Mask Test: FAU microbiologist checks face coverings for protection against COVID-19

(WSVN) - Masks have become a daily part of our lives. People wear all kinds, from surgical masks to fashion forward face coverings, but which ones offer the best protection from the coronavirus? In tonight’s 7 Investigates, 7’s Kevin Ozebek puts several popular masks to the test.

As COVID cases surge in South Florida, the mandate is clear: masks are a must, but are all of these different masks created equal?

To find out, we went inside the lab of Dr. Nwadiuto Esiobu.

Dr. Nwadiuto Esiobu, microbiologist, Florida Atlantic University: “When you kiss someone, you’re actually signing up to swap germs.”

She’s a microbiologist, with a sense of humor, at Florida Atlantic University.

She set up an experiment to see what mask most effectively blocks the tiny droplets we expel when we talk, sneeze, and of course, cough.

Dr. Nwadiuto Esiobu: “When you speak, you release droplets. Those droplets are microbe-laden, many bacteria, a lot of viruses, too.”

The guinea pigs in this experiment: Dr. Esiobu, one of her students and me.

Kevin Ozebek: “OK, so this first one is going to be no covering of my face or mouth, so we’re just going to cough on the petri dish, so let’s go.”

First we coughed without a mask right into a petri dish, and then coughed into a separate petri dish six inches away to see if distance matters.

Next, we all coughed through four different types of masks.

The KN-95 is a thick mask with five layers.

The surgical mask is lighter weight with three layers.

Kevin Ozebek: “Here we go.” (coughs)

The neck gaiter is thin, almost see-through.

Dr. Nwadiuto Esiobu: “I can see you very well.”

But it’s easy to pull on and off.

We also tested a double-layer homemade mask without a filter.

Kevin Ozebek: “A lot riding on this one: hand-sewn by our photographer’s fiancee. Here we go, five final coughs.”

To find out which mask keeps the most droplets in, the petri dishes have to incubate over the weekend.

We did the test on a Friday and came back on a Monday.

Dr. Nwadiuto Esiobu: “So the results are in. First, we found out that without the mask, you have a whole lot of growth.”

This is one of the petri dishes we coughed right on without a mask. Look at all the bacteria!

It’s the kind of germ transfer you can expect in close quarters.

Dr. Nwadiuto Esiobu: “This is likely what would happen if you’re at the bar. You are looking at bacterial colonies.”

There was a lot less bacteria in the petri dishes we coughed on while we were six inches away.

Kevin Ozebek: “What does this tell us about social distancing?”

Dr. Nwadiuto Esiobu: “It works.”

But check out the petri dishes we coughed on while we were wearing the KN-95 masks. They looked good as new.

Dr. Nwadiuto Esiobu: “Each time with this experiment, we find that 100% of the time, we got no aerosols passed through the KN-95s.”

When we used surgical masks, the petri dishes also grew no bacteria.

As for those cloth masks, homemade by Milvian, our photographer’s fiancee, they worked, too.

Dr. Nwadiuto Esiobu: “Absolutely no growth.”

The neck gaiter didn’t do as well.

You can see on one of the petri dishes there’s a bacteria colony, but even the gaiter blocks a large amount of potentially dangerous drops.

The bottom line: masks work.

Dr. Nwadiuto Esiobu: “Let’s take the politics out of this, and whenever it is necessary, wear the mask.”

You can do your own mask test right at home. Dr. Esiobu says, if you can see light through your mask, it’s too thin, or if you can blow a candle out while wearing it, you probably need a thicker one.


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