In This Guide
If your college program, placement, or new job just told you to get an N95 fit test, the first question is usually which mask to bring. N95 and KN95 masks look almost identical on a store shelf, they share the same 95% filtration number, and both get sold as respirators. For a fit test, though, they are not interchangeable, and showing up with the wrong one can mean a failed test or a wasted appointment.
This guide explains the real difference between N95 and KN95 masks, how a mask fit test works, what Canadian workplace standards expect, and how to prepare so you pass the first time.
What’s the Difference Between an N95 and a KN95?
The short answer is certification. An N95 is a respirator approved by NIOSH, the US National Institute for Occupational Safety and Health. Canada does not run its own respirator approval laboratory, so Canadian workplace respiratory protection programs have long relied on NIOSH certification. A KN95 is made to GB 2626, a Chinese standard. It is not NIOSH approved, even when the packaging says it is “equivalent.”
| Feature | N95 | KN95 |
|---|---|---|
| Certifying standard | NIOSH approval (US), the basis for Canadian workplace programs | GB 2626 (China), no NIOSH approval |
| Filtration rating | At least 95% of small airborne particles | At least 95% of small airborne particles |
| Typical straps | Two head straps | Ear loops |
| Seal to the face | Designed and tested to seal tightly | Often loose at the sides and nose |
| Accepted for a CSA Z94.4 workplace fit test | Yes, on the exact make, model and size | Generally no |
| Best use | Workplace respiratory protection | Everyday personal use |
How N95 and KN95 Filtration Standards Compare
On paper, both masks are rated to filter at least 95% of small airborne particles under lab conditions. The difference lies in everything around that number. NIOSH approval covers filtration, breathing resistance, labelling, and ongoing quality control at the manufacturer, and approved N95s carry an approval number you can check. KN95 quality has varied widely. During the COVID-19 pandemic, Health Canada flagged large quantities of imported KN95s that did not meet their own stated specifications.
In Canada there is now a third option. CSA Group published CSA Z94.4.1:21 in 2021, a made-in-Canada performance standard for filtering respirators. Masks certified to it are labelled CA-N95. The standard aligns with NIOSH and adds a quantitative fit test across a panel of users, plus breathability and shelf life testing.
Why Head Straps vs. Ear Loops Matter for a Seal
Filtration only works if the air you breathe actually passes through the filter. An N95 uses two elastic head straps, one around the crown and one at the back of the neck, which pull the mask firmly against your cheeks, chin, and nose bridge. Most KN95s use ear loops, which tug the sides of the mask toward your ears and often leave gaps along the cheeks. Air takes the easiest path, so a 95% filter with a gap at the side can let a large share of unfiltered air leak in around the edges. That gap is exactly what a fit test is designed to catch.
What Is a Mask Fit Test?
A mask fit test checks whether one specific make, model, and size of tight-fitting respirator seals properly to your face. Faces vary a lot in shape and size, so a mask that seals perfectly on one person can leak badly on another. The fit test is how you find out which mask works for you before you rely on it.
Qualitative vs. Quantitative Fit Testing
Qualitative fit testing is a pass or fail taste test. First, the fit tester checks that you can taste a weak test solution without a mask on, usually sweet saccharin or bitter Bitrex. Then you put on the respirator and a hood goes over your head. The tester sprays the solution into the hood while you work through a series of exercises, such as normal breathing, deep breathing, turning your head side to side, nodding, talking out loud, and bending over. If you taste the solution at any point, air is leaking in and the mask fails.
Quantitative fit testing uses a machine, such as a PortaCount, to count particles inside and outside the mask while you do similar exercises. It produces a number called a fit factor. For a half-facepiece respirator like an N95, the usual passing threshold is a fit factor of at least 100, meaning the air inside the mask has about one hundredth of the particles in the room air. Quantitative testing takes a little longer, but it gives an objective measurement instead of relying on taste.
Fit Test vs. Seal Check
A fit test happens at an appointment, gets documented, and is repeated at least every two years. A seal check, also called a user seal check, is something you do yourself every single time you put the mask on. Cover the front of the mask with both hands, breathe out gently and feel for air escaping around the edges, then breathe in and check that the mask pulls slightly toward your face. If you feel leaks, adjust the straps and nose clip and check again. A seal check never replaces a fit test, but it confirms the mask is on correctly for that shift.
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Can You Fit Test a KN95 Mask?
Technically, a fit tester can put any tight-fitting mask through the test procedure. In practice, a KN95 is generally not the right mask to bring to a workplace or placement fit test, for two reasons.
