There are a lot of different facepiece respirators available. If you’re like most people, you’ll be confused if you find these other masks and won’t be sure which to buy. Respirators are designated by a letter and number. NIOSH standards define these categories of filters: N95, N99, N100, R95, R99, R100, P95, P99, and P100.
Chapter 1. Respirator Letter Designation
The letter refers to the mask’s resistance to oil.
Section 1. N95 vs R95 vs P95
N – Not Resistant to Oil
R – Somewhat Resistant to Oil
P – Strongly Resistant to Oil (Oil Proof)
But what does that mean? Resistant to oil? This is primarily a concern in industrial environments but still something to keep in mind. Oil aerosols can degrade the performance and efficiency of your mask’s filter media by removing electrostatic charges. Electrostatic charges between the layers of filter media act as a magnet and help trap airborne particles.
R masks (somewhat resistant to oil) are only certified for up to 8 hours of service life, while P (strongly resistant to oil) are certified for up to 40 hours or 30 days of use, whichever comes first.
Chapter 2. Respirator Number Designation
The number refers to percentage of airborne particles the filter media will catch.
Section 1. N95 vs N99 vs N100
N95 respirators remove at least 95% of airborne particles with a size of 300nm
N99 respirators remove at least 99% of airborne particles
N100 respirators remove at least 99.97% of airborne particles
Here’s another thing to keep in mind — N99 and N100 masks are more dense than N95 masks, making it harder to breathe, which can lead to perspiration and moisture. Moisture can saturate the filter media and make it harder to breathe while also degrading filter efficiency. A N95 mask is probably your best option if you expect to be physically active.
Chapter 3. Preparing for an Ebola Outbreak? Which one should you buy?
You don’t need a R-rated or P-rated respirator. N95 masks will do the job, are cheaper than the rest, and buyable in bulk. You can also get them with an exhalation valve. Remember, all of these types of respirators are disposable and can’t be decontaminated.