Particle physicist Darrel Williams tested seven mask materials on BBC Morning Live to see how well they block aerosol droplets. Three-ply surgical masks, FFP1, and KN95 masks performed best. Single-layer cotton, snoods, and dust masks offered little protection.
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Now, it's never, ever been more important to stay safe and do our bit to prevent the spread of COVID Yeah.
One of the key ways to do that, of course, is to wear a face covering. But it turns out some masks are a lot more effective than others. We've done some exclusive lab research putting the most popular styles to the test. Sabrina Grant's got the results. It might just make you think about the one you're using.
From the classic to something more individual. The there's a face covering to suit every style, but this is one fashion essential where it's not just looks that matter. The big question is which type is most up to the job? When it comes to face coverings, I like to use this one, a nice disposable. It's practical and convenient. I hope it's protecting those around me and offering me some protection as well. But I'll be honest, I don't know if this is any more effective than any of the other face coverings out there. What are you using today?
Today I'm using, like, surgical. A face covering is a face covering. So six of one, half a dozen of the other. Really?
Do you use disposable ones?
No, no, no, no, no. They're hot and horrible and your face can't breathe and they make you sweaty.
Mouth, the nose and everything, I don't really think it works.
But are all face masks created equal? Dr. Vanessa Sancho Szemizu is a geneticist at Imperial College London, studying the virus. We're told to wear these face coverings because they protect others. But how exactly do they do that?
The virus usually transmits through water droplets, and these are produced when we speak, when we sneeze, when we cough. So anything that would prevent that from coming out of us to others is going to prevent transmission of the virus and infection.
How effectively our face masks do that is partly down to the fit, but the fabric they're made from can also make a huge difference. So exclusively for Morning Live, particle physicist Professor Darrel Williams is going to compare how well some of the most common materials stop those water droplets from escaping. So how does the test work?
We're going to generate a stream of water droplets. These are very small droplets. We call them aerosols. They're a similar size to the sort that would be emitted from your mouth if you were breathing or coughing or sneezing. In front of that aerosol, we're going to put this holder, and this holder has a sample from the different sorts of face masks. We can look and see how much of the aerosol penetrates through the mask.
For his test, the professors selected seven of the most widely available types of masks. First up, a simple 100% cotton fabric covering. This slow motion footage shows us exactly how many water droplets are able to pass through the mask.
We certainly saw a lot of materials come out at the start, so that doesn't look too good.
Not the best start, maybe. The government recommended two layer cotton covering will give better results.
Not seeing much come through. I think there's a little bit of penetration, but not a large amount.
What about a snood, a mixed fabric containing acrylic and polyester?
Yes, we can see some droplets breaking through.
Up next, a type of respirator mask, increasingly popular as people assume they offer better protection. This one's an ffp.
One can't see much coming through, so it seems to be giving fairly good performance.
If that one's looking good, how about a simple dust mask?
And we can already see there, there's a lot of material getting through that fabric, so it's acting as a very poor barrier.
Two more to go. This kind of mask, known as a KN95, there are no droplets of the.
Aerosol actually escaping from the fabric. This highlights its very good performance as a medium for capturing droplets.
And finally, the type I usually wear, a three ply surgical mask.
There's nothing visible to the eye at all. This material seems to be acting as a very good barrier to the aerosol droplets.
With the test complete, three types of masks have come out as the most effective. And I'm reassured to see that mine is one of them.
The three layers surgical mask, the FFP1 and the KN95 all performed the best. It had the two layers of cotton. It also performed very well. The last three here offered the worst performance from a barrier perspective. The one layer cotton, as in a T shirt, the snood offered poor performance. And certainly the dust cleaning mask offered a very poor barrier level indeed. Virtually none at all.
But of course, as well as what you're wearing, it's how you're wearing it that matters. Why is the fit of a face covering so important?
Because this is the only way you can trap all the water droplets coming out from you and preventing infection of others. I think men suffer a bit because of their beards and the beards catching on the mask and sort of pulling it down. Also with children, you know, masks have been made to fit adults. And then we also have people who actually, you know, can probably Put it on properly. But don't. I do see quite a few people wearing the masks with their nose out and not covering half the problem. So wearing the mask properly and effectively is the only way we can be sure that it actually has its intended effect.
But for the one I like to wear the surgical mask, there seems to be a lot of confusion and about how it should be worn. What side do you press against your face and what side do you have showing the white side against your face? Blue sides. If it's on the outside, protects other people. For myself, I'm not sure exactly how it works with. With side.
Well, sometimes I get confused, but I do know it's blue inside.
Okay. Blue inside, blue inside.
And the white on the outside.
Okay.
Oh, no, forgive me. I'm turning it around. It's the white inside. Yes. Minor, minor lighter blue.
That's okay. So does wearing a surgical mask the wrong way round make any difference to the water droplets which get through Back to the lab to find out. Professor Williams is doing a test on both sides.
I'm having a look at the moment. I can't see much coming out right now. We've actually tried both experiments. Now we've tried with the blue side out and the blue side in. And to a first order, they look to be quite similar. So I'd still keep. The conventional advice is to keep the colored side out. But they look to be very similar in their performance.
The good thing is they really do work.
They look like they work from here. Yes.
I'm pleased that the face covering I choose to wear performed well in today's test. It's worth considering wearing these over some of the other ones that we tested as less water droplets pass through. But whatever type you choose to wear, wearing one does lessen the chances of the virus being spread so easily.
