11 Tips for Optimum Mask Efficacy
Although the general public has been asked to wear masks for nearly a year, a number of misconceptions about proper use remain. Many of us may be wearing masks incorrectly, unknowingly reducing their efficacy and putting ourselves and those around us at greater risk of contracting and spreading COVID-19. Furthermore, we’ve learned a lot about mask usage in the past year.
That’s why the Center for Construction Research and Training (CPWR) invited Maryann D’Alessandro, director of the National Personal Protective Technology Laboratory (NPPTL), a research center of the National Institute for Occupational Safety and Health (NIOSH), to present a webinar sharing best practices and correcting common misconceptions. Here are 11 insights D’Alessandro shared.
1) Who has regulatory authority over respirators in U.S. occupational settings?
This depends. Authorities include NIOSH, the Occupational Health and Safety Administration (OSHA) and the U.S. Food and Drug Administration (FDA). NIOSH certifies respirators, while OSHA oversees workplace compliance. The FDA, however, certifies medical devices and has additional requirements for N95 masks used in healthcare settings.
2) As an employer, what do I need to do to comply with OSHA’s respirator regulations?
Proper respirator use in the workplace is outlined in OSHA’s 29 CFR 1910.134, which mandates medical evaluation, formal training and fit testing. D’Alessandro recommends reviewing the variety of resources available to guide compliance efforts.
“Construction is already familiar with fit testing because there are many exposures where employees are required to wear respirators in the workplace,” D’Alessandro said. She also recommends conducting a user seal test when a user first puts on a respirator to minimize face seal leakage and increase user confidence, though this does not replace a fit test.
“Respirators used in the general public are not subject to the same requirements as those in the workplace,” D’Alessandro added.
3) Am I wearing my mask properly?
For a respirator to be effective, it must be put on correctly, worn throughout the exposure, and fit snugly against the user’s face to ensure there are no gaps between the skin and the respirator seal.
She points out the possibility of facial hair compromising the respirator’s seal, sharing a graphic of various appropriate and interfering facial hair styles that went viral on social media. For example, soul patches and Zorro mustaches are unlikely to interfere with a respirator’s seal, whereas mutton chops and Fu Manchu mustaches will impact the seal and reduce the protection received by the wearer. See the graphic on this page.
4) Do masks protect me, the people around me, or both?
This also depends on the type of mask used, D’Alessandro said. Masks offering source control protect others, while respiratory protection protects the wearer. “There is some evidence,” D’Alessandro said, “that devices worn for source control provide some protection for wearers as well, though they are not equivalent to respiratory protection devices.”
5) How effective are different types of respiratory devices?
“Respirators and face masks have a wide range of filter efficiencies,” D’Alessandro said. A device rated P100 has a filter efficiency greater than 99.98 percent; an N95 mask, greater than 98.8 percent; an FDA surgical mask ranges from 12 to 98 percent; cloth masks range from 10 to 26 percent.
6) Do you have any recommendations for selecting a more effective cloth mask?
Choose a mask with two or more layers of washable, breathable fabric. Be sure the mask completely covers your nose and mouth, and fits snugly against the sides of your face. “You see a lot of people out there who have their nose exposed,” D’Alessandro said. “The nose is the entry portal for many viruses, so it’s very important to cover your nose and your mouth.”
For people who wear glasses, a mask that fits closely over one’s nose or a mask that has a nose wire can help to limit fogging. D’Alessandro also said to avoid masks intended for healthcare workers, such as N95 respirators and surgical masks.
NIOSH is involved in several initiatives to address gaps in non-occupational respiratory protection and source control, D’Alessandro said. She added that the American Society for Testing and Materials (ASTM) is working on a test method to determine filter efficiency for cloth masks.
7) Can I use a respirator with an exhalation valve?
“The current Centers for Disease Control (CDC) guidance is that you shouldn’t use a respirator with an exhalation valve,” D’Alessandro said. However, NIOSH published a report in December 2020 sharing recent findings that may contradict past guidance. “Our suspicion was that respirators with face valves would provide source control relatively equivalent to cloth face coverings and surgical masks because you don’t have the gaps on the side that you often have with cloth masks. That is what we found in our technical report, so we are working to update the guidance.”
Furthermore, she added that some manufacturers of respirators with exhalation valves are working on designated accessories to cover the valve. Some elastomeric respirators (EHMRs) also have exhalation valve covers, and some manufacturers of EHMRs are filtering exhaled breath coming out of the valves.
8) What about gaiters and face shields?
“There have been a few studies out there on gaiters that have shown they are not a good product to wear,” D’Alessandro said. “But other studies show that if you have at least two layers, like if you fold a gaiter to make it two layers, it could provide similar levels of protection and source control as a cloth mask.”
Face shields, she added, aren’t recommended because of the gaps around the sides that allow particles to go around the shield.
9) What about cleaning reusable respirators, such as EHMRs and powered air purifying respirators (PAPRs)?
Disinfection is not part of the NIOSH approval of respirators; NIOSH points to the manufacturer’s instructions. OSHA permits employers to use the cleaning recommendations provided by the manufacturer. Under crisis capacity guidelines, the CDC and NIOSH provide guidelines for disinfection, including the Bessessen protocol. Check the Environmental Protection Agency’s list of authorized disinfectants.
“We’ve seen an increase in use of NIOSH-approved air purifying respirators (PAPRs) not only in healthcare, but in construction as well,” D’Alessandro said.
10) Can I buy respirators from abroad?
“Roughly 60 percent of international respirators provide below 95 percent filtration efficiency,” D’Alessandro said. “If you plan to purchase respirators from other countries, I highly recommend looking at the FDA’s emergency use authorization list of respirators because those are the ones we’ve evaluated and we have confidence that they meet the requirements we expect them to meet. There are a lot of counterfeit and substandard products out there.”
Visit here to view the reports.
11) When should I wear a mask?
The CDC recommends wearing masks when around any individual not in your household, especially when you are not able to maintain the recommended social distance. D’Alessandro added that there has been evidence of transmission in outdoor settings when there have been gatherings of a larger number of people in a smaller outdoor setting. “Even if you’re in an outdoor setting, if you’re around others you should be wearing a mask or other device,” she said.
“We know the virus can still be spread even if someone doesn’t have symptoms,” D’Alessandro said. “By wearing these masks, they are most likely to reduce the spread in these public settings when they are worn by everyone.”
More Than Masks
Even when wearing a mask, D’Alessandro suggests social distancing, washing your hands often with soap and water for at least 20 seconds (or using a hand sanitizer with 60 percent alcohol, if soap and water is not readily accessible), and cleaning and disinfecting frequently touched surfaces.