For a lot of job sites, safety masks and respirators are an essential piece of PPE available from a trusted safety equipment supplier. The lungs are delicate, important organs that are hard to repair if they get damaged, and inhaling the wrong chemical can have devastating effects on other areas of the body as well. Protect yourself from invisible airborne particles by investing in a respirator or mask suited to your job.
How Masks and Respirators Are Rated
The National Institute for Occupational Safety and Health (NIOSH) is a division of the CDC. They determine the ratings that allow people to choose the right mask for the job. Because government agencies determine ratings for masks, purchasing more expensive brand name N95 masks won’t necessarily provide “better” protection.
The ratings are based on a performance standard. Both the filter material and the relative quality of the mask fit are factored into whether a mask earns a particular rating. The challenge in determining this is smoke with 0.3 micron sized particles. How well does the filter media catch these little buggers, and does the mask fit seal off the path for unfiltered air?
Modern filter media uses a built-in static charge to attract and retain particles as they are pulled through. Some grades of filter can have this static charge ruined when in contact with oil mist. The letter in a mask’s name tells you whether or not the mask can resist oil: N masks are not oil resistant, P masks are oil proof, and R masks are oil resistant.
The number in a rating tells you the minimum efficiency of the filter against airborne challenge particles: an N95 filter captures at least 95% of particles but isn’t oil-resistant, and a P100 filter captures at least 99.97% of particles at the 0.3-micron most-penetrating particle size (per NIOSH 42 CFR 84) and is oil-proof — the highest efficiency class recognized for negative-pressure filtering respirators. For a deeper explanation of the P100 class specifically, see What Does P100 Mean for Respirator Filters?.
Where to Use Your N95 Masks
N95 masks see a lot of use in industrial and construction applications where dust and liquids are a frequent hazard. They are NOT suited for areas with lead or asbestos particles, gases (which require a gas monitor for detection and a supplied-air respirator or gas-and-vapor cartridge for protection), oil-based particulates, aerosols, or certain healthcare applications. Specialized filters, cartridges, and respirators are needed for those hazards. Face masks are meant to be single-use and disposed of after removal, and they’re not meant to be shared.
Can N95 Masks Protect Me from a Virus?
N95 masks reduce transmission of respiratory viruses that spread through droplets from coughs and sneezes — the mask blocks the droplet, not the virus particle itself. The eyes are also a mucous-membrane pathway, so goggles or a face shield add protection in high-exposure settings. Wearing a mask has an additional benefit: it discourages face-touching, which is a common route for indirect virus transmission.
If you are the potentially infected person, avoid N95 masks with an exhalation valve — they breathe easier but release unfiltered air outward, which defeats source control. In healthcare or communal settings, use a valveless mask (or cover the valve). Fit and seal quality still matter for infection-control use just as they do for occupational particulate exposure.
Choosing the right PPE for your workers and job can seem like a daunting prospect, but it’s a necessary one to make sure that everyone stays healthy on the job. PK Safety carries a variety of respirators, face masks, and filters for every worksite need from a variety of trusted brands. Our safety experts can answer your questions about air quality, equipment, and worksite safety online or by phone at 800.829.9580.
Please keep in mind that PK Safety staff are not trained medical professionals and therefore cannot give medical advice. You can find additional information about the Coronavirus from the Centers for Disease Control and Prevention (CDC) by clicking here.
Frequently Asked Questions
What is the difference between N95 and P100 respirator filters?
N95 filters capture at least 95% of airborne particulates but are not oil-resistant — use them for dust and non-oil aerosols. P100 filters capture at least 99.97% of particulates at the 0.3-micron most-penetrating particle size (per NIOSH 42 CFR 84) and are oil-proof — use them for higher-hazard exposure, oil-based aerosols, and applications where higher efficiency is required. For a given seal quality, P100 offers meaningfully higher protection; for a given filter class, fit and seal quality determine actual protection more than the label.
What do the N, P, and R letters mean on respirator filters?
The letter indicates oil resistance, defined by NIOSH 42 CFR 84. N = Not resistant to oil — use only for non-oil particulate. R = Resistant to oil — approved for up to 8 hours of oil aerosol exposure. P = oil-Proof — approved for extended oil aerosol exposure. The number that follows (95, 99, or 100) is the minimum filter efficiency percentage. So a P100 filter is oil-proof and captures at least 99.97% of particulates.
Do N95 masks protect against viruses?
N95 masks reduce transmission of respiratory viruses primarily by blocking the droplets that carry the virus — not by filtering individual virus particles, which are generally smaller than the filter's rating specifies. For source control (blocking outward transmission from a potentially infected wearer), use a valveless mask; masks with exhalation valves release unfiltered air outward. Fit and seal quality remain critical: a poorly-fitting N95 mask provides significantly less protection than the 95% rating implies.
Can I use an N95 mask for asbestos or lead?
No. OSHA 29 CFR 1910.1001 (asbestos) and 29 CFR 1910.1025 (lead) require specific respirator selection based on measured airborne concentrations, and filtering facepiece respirators (disposable N95, N99, N100 masks) are not permitted for asbestos work regardless of filter efficiency — a half-mask or full-face reusable respirator with P100 filters is the minimum, with a supplied-air respirator required for higher exposure levels. For lead exposure above the OSHA action level, refer to 29 CFR 1910.1025 Appendix A for the required respirator based on measured air-lead concentration.
When would I use an R95 or R100 filter instead of an N95 or P100?
R-series filters are approved for oil-aerosol exposure for a limited service life (up to 8 hours). Use them when there is short-duration oil-mist exposure and you want a cheaper alternative to a P-series filter. For continuous or long-shift oil exposure (spray painting with oil-based finishes, metalworking with oil-based cutting fluids), a P-series filter is the correct choice because it has no time restriction under oil aerosol exposure.
Is a P100 filter always better than an N95 for particulate exposure?
For pure filtration efficiency, yes — P100 captures 99.97% of particulates vs 95% for N95. But real-world protection depends more on fit and seal quality than filter class. An N95 with a good fit test can outperform a P100 with a poor seal. Additionally, P100 filters cost more, add breathing resistance, and can cause user fatigue on long shifts. For most non-oil particulate exposure at or below the OSHA action level, N95 is sufficient; upgrade to P100 for higher exposure, longer service life before change-out, or when oil aerosol is present.
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