KF94 Masks vs. N95: Which Mask Is Better Against Coronavirus?
KF94s match up well, but are required to test for “CO2 clearance.”
Ever since the start of the coronavirus pandemic roughly eleven months ago, N95 masks, long considered the gold standard here in the United States, often have been in short supply.
This lingering issue has prompted both hospitals and the general public to search for viable alternatives—and two of the more popular non-N95 protective gear have been China’s KN95 masks and Korea’s KF94 masks.
While the KN95s have raised concerns in recent months about their actual effectiveness, the KF94 masks have proven to match up well with the N95s.
The KF94 and N95 masks do look similar and they have been shown to have the ability to filter nearly identical percentage of airborne particles—94 percent versus 95 percent.
Despite the 1 percent difference in filtration level, the N95 masks are known to be somewhat easier to breathe out of, which is known as “exhalation resistance.”
The KF94s, however, are required to test for “CO2 clearance,” which helps to prevent potentially dangerous levels of CO2 from building up inside the mask. N95 masks aren’t saddled with this particular requirement.
Also, unlike the N95s, the Korean masks must first pass human fit tests before receiving national certification.
As for the overall effectiveness in protecting the wearer and others nearby from contracting the virus, a recent Korean study suggests that both the KF94 and N95 masks perform at a similar level when compared to surgical masks.
For the study, seven patients who have been diagnosed with the coronavirus were instructed to cough five times, separated by twenty-second intervals, into each type of mask.
After analyzing the data, what the researchers discovered was that “SARS-CoV-2 was detected on the petri dishes after coughing in three out of seven cases with the surgical mask or no mask. Viral particles were not found in the petri dishes after coughing while wearing the N95 mask or the KF94 mask. While viral particles were detected in both the inner and outer surfaces of the surgical masks, those were detected only in the inner surfaces of the N95 and KF94 masks,” the study’s authors wrote.
The researchers concluded: “Surgical masks were less effective in filtering viral particles from coughing patients with SARS-CoV-2 infection. N95 masks and its equivalents efficiently blocked SARS-CoV-2 particles from coughing patients.”
Despite both masks’ demonstrated effectiveness, there is still room for improvement, according to Dr. Kim Mi-na, a professor who specializes in clinical microbiology and nosocomial infections at Asan Medical Center in Seoul.
“KF94 or N95 masks have an excellent function of capturing nasal mucus, but they are not effective if the face and mask edges are not adhered to each other,” she wrote in a recent op-ed published in the Journal of Korean Medical Science.
Furthermore, “they are not comfortable to wear for a long time” because “KF94 or N95 masks make it difficult to breathe … and the filter is vulnerable to moisture and should not be used for a long time. It is difficult for people infected with the disease to even use them.”
Kim added that surgical masks can be a solid alternative if one finds it overly bothersome to wear a KF94 or N95 mask.
“Surgical masks have long been proven to have the effect of preventing the spread of droplet infection. … They are the most recommended types of public masks to prepare for the COVID-19 pandemic,” she said.
“Cotton masks have a lower protection against droplet infection than surgical masks, so they should only be used when surgical masks are not available.”
One recent study out of the University of Georgia has discovered that even neck gaiters—tubes of performance fabric generally used for running and exercising outdoors—provide a level of protection against the coronavirus that is equivalent to cotton masks.
One-layer gaiters showed a 77 percent average reduction in respiratory droplets compared to no mask, two-layer face masks provided an 81 percent drop, and gaiters that boasted two or three layers (polyester and spandex) offered a 96 percent decrease in droplets.
In another research conducted by Duke University, N95 respirators with no valves garnered the highest score in the study. A disposable surgical mask made from polypropylene was the next-best option, followed by one made from two layers of cotton and one layer of synthetic material.
Ethen Kim Lieser is a Minneapolis-based Science and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.