First, it is about approval. CSA Z94.4, the national standard Canadian employers follow for respiratory protection programs, expects respirators certified by NIOSH, or the newer CA-N95 rating. A KN95 has neither, so even if it passes, it usually cannot be part of your employer’s or hospital’s approved respirator list. Second, it is about the seal. Ear-loop KN95s often fail the head-movement and bending exercises because the loops let the mask shift away from the face.
Health Canada’s own guidance during the pandemic acknowledged that KN95s differ from N95s and advised healthcare professionals to fit test any KN95 before relying on one. For students and new workers, the practical rule is simple: bring the exact NIOSH-approved N95, or CA-N95, make, model, and size that your school or employer has asked for. If they did not specify one, ask before your appointment.
Which Respirators Are Accepted in Canadian Workplaces?
Respiratory protection in Canadian workplaces is built around CAN/CSA-Z94.4-18, Selection, use, and care of respirators, reaffirmed in 2023. It is a program standard rather than a product certification. It tells employers how to assess hazards, choose the right class of respirator, train workers, run fit tests, and look after the equipment. Provinces bring it into force through their own occupational health and safety rules, and several Ontario regulations, including those covering designated substances such as asbestos on construction projects, reference CSA Z94.4 directly.
Under that framework, the respirators employers typically select are NIOSH-certified models, such as N95 filtering facepieces, elastomeric half-mask and full-face respirators, and powered air-purifying respirators, along with masks certified as CA-N95 under CSA Z94.4.1:21. Separately, Health Canada regulates N95s, KN95s, and similar masks sold for medical use as Class I medical devices. That oversight governs the sale of a product. It does not on its own make a mask suitable for a workplace respiratory protection program.
Who Needs an N95 Fit Test?

Anyone who has to wear a tight-fitting respirator for work or a clinical placement needs a fit test on that respirator first. For students, the requirement usually shows up on a pre-placement checklist.
- Healthcare students and workers: nursing, practical nursing, personal support worker, paramedic, respiratory therapy, and medical laboratory programs commonly require a valid N95 fit test before placement. Hospitals and long-term care homes use N95s for patients on airborne precautions, such as tuberculosis or measles, and during aerosol-generating procedures. Teams in these settings often train together through healthcare first aid and CPR training.
- Dental students and staff: dental hygiene and dental assisting programs, along with dental offices, often fit test staff because drills and ultrasonic scalers create aerosols. Clinics that need their whole team certified can look at first aid training for dental offices.
- Construction and the trades: cutting, grinding, or drilling concrete, brick, and stone releases crystalline silica dust. Drywall sanding, wood dust, mould removal, and insulation work can also require respirators. Asbestos work usually calls for a higher level of protection than a disposable N95. Site safety planning for these crews often goes hand in hand with first aid training for construction.
- Labs, agriculture, and manufacturing: lab technicians, workers handling grain or poultry dust, and production staff around fine particulates may also be required to wear fit-tested respirators.
Most placement checklists that include a fit test also include emergency response training. For healthcare students, that is usually current Basic Life Support (BLS) certification, which covers high-quality CPR, team-based resuscitation, and bag-valve-mask use. Booking both early keeps a missing card from delaying your first placement shift.
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How Often Do You Need a Fit Test, and What Makes One Fail?
Under CSA Z94.4, you need a fit test before you first use a tight-fitting respirator and at least once every two years after that. Some employers and hospitals test more often. You also need a new fit test sooner if:
- you switch to a different make, model, or size of N95, even from the same brand
- you gain or lose a significant amount of weight
- you have major dental work, such as new dentures, or facial surgery or scarring
- you or your supervisor notice that the mask no longer seals well during seal checks
The most common reasons people fail are a mask that is the wrong size for their face, facial hair or stubble under the seal, a nose clip that was not shaped properly, and straps that were placed too loosely or crossed. Failing is common and fixable. The fit tester will usually try a different size or model until one passes, and that becomes the mask listed on your fit test card. If no disposable N95 fits you, your employer may need to provide an elastomeric half-mask respirator or a loose-fitting powered air-purifying respirator.
How to Prepare for Your Mask Fit Test
- Be clean-shaven where the mask seals to your face, ideally within about 24 hours of the test. CSA Z94.4 does not allow facial hair under the sealing surface.
- Bring the exact N95 make, model, and size your school or employer requested, unopened if possible.
- Avoid eating, drinking anything except water, chewing gum, and smoking for at least 15 to 30 minutes beforehand, since these can affect a taste test.
- Remove facial jewellery that sits under the mask edge, and tie back long hair.
- Wear your glasses if you normally do, so the tester can check that they don’t push the mask out of position.
- Tell the tester about any breathing or heart condition first. Workers usually complete a health screening before respirator use.
