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Masks protect against COVID-19, but which mask is best?

Jan 20 2022

Masks are a key measure to reduce transmission of all variants of COVID-19, including Delta and Omicron. A well-fitted mask can protect a healthy person and also stop an asymptomatic person, who may be unaware they have the virus, from passing it on.

Since the beginning of the pandemic there has been different advice given about masks, but with the advent of the Omicron variant facemasks are again mandatory in NSW in some settings.

Since 24 December 2021, all people in NSW over the age of 12 are required to wear a face mask:

  • in an indoor area of premises other than a place of residence
  • in an indoor area on common property for residential premises
  • at a public transport waiting area
  • in a vehicle or vessel being used to provide a public transport service 
  • working at a hospitality venue and dealing directly with members of the public
  • on a domestic commercial aircraft, including when the aircraft is flying above NSW.

There are many types of masks available, but their effectiveness varies. A scarf or bandana is not a mask. While any mask is better than no mask, there are two essential qualities that determine how much protection you’ll get – filtration and fit. To work properly, it must cover the nose, mouth, cheeks and chin without leaving gaps on the sides. It’s not a chinstrap.

Cloth masks

Well-fitting, non-medical, multilayer cloth masks may be an acceptable option when other options are not available. Three-layer masks should be considered the minimum standard, preferably with a fluid repellent layer on the outside layer. Best practice is to have multiple masks for the day, and to wash the masks after each use in soap or detergent in hot water.

According to research by the American Conference of Governmental Industrial Hygienists
(ACGIH) cloth masks have 75% inward and outward leakage. Inward leakage is the percentage of particles entering the facepiece when the wearer is inhaling. Outward leakage refers to the percentage of particles exhaled by the wearer exiting the facepiece. Some places such as medical facilities will not allow entry to people wearing cloth masks.

Medical or Surgical masks

Medical or Surgical masks have three layers of synthetic, nonwoven materials with filtration layers sandwiched between. Because these masks are one size, there are often gaps at the sides which reduce their effectiveness. But this can be fixed with simple hacks like knotting the ear loops. These are superior to cloth masks and are an important measure in reducing transmission. Inward and outward leakage is 50%.


Respirators, usually known by their performance levels like P2, N95, KN95 or KF94 , when  worn correctly provide excellent protection against COVID-19. P2 is the Australian standard, N95 is American, KN95 meet Chinese specifications and KF94 is the Korean equivalent. Be aware of fake masks. Masks that meet the Australian Standard (AS/NZS 1716:2012) or international equivalent:

  • have the manufacturers name, trademark or trade name on the mask 
  • are certified by an independent body such as SAI Global, and have their licence number marked on the packaging 
  • are certified by the US National Institute for Occupational Safety and Health (NIOSH), if from the United States of America. 

You can buy them from reputable online or retail outlets including chemists and supermarkets.

Don't use masks with holes or a valve, you’ll breathe out the virus if you’re infected and won’t protect other people.  

To ensure the best fit and in particular when used in healthcare or industry, fit testing is often undertaken. Professional fit tests are carried out by someone with appropriate training, but you can perform a positive-pressure seal check by covering the respirator surface on a filtering facepiece, usually by using your hands, and trying to breathe out. If slight pressure builds up, that means air isn’t leaking around the edges of the respirator. A negative-pressure check involves covering the respirator surface on a filtering facepiece, typically using your hands and trying to breathe in. If no air enters, the seal is tight.


Can I reuse disposable masks?

Medical staff should not reuse masks. Most masks are rated single use only, so always follow the manufacturers recommendations. However, if you really need to re-wear your P2, N95, KN95 and KF94 mask, you should be able to if it is not damaged, soiled or wet.



It’s very difficult to wear a mask during vigorous physical activity. Masks also lose their effectiveness as moisture increases from heavy breathing or perspiration.

Well-fitted respirator masks such as P2 or N95 offer the best protection against COVID-19. If unavailable, then well-fitted surgical or medical masks are the next best. If neither of those options are available, then opt for a well-made and fitted cloth mask.


Remember, masks are just one part of the ‘do it all’ approach to help stop the spread of the virus and won’t be effective used alone. You should also practice social distancing and avoid crowded, close-contact and closed-in venues, ensure good ventilation of indoor spaces (open windows or have gatherings outside), follow the QR code check in procedure, maintain good hygiene practices (hand washing and sanitiser and regular cleaning of high touch surfaces and items) and get vaccinated including your booster shot as soon as you’re eligible.