You can choose to wear either one (or both) when you’re out, but what’s the difference?
People can choose to wear either a face mask or face shield when they leave the house, according to the Ministry of Health’s guidelines.
For the general public, a face mask or a face shield alone provides adequate protection, doctors say. However, those working in high-risk settings should wear both a mask and shield.
How to use
• Make sure your nose and mouth are covered.
• There should be no gaps between the mask and your face.
How they work
• Protects your nose and mouth from droplets that may contain virus particles.
• Prevents the virus from being spread by a sick person by acting as a barrier.
Pros and cons
• Prevents large infectious droplets from landing on a person’s nose and mouth.
• However, airborne aerosols (smaller invisible droplets) can still enter through the gaps.
• There is also a global shortage of surgical masks.
How to use
• Make sure your whole face is covered, from ear to ear and forehead to chin.
• There should be no gaps between the securing headpiece and the plastic shield
How they work
• Protects your eyes and other parts of the face from droplets that may contain virus particles, and prevents the virus from being spread by a sick person by acting as a barrier.
• It also prevents face masks from getting wet.
Pros and cons
• Relatively easy to make and can be cleaned easily.
• A person’s face is also fully visible, which some people may prefer.
• However, it lacks a good seal around the face, allowing aerosols to penetrate.
WHEN TO USE
• All types of masks, including face shields and reusable and homemade masks, offer adequate basic protection for the general public, says the Ministry of Health.
• Plastic spit guards which mainly cover the mouth are not acceptable.
• Surgical masks should be saved for those who need them most, such as healthcare workers.
• Healthcare workers are generally advised to use both face shields and face masks, as their work involves long hours of contact with patients and puts them at a higher risk of infection.
Droplets from coughing and sneezing
• A cough: 3,000 droplets.
• A sneeze: 40,000 droplets.
Droplets from talking and breathing
• An infected person with mild or no symptoms talking in a poorly ventilated space for five minutes can generate as many viral droplets as an infectious cough.
• Commuters should avoid talking on trains and buses.
Aerosols (smaller invisible droplets)
• These micron-sized droplets form a cloud that can linger in the air for minutes before they settle on surfaces.
• It is currently unclear whether Covid-19 can be transmitted through aerosols.
Larger visible droplets
• These fall to the floor within about two metres.
Recommended safe distance
• The US Centres for Disease Control and Prevention recommends safe distancing of two metres based on the assumption that transmission occurs primarily through the larger droplets.
• The World Health Organisation and Singapore’s Ministry of Health recommend physical distancing of at least one metre.
Travel range of aerosols
• However, it doesn’t mean there are no more droplets beyond two metres.
• Researchers from MIT have observed smaller cough droplets travelling up to five metres and sneeze droplets travelling up to eight metres.
• The travel range of these aerosols suggests that keeping a distance of two metres or more can potentially reduce the possibility of transmission.
Sources: USA Today, New York Times, Ministry of Health, National University Polyclinics, NTUC Health, Parkway Shenton, Alexandra Hospital, Straits Times Graphics
A version of this article first appeared on www.straitstimes.com.