Wait, are you wearing your mask wrongly?

Everywhere you look these days, you’re likely to spot a blue-and-white surgical mask.

Nearly two years into the Covid19 pandemic, face masks – whether they’re cotton or disposable ones – are a part of daily life now.

Because they’re such a key preventative tool against the virus, it’s important to wear them correctly. No, that’s not under your chin or white side out.

To clarify the right way to wear them, Stuff sought advice from Professor Michael Baker, who has been a strong proponent of masks to prevent Covid-19 transmission.

The coloured side – usually blue – goes on the outside, and the edge with a piece of wire, or something similar, in it goes to the top, over your nose, he said.

This side is water-resistant. The masks were originally intended for medical staff to protect themselves if they were doing procedures that generated splashes, Baker said.

Those splashes would hit the water-resistant surface on the outside of the mask.

The white side was more absorbent and should be worn against the face. This means it would suck up droplets and aerosols produced by the wearer.

‘‘They are colour side out like a raincoat. The white side is absorbent, a bit like a nappy,’’ Baker said.

‘‘They vary hugely in price and quality. The main problem with them is the fit isn’t great. So if you’re in a room with aerosols, you will be sucking the air in around the side of the mask. Also, if you fire out an aerosol, it won’t all get absorbed by the mask – quite a bit will go out of the side.’’ The piece of wire on one edge of a mask went over the wearer’s nose, Baker said. ‘‘That’s very important to improve the fit of the mask over your nose.’’

If masks were worn well, they were lifesaving and complemented the protection provided by vaccines.

He believed a national mask strategy was needed.