Originally published at: https://greysnet.com/2020/07/new-film-reveals-which-type-of-face-mask-works-best/
If you’re not sure whether wearing a face mask is worth it, or you are unsure which type of mask you should use, then a new study conducted by a team from the University of New South Wales should help you decide.
The team, made up of scientists and academics took videos of what happens when you talk, cough and sneeze — while not wearing a mask, wearing two different types of cloth masks, or wearing a surgical mask.
The results are clear. A surgical mask was the most effective at blocking droplets and aerosols from talking, coughing and sneezing. But if you can’t get hold of one, a cloth mask is the next best thing, and the more layers the better.
Here’s what they found
The team compared using no mask with two different types of cloth masks made from DIY templates provided online (one mask had a single layer of cloth; the other had two layers), and a three-layered surgical mask.
“We wanted to compare how effective different types of masks were at preventing outward transmission of droplets while talking, coughing and sneezing. These are the types of masks the public might use to reduce community transmission.”
“To visualise the droplets and aerosols you may not otherwise see, we used an LED lighting system with a high-speed camera.”
The test confirmed that even speaking generates substantial droplets. Coughing and sneezing generate even more.
A three-ply surgical mask was significantly better than a one-layered cloth mask at reducing droplet emissions caused by speaking, coughing and sneezing, followed by a double-layer cloth face covering.!(upload://bJg54Sdn7wEtLXMSJUqGlWpslcB.jpeg)
A single-layer cloth face covering also reduced the droplet spread caused by speaking, coughing and sneezing but was not as good as a two-layered cloth mask or surgical mask.
The evidence is mounting
In practice, we don’t yet know which has a greater effect — wearing masks to prevent infected people spreading to others or protecting non-infected people from inhaling infected aerosols. Both are equally important.
This new research demonstrates that wearing a face covering can significantly reduce the spread of airborne droplets from an infectious person.
It also demonstrates that throwing a scarf over your face is not as protective as a well designed cloth mask with several layers.!(upload://hNzvQrAnorePwYiEuvnGo2M5PQ.jpeg)
In Missouri, USA, two infected hairdressers kept working while infectious, but wore a mix of cloth and surgical masks, as did their 139 clients. No client was infected.
However, one of the hairdressers infected her household family members, as she did not wear a mask at home, and neither did her family.
This is reassuring evidence that infection risk is reduced when everyone wears masks.
What does this mean?
The wearing of face masks is becoming an increasingly important weapon in the fight against Coronavirus. Face masks are now mandatory on public transport across the UK as well as in shops in Scotland and England. Their use may be extended to other situations.
For the use of masks to be effective, it is important to know what type of mask works best. If you are using a cloth mask, here are some things to consider
- make sure the mask has a number of layers (at least three)
- look for a mask with a water-resistant fabric for the outer layer
- choose fabric with a high thread count (so a tighter weave, for instance from a good quality sheet is generally better than a fabric with a looser weave that you can clearly see light through)
- hybrid fabrics such as cotton–silk, cotton–chiffon, or cotton–flannel may be good choices because they provide better filtration and are more comfortable to wear
- make sure your mask fits and seals well around your face
- wash your mask daily after using it.
C Raina MacIntyre, Professor of Global Biosecurity, NHMRC Principal Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW; Abrar Ahmad Chughtai, Epidemiologist, UNSW; Charitha de Silva, Lecturer, UNSW; Con Doolan, Professor, School of Mechanical and Manufacturing Engineering, UNSW; Prateek Bahl, PhD Candidate, School of Mechanical and Manufacturing Engineering, UNSW, and Shovon Bhattacharjee, PhD Candidate, The Kirby Institute, UNSW
This article is republished from The Conversation