SINGAPORE — As the country grapples with the Covid-19 outbreak, one disturbing trend that has emerged recently is the incidence of face masks being disposed of indiscriminately.

Over the past week, TODAY has seen used masks haphazardly strewn on pavements and escalators, while pictures of masks in lifts and other public areas have emerged online.

Experts TODAY spoke to said that used masks lying around pose public health risks.

What are these risks, how should masks be disposed of and what if one wants to reuse his mask? TODAY finds the answers to these questions.

WHAT HAPPENS WHEN A USED MASK IS NOT PROPERLY DISPOSED OF?

Dr Wong Chen Seong, a consultant at the National Centre for Infectious Diseases, said that improperly discarded masks, especially those that are soiled or have a “large amount of respiratory secretions” on them, could be a potential health hazard should others come in contact with it.

“The way that the virus may be transmitted to others in this way is through contact — that is, if others inadvertently touch the soiled mask, and then their own face,” said Dr Wong.

Agreeing, Dr Leong Hoe Nam, an infectious diseases expert at Mount Elizabeth Novena Specialist Centre, added that an exposed mask carries with it a “small risk” of passing a virus through the air.

“If exposed to the open, with strong winds, there is a small risk of aerosolisation,” he said.

Aerosolisation refers to a process where a substance such as one’s spit or mucus is dispersed and transmitted through the air.

“Either way, (improperly discarding used face masks) is disgusting and unhealthy,” he added.

When left exposed, the experts predicted that the virus could survive for as long as a few hours to a few days.

Dr Wong said that in Singapore’s hot, humid climate, the virus will likely persist for no longer than two to three days, while Dr Leong said that the virus can survive “for hours” on an exposed surface.

Dr Leong added that different germs can survive on a used mask for different durations. For example, bacteria can live for months to years if kept in a cool place, he said.

FOLD, TIE, WRAP

Dr Leong detailed several steps to take should one want to dispose of a used face mask, which he shared in Mandarin on a live-streamed Q&A session with Chinese daily Lianhe Zaobao recently.

He said that one should always wash his hands before taking off the mask, as touching one’s face with unwashed hands would leave one more susceptible to illnesses.

After that, one should take off the mask, and fold it in half inwards, such that the droplets from the mouth and nose are not exposed. Then, fold the mask into another half, and then another half, until the mask looks like a roll. The mask can also be wrapped with its ear loops so that it will not unravel.

Then, Dr Leong said the user should wrap the mask in a piece of tissue, before throwing it into a rubbish bin.

Associate Professor Alex Cook, Vice Dean of research at the Saw Swee Hock School of Public Health at the National University of Singapore, said that those who are infected with a virus should be more mindful of where they discard their masks.

“If you are infected with a virus and are wearing a mask to prevent transmission — as you should — you can dispose of it in the regular bin,” said Dr Cook. “But it would be a good idea to put it in a bag and throw it immediately in the trash rather than leave it sitting exposed.”

WHAT IF YOU WANT TO REUSE YOUR MASK?

In general, one should change face masks regularly, usually once its inner lining becomes moist, said Dr Leong.

To reuse a face mask, Dr Leong said that one has to keep it dry so that it can last as long as possible. One should take off his mask without pulling it under the chin so that germs there will not attach to the mask.

“If dry, and the layers and shape are intact, I would consider putting it in a Ziploc bag with a desiccating gel,” he said.

Desiccating gel is a substance that absorbs moisture and can keep a mask dry. If the mask is dry and not torn, it can be reused for two to three days.

Even when one is sick, he can still reuse the mask, provided the mask is not shared.

“No harm (reusing the mask). Once you have been infected with a virus... It can’t reinfect you,” said Dr Leong.