In the peak of the flu season we might see many people wearing masks in physician offices and hospitals. In the news today, as the 2019 Novel Coronavirus (SARS-CoV-2) continues to spread, we see many images of people wearing different types of respirators, some are N95 respirators and others are surgical masks. Not all experts agree on the efficacy of these pieces of personal protective equipment in the face of viruses, but if you’re going to use them, it is important to know how, when and why.
OSHA’s Respiratory Protection standard (1910.134) provides information about requirements for staff who may potentially be exposed to airborne pathogens. These requirements include specific instructions for choosing the proper respirator, for providing fit-testing, and for user training. The College of American Pathologists (CAP) also expects labs to determine the risk of airborne pathogen exposure for each employee, and they require labs to have a plan which outlines engineering and work practice controls that reduce exposure potential.
The purpose of a respirator is to protect the employee from contaminated or oxygen-deficient air. Therefore, two classes of respirators are common; air-purifying respirators which use filters to remove contaminants from the air you breathe, and atmosphere-supplying respirators which provide clean air from an uncontaminated source. These types of respirators can also be classified further as tight-fitting or loose-fitting. Tight-fitting respirators need a tight seal between the respirator and the face and/or neck of the user in order to work properly. For now, let’s focus on the air-purifying respirators which are in high demand these days as a potential 2019-nCoV pandemic looms.
In the laboratory, N95 respirators are probably the most commonly-used respirators, often used for protection against tuberculosis and other airborne pathogens. These respirators filter out 95% of airborne pathogens that are 0.3 microns or larger. While the exact size of the 2019-nCoV is not yet known, most coronaviruses are slightly larger than 0.1 microns. Does that mean a N95 respirator (recommended by the CDC) will not offer protection from the coronavirus? Not necessarily.
According to biosafety expert Sean Kaufman (www.saferbehaviors.com), the filter in the N95 respirator works three ways- through interception, impaction, and diffusion. Interception collects larger particles which are blocked by mask fibers, and impaction collects larger particles which have too much inertia to be moved around the filter fibers. Diffusion occurs as smaller particles are bombarded with larger air molecules and are pushed against filter fibers. Most of the bacteria or virus particles are removed from the airstream making the respirator quite useful and protective (HEPA filters on a Biological Safety Cabinet work in much the same way).
Employees who may need to wear a tight-fitting respirator as part of their job are required to have fit-testing every year. This is required by OSHA, and contracted employees (such as pathologists) should be fit-tested as well. Employees who may need such respirators would be those who work in microbiology labs, cytology techs who participate in patient procedures, and others. Labs should perform a risk assessment for each job category to determine the type and level of potential harmful airborne exposure.
Procedure masks, such as those handed out when people suspect they have the flu, are not technically considered respirators. Often, the person who is sick will wear these masks in order to prevent the spread of droplets when coughing or sneezing. They can protect others in the area, but they do not protect the user from harmful airborne pathogens or vapors.
Can these surgical masks be useful for the healthy public when a coronavirus is present? Sean Kaufman says “yes. If you wear a surgical mask in a potentially contaminated environment (on a commuter bus, for example),” Kaufman says, “it can keep you from touching your nose or mouth- two major routes of entry for viruses. Behaviorally speaking, these masks do offer some protection.”
Knowing when and why you use a respirator is vital, but knowing how to use it is important as well. Tight-fitting respirators should never be used without fit-testing to make sure the correct size is being used. Otherwise, the protection offered will be limited. Make sure your staff is properly trained and protected to work in environments where the air is not safe to breathe, and teach others about the usefulness of respirators when the flu and other viruses are lurking!
–Dan Scungio, MT(ASCP), SLS, CQA (ASQ) has over 25 years experience as a certified medical technologist. Today he is the Laboratory Safety Officer for Sentara Healthcare, a system of seven hospitals and over 20 laboratories and draw sites in the Tidewater area of Virginia. He is also known as Dan the Lab Safety Man, a lab safety consultant, educator, and trainer.
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