N95 masks are a critical piece of personal protective equipment (PPE) designed to filter out at least 95% of airborne particles, including both large droplets and very small particles (down to 0.3 microns in size).
What Is an N95 Mask?
- Definition and Certification: An N95 respirator is a standardized mask that must filter at least 95% of airborne particles. It is approved by the National Institute for Occupational Safety and Health (NIOSH), which ensures that the mask meets strict criteria for manufacturing, labeling, fit, and filtration. This rigorous standard is what sets N95s apart from other face coverings.
- Respirator vs. Simple Face Mask: Unlike surgical or cloth masks—which primarily serve as a barrier to prevent the wearer’s respiratory droplets from reaching others—N95 respirators are designed to form a tight seal around the nose and mouth. This seal ensures that air passes through the filter material rather than leaking in around the edges, providing a high level of protection for the wearer against inhaling small, potentially harmful particles.
How Do N95 Masks Work?
- Filtration Mechanism: N95 masks are constructed with multiple layers of nonwoven meltblown polypropylene fabric. The key to their high filtration efficiency is the use of electrostatically charged fibers. These fibers attract and trap airborne particles using both mechanical capture and electrostatic attraction, effectively filtering out particles including dust, allergens, viruses (such as those causing influenza or COVID-19), and other contaminants.
- Fit and Seal: The effectiveness of an N95 mask is highly dependent on a proper fit. Because these masks are tight-fitting, they are designed to minimize gaps along the edges. A good seal is essential to ensure that most inhaled air passes directly through the filter material. For this reason, fit testing is recommended in healthcare and other high-risk settings to ensure that the mask conforms well to the wearer’s face.
Proper Use and Maintenance
- Donning the Mask:
- Begin by washing your hands thoroughly with soap and water or using a hand sanitizer with at least 60% alcohol.
- Place the mask on your face with the nosepiece at your fingertips.
- Position the top strap over your head near the crown and the bottom strap around the neck below the ears, making sure not to cross the straps.
- Once the mask is in place, mold the nosepiece snugly over your nose using your fingertips to reduce any air gaps.
- Seal Check: After donning the mask, perform a seal check by covering the mask with your hands and breathing in forcefully. If you feel air leaking at the edges or if your glasses fog up, adjust the mask. A proper seal is crucial for maximum protection.
- When to Replace: N95 respirators should be replaced when they become damaged, soiled, or if the straps lose their elasticity. They are designed for single use in many settings, though extended use or limited reuse might be practiced following specific guidelines in healthcare settings.
- Avoid Improper Sterilization: Do not attempt to wash or sterilize an N95 mask with methods such as microwaving or oven heating. Once an N95 respirator is no longer in optimal condition, it should be discarded.
Applications and Considerations
- High-Risk Environments: N95 masks are particularly important for healthcare workers, first responders, and other professionals who are at risk of exposure to airborne pathogens. They are also valuable in industrial environments where respirable particles are a concern.
- General Public Use: While N95s provide a higher level of protection compared to cloth or surgical masks, their use by the general public is usually prioritized for those in high-risk situations due to supply concerns, especially during events like pandemics. For everyday use, other well-fitted face masks may be recommended.
- Comfort and Breathing Resistance: Because N95 respirators are designed to form a tight seal, they can sometimes feel less comfortable than other masks, and they may make breathing a bit more laborious. Users with pre-existing respiratory or cardiac conditions should consult with a healthcare provider to ensure that an N95 is appropriate for them.
What’s the difference between a Surgical mask and an N95 Respirator?
Surgical masks and N95 respirators are both types of face coverings, but they serve different purposes and offer different levels of protection. Here’s a detailed breakdown of the differences:
1. Design & Fit
- Surgical Masks:
- Loose-Fitting: These masks are designed to cover the nose and mouth but do not form a tight seal against the face.
- Barrier Protection: They primarily serve as a barrier to protect others from droplets and splashes coming from the wearer.
- Regulatory Approval: Surgical masks are cleared by the FDA and are intended more for protecting the environment (e.g., during surgery) as opposed to filtering small airborne particles .
- N95 Respirators:
- Tight-Fitting: N95s are designed to form a close seal around the nose and mouth, which is crucial for their effectiveness.
- Filtration Efficiency: They are engineered to filter out at least 95% of airborne particles down to 0.3 microns and are tested and approved by NIOSH.
