequate protection.

“We were very surprised to learn that the amount of particles that were used when wearing the neck sleeve actually exceeded the amount released when the mask was not used. We want to emphasize that we really encourage people to wear masks, but we want them to wear masks that are really effective, ”Fisher said.

Although the detection method is quite simple (all you need is a laser, a box, a lens, and the phone’s camera), the scientist urges you not to test it at home, as improper use of the laser can cause irreversible damage to vision.

The researcher adds that this test is a great tool to illustrate to people that even homemade cotton masks can effectively protect against the spread of the virus.