Unmasking the Science behind Face Masks

Chan started the webinar by sharing the story of the face mask pioneer, Dr Wu Lien Teh. “Dr Wu was born on 10 March 1879 at Penang, Malaya. He was the first medical student of Chinese descent to study at the University of Cambridge, and the first Malayan nominated for the Nobel Prize in Physiology or Medicine, in 1935.  In addition, Dr Wu’s invention had contributed in eradicating the highly contagious pneumonic plague epidemic that occurred in the year 1910 – 1911, by inventing the surgical face covering. Furthermore, he is also the inventor of the Wu mask, which is the forerunner of today's N95 respirator. At the age of 58, Dr Wu eventually moved back to Malaya for retirement. Although he was retired, he still continued to provide free consultations and treatment for the poor community in Ipoh until he passed away at the age of 80 in 1960. Today, there are two streets in Georgetown, Penang and Ipoh Garden South, Perak that were named after him to honour his contributions and legacy. Apart from that, on 10 March 2021, Google certified Dr Wu’s recognition and contribution for his 142nd birthday on its home page,” she stated.

Furthermore, Chan highlighted Dr Wu’s practices in combating the epidemic, such as using the surgical mask with cotton and gauze material, and adding layers of cloth to it. Besides, he also imposed travelling restrictions and stopped train transportation to reduce the virus outbreak. He also established quarantine stations and hospitals for those who were infected with the virus to self-isolate, and practised the cremation of dead bodies in order to prevent the virus from spreading. Due to these practices, the epidemic was successfully contained four months later.

She further explained about the viruses and their transmissions, “The estimated size of the coronavirus is about 50 nanometer to 146 nanometer, which is smaller than bacteria and dust mite. Normally, the virus transmission takes place when our body comes into contact with a contaminated surface; from an infected individual to a susceptible host. The droplets from an infected individual travel directly to the mucosal surface and are inhaled by a non-infected individual. Then the evaporated airborne droplet nuclei from the infected individual are inhaled by the susceptible host.”

In addition, Chan stressed the importance of surgical mask materials and their types. “The surgical face mask layers are classified into three types, namely non-woven fabric (the outer layer), the melt blown fabric (the middle layer) and the soft fibre fabric (the inner layer). The function of the outer layer is to repel water, blood, and bodily fluid which stops the virus from entering our nose and mouth. The middle layer is important as a filter to stop the germs from entering and exiting from our face mask. The melt blown fabric (polypropylene) material is from a pile of really thin strands of plastics stacked on top of each other. Meanwhile, the function of the inner layer is to absorb water, sweat, and spits, and stop mucus from leaving the face mask when we cough, sneeze or talk,” she highlighted.

Chan also introduced Dr Peter Tsai, a Taiwan-born scientist who invented the electrostatic charging technology which is used to produce the filter media of masks, including medical and N95 masks, as well as heating, ventilating and air conditioning filters. She explained that the melt blowing system contains electrostatic charging materials to make the air filter electrets and these materials are also used in the making of N95 respirators and face masks.

“The KN95 and N95 have similar functions as they both filters out 95% of particles and they are both made in China. The KN95 face mask which comes in a tent-like shape, has a little pocket of air between the nose and the fabric. It also has a stricter requirement for breathability. Meanwhile, the KF94, which was made in South Korea, comes with an adjustable nose bridge function, and has the efficiency to filter out 94% of particles,” she emphasised.

The second speaker, Ho continued the session by sharing research studies pertaining to the effectiveness of face masks during a pandemic. He said, “Before the Covid-19, numerous studies showed that face mask provides a simple barrier to prevent the respiratory droplets from reaching others. These studies also showed that face masks have the tendency to reduce the spray of droplets when worn over the nose and mouth. Moreover, there is evidence that the masks can reduce airborne transmission since infectious aerosol particles can be released during breathing and speaking by asymptomatic infected individuals to healthy individuals.”

Ho added, “Using a correct mask is important for everyone to prevent the virus outbreak. Although we practice face mask wearing, not all masks provide the same protection. There are two important ways to make sure your mask works the best it can. Firstly, make sure the mask fits neatly against your face. Secondly, pick a mask with layers to keep your respiratory droplets in and others’ out. The Centers for Disease Control and Prevention (CDC) has publicly said that cloth face coverings are not intended to protect the wearer, however, it may prevent the spread of the virus from the wearer to others.”

Sharing about the dos and don’ts of face mask, he said, “We need to choose a mask with a nose wire (metal strip) along the top of the mask to prevent the air from leaking out from the top, and the wire can be bent according to the contour of your nose and fit it close to your face. Besides, we are encouraged to use a mask fitter or brace over a disposable mask/cloth mask to prevent air from leaking around the edges of the mask. Next, we need to check whether the face mask fits snugly over our nose, mouth and chin; and make sure no air is flowing from the area near our eyes or sides of the mask. If the mask has a good fit, you will feel warm air entering through the front of the mask, and may be able to see the mask material move in and out with each breath.” He also explained the effectiveness of using a cloth mask that has multiple layers of fabric, and wearing a disposable mask underneath a cloth mask. “Lastly, you may try the knot and tuck method. This method is to enable the disposable masks to fit better on your face. You can knot the ear loops of a 3-ply face mask where they join the edge of the mask, fold and tuck the unneeded material under the edges,” he enthused.

Nevertheless, he strongly advised the participants to not combine two disposable masks at the same time, as disposable masks are not designed to fit tightly, and wearing more than one will not improve the fit. Plus, he added we should not combine a KN95 face mask with any other mask as KN95 was designed to filter out 95% of particles and can help limit the spread of the virus. 

The insightful webinar ended with interactive Q&A and group photography sessions. This webinar is associated with SDG 3 – Good Health and Well Being, as it promotes the study of face masks in preventing a virus outbreak and protecting ourselves during a pandemic, and SDG 4— Quality Education, as it provides insightful knowledge about face masks and promotes lifelong learning opportunities to the participants.