Experiments with UNC-CH tested CDC double masking guidance

Raleigh, NC (WNCN) – Earlier this month, the CDC’s new guidance states that two masks are better than one.

Scientists at UNC Chapel Hill tested the guidance in their lab.

“I was wondering if the combined use of two of these masks would actually benefit,” said an expert in aerosol toxicology at the Center for Environmental Medicine, Asthma and Lung Biology. Pediatrics at UNC School of Medicine.

To test it, Clap had subjects enter a 10-foot x 10-foot chamber. It was filled with harmless particles. Clapp then used different layer combinations to test how much it became a mask.

Generally, a surgical mask or cloth mask alone can block about 40% of the particles.

Experiments at UNC Chapel Hill have revealed the following:

• Two surgical masks blocked 15% more particles
• Surgical mask on cloth mask blocks 10% more particles
• The cloth on the surgical mask blocks 40% more particles

CBS 17 asked if any combination of double masking would create the same level of protection as the N95 mask. These types of masks are still difficult to find.

“Except for one scenario, the surgical mask or procedure mask never reached the N95 threshold,” Clapp said.

But scientists say you may not need a mask that blocks 100 percent of dangerous particles.

Dr. Emily Sickbert Bennett, Director of Infection Prevention and Associate Professor at the UNC Medical Center, said: Treatment of infectious diseases at UNC School of Medicine.

Fits everything

According to Sickbert-Bennet, you can block 20% more particles by changing the mask to fit your face perfectly, without using layers. Adding gaiters on top of the surgical mask to create a tighter mask also greatly improves protection.

Dr. Clap says the materials used in surgical masks are very protective. They just don’t fit well.

“When you talk face-to-face, you’ll see a gap between the mask and the corner of your nose,” says Clap.

Those gaps are where you lose protection. That’s why layering a fitted cloth on top helps close these entry points.

However, Sickbert-Bennet said it is most important to wear a comfortable mask while covering the nose and mouth.

“It’s the most important double masking out there that both you and the person you’re interacting with are wearing masks,” said Sickbert-Bennet.

What to look for in a surgical mask

Surgical masks are everywhere from local dollar stores to the Amazon. The higher price does not necessarily mean more protection. Clap said he found differences in ear loops and mask sizes within the same manufacturer.

When purchasing a surgical mask, look for the following features:

• 3 layers
• Inner layer made of polypropylene
• Drip-proof
• ASTM certification (not important, but this assessment provides medical level protection)

Improve what you already have

The CDC recommends the use of mask fitters or braces, as fit is one of the most important attributes. These are accessories that are placed on top of the mask for a snug fit. The CDC said it could help reduce air leaks around the edges of the mask.

According to the CDC, fitters can improve filtration by up to 90%, regardless of mask material.

If you don’t have access to any of these, you may be able to use an old shoe store.

According to the CDC, fitter or brace alternatives include placing a thin nylon sock material around the neck and pulling it over the mask for a snug fit.

The CDC recommended a “knot and tack” method to prevent the surgical mask from leaking and ingesting as little virus particles as possible. Watch the video above for a tutorial on how to do this.

• Tie the ear loops of the 3-ply face mask where they will join the edges of the mask
• Fold the unwanted material and push it under the edge