How Does Respiratory Protection Fit Into Workplace Safety Training?
Respiratory protection is one layer of a much bigger safety picture. Under the hierarchy of controls, employers are expected to remove or reduce airborne hazards first, through steps like ventilation, wet cutting, dust extraction, or substitution, and use respirators where those controls are not enough. A fit test confirms that the last line of defence actually works.
The same jobs that require respirators tend to carry other risks: falls, cuts, burns, and sudden medical emergencies like cardiac arrest, a severe allergic reaction, or breathing difficulty. That is why workplaces that run a respiratory protection program usually also need trained first aiders on every shift. In Ontario, workplace first aid requirements now follow CSA Z1210:24, which renamed the core courses Basic First Aid (formerly Emergency First Aid) and Intermediate First Aid (formerly Standard First Aid). For many trades and industrial sites, Intermediate First Aid with CPR/AED Level C is the level employers look for.
For students, the takeaway is to treat your fit test, your first aid or BLS card, and your other placement requirements as one checklist rather than separate errands. For employers, combining respiratory protection training, fit testing through your occupational health provider, and on-site first aid and CPR training keeps everyone current on the same schedule.
Key Takeaway
N95 and KN95 masks share a 95% filtration rating, but only the N95 carries NIOSH approval and the head-strap design built to seal. Canadian workplace respirator programs follow CSA Z94.4, which expects NIOSH-certified or CA-N95 respirators, so a KN95 is generally not the mask to bring to a fit test. Get fit tested on the exact N95 make, model, and size you will wear, before first use and at least every two years, and pair it with the BLS or first aid certification your placement or job requires.
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Frequently Asked Questions: N95 vs. KN95 & Mask Fit Testing 2026
Q1: What is the difference between an N95 and a KN95 mask?
A: An N95 is a respirator certified by NIOSH, the US agency whose approval system Canadian workplace respirator programs rely on. A KN95 is made to GB 2626, a Chinese standard. Both are rated to filter at least 95% of small airborne particles in lab testing, but an N95 must also pass approval checks on fit, quality control, and labelling. Most N95s use two head straps that pull the mask firmly against the face, while most KN95s use ear loops, which usually produce a looser seal.
Q2: Can you use a KN95 mask for a workplace fit test in Canada?
A: Usually not. Workplace respirator programs in Canada follow CSA Z94.4, which expects respirators certified by NIOSH, or a Canadian CA-N95 rated under CSA Z94.4.1:21. A KN95 does not carry NIOSH approval, and most ear-loop KN95s cannot hold a reliable seal through a full fit test. If your employer or school asks you to bring a mask to your fit test, bring the exact N95 make, model, and size you will wear on the job, not a KN95.
Q3: What is a mask fit test?
A: A mask fit test checks whether a specific make, model, and size of tight-fitting respirator seals properly to your face. During a qualitative test, a trained fit tester sprays a sweet or bitter test solution around you while you wear the mask and move through set exercises. If you taste it, air is leaking in. A quantitative test uses a machine to count particles inside and outside the mask and calculates a fit factor. Passing confirms that the mask can actually protect you.
Q4: How often do you need an N95 fit test?
A: Under CSA Z94.4, workers who wear a tight-fitting respirator need a fit test before using it for the first time and at least once every two years after that. You also need a new test sooner if you switch to a different make, model, or size of N95, or if your face changes in a way that could affect the seal, such as significant weight gain or loss, major dental work, or facial surgery. Your fit test card lists the exact mask you passed with.
Q5: Do nursing and healthcare students need an N95 fit test?
A: Yes. Most Canadian nursing, practical nursing, personal support worker, paramedic, respiratory therapy, and dental programs require a valid N95 fit test before students start clinical placements. Hospitals and long-term care homes use N95s for patients on airborne precautions, such as tuberculosis or measles, and during aerosol-generating procedures. Placement checklists commonly pair the fit test with current Basic Life Support (BLS) certification, immunization records, and other pre-placement requirements, so check your program’s list early.
Q6: What is the difference between a fit test and a seal check?
A: A fit test is a formal, documented test done by a trained fit tester, usually every two years, to confirm that a specific respirator model and size fits your face. A seal check, also called a user seal check, is a quick self-check you do every single time you put the mask on. You cover the mask and breathe out gently, then breathe in, feeling for leaks around the edges. A seal check never replaces a fit test, and a fit test never replaces daily seal checks.
Q7: Is a KN95 better than a surgical mask?
