By Jaclyn Krah Cichowicz, MA; Christopher Coffey, Ph.D.; and Jonathan Szalajda, MS
(Released 10 June 2019) There are many things to consider in the process of preparing your health and safety for a public health emergency. Memories of emergencies, like last summer’s wildfires and the 2009 H1N1 influenza pandemic, remind us of the threat they can pose to respiratory health, and of the equal importance of an item that gets left out of most talk of emergency supplies—the respirator.
Respirators Used During a Public Health Emergency
One of the most common types of respirator used during a public health emergency is the filtering facepiece respirator (FFR), also called disposable respirators. As the name suggests, the entire respirator is discarded when it is no longer safe to use because of cleanliness, excessive breathing resistance, or physical damage.
FFRs remove particles from the inhaled airstream of the wearer through a filter media. When used in accordance with the manufacturer’s recommendations, these types of respirators are highly effective against bacteria and viruses, as well as other airborne particles like mold and wildfire smoke.
A second type of respirator used during a public health emergency is the elastomeric half facepiece respirator. Elastomeric half facepiece respirators are reusable devices with exchangeable cartridges or filters.
The facepiece is made of rubber or silicone that forms a seal against the user’s face, covering the nose and mouth just like the disposable FFRs. The attached filters and cartridges are replaceable and can be easily changed. These respirators can be used in emergencies to protect against gases, vapors, and/or particles. However, first they must be equipped with the appropriate filters and/or cartridges, fitted properly to the user, and used in accordance with the manufacturer’s recommendations.
Three key criteria are required for an FFR or elastomeric respirator to be effective:
- The respirator filter needs to be highly effective at capturing particles that pass through the filter;
- The respirator must also fit the user’s face snugly to minimize the number of particles that bypass the filter and get into the breathing zone through gaps between the user’s skin and the respirator seal; and
- The respirator has to be put on correctly and worn during the exposure[i].
These are explained in greater detail below and in the second installment of this blog.
Capturing Particles: The Difference between Respirators, Dust Masks, and Surgical Masks
Dust masks, surgical masks, and filtering facepiece respirators are all commercially available and work by placing a filter media over the nose and mouth. However, each was designed to serve a different purpose.
A common misconception is that a dust mask is equivalent to the similar-looking FFR. While dust masks will filter dust or other relatively harmless particles during activities like mowing the lawn, they have not undergone rigorous testing to ensure a necessary level of filtration against hazardous particles.
The National Institute for Occupational Safety and Health (NIOSH) Respirator Approval Program at the CDC tests and approves respirators used in occupational settings. To be approved, a respirator must meet the minimum performance requirements defined in Title 42, Part 84 of the Code of Federal Regulations (42 CFR 84). This approval process ensures a minimum level of worker protection from airborne particulates.
A respirator that has earned NIOSH approval will have specific labeling printed on the facepiece. You may see some dust masks on the local hardware store shelf labelled as “N95”, but if it does not contain the other components of the required label, most importantly the word “NIOSH,” it may not be NIOSH-approved and, therefore, cannot be relied on to provide the same level of protection. You can further ensure that you are using a NIOSH-approved respirator by checking for the model on the NIOSH Certified Equipment List or the NIOSH List of Approved Filtering Facepiece Respirators.
Similarly, surgical masks play an important role in healthcare, helping to prevent the spread of healthcare workers’ germs to others. In certain public health scenarios, the CDC recommends wearing surgical masks to prevent the spread of germs from coughing and sneezing[ii]. However, the filtration material in a surgical mask is not equivalent to that used in NIOSH-approved respirators, which protect the wearer from the atmosphere. A surgical mask also does not fit tight against the face like a filtering facepiece respirator.
A Snug Fit
When respirators are used in occupational settings, the Occupational Safety and Health Administration (OSHA) (29 CFR 1910.134) requires an annual respirator fit test to ensure that users receive the expected level of protection by minimizing any leakage of unfiltered contaminant through gaps between the face and facepiece. Because the effectiveness of this type of respirator relies upon the breathing air travelling through the filter, a tight seal to the user’s face is crucial. Particles in the air will take the path of least resistance and bypass the part of the respirator that captures or filters hazards.
Unlike NIOSH-approved respirators, dust and surgical masks do not seal against the wearer’s face to prevent this particle leakage. However, even NIOSH-approved respirators can easily have gaps in the seal if not worn properly, or if there is any obstruction between the respirator and the skin, such as jewelry, clothing, or, most commonly, facial hair.
Human hair looks thin to the naked eye, but is by comparison much larger than the particles in the air. The vast majority of particles, gases, and vapors are small enough to flow through the facial hair and into the respiratory tract. Some studies have shown that even a day or two of stubble can begin to reduce protection. Research tells us that the presence of facial hair under the sealing surface causes 20 to 1000 times more leakage compared to clean-shaven individuals[iii].
The public is at a disadvantage when purchasing and wearing a respirator off the shelf. Respirators worn in the workplace are tested for proper fit and potential leakage before they are used. Individuals who do not wear a respirator as a requirement of their job do not go through this process. We will discuss more about this potential risk in a later post that will explain how to properly wear a respirator, how to select a respirator, and the limitations of respirators for public use during emergencies.
[i] Shaffer, R.E., Cichowicz, J.M., Chew, G., ScD; and Hsu, J. Non-occupational Uses of Respiratory Protection – What Public Health Organizations and Users Need to Know http://blogs.cdc.gov/niosh-science-blog/2018/01/04/respirators-public-use/
[ii] Centers for Disease Control and Prevention. Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005. MMWR 2005;54(No. RR-17).
[iii] Stobbe, T.J., daRoza, R.A. and Watkins, M.A., 1988. Facial hair and respirator fit: a review of the literature. The American Industrial Hygiene Association Journal, 49(4), pp.199-204.
Released by the Centers for Disease Control and Prevention. Click here for source.