SINGAPORE - How good are the free reusable masks when it comes to protecting yourself against Covid-19?

While surgical masks are fluid-resistant and able to filter bacteria more effectively, reusable masks made of cloth or paper can still serve as a form of basic protection.

Reusable masks were distributed to all households in Singapore after the Government said last week it will no longer discourage people who are well from wearing masks because there is evidence showing a few people can be infected but not show any symptoms.

The authorities also announced on April 14 that it is now mandatory for everyone to wear a mask if they have to go out.

Q: Are the government-issued reusable masks effective?

A: Dr Teo Tee Hui, council member of The Institution of Engineers Singapore (IES), who is also a senior lecturer at the Singapore University of Technology and Design, said the reusable masks, which are made of cotton, provide between 50 and 60 per cent of filtration efficiency.

Therefore, it is highly advisable to wear these masks than to not wear any mask at all.

He added that to significantly reduce the risk of spreading the virus, it is important that the majority of the population wear masks.

Infectious diseases expert Leong Hoe Nam agreed that mask-wearing is important, even if it is a reusable one.

Citing a study on the effectiveness of masks made from tea towels , he said a home-made mask was 20 per cent as effective as a surgical one.

While the reusable cloth mask may not be of the same material as the one in the study, he noted that the effectiveness of wearing a mask cannot be looked at individually, but should be viewed collectively.

For instance, when a person who is sick goes out wearing a mask, the chances of spreading the virus are reduced by 50 per cent.

When the person comes in contact with someone who may not be sick but wears a mask, the risk of transmission is also reduced by another 50 per cent.

Such collective measures of mask-wearing could quadruple the effectiveness of preventing the virus from spreading between individuals.

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Q: If I have only the government-issued masks, will this be sufficient? If I have surgical masks, should I wear them instead?

A: If you have only the reusable mask, do wear it when you go out, but more importantly, adopt the physical distancing measures and personal hygiene.

Dr Leong said that following safe distancing measures by standing 2m apart from the person next to you takes precedence over mask-wearing, and something that must be practised even when wearing a mask.

If you have a supply of surgical masks, you could vary between which of the two masks to use based on the type of activity - wear the cloth one for "low-risk" activities, such as going for a short walk nearby or at a park, and the surgical one for "high-risk" activities, such as taking public transport, going to the supermarket, or buying take-out food.

Q: Could I reuse my surgical mask if I take good care of it?

A: Dr Leong said it is possible to reuse a surgical mask if it is well taken care of and that these four checks are done:

- Check the integrity of the mask; ensure that there are no holes

- Try it on, ensure that the ear loops still let you wear the mask securely on the face.

- Ensure the sides of the mask are still apposed to the cheek, as they should not be flimsy or loose.

- Do the breathing test: Breathe in and out through the mask. The air should be coming in from the centre of the mask, and not the sides.

If all four checks are done, the surgical mask can be reused for up to four or five days.

Dr Leong stressed that individuals should not share masks, and masks should be placed in a Ziplock bag for personal hygiene reasons.

Discard the mask if it is wet as wearing it could risk breaking its filter layer.

Those who are sick should cough out phlegm into a tissue paper before throwing it away. They should also wash their hands with soap before putting the mask back on.

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Q: Can I wear the reusable mask over a surgical mask to extend the shelf-life of the surgical mask?

A: Yes, said Dr Leong, but individuals should take care not to scrunch up the sides of the masks. They should also ensure that the four checks mentioned above are done at all times.

Those who want to make or purchase mask sleeves, which go over surgical masks to protect them, must ensure that they can breathe through the mask.

They should also ensure that the air is coming from the centre of the mask and not the sides so that there is air filtration.

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However, Dr Teo cautioned that layering two masks could trap heat and make it difficult for a person to breathe.

Q: What if I am sick and I do not have any surgical masks - can I wear the reusable ones too?

A: Yes, you can. However, you should adhere to safe distancing measures, especially when at home, to keep away from family members as much as possible and refrain from going out.

Q: How often should I wash the reusable mask? How do I take care of it?

A: Dr Leong said wash the mask once a day with warm water and soap, and wring it gently to dry.

The mask should be air dried, and not in the sun, as the colour could run and may destroy the fabric and filtering capabilities.

Q: What do I do if the reusable mask is too loose for me?

A: If the mask is too loose, make the necessary modifications so that the mask is securely fastened to the face.

Carry out the four checks on the mask to ensure that it will provide adequate protection.