Since the beginning of the Covid-19 pandemic, Kiwis have been encouraged to wear face coverings to stop the spread of the virus.
Masks can help to block viral particles expelled by an infected person, which can take the form of either droplets or tiny aerosols.
But which face masks are available in New Zealand, and which provide the best protection?
Several of the masks sold in New Zealand are either marked as KN95, N95 or P2. Those often relate to the standard to which a respiratory device is assessed, a Ministry of Health spokesperson said.
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KN95 and N95 masks
Unlike P2 or N95 respirators, most KN95 masks are manufactured with ear loops, rather than headband straps.
The New Zealand Occupational Hygiene Society said caution should be used when purchasing a respirator with ear loops, as tests have indicated it may be difficult to achieve an adequate fit.
Finley Biss, a spokesperson for the company Esko, which supplies respiratory protective equipment, said KN95s could be self-certified by the factory that made them.
However, N95 and P2 masks had to be certified by “a third party independent of the factory”, making them a “much safer bet”.
KN95 respirator masks are made from five layers of filters, and use a mechanical filter to block up to 95 per cent of harmful particles – hence the ‘95’ in its name.
N95s can also block up to 95 per cent of particles.
Surgical masks, meanwhile, were not designed to protect against ultra-contagious respiratory illnesses like Covid-19, Biss said.
“They are actually designed to protect the patient in a hospital, e.g. if the doctor sneezed whilst leaning over an open wound for example.
“Surgical masks also often have big gaps around the sides, where the virus can easily get past the mask.”
Testing conducted by the Environmental Protection Agency in the United States showed a surgical mask only filtered 38.5 per cent of particles.
P2 masks, on the other hand, did not mention their filtration level in their name, but it was very similar to that of the N95. The filtration level was 94.5 per cent, “so on paper, the three are essentially equivalent”, Biss said.
“Although N95 is recommended by the medical sector over P2, there is very little difference in their ability to protect – it is mainly that the P2 is traditionally an industrial respirator standard, where N95 is a medical one, so the medical profession are more familiar with them.
“For the general consumer on the street, P2 are much more readily available and can be purchased from most hardware & DIY stores at a fair price.”
Biss said a 20-pack of N95 masks was often the same or a lower price than the KN95, which retailed for between $5 and $10 each.
They were also a “fraction of the cost” of cloth masks.
“So just because the price is higher doesn’t mean you’re getting better protection.”
Experts said cloth masks should be a last option.
“Cloth masks typically have no guarantee on the level of filtration”, Biss said, making it difficult to tell whether they were offering any protection.
“They do look trendier, so it is understandable people wanting to wear them, but it is definitely a risk. One tip to increase protection is to double-mask, e.g. wear a thin fabric mask on top of a certified respirator so that it looks nicer.”
Biss said it was also important to wash cotton masks after every use to prevent breathing in harmful bacteria.
“As an indication, studies conducted by the EPA on various cloth masks found varying levels of protection, as low as 26.5 per cent.
“Interestingly the mask that tested the lowest was a generic black fabric cotton mask with ear loops (3 layer), which is the most popular mask style in New Zealand.”
Dr Lucy Telfar Barnard, a senior research fellow in public health from the University of Otago, said it was important to make sure masks had good filtration.
“Any cloth mask without a decent filter layer is barely effective,” she said.
“If we can at all, we should be upgrading to better filtration, ideally a respirator (P2/N95/KN95/KN94), or if not, a surgical mask.”
Telfar Barnard said there was an “urgent need to do better now”, before Omicron got out of managed isolation and into the community.
“That means each of us looking at how we can improve on how we wear masks now.
“Masks reduce the chances of catching [the] virus ourselves, and therefore reduce the chance of passing it on to others, and if we do pass it on or catch it, fewer particles can mean a less severe case.”