- Fit Testing: Because of their tight fit, users must be fit tested to ensure that there is minimal leakage around the edges .
2. Intended Use
- Surgical Masks:
- Fluid Resistance: Often used in medical settings to protect patients from droplets, splashes, and sprays during procedures.
- Source Control: They help prevent the spread of the wearer’s respiratory droplets into the environment.
- Everyday Use in Healthcare: Suitable for use during tasks that do not generate aerosols.
- N95 Respirators:
- Airborne Protection: Ideal for environments where there is a risk of inhaling small airborne particles, including viruses, bacteria, and other particulates.
- High-Risk Situations: Often used in situations involving aerosol-generating procedures or in settings where airborne transmission is a concern (such as during COVID-19 patient care) .
3. Filtration Efficiency
- Surgical Masks:
- Limited Filtration: While surgical masks can block large droplets and splashes, they are not designed to filter out smaller airborne particles effectively.
- No Guaranteed Seal: The loose fit means that unfiltered air can enter around the edges of the mask.
- N95 Respirators:
- High Filtration Capacity: N95s can filter out at least 95% of tiny airborne particles when properly fitted.
- Seal-Based Protection: The design and fit minimize gaps, ensuring that most inhaled air passes through the filter material.
Each type of mask is appropriate for different settings, and understanding these differences is crucial when determining the right personal protective equipment (PPE) for specific scenarios.
When should N95 respirators be used?
For health care providers, an N95 respirator should be worn when caring for someone with COVID-19, during aerosol-generating procedures in patients with suspected or confirmed seasonal influenza, and when caring for patients with confirmed infectious diseases requiring airborne precautions
- By individuals at increased risk for severe illness such as those who are immunocompromised, older adults, and those with certain underlying medical conditions
- When working in areas where you are exposed to large numbers of people (i.e., grocery store workers)
- When traveling by airplane, bus, train, or other forms of public transportation
- If physical distancing is not possible such as crowded indoor or outdoor settings
- If you are not up to date on your COVID-19 vaccinations
When shouldn’t N95 respirators be used?
Do not wear a NIOSH-approved respirator mask if it is hard to breath while wearing one or if it becomes wet or dirty. Also, do not use N95 respirators with other masks or respirators.
How can you recognize an authentic N95 respirator?
According to NIOSH, individual filtering facepiece respirators are required to have the following markings (CDC, 2021):
- Name of manufacturer, a registered trademark, or abbreviation of the business name as recognized by NIOSH.
- NIOSH in block letters or the NIOSH logo.
- NIOSH Testing and Certification approval number, e.g., TC-84A-XXXX.
- NIOSH filter series and filter efficiency level, e.g., N95, N99, N100, R95, P95, P99, P100.
- Model number or part number: The approval holder’s respirator model number or part number, represented by a series of numbers or alphanumeric markings, e.g., 8577 or 8577A.
NIOSH recommends the lot number and/or date of manufacture also be included, however, this is not required.
General N95 Respirator Precautions (FDA, 2021):
- People with chronic respiratory, cardiac, or other medical conditions that cause breathing difficulties should check with their health care provider before using an N95 respirator as N95 respirators can make breathing more difficult.
- All FDA-cleared N95 respirators are labeled as “single-use,” disposable devices. If your respirator is damaged or soiled, or if breathing becomes difficult, you should remove the respirator, discard it properly, and replace it with a new one.
- N95 respirators are not designed for children or people with facial hair because a proper fit cannot be achieved and therefore may not provide full protection.
As always, be sure to follow your institution’s policy for personal protective equipment and the use of FFRs and N95 respirators.
REFERENCES
- Centers for Disease Control and Prevention (2022, January 14). Types of Masks and Respirators. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/types-of-masks.html
- Centers for Disease Control and Prevention (2021, September 15). NIOSH- Approved Particulate Filtering Facepiece Respirators. https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/default.html
- D’Alessandro, M. & Cichowicz, J.K. (2020). Proper N95 Respirator Use for Respiratory Protection Preparedness. Centers for Disease Control and Prevention. https://blogs.cdc.gov/niosh-science-blog/2020/03/16/n95-preparedness/
- U.S. Food & Drug Administration (2021, September 15). N95 Respirators, Surgical Masks, Face Masks, and Barrier Face Coverings. https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respirators-surgical-masks-face-masks-and-barrier-face-coverings
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