Your basic guide to different types of face masks and their benefits

Cotton gauze face mask

These are the most common and most basic types of face masks. When the weather is cold (most notably in places like Korea and northern China), people tend to wear these cotton masks to shield their faces from the cold winds. We often see Korean pop idols wear these face masks, so much so that they have become a fashion accessory. While washable and reusable, these cotton masks have not been scientifically proven to filter out harmful bacteria, particles, or viruses, and mostly protect from dirt and dust.

Mostly effective against: Dust, dirt

Japanese Pitta mask

Made with activated charcoal to counter odours, the Pitta mask is Japan’s alternative to cotton face masks. The whole mask is made completely of polyurethane, the same material used to make sponges. It has gained popularity in mainland China, Taiwan, Korea, and India with its sleek design, and claims to be reusable up to three times after washing. Pitta masks have the added benefit of fitting snugly and tightly around faces, but it is not proven that they protect against transmission of bacterias or viruses.

Mostly effective against: Odours, dust, pollen

Cotton mask with filters

Developed by local scientist Dr K. Kwong with support from experts and volunteers, the HK Mask is the latest invention in the field of face masks. Targeting the mask shortage problem in Hong Kong, this model consists of a reusable, handmade cotton cover with a piece of filter sandwiched in-between that can be removed and replaced.

Designed for better protection compared to the generic DIY mask, this mask allows for flexibility in selecting a filter based on the users’ needs. Choices range from pocket tissue paper and kitchen paper to more high-tech microfibre and nanofibre films, which alleviates the shortage of raw materials for surgical masks. It is recommended to replace the cotton cover and the filter every four hours. While the cotton cover can be washed and ironed for sanitation, the filters should not be reused.

It is expected that mass production will start in mid-March, with a minimum monthly production capacity of two million pieces, which will gradually increase to up to three million. The team also targets to set an affordable price for nanofibre filter. We will update as we receive more information.

Mostly effective against: Pollen, dust, bacteria (depending on your choice of filter)

Activated carbon masks

These grey-coloured face masks have a similar shape and structure to surgical face masks, but they are made with layers of fabric infused with activated carbon. Their main purpose is to counter odours and gases. It is common to see activated carbon masks in Asia as a countermeasure against air pollution.

Although some may be reusable, it is not recommended to do so since the filtration efficiency of the mask will drop. While these may help you breathe easier in the smog-choked streets of Hong Kong, there is no scientific evidence that supports their bacterial- and viral-filtration performance.

Mostly effective against: Odours, pollen, dust

Surgical face mask

Standard-issue surgical masks are designed to catch the wearer’s own bodily fluids, such as saliva, spittle, and nasal discharge, and prevent infectious liquid droplets from spreading to others. Commonly seen around Hong Kong, these masks are used by medical practitioners during surgery, for example, to prevent the transmission of bacteria while patients are on the operating table.

Surgical face masks are effective at blocking large particles and droplets from transferring through the mask, but they cannot prevent small virus particles from getting around the edges or landing on the surface of the mask. Rather than protecting the wearer from airborne particles or otherwise, it is more effective at catching liquid droplets and aerosols from the wearer themselves.

Mostly effective against: Pollen, dust, bacteria

N95 respirator

The N95 respirator is a fitted apparatus designed to block particles by filtering the air as it passes through the mask. It has the highest efficiency out of all the face masks generally available in Hong Kong and gets its name from the fact that it blocks at least 95 percent of tiny particles.

These respirators can get uncomfortably warm due to the density of the materials used, so much so that wearers find it difficult to breathe—that’s why they are usually reserved for healthcare workers who are trained in putting them on properly and require this specific type of high filtration efficiency for their work.

Mostly effective against: Pollen, dust, bacteria

Ultimately, no matter how high the filtration efficiency of your face mask, the best defence recommended by medical professionals against viruses, bacteria, and cross-contamination is cleaning your hands regularly and avoid touching your face with unwashed fingers. Given how there is a shortage of face masks around Hong Kong, paying attention to your personal hygiene is the best thing you can do for yourself.

_{Sources: Professor David SC HUI, BBS, Consumer Council HK, Ying-Hai High School}