A: A well-made KN95 generally filters fine particles better than a loose surgical or procedure mask, which is designed mainly to block splashes and droplets and protect others from the wearer. For everyday personal use, a good KN95 can offer more protection than a surgical mask. For workplace protection against airborne hazards that require a respirator, neither one is the right choice. That job calls for a fit-tested, NIOSH-approved N95 or another certified respirator selected under a respiratory protection program.
More FAQs: Fit Test Preparation, Standards & Who Needs One
Q8: What happens if you fail an N95 fit test?
A: Failing a fit test simply means that particular mask does not seal to your face. It is common and does not mean anything is wrong with you. The fit tester will usually try a different size or a different make and model of N95 until you find one that passes. Once you pass, you should only wear that exact mask for work that requires respiratory protection. If no disposable N95 fits, your employer may need to provide an elastomeric half-mask respirator or a powered air-purifying respirator instead.
Q9: Can you get fit tested with a beard?
A: No. CSA Z94.4 does not allow facial hair, including stubble, to sit between the skin and the sealing surface of a tight-fitting respirator during a fit test or on the job, since hair breaks the seal and lets unfiltered air leak in. Most fit testers ask you to be clean-shaven within about 24 hours of your appointment. Workers who keep a beard for religious, medical, or personal reasons may be offered a loose-fitting powered air-purifying respirator, which does not need a facial seal.
Q10: How should you prepare for a mask fit test?
A: Arrive clean-shaven where the mask seals to your face, and bring the exact N95 make, model, and size your employer or school asked for. Avoid eating, drinking anything other than water, chewing gum, and smoking for at least 15 to 30 minutes beforehand, since these can affect a taste-based qualitative test. Remove facial jewellery that sits under the mask edge, and tie back long hair. If you wear glasses, wear them during the test so the fit tester can check for interference.
Q11: Do KN95 masks sold in Canada need Health Canada approval?
A: In Canada, N95, KN95, and similar respirators sold for medical use are classified as Class I medical devices and fall under Health Canada oversight. During the COVID-19 pandemic, Health Canada also flagged large quantities of imported KN95s that did not meet their stated technical specifications. Health Canada oversight of a product for sale is different from workplace respirator approval, though. For a workplace respiratory protection program, employers look for NIOSH certification or a CA-N95 rating under CSA Z94.4.1:21.
Q12: What is a CA-N95 respirator?
A: A CA-N95 is a filtering respirator certified to CSA Z94.4.1:21, a Canadian performance standard for filtering respirators published by CSA Group in 2021. The standard aligns closely with NIOSH requirements and adds extra checks, including a quantitative fit test across a panel of users, along with breathability, comfort, and shelf life testing. A CA-N95 offers the same 95% filtration class as a NIOSH N95. You still need your own individual fit test on the exact CA-N95 model and size you will wear.
Q13: Which workers in construction and the trades need N95 fit testing?
A: Workers who cut, grind, or drill concrete, brick, or stone can be exposed to crystalline silica dust, one of the most common reasons tradespeople need respiratory protection. Drywall sanding, wood dust, mould removal, insulation work, and some demolition jobs also call for respirators. Asbestos work usually needs a higher level of protection than a disposable N95. Whenever a hazard assessment says a tight-fitting respirator is required, the worker needs a fit test on that exact respirator before starting the job.
Q14: Who is allowed to perform a respirator fit test?
A: A respirator fit test should be done by a person trained and competent in the fit testing method being used, whether that is a qualitative taste test or a quantitative test with a particle-counting machine. Many hospitals, colleges, and larger employers have in-house fit testers as part of their respiratory protection program, while smaller workplaces often book an outside occupational health and safety provider. The fit tester records the respirator make, model, size, test method, and result, and you receive a card or certificate.
Q15: Do you need first aid or CPR training in addition to a mask fit test?
A: Often, yes. A fit test only covers respiratory protection, and most placements and jobs that require one also require emergency response training. Healthcare students and clinical staff usually need Basic Life Support (BLS). Workers in construction, manufacturing, and other trades often need Intermediate First Aid (formerly Standard First Aid) with CPR Level C for workplace first aid requirements. Checking your full placement or job checklist early lets you schedule your fit test and certification courses well before your start date.
Reviewed & Sourced
Written and reviewed by Ashkon Pourheidary, B.Sc. (Hons) Neuroscience, Co-Founder of Coast2Coast First Aid & Aquatics and Canadian Red Cross Instructor Trainer since 2011. Last updated October 8, 2026.
Sources: CSA Group, CAN/CSA-Z94.4-18 (R2023), Selection, use, and care of respirators; CSA Group, CSA Z94.4.1:21, Performance of filtering respirators; Health Canada guidance on the market authorization of N95 and KN95 respirators as Class I medical devices.


















