Not all masks do the same job — and the difference can be your breath
A surgical mask is a barrier. A respirator is a seal. Here's the plain-English guide to N95, FFP2, FFP3 and the humble surgical mask — what they filter, how to know yours fits, and when each one belongs on your face. Supportive explainer, not medical or purchasing advice; always follow your facility's policy and official guidance.
Mask vs respirator: the one distinction that matters
People use "mask" for everything, but the gear splits into two families. A surgical mask (a.k.a. medical mask) is a loose-fitting fluid barrier — it stops your droplets reaching a patient and shields your face from splashes and sprays. It is not sealed to your face, so unfiltered air slips around the edges.
A respirator — N95, FFP2, FFP3, KN95 — is tested to filter a minimum percentage of tiny airborne particles and is designed to seal tightly to your skin, so the air you breathe actually goes through the filter. That seal is the whole point, which is why respirators need fit testing and a beard-free sealing surface. Get the seal wrong and a 95% filter performs nothing like 95%.
What each one actually filters
Minimum filtration efficiency under each standard, tested against tiny particles (around 0.3 µm — close to the hardest size to catch). Higher isn't always "better for the task" — it's about the right tool for the exposure.
A fluid/droplet barrier — not a sealed respirator; protection varies and edges leak
N95 ≥95%, FFP2 ≥94%, KN95 ≥95% — treated as broadly equivalent classes
EU standard, ≥99% — for higher-risk aerosol-generating procedures
NIOSH N99 ≥99%, N100/P100 ≥99.97% of airborne particles
The 30-second user seal check (every single time you don a respirator)
A seal check is NOT a fit test — fit testing is a formal annual procedure your facility runs. The seal check is the quick check you do yourself each time you put a respirator on, following OSHA Appendix B-1 and your facility's policy.
Don it properly first
Cup the respirator under your chin, straps over the crown and base of the neck (not crossed), and mould the nose clip firmly over the bridge of your nose with both hands — one-handed pinching leaves gaps.
Positive-pressure check
Cover the front of the respirator with both hands and exhale gently. If you feel air leaking around your nose, chin or cheeks, re-seat the mask and adjust the nose clip — a good seal builds slight pressure inside without leaking out.
Negative-pressure check
Cover the respirator and inhale sharply. The facepiece should collapse slightly inward and you should feel no air sneaking in around the edges. If it does, reposition and try again.
Mind the sealing surface
Even a day of stubble breaks the seal. Facial hair that crosses the sealing area is the most common reason a respirator quietly fails — clean-shaven along the seal, or use a loose-fitting powered alternative per policy.
If it won't seal, stop and swap
A respirator that won't pass a seal check is offering surgical-mask-level edge leakage at best. Try a different size or model your facility has been fit-tested you on — don't just push through a shift in it.
Nobody warned me in my first week that a beard the morning shift didn't see would let air straight past a 'sealed' mask. The seal check takes ten seconds. Do it every time, even when you're slammed.
Straight answers on masks and respirators
Is a KN95 the same as an N95?
They're close cousins. N95 follows the US NIOSH standard, KN95 follows the Chinese GB standard, and FFP2 follows the European EN 149 standard — 3M and others treat KN95, FFP2, AS/NZ P2, Korea 1st Class and Japan DS as broadly equivalent to NIOSH N95 (all roughly ≥94–95% filtration). The catch is counterfeits: only respirators that genuinely meet the standard and seal to your face perform as rated. Follow your facility's approved-product list.
When do I need a respirator instead of a surgical mask?
This is a clinical and facility-policy call, not ours to make — but the general principle from CDC/WHO is that respirators (N95/FFP2 and above) are for protection against airborne and aerosol exposures, while surgical masks are fluid barriers and source control. FFP3 or N99-class is often reserved for higher-risk aerosol-generating procedures. Always follow your local infection-prevention guidance and risk assessment.
Does a higher number always mean better protection for me?
Not on its own. A perfectly-rated FFP3 that doesn't seal protects you less than a well-fitted N95. Filtration is only half the story — the seal delivers it. That's why fit testing and the per-use seal check matter as much as the filter rating.
Can I reuse a respirator?
In normal practice respirators are single-use, but CDC published conservation and limited-reuse strategies during shortages. Whether, and how, to reuse is governed by your facility's policy — don't improvise. If it's soiled, damaged, hard to breathe through, or fails a seal check, take it out of service.
What do I do if my facility can't fit-test me?
Raise it — fit testing is an OSHA requirement (annually) for tight-fitting respirators, and a missing program is a worker-safety issue worth escalating to your manager or safety officer, not something to quietly absorb. Until you're fit-tested on a model, you don't actually know it seals on your face.
Keep going through the protection basics
Masks are one layer. The rest of the kit and the habits around it matter just as much.
Face shields & eye protection
When and why splashes need more than a mask — goggles, shields and the gaps people miss.
Read the guideGowns, gloves & scrubs
AAMI gown levels, glove basics, and dressing in an order that doesn't contaminate you.
Read the guideInfection prevention guidelines
Hand hygiene, the WHO moments, and how the pieces fit into one routine.
Read the guideWe're here for the people who never leave the floor
Feed The Line started by feeding frontline healthcare workers during the pandemic. We're still in your corner — sharing plain, practical, no-strings support for the staff who keep everyone else going. Educational only: for clinical or PPE decisions, follow CDC, WHO, OSHA, NIOSH and your facility's official guidance.