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So what is a KF94 mask, exactly? If you have shopped for Korean masks, you have seen "KF94" everywhere — but few sellers explain what the rating really means. This guide breaks down the KF standard, the layered structure inside, and the one design detail that decides whether a mask is comfortable enough to wear all day.
What does "KF94" mean?
KF stands for "Korea Filter" — a national standard set and certified by Korea's Ministry of Food and Drug Safety (MFDS). The number after it tells you the filtration grade. A KF94 mask is built to filter at least 94% of test particles around 0.4 microns in size, measured under the Korean standard.
Because it is a Korean government grade, KF94 is its own classification — separate from other countries' systems. It is not the same label as ratings used in the US or China, even though people often compare them. We cover those differences in our KF94 vs KN95 vs surgical guide.
The KF rating family
| Grade | Filters at least | Typical use |
|---|---|---|
| KF80 | 80% of particles | Everyday, fine dust, breathable daily wear |
| KF94 | 94% of particles | Higher filtration, yellow dust & haze season |
| KF99 | 99% of particles | Maximum filtration, heaviest air pollution |
Higher numbers filter more — but also breathe a little harder. KF94 is the everyday sweet spot: strong filtration that is still comfortable for hours.
What's inside a KF94 mask?
A quality KF94 is not a single sheet of fabric. AirDays KF94 masks use a 4-layer structure, where each layer does a different job:
- Outer layer (SSS): a soft spunbond shell that blocks larger particles and water droplets.
- Middle layer: support fabric that holds the 3D shape so the mask keeps its form.
- Meltblown filter: the core filtration layer — the fine fibers that capture small particles.
- Inner layer (SSS): a smooth, skin-friendly surface that sits against your face.
This layering is why a real KF94 filters far more than a basic cloth or single-ply mask, while staying light enough for daily use.
Bird-beak vs flat-fold: the comfort difference
Two KF94 masks can have the same filtration grade and feel completely different to wear. The reason is shape.
Flat / 2D fold
Lies closer to the face. Compact and easy to carry, but the fabric can touch your lips when you talk, and can feel warmer over long periods.
Bird-beak (3D)
AirDays uses a structured 3.5cm air pocket in front of the mouth. Fabric stays off your lips, so it is easier to talk, breathe, and wear for hours — with less fogging for glasses wearers.
That roomy front is the AirDays signature. We explain exactly why it matters in Why bird-beak masks are more comfortable.
How easy is it to breathe?
Breathing resistance is measured in pascals (Pa) — lower is easier. AirDays KF94 masks are tested at around 12Pa, well within a comfortable range for all-day wear. Lightweight construction means many people forget they have it on.
KF94, KF-AD — what's the difference?
You will also see KF-AD (Anti-Droplet) masks. These are a lighter, breathable everyday option focused on blocking larger droplets and dust, with a thinner structure than a full KF94. Think of KF94 as the higher-filtration choice, and KF-AD as the light, airy daily option for warmer days.
How to choose the right KF94
- Get the size right. A good seal matters more than the grade on the box. AirDays offers Small, Medium, Large and Extra Large, plus a dedicated Kids line for little faces.
- Pick your shape. Bird-beak for comfort and talking; slim-fit for a closer, lower-profile look.
- Match it to your day. KF94 for haze and yellow-dust season, KF-AD for light everyday wear. See our haze & yellow dust season guide.
- Check where it's made. AirDays masks are made in Korea by COOS Co., Ltd, MFDS-registered and rated "Excellent" by Germany's Dermatest.
Shop AirDays KF94
All AirDays masks are made in Korea and shipped worldwide with duties included — no surprise customs fees. Here are a few popular picks to start with:
KF94 Bird-Beak Mask — Medium
from $7.99 / pack
KF94 Bird-Beak Mask — Large White
from $16.99 / pack
KF94 Kids Mask — Small
from $44.99 / pack
Frequently asked questions
Is KF94 the same as KN95 or N95?
No. KF94 is the Korean government's filtration standard, while KN95 (China) and N95 (US) are different countries' systems with their own tests. They are often compared, but they are not the same certification. See our full comparison.
How long can I wear one KF94 mask?
A KF94 is designed for single-day use. Replace it when it becomes damp, soiled, or loses its shape. For daily wearers, multi-packs are the most economical option.
Are KF94 masks reusable or washable?
No. The meltblown filter layer is not designed to be washed — washing damages its filtration. KF94 masks are disposable.
Which size should I choose?
Most adults fit Medium or Large; choose Extra Large for broader faces and the Kids line for children. A snug seal with no side gaps is what you are aiming for.
Keep reading
This article is for general informational purposes only and describes product features and standards. It is not medical advice and makes no claim to prevent, treat, or cure any illness. Always follow guidance from your local health authority and qualified professionals. AirDays KF94 masks are made in Korea and certified to the KF94 standard by Korea's MFDS.
