Can surgical masks be worn on both sides, and which side guards against the haze? askST clears the air

There is only one way to wear the good quality surgical masks that most people are familiar with - with the coloured side facing outwards. ST PHOTO: LIM YAOHUI

SINGAPORE - Can a surgical mask be worn two ways, and does it protect against the haze?

With air pollution hitting unhealthy levels here, and misinformation rife on how and when to wear various masks, The Straits Times shows you the correct mask to wear for different scenarios, and how to wear it.

One reader asked ST whether it is true that the white side of the surgical mask is the filter, citing information online which said that when people are sick, they should be wearing the mask with the white side facing towards them to prevent their germs escaping.

It added that people should wear the mask with the white side facing outwards if they want to protect themselves from pollution and illness.

This is false.

Good quality surgical masks that most people are familiar with have three layers: two outer layers (one white and one coloured), and a middle layer which acts as the filter. There is only one way to wear them: with the coloured side facing outwards.

The white side is actually an absorbent material, said the Health Sciences Authority. Breathing in a mask can often be humid and uncomfortable, and this absorbent white layer is meant to help with that. Both the middle and coloured outer layers are water-repellent, to prevent any bodily fluids (for example, sweat, blood or mucus) from being absorbed into the mask.

Wearing the mask the wrong way around can reduce its effectiveness and increase discomfort.

Surgical masks also do not provide adequate protection from environmental pollutants. They are typically worn to prevent splashes of bodily fluids (for example, from sneezes and runny noses) from being exchanged with the wearer and anyone else.

Because they do not fit tightly around a wearer's mouth and nose, pollutants can be breathed in from the sides of the mask. Surgical masks are also not designed to filter small dust particles but are, instead, designed to catch aerosols or liquid droplets.

To protect themselves from the haze, people should use an N95 respirator. These masks are designed for a better fit than conventional surgical masks. Look for respirators that fit over your mouth and nose snugly and that have at least a 95 per cent filtration efficiency. Users should also carefully follow the instructions on how to wear the mask.

HSA advises people to not wear the same surgical or N95 mask for an entire day, and to change masks regularly. The make of different respirators varies slightly, so wearers should read the specific instructions for their mask to find out how long they should be wearing it.

Users should also minimise the amount of talking they do behind the mask to reduce condensation that may reduce its effective lifespan.

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