Dust Mask, KN95 or Respirator: Which Protection Do You Need?
By Fire Safety BD · Last updated
What surgical masks, dust masks, KN95 masks and half-face respirators are each made for, and why fit matters as much as the filter.
"Mask" covers very different products. Choosing the wrong one gives a feeling of protection without the protection. Start from what is in the air: dust, droplets, or gas and vapour.
The four common types
| Type | Made for | Not for |
|---|---|---|
| Surgical mask | Blocking droplets and splashes; loose fit | Fine dust, fumes, gases |
| Disposable dust mask | Nuisance dust — sweeping, sanding, handling dry goods | Fine or hazardous dust, gases |
| KN95 mask | Filtering fine airborne particles when sealed to the face | Gases, vapours, oxygen-poor spaces |
| Half-face respirator | Particles, gases or vapours, depending on the filter or cartridge fitted | Substances the fitted cartridge is not made for; oxygen-poor spaces |
Fit matters as much as the filter
Air takes the easiest path. If a mask leaks at the nose or cheeks, the air you breathe goes round the filter, not through it.
- Press the nose clip to the shape of your nose.
- Both straps on, the mask covering nose and chin.
- Cup your hands over it and breathe out: you should not feel air escaping at the edges.
- A beard or stubble breaks the seal of a tight-fitting mask.
Half-face respirators and cartridges
A half-face respirator is reusable; the cartridges and filters are what do the work, and they are specific. A particle filter does nothing against solvent vapour, and a vapour cartridge has a limited life once opened. Match the cartridge to the substance using the product label or its safety data sheet, and change it as the manufacturer directs — or sooner if you can smell or taste the substance, or breathing becomes harder.
Limits to remember
- None of these supplies oxygen. They must not be used in tanks, pits or other confined spaces where the air may be short of oxygen.
- Disposable masks are for limited use. Replace one that is damp, dirty, damaged or hard to breathe through.
- For hazardous substances, have a competent person select the protection.
Frequently asked questions
Will a KN95 mask protect me from paint or chemical fumes?
No. A KN95 filters particles such as dust, not gases or vapours. Solvent and chemical vapours need a respirator fitted with the cartridge made for that substance.
Can I use a mask or respirator to escape a fire?
No. These filter the air around you; they do not supply oxygen and do not remove the toxic gases in smoke. In a fire, get low and get out.