How Long To Wear Surgical Masks & N95 Respirators For Best Performance

As we become accustomed to a world with Coronavirus, clients have increasingly asked us for guidance on how long to wear surgical masks and N95 respirators for best performance. While we are not medical professionals, here’s some information that may help you.

(Please note, unfortunately, we cannot advise you about the safety of face masks that you purchase as a regular consumer. We deal with businesses only. So we will not be able to respond to messages and calls about this.)

How long surgical masks and N95 respirators can be worn depends on the mask type

The decision on how long to wear surgical masks and N95 respirators for must also take into account the manufacturer’s guidance, environment, and conditions that the mask is subject to.

How long can you wear a surgical mask?

Surgical masks can typically be worn for up to 8 hours, or until they become soiled or too moist.

How long does an N95 mask last?

Manufacturer guidance typically suggests that N95 respirators can be worn for 3-4 hours at a time.

How to make sure what the time duration is?

At the time of testing in a laboratory, the manufacturer will have suggested the appropriate length of time. It may be written in the detailed lab test report for the mask.


Is an N95 respirator ‘better’ than a surgical mask?

Both mask types are capable of filtering out airborne particles from the air you breathe. However, according to the Washington Post in ‘Why most of us should be wearing N95 masks’:

When worn properly, N95s can filter out at least 95 percent of particles in the air, including the virus that causes covid-19.

According to the CDC, well-fitting N95s are the most protective [mask type], followed by KN95s and surgical masks. Chinese-made KN95s are supposed to be of a standard comparable to N95s, and many are of high quality, but they do not go through the NIOSH approval process. “Loosely woven cloth coverings” are the least protective.


In light of the fast-spreading Omicron variant, N95 masks are recommended due to their airtight fit around the face assuring that the user is breathing filtered air. Surgical masks usually have large gaps at their sides that can allow too much unfiltered air to pass, thereby exposing the wearer to more risk.


Can surgical masks and N95 respirators be reused?

Many manufacturers’ advice is that single-use products like medical surgical masks and respirators should not be reused after being worn on one occasion. To define ‘re-use,’ this is where the face mask or respirator is removed and put on again later.

Respirator masks are in particularly short supply during the pandemic and some hospitals have chosen to reuse them in limited amounts. The CDC says the following about respirator reuse:

If no manufacturer guidance is available, preliminary data suggests limiting the number of reuses to no more than five uses per device to ensure an adequate safety margin.


Due to the shortage of PPE in the USA, some healthcare providers implemented sterilization machines for used N95 respirator masks, effectively allowing them to be reused on different occasions. It is said that the technology:

…had 99.9% efficiency in killing bacterial spores and sterilization could be performed up to 20 times before damaging a respirator.


Reusing single-use PPE in a hospital environment is not recommended by manufacturers, and while the FDA cleared the sterilization machines for use, they warned the manufacturer not to endorse the technology as being ‘safe or effective for the prevention or treatment of COVID-19.’ However, in light of the infectious Omicron variant’s rise around the world, reusing PPE like face masks is considered a good option for the public unless they have become worn out or soiled.


Can these masks be worn for longer than recommended (extended use)?

During the coronavirus pandemic, many healthcare professionals have worn face masks for longer which otherwise may have been discarded between patient encounters, as long as they are dealing with patients suffering from the same condition (i.e. COVID-19) because of shortages in such equipment.

The FDA says this about surgical mask extended wear:

During times of limited access to surgical masks, facilities could consider having health care providers continue to wear the same surgical mask (i.e., extended use), remove only used gloves and gowns , and perform hand hygiene between treating patients with the same infectious disease diagnosis or exposure who are maintained in a confined area. If the mask, gloves, or gowns become contaminated, replace them.


The CDC states that respirators may also be used for an extended period if necessary:

A key consideration for safe extended use is that the respirator must maintain its fit and function. Workers in other industries routinely use N95 respirators for several hours uninterrupted. Experience in these settings indicates that respirators can function within their design specifications for 8 hours of continuous or intermittent use.


They go on to make the point that: ‘Extended use is favored over reuse because it is expected to involve less touching of the respirator and therefore less risk of contact transmission.’

In light of Omicron in 2022, does the advice about wearing N95 masks change?

