ECU researchers prove respirator effectiveness against airborne pathogens
A recent study by a team of East Carolina University researchers confirmed that while N95 respirator masks are more expensive and a bit less comfortable, they offer much greater protection against catching COVID-19 and other airborne infections than reusable cloth face coverings.
Dr. Sinan Sousan, an assistant professor at the Brody School of Medicine — joined by Dr. Jo Anne Balanay and Public Health and Honors College student Omar Chaaban, of ECU’s College of Health and Human Performance — proved as much in a study of five different N95-alternative (KN95) respirators and five commercially available cloth face coverings. The results of the study were published in the American Journal of Infection Control.
The defining memory of the COVID-19 pandemic may well be masks. For years, when out of our protective bubbles of home, masks became ubiquitous — on kids and older adults, required for entering stores and attending schools. The research conducted by Sousan, Balanay and Chaaban suggests, however, that the cloth masks that many of us relied on over the past few years are of little value in protecting ourselves from respiratory viruses like COVID-19. The study confirmed that in the face of potential COVID-19 variants or other novel respiratory viruses, the only reliable protection is the government-approved N95 respirator mask and some KN95 alternatives.
“No one likes to wear respirators or masks, we know that,” said Balanay, an environmental health professor in the Department of Health Education and Promotion. “But wearing them, particularly the N95 respirators which reliably filter the vast majority of airborne particles from the air, is really the best option that we have in the face of a pandemic. Other than vaccines and proper ventilation, good quality respirators are one of the best way to protect ourselves, and I think this research clearly proves that fact.”
The N95 mask is the most efficient, and cost effective, filter of airborne contaminants and disease-causing infectious agents, including bacteria and viruses like COVID-19. As the name suggests, the N95 mask filters about 95% of potentially harmful particles.
N95 masks approved by the National Institute for Occupational Safety and Health, have been evaluated with high-tech scanning equipment and repeatedly showed filtering of more than 96% of particles. When the same scanning equipment was used to test the filtration capacity of non-NIOSH approved respirators, such as home-made cloth masks and those made of other fabrics, researchers determined that the masks allowed 10% to 65% percent of potentially harmful particles to penetrate through the masking material.
For this study, researchers used an industry-standard, commercially available adult N95 mask as a control and tested an additional five N95-alternative masks and five cloth face coverings, all for adults and purchased from the “bestselling” list of protective equipment sold by a global internet-based retailer. Of the tested KN95 masks, only two provided 95% or better filtration.
“The testing of the N95 masks showed that there was some measure of variability in the quality control, meaning that even the masks labeled as being KN95-quality respirators couldn’t be trusted in all cases,” said Sousan, a public health researcher in Brody’s Department of Public Health. “As for the cloth face coverings, they were well below the NIOSH standard of 95% filtration, which is what we expected.”
The researchers graded the different masks and face coverings based on metrics of protection, comfort and affordability which resulted in a composite “quality factor” grading scale of 0-100, with 100 being the highest score possible. The control N95 mask was graded highest at 58 and the other KN95 masks fluctuating between 32 and 50, in part due to the recommended one-time use nature of N95 masks and their relative lack of comfort.
While the comfort level of the cloth face coverings generally tested higher than the N95 masks, their quality factor was substantially lower — graded around 4-10 — due to the fabric’s permeability, which rendered the cloth face coverings poor protectors against respiratory infections.
“What I think this study reaffirms is that the better quality N95 masks are more reliable at protecting us against COVID-19 and likely other airborne infections that we will face in the future, but they are not very comfortable, and they aren’t cheap,” Sousan said. “The cloth face coverings are better than nothing, but they aren’t really good at protecting against the spread of respiratory viruses.”