Respirator Masks And Filter Cartridges

Respiratory protection must be suited to the environment that relates to its use. That simple dust mask used to woodworking will not provide protection against paint fumes. And, when painting with oil it is important to ensure your filter is rated P, so as to be resistant to oil. No matter the mask or rating, the fit must be secure. Typically, an N95 is easier to wear comfortably, whereas a R99 or P99 increases breathing fatigue due to the higher degree of filtration.  

Respiratory Filter Ratings

Letter Classes

  • N - Not Suitable for Oil-Based Contaminants
  • R - Limited Oil Resistance. Not suitable for more than 8 hours of use (Source: UMM)
  • P - Resistant to Oil.

Number Classes

  • 95 - Filters 95% of particles*
  • 99 - Filters 99% of particles
  • 100 - Filters between 99.7% and 99.9% of particles

*An N95 mask will filter 95% of non-oil based contaminants that are greater than or equal to 0.3 microns in size.

Example Particle Sizes

Particle Particle Size
Anthrax 1 - 5
Asbestos 0.7 - 90
Atmospheric Dust 0.001 - 40
Bacteria 0.3 - 60
Beach Sand 100 - 10000
Bone Dust 3 - 300
Bromine 0.1 - 0.7
Carbon Dioxide 0.00065
Copier Toner 0.5 - 15
Corn Starch 0.1 - 0.8
Fiberglass Insulation 1 - 1000
Lead 0.1 - 0.7
Metallurgical Dust 0.1 - 1000
Mold Spores 10 - 30
Oil Smoke 0.03 - 1
One inch 25400
Oxygen 0.0005
Pesticides & Herbicides 0.001
Radioactive Fallout 0.1 - 10
Red Blood Cells 5 - 10
Saw Dust 30 - 600
Smoke from Natural Materials 0.01 - 0.1
Smoke from Synthetic Materials 1 - 50
Spores 3 - 40
Sugars 0.0008 - 0.005
Tobacco Smoke 0.01 - 4
Typical Atmospheric Dust 0.001 to 30


Engineering ToolBox, (2005). Particle Sizes. [online] Available at: [10 May 2021]

N95 Masks

N95 Masks are effective against preventing the spread of covid-19, swine flu, avian flu, and common flu viruses. a 3M 8210 N95 Mask fit over the nose and mouth without the more taxing filtration of reusable respirator masks. Regardless, the edges are designed to fit snugly to prevent air leakage.

R95 vs P95 Masks

R95 Masks are suitable for eight hours of exposure to oil-based contamination. Whereas a P95 mask can last up to forty hours due to its stronger oil resistance. Oil based contaminants are common in fields that spray with paint and pesticides. The safety material on your hazard will inform you as to whether you need a P95, R95, or N95 mask.

Reusable Respirators

Reusable respirators surpass the filtration abilities of disposable masks, because cartridges can filter organic vapors such as tear gas. Reusable respirators can be stored for years when left unopened. Properly cared for masks can last years as well, but should be replaced immediately once a tight seal for no loner be kept.

Filters for Reusable Respirators

Filters and cartridges are used with reusable half and full face respirators. Reusable respirators provide a more secure fit for the user.

Ensure that filters and cartridges are changed when needed. High risk environments should take caution and change filters frequently.

Particulate filters:

  • When breathing becomes difficult and uncomfortable
  • You start to smell any pollutants
  • The filter has been damaged in any way

Gas/Vapour filters:

  • You can smell or taste contaminants;
  • It is past the expiry date
  • They have been out of the original packaging for 6 months or more