Updated January 2022:

As the highly infectious Omicron variant has spread around the world, governments and medical professionals have urged the public to consider using N95 or KN95 respirator masks instead of cloth face coverings or medical surgical masks. Respirator masks, as discussed, provide a tighter fit around the face and filter the air more effectively, providing more protection from infection.

In the USA, the CDC has made it very clear that N95 masks are a good option to protect against Omicron.

The CDC said in its updated guidance that it “continues to recommend that you wear the most protective mask you can that fits well and that you will wear consistently.”

A mask should fit close to the face without any gaps, and be comfortable enough to wear for long periods of time when needed, it said.


The issue is access to good-quality N95 or KN95 respirator masks as most people don’t have a ready supply of them, not forgetting that they’re more expensive than cloth face coverings or surgical masks, too. So getting more life out of a respirator mask is a good idea if possible, but there’s some advice about doing this carefully.

According to the Washington post:

3M, which says it is the largest manufacturer of N95 respirators in the United States, [says] their masks can be reused as long as it “still forms a good seal to the face and is not dirty, damaged, or difficult to breathe through.” The company said to store the masks in a “breathable paper bag,” and to wash your hands between uses.


The problem with wearing N95 respirators for extended periods

N95 respirators filter the air that the wearer breathes, removing airborne particulates, such as virus particles, and protecting the user. The need to breathe through the materials puts a strain on the user, and so while extended use may be possible, it is not easy or recommended:

When worn properly, these respirator masks get very hot inside and are very difficult to breathe in due to the pressure change between the air inside and the outside atmosphere. It is like breathing through a blanket and can become distressing to the user. A user’s blood-oxygen saturation can drop and carbon dioxide increases significantly with correct and prolonged use. Even a healthy and fit adult could find wearing an N95, if put on correctly, difficult after an hour or so of use. An older person or an immunocompromised individual likely would have a very hard time using an N95 mask even for a short time. Wearers may take it off for a break which would reduce its protection. Children and infants are also generally not appropriate candidates for wearing N95s as the risk of suffocation is higher.


Be aware of moisture’s effect on mask life

The Nursing Times makes the point that:

A mask wet with exhaled moisture has increased resistance to airflow, is less efficient at filtering bacteria and has increased venting. Current recommendations are that a new surgical mask is used for each surgical case and that they should be changed when wet.

This point is echoed by the WHO as well, therefore, if a mask has become wet (or soiled, of course), it should be disposed of regardless of the length of time that it has been worn.

We’ve previously made the link between moisture and increased risk of infection in this blog post, too: Is It Safe To Receive Packages From China? [Coronavirus FAQs]


How about when the general public wears masks?

Some European countries have now also mandated that people wear face masks when outside in public, such as in Austria when shopping. Therefore the question of how long face masks should be worn in public must also be addressed.

In some Asian countries, the general population are provided with a ready source of surgical masks to wear to slow infection rates. For example, in Taiwan, citizens are guaranteed to able to purchase 3 surgical masks per week from chemists.

While it is recommended to dispose of surgical masks after a day of wear, this would seem to suggest an expectation for the general public in Taiwan to practice ‘extended use’ of face masks, and, anecdotally, we have also seen people in China who have worn a single mask for a couple of days before changing to a new one.

Given that the risk of viral transmission is far greater in a COVID-19 hospital ward than, say, an office or supermarket where social-distancing rules are being applied, the question of how to long to wear face masks for is different, and it is probably fair to say that, for the public, limited extended use of face masks is still better than not wearing them at all (especially with the Omicron variant lying in wait).


Learn more about importing face masks during the pandemic

If you’re interested in purchasing face masks, read this general blog post: Face Mask Regulations and China Export Challenges For Buyers During The Coronavirus Pandemic

Then you may like these pages specific to your region:

Or, reach out to our team if you need help with purchasing:

Are you a business with questions about arranging your order of medical supplies or PPE?
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2 responses to “How Long To Wear Surgical Masks & N95 Respirators For Best Performance”

  1. Hermione Finnigan says:

    Thank you for posting this information. It is invaluable! Yes, the information evolves and is revised accordingly. However, that’s what science is all about, including PPEs.

  2. Christy says:

    So informative. I’ve been so confused about the correct use and kinds to wear, when.
    This was so helpful.
    Thank you

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